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linux-sg2042/tools/lib/bpf/libbpf.c

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// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
/*
* Common eBPF ELF object loading operations.
*
* Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
* Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
* Copyright (C) 2015 Huawei Inc.
* Copyright (C) 2017 Nicira, Inc.
* Copyright (C) 2019 Isovalent, Inc.
*/
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <libgen.h>
#include <inttypes.h>
#include <string.h>
#include <unistd.h>
#include <endian.h>
#include <fcntl.h>
#include <errno.h>
#include <asm/unistd.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/bpf.h>
#include <linux/btf.h>
#include <linux/filter.h>
#include <linux/list.h>
#include <linux/limits.h>
#include <linux/perf_event.h>
#include <linux/ring_buffer.h>
#include <linux/version.h>
#include <sys/epoll.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/vfs.h>
#include <sys/utsname.h>
#include <tools/libc_compat.h>
#include <libelf.h>
#include <gelf.h>
#include "libbpf.h"
#include "bpf.h"
#include "btf.h"
#include "str_error.h"
#include "libbpf_internal.h"
#include "hashmap.h"
#ifndef EM_BPF
#define EM_BPF 247
#endif
#ifndef BPF_FS_MAGIC
#define BPF_FS_MAGIC 0xcafe4a11
#endif
/* vsprintf() in __base_pr() uses nonliteral format string. It may break
* compilation if user enables corresponding warning. Disable it explicitly.
*/
#pragma GCC diagnostic ignored "-Wformat-nonliteral"
#define __printf(a, b) __attribute__((format(printf, a, b)))
static int __base_pr(enum libbpf_print_level level, const char *format,
va_list args)
{
if (level == LIBBPF_DEBUG)
return 0;
return vfprintf(stderr, format, args);
}
static libbpf_print_fn_t __libbpf_pr = __base_pr;
libbpf_print_fn_t libbpf_set_print(libbpf_print_fn_t fn)
{
libbpf_print_fn_t old_print_fn = __libbpf_pr;
__libbpf_pr = fn;
return old_print_fn;
}
__printf(2, 3)
void libbpf_print(enum libbpf_print_level level, const char *format, ...)
{
va_list args;
if (!__libbpf_pr)
return;
va_start(args, format);
__libbpf_pr(level, format, args);
va_end(args);
}
#define STRERR_BUFSIZE 128
#define CHECK_ERR(action, err, out) do { \
err = action; \
if (err) \
goto out; \
} while (0)
/* Copied from tools/perf/util/util.h */
#ifndef zfree
# define zfree(ptr) ({ free(*ptr); *ptr = NULL; })
#endif
#ifndef zclose
# define zclose(fd) ({ \
int ___err = 0; \
if ((fd) >= 0) \
___err = close((fd)); \
fd = -1; \
___err; })
#endif
#ifdef HAVE_LIBELF_MMAP_SUPPORT
# define LIBBPF_ELF_C_READ_MMAP ELF_C_READ_MMAP
#else
# define LIBBPF_ELF_C_READ_MMAP ELF_C_READ
#endif
static inline __u64 ptr_to_u64(const void *ptr)
{
return (__u64) (unsigned long) ptr;
}
struct bpf_capabilities {
/* v4.14: kernel support for program & map names. */
__u32 name:1;
/* v5.2: kernel support for global data sections. */
__u32 global_data:1;
/* BTF_KIND_FUNC and BTF_KIND_FUNC_PROTO support */
__u32 btf_func:1;
/* BTF_KIND_VAR and BTF_KIND_DATASEC support */
__u32 btf_datasec:1;
/* BPF_F_MMAPABLE is supported for arrays */
__u32 array_mmap:1;
};
/*
* bpf_prog should be a better name but it has been used in
* linux/filter.h.
*/
struct bpf_program {
/* Index in elf obj file, for relocation use. */
int idx;
char *name;
int prog_ifindex;
char *section_name;
/* section_name with / replaced by _; makes recursive pinning
* in bpf_object__pin_programs easier
*/
char *pin_name;
struct bpf_insn *insns;
size_t insns_cnt, main_prog_cnt;
enum bpf_prog_type type;
struct reloc_desc {
enum {
RELO_LD64,
RELO_CALL,
RELO_DATA,
} type;
int insn_idx;
int map_idx;
int sym_off;
} *reloc_desc;
int nr_reloc;
int log_level;
struct {
int nr;
int *fds;
} instances;
bpf_program_prep_t preprocessor;
struct bpf_object *obj;
void *priv;
bpf_program_clear_priv_t clear_priv;
enum bpf_attach_type expected_attach_type;
__u32 attach_btf_id;
__u32 attach_prog_fd;
void *func_info;
__u32 func_info_rec_size;
__u32 func_info_cnt;
struct bpf_capabilities *caps;
void *line_info;
__u32 line_info_rec_size;
__u32 line_info_cnt;
__u32 prog_flags;
};
enum libbpf_map_type {
LIBBPF_MAP_UNSPEC,
LIBBPF_MAP_DATA,
LIBBPF_MAP_BSS,
LIBBPF_MAP_RODATA,
};
static const char * const libbpf_type_to_btf_name[] = {
[LIBBPF_MAP_DATA] = ".data",
[LIBBPF_MAP_BSS] = ".bss",
[LIBBPF_MAP_RODATA] = ".rodata",
};
struct bpf_map {
int fd;
char *name;
int sec_idx;
size_t sec_offset;
int map_ifindex;
int inner_map_fd;
struct bpf_map_def def;
__u32 btf_key_type_id;
__u32 btf_value_type_id;
void *priv;
bpf_map_clear_priv_t clear_priv;
enum libbpf_map_type libbpf_type;
char *pin_path;
bool pinned;
bool reused;
};
struct bpf_secdata {
void *rodata;
void *data;
};
static LIST_HEAD(bpf_objects_list);
struct bpf_object {
char name[BPF_OBJ_NAME_LEN];
char license[64];
__u32 kern_version;
struct bpf_program *programs;
size_t nr_programs;
struct bpf_map *maps;
size_t nr_maps;
size_t maps_cap;
struct bpf_secdata sections;
bool loaded;
bool has_pseudo_calls;
bool relaxed_core_relocs;
/*
* Information when doing elf related work. Only valid if fd
* is valid.
*/
struct {
int fd;
const void *obj_buf;
size_t obj_buf_sz;
Elf *elf;
GElf_Ehdr ehdr;
Elf_Data *symbols;
Elf_Data *data;
Elf_Data *rodata;
Elf_Data *bss;
size_t strtabidx;
struct {
GElf_Shdr shdr;
Elf_Data *data;
} *reloc_sects;
int nr_reloc_sects;
int maps_shndx;
int btf_maps_shndx;
int text_shndx;
int data_shndx;
int rodata_shndx;
int bss_shndx;
} efile;
/*
* All loaded bpf_object is linked in a list, which is
* hidden to caller. bpf_objects__<func> handlers deal with
* all objects.
*/
struct list_head list;
struct btf *btf;
struct btf_ext *btf_ext;
void *priv;
bpf_object_clear_priv_t clear_priv;
struct bpf_capabilities caps;
char path[];
};
#define obj_elf_valid(o) ((o)->efile.elf)
void bpf_program__unload(struct bpf_program *prog)
{
int i;
if (!prog)
return;
/*
* If the object is opened but the program was never loaded,
* it is possible that prog->instances.nr == -1.
*/
if (prog->instances.nr > 0) {
for (i = 0; i < prog->instances.nr; i++)
zclose(prog->instances.fds[i]);
} else if (prog->instances.nr != -1) {
pr_warn("Internal error: instances.nr is %d\n",
prog->instances.nr);
}
prog->instances.nr = -1;
zfree(&prog->instances.fds);
zfree(&prog->func_info);
zfree(&prog->line_info);
}
static void bpf_program__exit(struct bpf_program *prog)
{
if (!prog)
return;
if (prog->clear_priv)
prog->clear_priv(prog, prog->priv);
prog->priv = NULL;
prog->clear_priv = NULL;
bpf_program__unload(prog);
zfree(&prog->name);
zfree(&prog->section_name);
zfree(&prog->pin_name);
zfree(&prog->insns);
zfree(&prog->reloc_desc);
prog->nr_reloc = 0;
prog->insns_cnt = 0;
prog->idx = -1;
}
static char *__bpf_program__pin_name(struct bpf_program *prog)
{
char *name, *p;
name = p = strdup(prog->section_name);
while ((p = strchr(p, '/')))
*p = '_';
return name;
}
static int
bpf_program__init(void *data, size_t size, char *section_name, int idx,
struct bpf_program *prog)
{
const size_t bpf_insn_sz = sizeof(struct bpf_insn);
if (size == 0 || size % bpf_insn_sz) {
pr_warn("corrupted section '%s', size: %zu\n",
section_name, size);
return -EINVAL;
}
memset(prog, 0, sizeof(*prog));
prog->section_name = strdup(section_name);
if (!prog->section_name) {
pr_warn("failed to alloc name for prog under section(%d) %s\n",
idx, section_name);
goto errout;
}
prog->pin_name = __bpf_program__pin_name(prog);
if (!prog->pin_name) {
pr_warn("failed to alloc pin name for prog under section(%d) %s\n",
idx, section_name);
goto errout;
}
prog->insns = malloc(size);
if (!prog->insns) {
pr_warn("failed to alloc insns for prog under section %s\n",
section_name);
goto errout;
}
prog->insns_cnt = size / bpf_insn_sz;
memcpy(prog->insns, data, size);
prog->idx = idx;
prog->instances.fds = NULL;
prog->instances.nr = -1;
prog->type = BPF_PROG_TYPE_UNSPEC;
return 0;
errout:
bpf_program__exit(prog);
return -ENOMEM;
}
static int
bpf_object__add_program(struct bpf_object *obj, void *data, size_t size,
char *section_name, int idx)
{
struct bpf_program prog, *progs;
int nr_progs, err;
err = bpf_program__init(data, size, section_name, idx, &prog);
if (err)
return err;
prog.caps = &obj->caps;
progs = obj->programs;
nr_progs = obj->nr_programs;
progs = reallocarray(progs, nr_progs + 1, sizeof(progs[0]));
if (!progs) {
/*
* In this case the original obj->programs
* is still valid, so don't need special treat for
* bpf_close_object().
*/
pr_warn("failed to alloc a new program under section '%s'\n",
section_name);
bpf_program__exit(&prog);
return -ENOMEM;
}
pr_debug("found program %s\n", prog.section_name);
obj->programs = progs;
obj->nr_programs = nr_progs + 1;
prog.obj = obj;
progs[nr_progs] = prog;
return 0;
}
static int
bpf_object__init_prog_names(struct bpf_object *obj)
{
Elf_Data *symbols = obj->efile.symbols;
struct bpf_program *prog;
size_t pi, si;
for (pi = 0; pi < obj->nr_programs; pi++) {
const char *name = NULL;
prog = &obj->programs[pi];
for (si = 0; si < symbols->d_size / sizeof(GElf_Sym) && !name;
si++) {
GElf_Sym sym;
if (!gelf_getsym(symbols, si, &sym))
continue;
if (sym.st_shndx != prog->idx)
continue;
if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL)
continue;
name = elf_strptr(obj->efile.elf,
obj->efile.strtabidx,
sym.st_name);
if (!name) {
pr_warn("failed to get sym name string for prog %s\n",
prog->section_name);
return -LIBBPF_ERRNO__LIBELF;
}
}
if (!name && prog->idx == obj->efile.text_shndx)
name = ".text";
if (!name) {
pr_warn("failed to find sym for prog %s\n",
prog->section_name);
return -EINVAL;
}
prog->name = strdup(name);
if (!prog->name) {
pr_warn("failed to allocate memory for prog sym %s\n",
name);
return -ENOMEM;
}
}
return 0;
}
static __u32 get_kernel_version(void)
{
__u32 major, minor, patch;
struct utsname info;
uname(&info);
if (sscanf(info.release, "%u.%u.%u", &major, &minor, &patch) != 3)
return 0;
return KERNEL_VERSION(major, minor, patch);
}
static struct bpf_object *bpf_object__new(const char *path,
const void *obj_buf,
size_t obj_buf_sz,
const char *obj_name)
{
struct bpf_object *obj;
char *end;
obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1);
if (!obj) {
pr_warn("alloc memory failed for %s\n", path);
return ERR_PTR(-ENOMEM);
}
strcpy(obj->path, path);
if (obj_name) {
strncpy(obj->name, obj_name, sizeof(obj->name) - 1);
obj->name[sizeof(obj->name) - 1] = 0;
} else {
/* Using basename() GNU version which doesn't modify arg. */
strncpy(obj->name, basename((void *)path),
sizeof(obj->name) - 1);
end = strchr(obj->name, '.');
if (end)
*end = 0;
}
obj->efile.fd = -1;
/*
* Caller of this function should also call
* bpf_object__elf_finish() after data collection to return
* obj_buf to user. If not, we should duplicate the buffer to
* avoid user freeing them before elf finish.
*/
obj->efile.obj_buf = obj_buf;
obj->efile.obj_buf_sz = obj_buf_sz;
obj->efile.maps_shndx = -1;
obj->efile.btf_maps_shndx = -1;
obj->efile.data_shndx = -1;
obj->efile.rodata_shndx = -1;
obj->efile.bss_shndx = -1;
obj->kern_version = get_kernel_version();
obj->loaded = false;
INIT_LIST_HEAD(&obj->list);
list_add(&obj->list, &bpf_objects_list);
return obj;
}
static void bpf_object__elf_finish(struct bpf_object *obj)
{
if (!obj_elf_valid(obj))
return;
if (obj->efile.elf) {
elf_end(obj->efile.elf);
obj->efile.elf = NULL;
}
obj->efile.symbols = NULL;
obj->efile.data = NULL;
obj->efile.rodata = NULL;
obj->efile.bss = NULL;
zfree(&obj->efile.reloc_sects);
obj->efile.nr_reloc_sects = 0;
zclose(obj->efile.fd);
obj->efile.obj_buf = NULL;
obj->efile.obj_buf_sz = 0;
}
static int bpf_object__elf_init(struct bpf_object *obj)
{
int err = 0;
GElf_Ehdr *ep;
if (obj_elf_valid(obj)) {
pr_warn("elf init: internal error\n");
return -LIBBPF_ERRNO__LIBELF;
}
if (obj->efile.obj_buf_sz > 0) {
/*
* obj_buf should have been validated by
* bpf_object__open_buffer().
*/
obj->efile.elf = elf_memory((char *)obj->efile.obj_buf,
obj->efile.obj_buf_sz);
} else {
obj->efile.fd = open(obj->path, O_RDONLY);
if (obj->efile.fd < 0) {
char errmsg[STRERR_BUFSIZE], *cp;
err = -errno;
cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
pr_warn("failed to open %s: %s\n", obj->path, cp);
return err;
}
obj->efile.elf = elf_begin(obj->efile.fd,
LIBBPF_ELF_C_READ_MMAP, NULL);
}
if (!obj->efile.elf) {
pr_warn("failed to open %s as ELF file\n", obj->path);
err = -LIBBPF_ERRNO__LIBELF;
goto errout;
}
if (!gelf_getehdr(obj->efile.elf, &obj->efile.ehdr)) {
pr_warn("failed to get EHDR from %s\n", obj->path);
err = -LIBBPF_ERRNO__FORMAT;
goto errout;
}
ep = &obj->efile.ehdr;
/* Old LLVM set e_machine to EM_NONE */
if (ep->e_type != ET_REL ||
(ep->e_machine && ep->e_machine != EM_BPF)) {
pr_warn("%s is not an eBPF object file\n", obj->path);
err = -LIBBPF_ERRNO__FORMAT;
goto errout;
}
return 0;
errout:
bpf_object__elf_finish(obj);
return err;
}
static int bpf_object__check_endianness(struct bpf_object *obj)
{
#if __BYTE_ORDER == __LITTLE_ENDIAN
if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
return 0;
#elif __BYTE_ORDER == __BIG_ENDIAN
if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2MSB)
return 0;
#else
# error "Unrecognized __BYTE_ORDER__"
#endif
pr_warn("endianness mismatch.\n");
return -LIBBPF_ERRNO__ENDIAN;
}
static int
bpf_object__init_license(struct bpf_object *obj, void *data, size_t size)
{
memcpy(obj->license, data, min(size, sizeof(obj->license) - 1));
pr_debug("license of %s is %s\n", obj->path, obj->license);
return 0;
}
static int
bpf_object__init_kversion(struct bpf_object *obj, void *data, size_t size)
{
__u32 kver;
if (size != sizeof(kver)) {
pr_warn("invalid kver section in %s\n", obj->path);
return -LIBBPF_ERRNO__FORMAT;
}
memcpy(&kver, data, sizeof(kver));
obj->kern_version = kver;
pr_debug("kernel version of %s is %x\n", obj->path, obj->kern_version);
return 0;
}
static int compare_bpf_map(const void *_a, const void *_b)
{
const struct bpf_map *a = _a;
const struct bpf_map *b = _b;
if (a->sec_idx != b->sec_idx)
return a->sec_idx - b->sec_idx;
return a->sec_offset - b->sec_offset;
}
static bool bpf_map_type__is_map_in_map(enum bpf_map_type type)
{
if (type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
type == BPF_MAP_TYPE_HASH_OF_MAPS)
return true;
return false;
}
static int bpf_object_search_section_size(const struct bpf_object *obj,
const char *name, size_t *d_size)
{
const GElf_Ehdr *ep = &obj->efile.ehdr;
Elf *elf = obj->efile.elf;
Elf_Scn *scn = NULL;
int idx = 0;
while ((scn = elf_nextscn(elf, scn)) != NULL) {
const char *sec_name;
Elf_Data *data;
GElf_Shdr sh;
idx++;
if (gelf_getshdr(scn, &sh) != &sh) {
pr_warn("failed to get section(%d) header from %s\n",
idx, obj->path);
return -EIO;
}
sec_name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
if (!sec_name) {
pr_warn("failed to get section(%d) name from %s\n",
idx, obj->path);
return -EIO;
}
if (strcmp(name, sec_name))
continue;
data = elf_getdata(scn, 0);
if (!data) {
pr_warn("failed to get section(%d) data from %s(%s)\n",
idx, name, obj->path);
return -EIO;
}
*d_size = data->d_size;
return 0;
}
return -ENOENT;
}
int bpf_object__section_size(const struct bpf_object *obj, const char *name,
__u32 *size)
{
int ret = -ENOENT;
size_t d_size;
*size = 0;
if (!name) {
return -EINVAL;
} else if (!strcmp(name, ".data")) {
if (obj->efile.data)
*size = obj->efile.data->d_size;
} else if (!strcmp(name, ".bss")) {
if (obj->efile.bss)
*size = obj->efile.bss->d_size;
} else if (!strcmp(name, ".rodata")) {
if (obj->efile.rodata)
*size = obj->efile.rodata->d_size;
} else {
ret = bpf_object_search_section_size(obj, name, &d_size);
if (!ret)
*size = d_size;
}
return *size ? 0 : ret;
}
int bpf_object__variable_offset(const struct bpf_object *obj, const char *name,
__u32 *off)
{
Elf_Data *symbols = obj->efile.symbols;
const char *sname;
size_t si;
if (!name || !off)
return -EINVAL;
for (si = 0; si < symbols->d_size / sizeof(GElf_Sym); si++) {
GElf_Sym sym;
if (!gelf_getsym(symbols, si, &sym))
continue;
if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL ||
GELF_ST_TYPE(sym.st_info) != STT_OBJECT)
continue;
sname = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
sym.st_name);
if (!sname) {
pr_warn("failed to get sym name string for var %s\n",
name);
return -EIO;
}
if (strcmp(name, sname) == 0) {
*off = sym.st_value;
return 0;
}
}
return -ENOENT;
}
static struct bpf_map *bpf_object__add_map(struct bpf_object *obj)
{
struct bpf_map *new_maps;
size_t new_cap;
int i;
if (obj->nr_maps < obj->maps_cap)
return &obj->maps[obj->nr_maps++];
new_cap = max((size_t)4, obj->maps_cap * 3 / 2);
new_maps = realloc(obj->maps, new_cap * sizeof(*obj->maps));
if (!new_maps) {
pr_warn("alloc maps for object failed\n");
return ERR_PTR(-ENOMEM);
}
obj->maps_cap = new_cap;
obj->maps = new_maps;
/* zero out new maps */
memset(obj->maps + obj->nr_maps, 0,
(obj->maps_cap - obj->nr_maps) * sizeof(*obj->maps));
/*
* fill all fd with -1 so won't close incorrect fd (fd=0 is stdin)
* when failure (zclose won't close negative fd)).
*/
for (i = obj->nr_maps; i < obj->maps_cap; i++) {
obj->maps[i].fd = -1;
obj->maps[i].inner_map_fd = -1;
}
return &obj->maps[obj->nr_maps++];
}
static int
bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type,
int sec_idx, Elf_Data *data, void **data_buff)
{
char map_name[BPF_OBJ_NAME_LEN];
struct bpf_map_def *def;
struct bpf_map *map;
map = bpf_object__add_map(obj);
if (IS_ERR(map))
return PTR_ERR(map);
map->libbpf_type = type;
map->sec_idx = sec_idx;
map->sec_offset = 0;
snprintf(map_name, sizeof(map_name), "%.8s%.7s", obj->name,
libbpf_type_to_btf_name[type]);
map->name = strdup(map_name);
if (!map->name) {
pr_warn("failed to alloc map name\n");
return -ENOMEM;
}
def = &map->def;
def->type = BPF_MAP_TYPE_ARRAY;
def->key_size = sizeof(int);
def->value_size = data->d_size;
def->max_entries = 1;
def->map_flags = type == LIBBPF_MAP_RODATA ? BPF_F_RDONLY_PROG : 0;
if (obj->caps.array_mmap)
def->map_flags |= BPF_F_MMAPABLE;
pr_debug("map '%s' (global data): at sec_idx %d, offset %zu, flags %x.\n",
map_name, map->sec_idx, map->sec_offset, def->map_flags);
if (data_buff) {
*data_buff = malloc(data->d_size);
if (!*data_buff) {
zfree(&map->name);
pr_warn("failed to alloc map content buffer\n");
return -ENOMEM;
}
memcpy(*data_buff, data->d_buf, data->d_size);
}
pr_debug("map %td is \"%s\"\n", map - obj->maps, map->name);
return 0;
}
static int bpf_object__init_global_data_maps(struct bpf_object *obj)
{
int err;
if (!obj->caps.global_data)
return 0;
/*
* Populate obj->maps with libbpf internal maps.
*/
if (obj->efile.data_shndx >= 0) {
err = bpf_object__init_internal_map(obj, LIBBPF_MAP_DATA,
obj->efile.data_shndx,
obj->efile.data,
&obj->sections.data);
if (err)
return err;
}
if (obj->efile.rodata_shndx >= 0) {
err = bpf_object__init_internal_map(obj, LIBBPF_MAP_RODATA,
obj->efile.rodata_shndx,
obj->efile.rodata,
&obj->sections.rodata);
if (err)
return err;
}
if (obj->efile.bss_shndx >= 0) {
err = bpf_object__init_internal_map(obj, LIBBPF_MAP_BSS,
obj->efile.bss_shndx,
obj->efile.bss, NULL);
if (err)
return err;
}
return 0;
}
static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
{
Elf_Data *symbols = obj->efile.symbols;
int i, map_def_sz = 0, nr_maps = 0, nr_syms;
Elf_Data *data = NULL;
Elf_Scn *scn;
if (obj->efile.maps_shndx < 0)
return 0;
if (!symbols)
return -EINVAL;
scn = elf_getscn(obj->efile.elf, obj->efile.maps_shndx);
if (scn)
data = elf_getdata(scn, NULL);
if (!scn || !data) {
pr_warn("failed to get Elf_Data from map section %d\n",
obj->efile.maps_shndx);
return -EINVAL;
}
/*
* Count number of maps. Each map has a name.
* Array of maps is not supported: only the first element is
* considered.
*
* TODO: Detect array of map and report error.
*/
nr_syms = symbols->d_size / sizeof(GElf_Sym);
for (i = 0; i < nr_syms; i++) {
GElf_Sym sym;
if (!gelf_getsym(symbols, i, &sym))
continue;
if (sym.st_shndx != obj->efile.maps_shndx)
continue;
nr_maps++;
}
/* Assume equally sized map definitions */
pr_debug("maps in %s: %d maps in %zd bytes\n",
obj->path, nr_maps, data->d_size);
if (!data->d_size || nr_maps == 0 || (data->d_size % nr_maps) != 0) {
pr_warn("unable to determine map definition size section %s, %d maps in %zd bytes\n",
obj->path, nr_maps, data->d_size);
return -EINVAL;
}
map_def_sz = data->d_size / nr_maps;
/* Fill obj->maps using data in "maps" section. */
for (i = 0; i < nr_syms; i++) {
GElf_Sym sym;
const char *map_name;
struct bpf_map_def *def;
struct bpf_map *map;
if (!gelf_getsym(symbols, i, &sym))
continue;
if (sym.st_shndx != obj->efile.maps_shndx)
continue;
map = bpf_object__add_map(obj);
if (IS_ERR(map))
return PTR_ERR(map);
map_name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
sym.st_name);
if (!map_name) {
pr_warn("failed to get map #%d name sym string for obj %s\n",
i, obj->path);
return -LIBBPF_ERRNO__FORMAT;
}
map->libbpf_type = LIBBPF_MAP_UNSPEC;
map->sec_idx = sym.st_shndx;
map->sec_offset = sym.st_value;
pr_debug("map '%s' (legacy): at sec_idx %d, offset %zu.\n",
map_name, map->sec_idx, map->sec_offset);
if (sym.st_value + map_def_sz > data->d_size) {
pr_warn("corrupted maps section in %s: last map \"%s\" too small\n",
obj->path, map_name);
return -EINVAL;
}
map->name = strdup(map_name);
if (!map->name) {
pr_warn("failed to alloc map name\n");
return -ENOMEM;
}
pr_debug("map %d is \"%s\"\n", i, map->name);
def = (struct bpf_map_def *)(data->d_buf + sym.st_value);
/*
* If the definition of the map in the object file fits in
* bpf_map_def, copy it. Any extra fields in our version
* of bpf_map_def will default to zero as a result of the
* calloc above.
*/
if (map_def_sz <= sizeof(struct bpf_map_def)) {
memcpy(&map->def, def, map_def_sz);
} else {
/*
* Here the map structure being read is bigger than what
* we expect, truncate if the excess bits are all zero.
* If they are not zero, reject this map as
* incompatible.
*/
char *b;
for (b = ((char *)def) + sizeof(struct bpf_map_def);
b < ((char *)def) + map_def_sz; b++) {
if (*b != 0) {
pr_warn("maps section in %s: \"%s\" has unrecognized, non-zero options\n",
obj->path, map_name);
if (strict)
return -EINVAL;
}
}
memcpy(&map->def, def, sizeof(struct bpf_map_def));
}
}
return 0;
}
static const struct btf_type *
skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id)
{
const struct btf_type *t = btf__type_by_id(btf, id);
if (res_id)
*res_id = id;
while (btf_is_mod(t) || btf_is_typedef(t)) {
if (res_id)
*res_id = t->type;
t = btf__type_by_id(btf, t->type);
}
return t;
}
/*
* Fetch integer attribute of BTF map definition. Such attributes are
* represented using a pointer to an array, in which dimensionality of array
* encodes specified integer value. E.g., int (*type)[BPF_MAP_TYPE_ARRAY];
* encodes `type => BPF_MAP_TYPE_ARRAY` key/value pair completely using BTF
* type definition, while using only sizeof(void *) space in ELF data section.
*/
static bool get_map_field_int(const char *map_name, const struct btf *btf,
const struct btf_type *def,
const struct btf_member *m, __u32 *res)
{
const struct btf_type *t = skip_mods_and_typedefs(btf, m->type, NULL);
const char *name = btf__name_by_offset(btf, m->name_off);
const struct btf_array *arr_info;
const struct btf_type *arr_t;
if (!btf_is_ptr(t)) {
pr_warn("map '%s': attr '%s': expected PTR, got %u.\n",
map_name, name, btf_kind(t));
return false;
}
arr_t = btf__type_by_id(btf, t->type);
if (!arr_t) {
pr_warn("map '%s': attr '%s': type [%u] not found.\n",
map_name, name, t->type);
return false;
}
if (!btf_is_array(arr_t)) {
pr_warn("map '%s': attr '%s': expected ARRAY, got %u.\n",
map_name, name, btf_kind(arr_t));
return false;
}
arr_info = btf_array(arr_t);
*res = arr_info->nelems;
return true;
}
static int build_map_pin_path(struct bpf_map *map, const char *path)
{
char buf[PATH_MAX];
int err, len;
if (!path)
path = "/sys/fs/bpf";
len = snprintf(buf, PATH_MAX, "%s/%s", path, bpf_map__name(map));
if (len < 0)
return -EINVAL;
else if (len >= PATH_MAX)
return -ENAMETOOLONG;
err = bpf_map__set_pin_path(map, buf);
if (err)
return err;
return 0;
}
static int bpf_object__init_user_btf_map(struct bpf_object *obj,
const struct btf_type *sec,
int var_idx, int sec_idx,
const Elf_Data *data, bool strict,
const char *pin_root_path)
{
const struct btf_type *var, *def, *t;
const struct btf_var_secinfo *vi;
const struct btf_var *var_extra;
const struct btf_member *m;
const char *map_name;
struct bpf_map *map;
int vlen, i;
vi = btf_var_secinfos(sec) + var_idx;
var = btf__type_by_id(obj->btf, vi->type);
var_extra = btf_var(var);
map_name = btf__name_by_offset(obj->btf, var->name_off);
vlen = btf_vlen(var);
if (map_name == NULL || map_name[0] == '\0') {
pr_warn("map #%d: empty name.\n", var_idx);
return -EINVAL;
}
if ((__u64)vi->offset + vi->size > data->d_size) {
pr_warn("map '%s' BTF data is corrupted.\n", map_name);
return -EINVAL;
}
if (!btf_is_var(var)) {
pr_warn("map '%s': unexpected var kind %u.\n",
map_name, btf_kind(var));
return -EINVAL;
}
if (var_extra->linkage != BTF_VAR_GLOBAL_ALLOCATED &&
var_extra->linkage != BTF_VAR_STATIC) {
pr_warn("map '%s': unsupported var linkage %u.\n",
map_name, var_extra->linkage);
return -EOPNOTSUPP;
}
def = skip_mods_and_typedefs(obj->btf, var->type, NULL);
if (!btf_is_struct(def)) {
pr_warn("map '%s': unexpected def kind %u.\n",
map_name, btf_kind(var));
return -EINVAL;
}
if (def->size > vi->size) {
pr_warn("map '%s': invalid def size.\n", map_name);
return -EINVAL;
}
map = bpf_object__add_map(obj);
if (IS_ERR(map))
return PTR_ERR(map);
map->name = strdup(map_name);
if (!map->name) {
pr_warn("map '%s': failed to alloc map name.\n", map_name);
return -ENOMEM;
}
map->libbpf_type = LIBBPF_MAP_UNSPEC;
map->def.type = BPF_MAP_TYPE_UNSPEC;
map->sec_idx = sec_idx;
map->sec_offset = vi->offset;
pr_debug("map '%s': at sec_idx %d, offset %zu.\n",
map_name, map->sec_idx, map->sec_offset);
vlen = btf_vlen(def);
m = btf_members(def);
for (i = 0; i < vlen; i++, m++) {
const char *name = btf__name_by_offset(obj->btf, m->name_off);
if (!name) {
pr_warn("map '%s': invalid field #%d.\n", map_name, i);
return -EINVAL;
}
if (strcmp(name, "type") == 0) {
if (!get_map_field_int(map_name, obj->btf, def, m,
&map->def.type))
return -EINVAL;
pr_debug("map '%s': found type = %u.\n",
map_name, map->def.type);
} else if (strcmp(name, "max_entries") == 0) {
if (!get_map_field_int(map_name, obj->btf, def, m,
&map->def.max_entries))
return -EINVAL;
pr_debug("map '%s': found max_entries = %u.\n",
map_name, map->def.max_entries);
} else if (strcmp(name, "map_flags") == 0) {
if (!get_map_field_int(map_name, obj->btf, def, m,
&map->def.map_flags))
return -EINVAL;
pr_debug("map '%s': found map_flags = %u.\n",
map_name, map->def.map_flags);
} else if (strcmp(name, "key_size") == 0) {
__u32 sz;
if (!get_map_field_int(map_name, obj->btf, def, m,
&sz))
return -EINVAL;
pr_debug("map '%s': found key_size = %u.\n",
map_name, sz);
if (map->def.key_size && map->def.key_size != sz) {
pr_warn("map '%s': conflicting key size %u != %u.\n",
map_name, map->def.key_size, sz);
return -EINVAL;
}
map->def.key_size = sz;
} else if (strcmp(name, "key") == 0) {
__s64 sz;
t = btf__type_by_id(obj->btf, m->type);
if (!t) {
pr_warn("map '%s': key type [%d] not found.\n",
map_name, m->type);
return -EINVAL;
}
if (!btf_is_ptr(t)) {
pr_warn("map '%s': key spec is not PTR: %u.\n",
map_name, btf_kind(t));
return -EINVAL;
}
sz = btf__resolve_size(obj->btf, t->type);
if (sz < 0) {
pr_warn("map '%s': can't determine key size for type [%u]: %lld.\n",
map_name, t->type, sz);
return sz;
}
pr_debug("map '%s': found key [%u], sz = %lld.\n",
map_name, t->type, sz);
if (map->def.key_size && map->def.key_size != sz) {
pr_warn("map '%s': conflicting key size %u != %lld.\n",
map_name, map->def.key_size, sz);
return -EINVAL;
}
map->def.key_size = sz;
map->btf_key_type_id = t->type;
} else if (strcmp(name, "value_size") == 0) {
__u32 sz;
if (!get_map_field_int(map_name, obj->btf, def, m,
&sz))
return -EINVAL;
pr_debug("map '%s': found value_size = %u.\n",
map_name, sz);
if (map->def.value_size && map->def.value_size != sz) {
pr_warn("map '%s': conflicting value size %u != %u.\n",
map_name, map->def.value_size, sz);
return -EINVAL;
}
map->def.value_size = sz;
} else if (strcmp(name, "value") == 0) {
__s64 sz;
t = btf__type_by_id(obj->btf, m->type);
if (!t) {
pr_warn("map '%s': value type [%d] not found.\n",
map_name, m->type);
return -EINVAL;
}
if (!btf_is_ptr(t)) {
pr_warn("map '%s': value spec is not PTR: %u.\n",
map_name, btf_kind(t));
return -EINVAL;
}
sz = btf__resolve_size(obj->btf, t->type);
if (sz < 0) {
pr_warn("map '%s': can't determine value size for type [%u]: %lld.\n",
map_name, t->type, sz);
return sz;
}
pr_debug("map '%s': found value [%u], sz = %lld.\n",
map_name, t->type, sz);
if (map->def.value_size && map->def.value_size != sz) {
pr_warn("map '%s': conflicting value size %u != %lld.\n",
map_name, map->def.value_size, sz);
return -EINVAL;
}
map->def.value_size = sz;
map->btf_value_type_id = t->type;
} else if (strcmp(name, "pinning") == 0) {
__u32 val;
int err;
if (!get_map_field_int(map_name, obj->btf, def, m,
&val))
return -EINVAL;
pr_debug("map '%s': found pinning = %u.\n",
map_name, val);
if (val != LIBBPF_PIN_NONE &&
val != LIBBPF_PIN_BY_NAME) {
pr_warn("map '%s': invalid pinning value %u.\n",
map_name, val);
return -EINVAL;
}
if (val == LIBBPF_PIN_BY_NAME) {
err = build_map_pin_path(map, pin_root_path);
if (err) {
pr_warn("map '%s': couldn't build pin path.\n",
map_name);
return err;
}
}
} else {
if (strict) {
pr_warn("map '%s': unknown field '%s'.\n",
map_name, name);
return -ENOTSUP;
}
pr_debug("map '%s': ignoring unknown field '%s'.\n",
map_name, name);
}
}
if (map->def.type == BPF_MAP_TYPE_UNSPEC) {
pr_warn("map '%s': map type isn't specified.\n", map_name);
return -EINVAL;
}
return 0;
}
static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict,
const char *pin_root_path)
{
const struct btf_type *sec = NULL;
int nr_types, i, vlen, err;
const struct btf_type *t;
const char *name;
Elf_Data *data;
Elf_Scn *scn;
if (obj->efile.btf_maps_shndx < 0)
return 0;
scn = elf_getscn(obj->efile.elf, obj->efile.btf_maps_shndx);
if (scn)
data = elf_getdata(scn, NULL);
if (!scn || !data) {
pr_warn("failed to get Elf_Data from map section %d (%s)\n",
obj->efile.maps_shndx, MAPS_ELF_SEC);
return -EINVAL;
}
nr_types = btf__get_nr_types(obj->btf);
for (i = 1; i <= nr_types; i++) {
t = btf__type_by_id(obj->btf, i);
if (!btf_is_datasec(t))
continue;
name = btf__name_by_offset(obj->btf, t->name_off);
if (strcmp(name, MAPS_ELF_SEC) == 0) {
sec = t;
break;
}
}
if (!sec) {
pr_warn("DATASEC '%s' not found.\n", MAPS_ELF_SEC);
return -ENOENT;
}
vlen = btf_vlen(sec);
for (i = 0; i < vlen; i++) {
err = bpf_object__init_user_btf_map(obj, sec, i,
obj->efile.btf_maps_shndx,
data, strict,
pin_root_path);
if (err)
return err;
}
return 0;
}
static int bpf_object__init_maps(struct bpf_object *obj, bool relaxed_maps,
const char *pin_root_path)
{
bool strict = !relaxed_maps;
int err;
err = bpf_object__init_user_maps(obj, strict);
if (err)
return err;
err = bpf_object__init_user_btf_maps(obj, strict, pin_root_path);
if (err)
return err;
err = bpf_object__init_global_data_maps(obj);
if (err)
return err;
if (obj->nr_maps) {
qsort(obj->maps, obj->nr_maps, sizeof(obj->maps[0]),
compare_bpf_map);
}
return 0;
}
static bool section_have_execinstr(struct bpf_object *obj, int idx)
{
Elf_Scn *scn;
GElf_Shdr sh;
scn = elf_getscn(obj->efile.elf, idx);
if (!scn)
return false;
if (gelf_getshdr(scn, &sh) != &sh)
return false;
if (sh.sh_flags & SHF_EXECINSTR)
return true;
return false;
}
static void bpf_object__sanitize_btf(struct bpf_object *obj)
{
bool has_datasec = obj->caps.btf_datasec;
bool has_func = obj->caps.btf_func;
struct btf *btf = obj->btf;
struct btf_type *t;
int i, j, vlen;
if (!obj->btf || (has_func && has_datasec))
return;
for (i = 1; i <= btf__get_nr_types(btf); i++) {
t = (struct btf_type *)btf__type_by_id(btf, i);
if (!has_datasec && btf_is_var(t)) {
/* replace VAR with INT */
t->info = BTF_INFO_ENC(BTF_KIND_INT, 0, 0);
/*
* using size = 1 is the safest choice, 4 will be too
* big and cause kernel BTF validation failure if
* original variable took less than 4 bytes
*/
t->size = 1;
*(int *)(t + 1) = BTF_INT_ENC(0, 0, 8);
} else if (!has_datasec && btf_is_datasec(t)) {
/* replace DATASEC with STRUCT */
const struct btf_var_secinfo *v = btf_var_secinfos(t);
struct btf_member *m = btf_members(t);
struct btf_type *vt;
char *name;
name = (char *)btf__name_by_offset(btf, t->name_off);
while (*name) {
if (*name == '.')
*name = '_';
name++;
}
vlen = btf_vlen(t);
t->info = BTF_INFO_ENC(BTF_KIND_STRUCT, 0, vlen);
for (j = 0; j < vlen; j++, v++, m++) {
/* order of field assignments is important */
m->offset = v->offset * 8;
m->type = v->type;
/* preserve variable name as member name */
vt = (void *)btf__type_by_id(btf, v->type);
m->name_off = vt->name_off;
}
} else if (!has_func && btf_is_func_proto(t)) {
/* replace FUNC_PROTO with ENUM */
vlen = btf_vlen(t);
t->info = BTF_INFO_ENC(BTF_KIND_ENUM, 0, vlen);
t->size = sizeof(__u32); /* kernel enforced */
} else if (!has_func && btf_is_func(t)) {
/* replace FUNC with TYPEDEF */
t->info = BTF_INFO_ENC(BTF_KIND_TYPEDEF, 0, 0);
}
}
}
static void bpf_object__sanitize_btf_ext(struct bpf_object *obj)
{
if (!obj->btf_ext)
return;
if (!obj->caps.btf_func) {
btf_ext__free(obj->btf_ext);
obj->btf_ext = NULL;
}
}
static bool bpf_object__is_btf_mandatory(const struct bpf_object *obj)
{
return obj->efile.btf_maps_shndx >= 0;
}
static int bpf_object__init_btf(struct bpf_object *obj,
Elf_Data *btf_data,
Elf_Data *btf_ext_data)
{
bool btf_required = bpf_object__is_btf_mandatory(obj);
int err = 0;
if (btf_data) {
obj->btf = btf__new(btf_data->d_buf, btf_data->d_size);
if (IS_ERR(obj->btf)) {
pr_warn("Error loading ELF section %s: %d.\n",
BTF_ELF_SEC, err);
goto out;
}
err = btf__finalize_data(obj, obj->btf);
if (err) {
pr_warn("Error finalizing %s: %d.\n", BTF_ELF_SEC, err);
goto out;
}
}
if (btf_ext_data) {
if (!obj->btf) {
pr_debug("Ignore ELF section %s because its depending ELF section %s is not found.\n",
BTF_EXT_ELF_SEC, BTF_ELF_SEC);
goto out;
}
obj->btf_ext = btf_ext__new(btf_ext_data->d_buf,
btf_ext_data->d_size);
if (IS_ERR(obj->btf_ext)) {
pr_warn("Error loading ELF section %s: %ld. Ignored and continue.\n",
BTF_EXT_ELF_SEC, PTR_ERR(obj->btf_ext));
obj->btf_ext = NULL;
goto out;
}
}
out:
if (err || IS_ERR(obj->btf)) {
if (btf_required)
err = err ? : PTR_ERR(obj->btf);
else
err = 0;
if (!IS_ERR_OR_NULL(obj->btf))
btf__free(obj->btf);
obj->btf = NULL;
}
if (btf_required && !obj->btf) {
pr_warn("BTF is required, but is missing or corrupted.\n");
return err == 0 ? -ENOENT : err;
}
return 0;
}
static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj)
{
int err = 0;
if (!obj->btf)
return 0;
bpf_object__sanitize_btf(obj);
bpf_object__sanitize_btf_ext(obj);
err = btf__load(obj->btf);
if (err) {
pr_warn("Error loading %s into kernel: %d.\n",
BTF_ELF_SEC, err);
btf__free(obj->btf);
obj->btf = NULL;
/* btf_ext can't exist without btf, so free it as well */
if (obj->btf_ext) {
btf_ext__free(obj->btf_ext);
obj->btf_ext = NULL;
}
if (bpf_object__is_btf_mandatory(obj))
return err;
}
return 0;
}
static int bpf_object__elf_collect(struct bpf_object *obj, bool relaxed_maps,
const char *pin_root_path)
{
Elf *elf = obj->efile.elf;
GElf_Ehdr *ep = &obj->efile.ehdr;
Elf_Data *btf_ext_data = NULL;
Elf_Data *btf_data = NULL;
Elf_Scn *scn = NULL;
int idx = 0, err = 0;
/* Elf is corrupted/truncated, avoid calling elf_strptr. */
if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) {
pr_warn("failed to get e_shstrndx from %s\n", obj->path);
return -LIBBPF_ERRNO__FORMAT;
}
while ((scn = elf_nextscn(elf, scn)) != NULL) {
char *name;
GElf_Shdr sh;
Elf_Data *data;
idx++;
if (gelf_getshdr(scn, &sh) != &sh) {
pr_warn("failed to get section(%d) header from %s\n",
idx, obj->path);
return -LIBBPF_ERRNO__FORMAT;
}
name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
if (!name) {
pr_warn("failed to get section(%d) name from %s\n",
idx, obj->path);
return -LIBBPF_ERRNO__FORMAT;
}
data = elf_getdata(scn, 0);
if (!data) {
pr_warn("failed to get section(%d) data from %s(%s)\n",
idx, name, obj->path);
return -LIBBPF_ERRNO__FORMAT;
}
pr_debug("section(%d) %s, size %ld, link %d, flags %lx, type=%d\n",
idx, name, (unsigned long)data->d_size,
(int)sh.sh_link, (unsigned long)sh.sh_flags,
(int)sh.sh_type);
if (strcmp(name, "license") == 0) {
err = bpf_object__init_license(obj,
data->d_buf,
data->d_size);
if (err)
return err;
} else if (strcmp(name, "version") == 0) {
err = bpf_object__init_kversion(obj,
data->d_buf,
data->d_size);
if (err)
return err;
} else if (strcmp(name, "maps") == 0) {
obj->efile.maps_shndx = idx;
} else if (strcmp(name, MAPS_ELF_SEC) == 0) {
obj->efile.btf_maps_shndx = idx;
} else if (strcmp(name, BTF_ELF_SEC) == 0) {
btf_data = data;
} else if (strcmp(name, BTF_EXT_ELF_SEC) == 0) {
btf_ext_data = data;
} else if (sh.sh_type == SHT_SYMTAB) {
if (obj->efile.symbols) {
pr_warn("bpf: multiple SYMTAB in %s\n",
obj->path);
return -LIBBPF_ERRNO__FORMAT;
}
obj->efile.symbols = data;
obj->efile.strtabidx = sh.sh_link;
} else if (sh.sh_type == SHT_PROGBITS && data->d_size > 0) {
if (sh.sh_flags & SHF_EXECINSTR) {
if (strcmp(name, ".text") == 0)
obj->efile.text_shndx = idx;
err = bpf_object__add_program(obj, data->d_buf,
data->d_size,
name, idx);
if (err) {
char errmsg[STRERR_BUFSIZE];
char *cp;
cp = libbpf_strerror_r(-err, errmsg,
sizeof(errmsg));
pr_warn("failed to alloc program %s (%s): %s",
name, obj->path, cp);
return err;
}
} else if (strcmp(name, ".data") == 0) {
obj->efile.data = data;
obj->efile.data_shndx = idx;
} else if (strcmp(name, ".rodata") == 0) {
obj->efile.rodata = data;
obj->efile.rodata_shndx = idx;
} else {
pr_debug("skip section(%d) %s\n", idx, name);
}
} else if (sh.sh_type == SHT_REL) {
int nr_sects = obj->efile.nr_reloc_sects;
void *sects = obj->efile.reloc_sects;
int sec = sh.sh_info; /* points to other section */
/* Only do relo for section with exec instructions */
if (!section_have_execinstr(obj, sec)) {
pr_debug("skip relo %s(%d) for section(%d)\n",
name, idx, sec);
continue;
}
sects = reallocarray(sects, nr_sects + 1,
sizeof(*obj->efile.reloc_sects));
if (!sects) {
pr_warn("reloc_sects realloc failed\n");
return -ENOMEM;
}
obj->efile.reloc_sects = sects;
obj->efile.nr_reloc_sects++;
obj->efile.reloc_sects[nr_sects].shdr = sh;
obj->efile.reloc_sects[nr_sects].data = data;
} else if (sh.sh_type == SHT_NOBITS && strcmp(name, ".bss") == 0) {
obj->efile.bss = data;
obj->efile.bss_shndx = idx;
} else {
pr_debug("skip section(%d) %s\n", idx, name);
}
}
if (!obj->efile.strtabidx || obj->efile.strtabidx > idx) {
pr_warn("Corrupted ELF file: index of strtab invalid\n");
return -LIBBPF_ERRNO__FORMAT;
}
err = bpf_object__init_btf(obj, btf_data, btf_ext_data);
if (!err)
err = bpf_object__init_maps(obj, relaxed_maps, pin_root_path);
if (!err)
err = bpf_object__sanitize_and_load_btf(obj);
if (!err)
err = bpf_object__init_prog_names(obj);
return err;
}
static struct bpf_program *
bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx)
{
struct bpf_program *prog;
size_t i;
for (i = 0; i < obj->nr_programs; i++) {
prog = &obj->programs[i];
if (prog->idx == idx)
return prog;
}
return NULL;
}
struct bpf_program *
bpf_object__find_program_by_title(const struct bpf_object *obj,
const char *title)
{
struct bpf_program *pos;
bpf_object__for_each_program(pos, obj) {
if (pos->section_name && !strcmp(pos->section_name, title))
return pos;
}
return NULL;
}
static bool bpf_object__shndx_is_data(const struct bpf_object *obj,
int shndx)
{
return shndx == obj->efile.data_shndx ||
shndx == obj->efile.bss_shndx ||
shndx == obj->efile.rodata_shndx;
}
static bool bpf_object__shndx_is_maps(const struct bpf_object *obj,
int shndx)
{
return shndx == obj->efile.maps_shndx ||
shndx == obj->efile.btf_maps_shndx;
}
static enum libbpf_map_type
bpf_object__section_to_libbpf_map_type(const struct bpf_object *obj, int shndx)
{
if (shndx == obj->efile.data_shndx)
return LIBBPF_MAP_DATA;
else if (shndx == obj->efile.bss_shndx)
return LIBBPF_MAP_BSS;
else if (shndx == obj->efile.rodata_shndx)
return LIBBPF_MAP_RODATA;
else
return LIBBPF_MAP_UNSPEC;
}
static int bpf_program__record_reloc(struct bpf_program *prog,
struct reloc_desc *reloc_desc,
__u32 insn_idx, const char *name,
const GElf_Sym *sym, const GElf_Rel *rel)
{
struct bpf_insn *insn = &prog->insns[insn_idx];
size_t map_idx, nr_maps = prog->obj->nr_maps;
struct bpf_object *obj = prog->obj;
__u32 shdr_idx = sym->st_shndx;
enum libbpf_map_type type;
struct bpf_map *map;
/* sub-program call relocation */
if (insn->code == (BPF_JMP | BPF_CALL)) {
if (insn->src_reg != BPF_PSEUDO_CALL) {
pr_warn("incorrect bpf_call opcode\n");
return -LIBBPF_ERRNO__RELOC;
}
/* text_shndx can be 0, if no default "main" program exists */
if (!shdr_idx || shdr_idx != obj->efile.text_shndx) {
pr_warn("bad call relo against section %u\n", shdr_idx);
return -LIBBPF_ERRNO__RELOC;
}
if (sym->st_value % 8) {
pr_warn("bad call relo offset: %llu\n", (__u64)sym->st_value);
return -LIBBPF_ERRNO__RELOC;
}
reloc_desc->type = RELO_CALL;
reloc_desc->insn_idx = insn_idx;
reloc_desc->sym_off = sym->st_value;
obj->has_pseudo_calls = true;
return 0;
}
if (insn->code != (BPF_LD | BPF_IMM | BPF_DW)) {
pr_warn("invalid relo for insns[%d].code 0x%x\n",
insn_idx, insn->code);
return -LIBBPF_ERRNO__RELOC;
}
if (!shdr_idx || shdr_idx >= SHN_LORESERVE) {
pr_warn("invalid relo for \'%s\' in special section 0x%x; forgot to initialize global var?..\n",
name, shdr_idx);
return -LIBBPF_ERRNO__RELOC;
}
type = bpf_object__section_to_libbpf_map_type(obj, shdr_idx);
/* generic map reference relocation */
if (type == LIBBPF_MAP_UNSPEC) {
if (!bpf_object__shndx_is_maps(obj, shdr_idx)) {
pr_warn("bad map relo against section %u\n",
shdr_idx);
return -LIBBPF_ERRNO__RELOC;
}
for (map_idx = 0; map_idx < nr_maps; map_idx++) {
map = &obj->maps[map_idx];
if (map->libbpf_type != type ||
map->sec_idx != sym->st_shndx ||
map->sec_offset != sym->st_value)
continue;
pr_debug("found map %zd (%s, sec %d, off %zu) for insn %u\n",
map_idx, map->name, map->sec_idx,
map->sec_offset, insn_idx);
break;
}
if (map_idx >= nr_maps) {
pr_warn("map relo failed to find map for sec %u, off %llu\n",
shdr_idx, (__u64)sym->st_value);
return -LIBBPF_ERRNO__RELOC;
}
reloc_desc->type = RELO_LD64;
reloc_desc->insn_idx = insn_idx;
reloc_desc->map_idx = map_idx;
reloc_desc->sym_off = 0; /* sym->st_value determines map_idx */
return 0;
}
/* global data map relocation */
if (!bpf_object__shndx_is_data(obj, shdr_idx)) {
pr_warn("bad data relo against section %u\n", shdr_idx);
return -LIBBPF_ERRNO__RELOC;
}
if (!obj->caps.global_data) {
pr_warn("relocation: kernel does not support global \'%s\' variable access in insns[%d]\n",
name, insn_idx);
return -LIBBPF_ERRNO__RELOC;
}
for (map_idx = 0; map_idx < nr_maps; map_idx++) {
map = &obj->maps[map_idx];
if (map->libbpf_type != type)
continue;
pr_debug("found data map %zd (%s, sec %d, off %zu) for insn %u\n",
map_idx, map->name, map->sec_idx, map->sec_offset,
insn_idx);
break;
}
if (map_idx >= nr_maps) {
pr_warn("data relo failed to find map for sec %u\n",
shdr_idx);
return -LIBBPF_ERRNO__RELOC;
}
reloc_desc->type = RELO_DATA;
reloc_desc->insn_idx = insn_idx;
reloc_desc->map_idx = map_idx;
reloc_desc->sym_off = sym->st_value;
return 0;
}
static int
bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr,
Elf_Data *data, struct bpf_object *obj)
{
Elf_Data *symbols = obj->efile.symbols;
int err, i, nrels;
pr_debug("collecting relocating info for: '%s'\n", prog->section_name);
nrels = shdr->sh_size / shdr->sh_entsize;
prog->reloc_desc = malloc(sizeof(*prog->reloc_desc) * nrels);
if (!prog->reloc_desc) {
pr_warn("failed to alloc memory in relocation\n");
return -ENOMEM;
}
prog->nr_reloc = nrels;
for (i = 0; i < nrels; i++) {
const char *name;
__u32 insn_idx;
GElf_Sym sym;
GElf_Rel rel;
if (!gelf_getrel(data, i, &rel)) {
pr_warn("relocation: failed to get %d reloc\n", i);
return -LIBBPF_ERRNO__FORMAT;
}
if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) {
pr_warn("relocation: symbol %"PRIx64" not found\n",
GELF_R_SYM(rel.r_info));
return -LIBBPF_ERRNO__FORMAT;
}
if (rel.r_offset % sizeof(struct bpf_insn))
return -LIBBPF_ERRNO__FORMAT;
insn_idx = rel.r_offset / sizeof(struct bpf_insn);
name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
sym.st_name) ? : "<?>";
pr_debug("relo for shdr %u, symb %llu, value %llu, type %d, bind %d, name %d (\'%s\'), insn %u\n",
(__u32)sym.st_shndx, (__u64)GELF_R_SYM(rel.r_info),
(__u64)sym.st_value, GELF_ST_TYPE(sym.st_info),
GELF_ST_BIND(sym.st_info), sym.st_name, name,
insn_idx);
err = bpf_program__record_reloc(prog, &prog->reloc_desc[i],
insn_idx, name, &sym, &rel);
if (err)
return err;
}
return 0;
}
static int bpf_map_find_btf_info(struct bpf_object *obj, struct bpf_map *map)
{
struct bpf_map_def *def = &map->def;
__u32 key_type_id = 0, value_type_id = 0;
int ret;
/* if it's BTF-defined map, we don't need to search for type IDs */
if (map->sec_idx == obj->efile.btf_maps_shndx)
return 0;
if (!bpf_map__is_internal(map)) {
ret = btf__get_map_kv_tids(obj->btf, map->name, def->key_size,
def->value_size, &key_type_id,
&value_type_id);
} else {
/*
* LLVM annotates global data differently in BTF, that is,
* only as '.data', '.bss' or '.rodata'.
*/
ret = btf__find_by_name(obj->btf,
libbpf_type_to_btf_name[map->libbpf_type]);
}
if (ret < 0)
return ret;
map->btf_key_type_id = key_type_id;
map->btf_value_type_id = bpf_map__is_internal(map) ?
ret : value_type_id;
return 0;
}
int bpf_map__reuse_fd(struct bpf_map *map, int fd)
{
struct bpf_map_info info = {};
__u32 len = sizeof(info);
int new_fd, err;
char *new_name;
err = bpf_obj_get_info_by_fd(fd, &info, &len);
if (err)
return err;
new_name = strdup(info.name);
if (!new_name)
return -errno;
new_fd = open("/", O_RDONLY | O_CLOEXEC);
if (new_fd < 0) {
err = -errno;
goto err_free_new_name;
}
new_fd = dup3(fd, new_fd, O_CLOEXEC);
if (new_fd < 0) {
err = -errno;
goto err_close_new_fd;
}
err = zclose(map->fd);
if (err) {
err = -errno;
goto err_close_new_fd;
}
free(map->name);
map->fd = new_fd;
map->name = new_name;
map->def.type = info.type;
map->def.key_size = info.key_size;
map->def.value_size = info.value_size;
map->def.max_entries = info.max_entries;
map->def.map_flags = info.map_flags;
map->btf_key_type_id = info.btf_key_type_id;
map->btf_value_type_id = info.btf_value_type_id;
map->reused = true;
return 0;
err_close_new_fd:
close(new_fd);
err_free_new_name:
free(new_name);
return err;
}
int bpf_map__resize(struct bpf_map *map, __u32 max_entries)
{
if (!map || !max_entries)
return -EINVAL;
/* If map already created, its attributes can't be changed. */
if (map->fd >= 0)
return -EBUSY;
map->def.max_entries = max_entries;
return 0;
}
static int
bpf_object__probe_name(struct bpf_object *obj)
{
struct bpf_load_program_attr attr;
char *cp, errmsg[STRERR_BUFSIZE];
struct bpf_insn insns[] = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
};
int ret;
/* make sure basic loading works */
memset(&attr, 0, sizeof(attr));
attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
attr.insns = insns;
attr.insns_cnt = ARRAY_SIZE(insns);
attr.license = "GPL";
ret = bpf_load_program_xattr(&attr, NULL, 0);
if (ret < 0) {
cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
pr_warn("Error in %s():%s(%d). Couldn't load basic 'r0 = 0' BPF program.\n",
__func__, cp, errno);
return -errno;
}
close(ret);
/* now try the same program, but with the name */
attr.name = "test";
ret = bpf_load_program_xattr(&attr, NULL, 0);
if (ret >= 0) {
obj->caps.name = 1;
close(ret);
}
return 0;
}
static int
bpf_object__probe_global_data(struct bpf_object *obj)
{
struct bpf_load_program_attr prg_attr;
struct bpf_create_map_attr map_attr;
char *cp, errmsg[STRERR_BUFSIZE];
struct bpf_insn insns[] = {
BPF_LD_MAP_VALUE(BPF_REG_1, 0, 16),
BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 42),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
};
int ret, map;
memset(&map_attr, 0, sizeof(map_attr));
map_attr.map_type = BPF_MAP_TYPE_ARRAY;
map_attr.key_size = sizeof(int);
map_attr.value_size = 32;
map_attr.max_entries = 1;
map = bpf_create_map_xattr(&map_attr);
if (map < 0) {
cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
pr_warn("Error in %s():%s(%d). Couldn't create simple array map.\n",
__func__, cp, errno);
return -errno;
}
insns[0].imm = map;
memset(&prg_attr, 0, sizeof(prg_attr));
prg_attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
prg_attr.insns = insns;
prg_attr.insns_cnt = ARRAY_SIZE(insns);
prg_attr.license = "GPL";
ret = bpf_load_program_xattr(&prg_attr, NULL, 0);
if (ret >= 0) {
obj->caps.global_data = 1;
close(ret);
}
close(map);
return 0;
}
static int bpf_object__probe_btf_func(struct bpf_object *obj)
{
static const char strs[] = "\0int\0x\0a";
/* void x(int a) {} */
__u32 types[] = {
/* int */
BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
/* FUNC_PROTO */ /* [2] */
BTF_TYPE_ENC(0, BTF_INFO_ENC(BTF_KIND_FUNC_PROTO, 0, 1), 0),
BTF_PARAM_ENC(7, 1),
/* FUNC x */ /* [3] */
BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0), 2),
};
int btf_fd;
btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types),
strs, sizeof(strs));
if (btf_fd >= 0) {
obj->caps.btf_func = 1;
close(btf_fd);
return 1;
}
return 0;
}
static int bpf_object__probe_btf_datasec(struct bpf_object *obj)
{
static const char strs[] = "\0x\0.data";
/* static int a; */
__u32 types[] = {
/* int */
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
/* VAR x */ /* [2] */
BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_VAR, 0, 0), 1),
BTF_VAR_STATIC,
/* DATASEC val */ /* [3] */
BTF_TYPE_ENC(3, BTF_INFO_ENC(BTF_KIND_DATASEC, 0, 1), 4),
BTF_VAR_SECINFO_ENC(2, 0, 4),
};
int btf_fd;
btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types),
strs, sizeof(strs));
if (btf_fd >= 0) {
obj->caps.btf_datasec = 1;
close(btf_fd);
return 1;
}
return 0;
}
static int bpf_object__probe_array_mmap(struct bpf_object *obj)
{
struct bpf_create_map_attr attr = {
.map_type = BPF_MAP_TYPE_ARRAY,
.map_flags = BPF_F_MMAPABLE,
.key_size = sizeof(int),
.value_size = sizeof(int),
.max_entries = 1,
};
int fd;
fd = bpf_create_map_xattr(&attr);
if (fd >= 0) {
obj->caps.array_mmap = 1;
close(fd);
return 1;
}
return 0;
}
static int
bpf_object__probe_caps(struct bpf_object *obj)
{
int (*probe_fn[])(struct bpf_object *obj) = {
bpf_object__probe_name,
bpf_object__probe_global_data,
bpf_object__probe_btf_func,
bpf_object__probe_btf_datasec,
bpf_object__probe_array_mmap,
};
int i, ret;
for (i = 0; i < ARRAY_SIZE(probe_fn); i++) {
ret = probe_fn[i](obj);
if (ret < 0)
pr_debug("Probe #%d failed with %d.\n", i, ret);
}
return 0;
}
static bool map_is_reuse_compat(const struct bpf_map *map, int map_fd)
{
struct bpf_map_info map_info = {};
char msg[STRERR_BUFSIZE];
__u32 map_info_len;
map_info_len = sizeof(map_info);
if (bpf_obj_get_info_by_fd(map_fd, &map_info, &map_info_len)) {
pr_warn("failed to get map info for map FD %d: %s\n",
map_fd, libbpf_strerror_r(errno, msg, sizeof(msg)));
return false;
}
return (map_info.type == map->def.type &&
map_info.key_size == map->def.key_size &&
map_info.value_size == map->def.value_size &&
map_info.max_entries == map->def.max_entries &&
map_info.map_flags == map->def.map_flags);
}
static int
bpf_object__reuse_map(struct bpf_map *map)
{
char *cp, errmsg[STRERR_BUFSIZE];
int err, pin_fd;
pin_fd = bpf_obj_get(map->pin_path);
if (pin_fd < 0) {
err = -errno;
if (err == -ENOENT) {
pr_debug("found no pinned map to reuse at '%s'\n",
map->pin_path);
return 0;
}
cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg));
pr_warn("couldn't retrieve pinned map '%s': %s\n",
map->pin_path, cp);
return err;
}
if (!map_is_reuse_compat(map, pin_fd)) {
pr_warn("couldn't reuse pinned map at '%s': parameter mismatch\n",
map->pin_path);
close(pin_fd);
return -EINVAL;
}
err = bpf_map__reuse_fd(map, pin_fd);
if (err) {
close(pin_fd);
return err;
}
map->pinned = true;
pr_debug("reused pinned map at '%s'\n", map->pin_path);
return 0;
}
static int
bpf_object__populate_internal_map(struct bpf_object *obj, struct bpf_map *map)
{
char *cp, errmsg[STRERR_BUFSIZE];
int err, zero = 0;
__u8 *data;
/* Nothing to do here since kernel already zero-initializes .bss map. */
if (map->libbpf_type == LIBBPF_MAP_BSS)
return 0;
data = map->libbpf_type == LIBBPF_MAP_DATA ?
obj->sections.data : obj->sections.rodata;
err = bpf_map_update_elem(map->fd, &zero, data, 0);
/* Freeze .rodata map as read-only from syscall side. */
if (!err && map->libbpf_type == LIBBPF_MAP_RODATA) {
err = bpf_map_freeze(map->fd);
if (err) {
cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
pr_warn("Error freezing map(%s) as read-only: %s\n",
map->name, cp);
err = 0;
}
}
return err;
}
static int
bpf_object__create_maps(struct bpf_object *obj)
{
struct bpf_create_map_attr create_attr = {};
int nr_cpus = 0;
unsigned int i;
int err;
for (i = 0; i < obj->nr_maps; i++) {
struct bpf_map *map = &obj->maps[i];
struct bpf_map_def *def = &map->def;
char *cp, errmsg[STRERR_BUFSIZE];
int *pfd = &map->fd;
if (map->pin_path) {
err = bpf_object__reuse_map(map);
if (err) {
pr_warn("error reusing pinned map %s\n",
map->name);
return err;
}
}
if (map->fd >= 0) {
pr_debug("skip map create (preset) %s: fd=%d\n",
map->name, map->fd);
continue;
}
if (obj->caps.name)
create_attr.name = map->name;
create_attr.map_ifindex = map->map_ifindex;
create_attr.map_type = def->type;
create_attr.map_flags = def->map_flags;
create_attr.key_size = def->key_size;
create_attr.value_size = def->value_size;
if (def->type == BPF_MAP_TYPE_PERF_EVENT_ARRAY &&
!def->max_entries) {
if (!nr_cpus)
nr_cpus = libbpf_num_possible_cpus();
if (nr_cpus < 0) {
pr_warn("failed to determine number of system CPUs: %d\n",
nr_cpus);
err = nr_cpus;
goto err_out;
}
pr_debug("map '%s': setting size to %d\n",
map->name, nr_cpus);
create_attr.max_entries = nr_cpus;
} else {
create_attr.max_entries = def->max_entries;
}
create_attr.btf_fd = 0;
create_attr.btf_key_type_id = 0;
create_attr.btf_value_type_id = 0;
if (bpf_map_type__is_map_in_map(def->type) &&
map->inner_map_fd >= 0)
create_attr.inner_map_fd = map->inner_map_fd;
if (obj->btf && !bpf_map_find_btf_info(obj, map)) {
create_attr.btf_fd = btf__fd(obj->btf);
create_attr.btf_key_type_id = map->btf_key_type_id;
create_attr.btf_value_type_id = map->btf_value_type_id;
}
*pfd = bpf_create_map_xattr(&create_attr);
if (*pfd < 0 && (create_attr.btf_key_type_id ||
create_attr.btf_value_type_id)) {
err = -errno;
cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
pr_warn("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n",
map->name, cp, err);
create_attr.btf_fd = 0;
create_attr.btf_key_type_id = 0;
create_attr.btf_value_type_id = 0;
map->btf_key_type_id = 0;
map->btf_value_type_id = 0;
*pfd = bpf_create_map_xattr(&create_attr);
}
if (*pfd < 0) {
size_t j;
err = -errno;
err_out:
cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
pr_warn("failed to create map (name: '%s'): %s(%d)\n",
map->name, cp, err);
for (j = 0; j < i; j++)
zclose(obj->maps[j].fd);
return err;
}
if (bpf_map__is_internal(map)) {
err = bpf_object__populate_internal_map(obj, map);
if (err < 0) {
zclose(*pfd);
goto err_out;
}
}
if (map->pin_path && !map->pinned) {
err = bpf_map__pin(map, NULL);
if (err) {
pr_warn("failed to auto-pin map name '%s' at '%s'\n",
map->name, map->pin_path);
return err;
}
}
pr_debug("created map %s: fd=%d\n", map->name, *pfd);
}
return 0;
}
static int
check_btf_ext_reloc_err(struct bpf_program *prog, int err,
void *btf_prog_info, const char *info_name)
{
if (err != -ENOENT) {
pr_warn("Error in loading %s for sec %s.\n",
info_name, prog->section_name);
return err;
}
/* err == -ENOENT (i.e. prog->section_name not found in btf_ext) */
if (btf_prog_info) {
/*
* Some info has already been found but has problem
* in the last btf_ext reloc. Must have to error out.
*/
pr_warn("Error in relocating %s for sec %s.\n",
info_name, prog->section_name);
return err;
}
/* Have problem loading the very first info. Ignore the rest. */
pr_warn("Cannot find %s for main program sec %s. Ignore all %s.\n",
info_name, prog->section_name, info_name);
return 0;
}
static int
bpf_program_reloc_btf_ext(struct bpf_program *prog, struct bpf_object *obj,
const char *section_name, __u32 insn_offset)
{
int err;
if (!insn_offset || prog->func_info) {
/*
* !insn_offset => main program
*
* For sub prog, the main program's func_info has to
* be loaded first (i.e. prog->func_info != NULL)
*/
err = btf_ext__reloc_func_info(obj->btf, obj->btf_ext,
section_name, insn_offset,
&prog->func_info,
&prog->func_info_cnt);
if (err)
return check_btf_ext_reloc_err(prog, err,
prog->func_info,
"bpf_func_info");
prog->func_info_rec_size = btf_ext__func_info_rec_size(obj->btf_ext);
}
if (!insn_offset || prog->line_info) {
err = btf_ext__reloc_line_info(obj->btf, obj->btf_ext,
section_name, insn_offset,
&prog->line_info,
&prog->line_info_cnt);
if (err)
return check_btf_ext_reloc_err(prog, err,
prog->line_info,
"bpf_line_info");
prog->line_info_rec_size = btf_ext__line_info_rec_size(obj->btf_ext);
}
return 0;
}
#define BPF_CORE_SPEC_MAX_LEN 64
/* represents BPF CO-RE field or array element accessor */
struct bpf_core_accessor {
__u32 type_id; /* struct/union type or array element type */
__u32 idx; /* field index or array index */
const char *name; /* field name or NULL for array accessor */
};
struct bpf_core_spec {
const struct btf *btf;
/* high-level spec: named fields and array indices only */
struct bpf_core_accessor spec[BPF_CORE_SPEC_MAX_LEN];
/* high-level spec length */
int len;
/* raw, low-level spec: 1-to-1 with accessor spec string */
int raw_spec[BPF_CORE_SPEC_MAX_LEN];
/* raw spec length */
int raw_len;
/* field bit offset represented by spec */
__u32 bit_offset;
};
static bool str_is_empty(const char *s)
{
return !s || !s[0];
}
/*
* Turn bpf_field_reloc into a low- and high-level spec representation,
* validating correctness along the way, as well as calculating resulting
* field bit offset, specified by accessor string. Low-level spec captures
* every single level of nestedness, including traversing anonymous
* struct/union members. High-level one only captures semantically meaningful
* "turning points": named fields and array indicies.
* E.g., for this case:
*
* struct sample {
* int __unimportant;
* struct {
* int __1;
* int __2;
* int a[7];
* };
* };
*
* struct sample *s = ...;
*
* int x = &s->a[3]; // access string = '0:1:2:3'
*
* Low-level spec has 1:1 mapping with each element of access string (it's
* just a parsed access string representation): [0, 1, 2, 3].
*
* High-level spec will capture only 3 points:
* - intial zero-index access by pointer (&s->... is the same as &s[0]...);
* - field 'a' access (corresponds to '2' in low-level spec);
* - array element #3 access (corresponds to '3' in low-level spec).
*
*/
static int bpf_core_spec_parse(const struct btf *btf,
__u32 type_id,
const char *spec_str,
struct bpf_core_spec *spec)
{
int access_idx, parsed_len, i;
const struct btf_type *t;
const char *name;
__u32 id;
__s64 sz;
if (str_is_empty(spec_str) || *spec_str == ':')
return -EINVAL;
memset(spec, 0, sizeof(*spec));
spec->btf = btf;
/* parse spec_str="0:1:2:3:4" into array raw_spec=[0, 1, 2, 3, 4] */
while (*spec_str) {
if (*spec_str == ':')
++spec_str;
if (sscanf(spec_str, "%d%n", &access_idx, &parsed_len) != 1)
return -EINVAL;
if (spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
return -E2BIG;
spec_str += parsed_len;
spec->raw_spec[spec->raw_len++] = access_idx;
}
if (spec->raw_len == 0)
return -EINVAL;
/* first spec value is always reloc type array index */
t = skip_mods_and_typedefs(btf, type_id, &id);
if (!t)
return -EINVAL;
access_idx = spec->raw_spec[0];
spec->spec[0].type_id = id;
spec->spec[0].idx = access_idx;
spec->len++;
sz = btf__resolve_size(btf, id);
if (sz < 0)
return sz;
spec->bit_offset = access_idx * sz * 8;
for (i = 1; i < spec->raw_len; i++) {
t = skip_mods_and_typedefs(btf, id, &id);
if (!t)
return -EINVAL;
access_idx = spec->raw_spec[i];
if (btf_is_composite(t)) {
const struct btf_member *m;
__u32 bit_offset;
if (access_idx >= btf_vlen(t))
return -EINVAL;
bit_offset = btf_member_bit_offset(t, access_idx);
spec->bit_offset += bit_offset;
m = btf_members(t) + access_idx;
if (m->name_off) {
name = btf__name_by_offset(btf, m->name_off);
if (str_is_empty(name))
return -EINVAL;
spec->spec[spec->len].type_id = id;
spec->spec[spec->len].idx = access_idx;
spec->spec[spec->len].name = name;
spec->len++;
}
id = m->type;
} else if (btf_is_array(t)) {
const struct btf_array *a = btf_array(t);
t = skip_mods_and_typedefs(btf, a->type, &id);
if (!t || access_idx >= a->nelems)
return -EINVAL;
spec->spec[spec->len].type_id = id;
spec->spec[spec->len].idx = access_idx;
spec->len++;
sz = btf__resolve_size(btf, id);
if (sz < 0)
return sz;
spec->bit_offset += access_idx * sz * 8;
} else {
pr_warn("relo for [%u] %s (at idx %d) captures type [%d] of unexpected kind %d\n",
type_id, spec_str, i, id, btf_kind(t));
return -EINVAL;
}
}
return 0;
}
static bool bpf_core_is_flavor_sep(const char *s)
{
/* check X___Y name pattern, where X and Y are not underscores */
return s[0] != '_' && /* X */
s[1] == '_' && s[2] == '_' && s[3] == '_' && /* ___ */
s[4] != '_'; /* Y */
}
/* Given 'some_struct_name___with_flavor' return the length of a name prefix
* before last triple underscore. Struct name part after last triple
* underscore is ignored by BPF CO-RE relocation during relocation matching.
*/
static size_t bpf_core_essential_name_len(const char *name)
{
size_t n = strlen(name);
int i;
for (i = n - 5; i >= 0; i--) {
if (bpf_core_is_flavor_sep(name + i))
return i + 1;
}
return n;
}
/* dynamically sized list of type IDs */
struct ids_vec {
__u32 *data;
int len;
};
static void bpf_core_free_cands(struct ids_vec *cand_ids)
{
free(cand_ids->data);
free(cand_ids);
}
static struct ids_vec *bpf_core_find_cands(const struct btf *local_btf,
__u32 local_type_id,
const struct btf *targ_btf)
{
size_t local_essent_len, targ_essent_len;
const char *local_name, *targ_name;
const struct btf_type *t;
struct ids_vec *cand_ids;
__u32 *new_ids;
int i, err, n;
t = btf__type_by_id(local_btf, local_type_id);
if (!t)
return ERR_PTR(-EINVAL);
local_name = btf__name_by_offset(local_btf, t->name_off);
if (str_is_empty(local_name))
return ERR_PTR(-EINVAL);
local_essent_len = bpf_core_essential_name_len(local_name);
cand_ids = calloc(1, sizeof(*cand_ids));
if (!cand_ids)
return ERR_PTR(-ENOMEM);
n = btf__get_nr_types(targ_btf);
for (i = 1; i <= n; i++) {
t = btf__type_by_id(targ_btf, i);
targ_name = btf__name_by_offset(targ_btf, t->name_off);
if (str_is_empty(targ_name))
continue;
targ_essent_len = bpf_core_essential_name_len(targ_name);
if (targ_essent_len != local_essent_len)
continue;
if (strncmp(local_name, targ_name, local_essent_len) == 0) {
pr_debug("[%d] %s: found candidate [%d] %s\n",
local_type_id, local_name, i, targ_name);
new_ids = realloc(cand_ids->data, cand_ids->len + 1);
if (!new_ids) {
err = -ENOMEM;
goto err_out;
}
cand_ids->data = new_ids;
cand_ids->data[cand_ids->len++] = i;
}
}
return cand_ids;
err_out:
bpf_core_free_cands(cand_ids);
return ERR_PTR(err);
}
/* Check two types for compatibility, skipping const/volatile/restrict and
* typedefs, to ensure we are relocating compatible entities:
* - any two STRUCTs/UNIONs are compatible and can be mixed;
* - any two FWDs are compatible, if their names match (modulo flavor suffix);
* - any two PTRs are always compatible;
* - for ENUMs, names should be the same (ignoring flavor suffix) or at
* least one of enums should be anonymous;
* - for ENUMs, check sizes, names are ignored;
* - for INT, size and signedness are ignored;
* - for ARRAY, dimensionality is ignored, element types are checked for
* compatibility recursively;
* - everything else shouldn't be ever a target of relocation.
* These rules are not set in stone and probably will be adjusted as we get
* more experience with using BPF CO-RE relocations.
*/
static int bpf_core_fields_are_compat(const struct btf *local_btf,
__u32 local_id,
const struct btf *targ_btf,
__u32 targ_id)
{
const struct btf_type *local_type, *targ_type;
recur:
local_type = skip_mods_and_typedefs(local_btf, local_id, &local_id);
targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id);
if (!local_type || !targ_type)
return -EINVAL;
if (btf_is_composite(local_type) && btf_is_composite(targ_type))
return 1;
if (btf_kind(local_type) != btf_kind(targ_type))
return 0;
switch (btf_kind(local_type)) {
case BTF_KIND_PTR:
return 1;
case BTF_KIND_FWD:
case BTF_KIND_ENUM: {
const char *local_name, *targ_name;
size_t local_len, targ_len;
local_name = btf__name_by_offset(local_btf,
local_type->name_off);
targ_name = btf__name_by_offset(targ_btf, targ_type->name_off);
local_len = bpf_core_essential_name_len(local_name);
targ_len = bpf_core_essential_name_len(targ_name);
/* one of them is anonymous or both w/ same flavor-less names */
return local_len == 0 || targ_len == 0 ||
(local_len == targ_len &&
strncmp(local_name, targ_name, local_len) == 0);
}
case BTF_KIND_INT:
/* just reject deprecated bitfield-like integers; all other
* integers are by default compatible between each other
*/
return btf_int_offset(local_type) == 0 &&
btf_int_offset(targ_type) == 0;
case BTF_KIND_ARRAY:
local_id = btf_array(local_type)->type;
targ_id = btf_array(targ_type)->type;
goto recur;
default:
pr_warn("unexpected kind %d relocated, local [%d], target [%d]\n",
btf_kind(local_type), local_id, targ_id);
return 0;
}
}
/*
* Given single high-level named field accessor in local type, find
* corresponding high-level accessor for a target type. Along the way,
* maintain low-level spec for target as well. Also keep updating target
* bit offset.
*
* Searching is performed through recursive exhaustive enumeration of all
* fields of a struct/union. If there are any anonymous (embedded)
* structs/unions, they are recursively searched as well. If field with
* desired name is found, check compatibility between local and target types,
* before returning result.
*
* 1 is returned, if field is found.
* 0 is returned if no compatible field is found.
* <0 is returned on error.
*/
static int bpf_core_match_member(const struct btf *local_btf,
const struct bpf_core_accessor *local_acc,
const struct btf *targ_btf,
__u32 targ_id,
struct bpf_core_spec *spec,
__u32 *next_targ_id)
{
const struct btf_type *local_type, *targ_type;
const struct btf_member *local_member, *m;
const char *local_name, *targ_name;
__u32 local_id;
int i, n, found;
targ_type = skip_mods_and_typedefs(targ_btf, targ_id, &targ_id);
if (!targ_type)
return -EINVAL;
if (!btf_is_composite(targ_type))
return 0;
local_id = local_acc->type_id;
local_type = btf__type_by_id(local_btf, local_id);
local_member = btf_members(local_type) + local_acc->idx;
local_name = btf__name_by_offset(local_btf, local_member->name_off);
n = btf_vlen(targ_type);
m = btf_members(targ_type);
for (i = 0; i < n; i++, m++) {
__u32 bit_offset;
bit_offset = btf_member_bit_offset(targ_type, i);
/* too deep struct/union/array nesting */
if (spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
return -E2BIG;
/* speculate this member will be the good one */
spec->bit_offset += bit_offset;
spec->raw_spec[spec->raw_len++] = i;
targ_name = btf__name_by_offset(targ_btf, m->name_off);
if (str_is_empty(targ_name)) {
/* embedded struct/union, we need to go deeper */
found = bpf_core_match_member(local_btf, local_acc,
targ_btf, m->type,
spec, next_targ_id);
if (found) /* either found or error */
return found;
} else if (strcmp(local_name, targ_name) == 0) {
/* matching named field */
struct bpf_core_accessor *targ_acc;
targ_acc = &spec->spec[spec->len++];
targ_acc->type_id = targ_id;
targ_acc->idx = i;
targ_acc->name = targ_name;
*next_targ_id = m->type;
found = bpf_core_fields_are_compat(local_btf,
local_member->type,
targ_btf, m->type);
if (!found)
spec->len--; /* pop accessor */
return found;
}
/* member turned out not to be what we looked for */
spec->bit_offset -= bit_offset;
spec->raw_len--;
}
return 0;
}
/*
* Try to match local spec to a target type and, if successful, produce full
* target spec (high-level, low-level + bit offset).
*/
static int bpf_core_spec_match(struct bpf_core_spec *local_spec,
const struct btf *targ_btf, __u32 targ_id,
struct bpf_core_spec *targ_spec)
{
const struct btf_type *targ_type;
const struct bpf_core_accessor *local_acc;
struct bpf_core_accessor *targ_acc;
int i, sz, matched;
memset(targ_spec, 0, sizeof(*targ_spec));
targ_spec->btf = targ_btf;
local_acc = &local_spec->spec[0];
targ_acc = &targ_spec->spec[0];
for (i = 0; i < local_spec->len; i++, local_acc++, targ_acc++) {
targ_type = skip_mods_and_typedefs(targ_spec->btf, targ_id,
&targ_id);
if (!targ_type)
return -EINVAL;
if (local_acc->name) {
matched = bpf_core_match_member(local_spec->btf,
local_acc,
targ_btf, targ_id,
targ_spec, &targ_id);
if (matched <= 0)
return matched;
} else {
/* for i=0, targ_id is already treated as array element
* type (because it's the original struct), for others
* we should find array element type first
*/
if (i > 0) {
const struct btf_array *a;
if (!btf_is_array(targ_type))
return 0;
a = btf_array(targ_type);
if (local_acc->idx >= a->nelems)
return 0;
if (!skip_mods_and_typedefs(targ_btf, a->type,
&targ_id))
return -EINVAL;
}
/* too deep struct/union/array nesting */
if (targ_spec->raw_len == BPF_CORE_SPEC_MAX_LEN)
return -E2BIG;
targ_acc->type_id = targ_id;
targ_acc->idx = local_acc->idx;
targ_acc->name = NULL;
targ_spec->len++;
targ_spec->raw_spec[targ_spec->raw_len] = targ_acc->idx;
targ_spec->raw_len++;
sz = btf__resolve_size(targ_btf, targ_id);
if (sz < 0)
return sz;
targ_spec->bit_offset += local_acc->idx * sz * 8;
}
}
return 1;
}
static int bpf_core_calc_field_relo(const struct bpf_program *prog,
const struct bpf_field_reloc *relo,
const struct bpf_core_spec *spec,
__u32 *val, bool *validate)
{
const struct bpf_core_accessor *acc = &spec->spec[spec->len - 1];
const struct btf_type *t = btf__type_by_id(spec->btf, acc->type_id);
__u32 byte_off, byte_sz, bit_off, bit_sz;
const struct btf_member *m;
const struct btf_type *mt;
bool bitfield;
__s64 sz;
/* a[n] accessor needs special handling */
if (!acc->name) {
if (relo->kind == BPF_FIELD_BYTE_OFFSET) {
*val = spec->bit_offset / 8;
} else if (relo->kind == BPF_FIELD_BYTE_SIZE) {
sz = btf__resolve_size(spec->btf, acc->type_id);
if (sz < 0)
return -EINVAL;
*val = sz;
} else {
pr_warn("prog '%s': relo %d at insn #%d can't be applied to array access\n",
bpf_program__title(prog, false),
relo->kind, relo->insn_off / 8);
return -EINVAL;
}
if (validate)
*validate = true;
return 0;
}
m = btf_members(t) + acc->idx;
mt = skip_mods_and_typedefs(spec->btf, m->type, NULL);
bit_off = spec->bit_offset;
bit_sz = btf_member_bitfield_size(t, acc->idx);
bitfield = bit_sz > 0;
if (bitfield) {
byte_sz = mt->size;
byte_off = bit_off / 8 / byte_sz * byte_sz;
/* figure out smallest int size necessary for bitfield load */
while (bit_off + bit_sz - byte_off * 8 > byte_sz * 8) {
if (byte_sz >= 8) {
/* bitfield can't be read with 64-bit read */
pr_warn("prog '%s': relo %d at insn #%d can't be satisfied for bitfield\n",
bpf_program__title(prog, false),
relo->kind, relo->insn_off / 8);
return -E2BIG;
}
byte_sz *= 2;
byte_off = bit_off / 8 / byte_sz * byte_sz;
}
} else {
sz = btf__resolve_size(spec->btf, m->type);
if (sz < 0)
return -EINVAL;
byte_sz = sz;
byte_off = spec->bit_offset / 8;
bit_sz = byte_sz * 8;
}
/* for bitfields, all the relocatable aspects are ambiguous and we
* might disagree with compiler, so turn off validation of expected
* value, except for signedness
*/
if (validate)
*validate = !bitfield;
switch (relo->kind) {
case BPF_FIELD_BYTE_OFFSET:
*val = byte_off;
break;
case BPF_FIELD_BYTE_SIZE:
*val = byte_sz;
break;
case BPF_FIELD_SIGNED:
/* enums will be assumed unsigned */
*val = btf_is_enum(mt) ||
(btf_int_encoding(mt) & BTF_INT_SIGNED);
if (validate)
*validate = true; /* signedness is never ambiguous */
break;
case BPF_FIELD_LSHIFT_U64:
#if __BYTE_ORDER == __LITTLE_ENDIAN
*val = 64 - (bit_off + bit_sz - byte_off * 8);
#else
*val = (8 - byte_sz) * 8 + (bit_off - byte_off * 8);
#endif
break;
case BPF_FIELD_RSHIFT_U64:
*val = 64 - bit_sz;
if (validate)
*validate = true; /* right shift is never ambiguous */
break;
case BPF_FIELD_EXISTS:
default:
pr_warn("prog '%s': unknown relo %d at insn #%d\n",
bpf_program__title(prog, false),
relo->kind, relo->insn_off / 8);
return -EINVAL;
}
return 0;
}
/*
* Patch relocatable BPF instruction.
*
* Patched value is determined by relocation kind and target specification.
* For field existence relocation target spec will be NULL if field is not
* found.
* Expected insn->imm value is determined using relocation kind and local
* spec, and is checked before patching instruction. If actual insn->imm value
* is wrong, bail out with error.
*
* Currently three kinds of BPF instructions are supported:
* 1. rX = <imm> (assignment with immediate operand);
* 2. rX += <imm> (arithmetic operations with immediate operand);
*/
static int bpf_core_reloc_insn(struct bpf_program *prog,
const struct bpf_field_reloc *relo,
const struct bpf_core_spec *local_spec,
const struct bpf_core_spec *targ_spec)
{
bool failed = false, validate = true;
__u32 orig_val, new_val;
struct bpf_insn *insn;
int insn_idx, err;
__u8 class;
if (relo->insn_off % sizeof(struct bpf_insn))
return -EINVAL;
insn_idx = relo->insn_off / sizeof(struct bpf_insn);
if (relo->kind == BPF_FIELD_EXISTS) {
orig_val = 1; /* can't generate EXISTS relo w/o local field */
new_val = targ_spec ? 1 : 0;
} else if (!targ_spec) {
failed = true;
new_val = (__u32)-1;
} else {
err = bpf_core_calc_field_relo(prog, relo, local_spec,
&orig_val, &validate);
if (err)
return err;
err = bpf_core_calc_field_relo(prog, relo, targ_spec,
&new_val, NULL);
if (err)
return err;
}
insn = &prog->insns[insn_idx];
class = BPF_CLASS(insn->code);
if (class == BPF_ALU || class == BPF_ALU64) {
if (BPF_SRC(insn->code) != BPF_K)
return -EINVAL;
if (!failed && validate && insn->imm != orig_val) {
pr_warn("prog '%s': unexpected insn #%d value: got %u, exp %u -> %u\n",
bpf_program__title(prog, false), insn_idx,
insn->imm, orig_val, new_val);
return -EINVAL;
}
orig_val = insn->imm;
insn->imm = new_val;
pr_debug("prog '%s': patched insn #%d (ALU/ALU64)%s imm %u -> %u\n",
bpf_program__title(prog, false), insn_idx,
failed ? " w/ failed reloc" : "", orig_val, new_val);
} else {
pr_warn("prog '%s': trying to relocate unrecognized insn #%d, code:%x, src:%x, dst:%x, off:%x, imm:%x\n",
bpf_program__title(prog, false),
insn_idx, insn->code, insn->src_reg, insn->dst_reg,
insn->off, insn->imm);
return -EINVAL;
}
return 0;
}
static struct btf *btf_load_raw(const char *path)
{
struct btf *btf;
size_t read_cnt;
struct stat st;
void *data;
FILE *f;
if (stat(path, &st))
return ERR_PTR(-errno);
data = malloc(st.st_size);
if (!data)
return ERR_PTR(-ENOMEM);
f = fopen(path, "rb");
if (!f) {
btf = ERR_PTR(-errno);
goto cleanup;
}
read_cnt = fread(data, 1, st.st_size, f);
fclose(f);
if (read_cnt < st.st_size) {
btf = ERR_PTR(-EBADF);
goto cleanup;
}
btf = btf__new(data, read_cnt);
cleanup:
free(data);
return btf;
}
/*
* Probe few well-known locations for vmlinux kernel image and try to load BTF
* data out of it to use for target BTF.
*/
static struct btf *bpf_core_find_kernel_btf(void)
{
struct {
const char *path_fmt;
bool raw_btf;
} locations[] = {
/* try canonical vmlinux BTF through sysfs first */
{ "/sys/kernel/btf/vmlinux", true /* raw BTF */ },
/* fall back to trying to find vmlinux ELF on disk otherwise */
{ "/boot/vmlinux-%1$s" },
{ "/lib/modules/%1$s/vmlinux-%1$s" },
{ "/lib/modules/%1$s/build/vmlinux" },
{ "/usr/lib/modules/%1$s/kernel/vmlinux" },
{ "/usr/lib/debug/boot/vmlinux-%1$s" },
{ "/usr/lib/debug/boot/vmlinux-%1$s.debug" },
{ "/usr/lib/debug/lib/modules/%1$s/vmlinux" },
};
char path[PATH_MAX + 1];
struct utsname buf;
struct btf *btf;
int i;
uname(&buf);
for (i = 0; i < ARRAY_SIZE(locations); i++) {
snprintf(path, PATH_MAX, locations[i].path_fmt, buf.release);
if (access(path, R_OK))
continue;
if (locations[i].raw_btf)
btf = btf_load_raw(path);
else
btf = btf__parse_elf(path, NULL);
pr_debug("loading kernel BTF '%s': %ld\n",
path, IS_ERR(btf) ? PTR_ERR(btf) : 0);
if (IS_ERR(btf))
continue;
return btf;
}
pr_warn("failed to find valid kernel BTF\n");
return ERR_PTR(-ESRCH);
}
/* Output spec definition in the format:
* [<type-id>] (<type-name>) + <raw-spec> => <offset>@<spec>,
* where <spec> is a C-syntax view of recorded field access, e.g.: x.a[3].b
*/
static void bpf_core_dump_spec(int level, const struct bpf_core_spec *spec)
{
const struct btf_type *t;
const char *s;
__u32 type_id;
int i;
type_id = spec->spec[0].type_id;
t = btf__type_by_id(spec->btf, type_id);
s = btf__name_by_offset(spec->btf, t->name_off);
libbpf_print(level, "[%u] %s + ", type_id, s);
for (i = 0; i < spec->raw_len; i++)
libbpf_print(level, "%d%s", spec->raw_spec[i],
i == spec->raw_len - 1 ? " => " : ":");
libbpf_print(level, "%u.%u @ &x",
spec->bit_offset / 8, spec->bit_offset % 8);
for (i = 0; i < spec->len; i++) {
if (spec->spec[i].name)
libbpf_print(level, ".%s", spec->spec[i].name);
else
libbpf_print(level, "[%u]", spec->spec[i].idx);
}
}
static size_t bpf_core_hash_fn(const void *key, void *ctx)
{
return (size_t)key;
}
static bool bpf_core_equal_fn(const void *k1, const void *k2, void *ctx)
{
return k1 == k2;
}
static void *u32_as_hash_key(__u32 x)
{
return (void *)(uintptr_t)x;
}
/*
* CO-RE relocate single instruction.
*
* The outline and important points of the algorithm:
* 1. For given local type, find corresponding candidate target types.
* Candidate type is a type with the same "essential" name, ignoring
* everything after last triple underscore (___). E.g., `sample`,
* `sample___flavor_one`, `sample___flavor_another_one`, are all candidates
* for each other. Names with triple underscore are referred to as
* "flavors" and are useful, among other things, to allow to
* specify/support incompatible variations of the same kernel struct, which
* might differ between different kernel versions and/or build
* configurations.
*
* N.B. Struct "flavors" could be generated by bpftool's BTF-to-C
* converter, when deduplicated BTF of a kernel still contains more than
* one different types with the same name. In that case, ___2, ___3, etc
* are appended starting from second name conflict. But start flavors are
* also useful to be defined "locally", in BPF program, to extract same
* data from incompatible changes between different kernel
* versions/configurations. For instance, to handle field renames between
* kernel versions, one can use two flavors of the struct name with the
* same common name and use conditional relocations to extract that field,
* depending on target kernel version.
* 2. For each candidate type, try to match local specification to this
* candidate target type. Matching involves finding corresponding
* high-level spec accessors, meaning that all named fields should match,
* as well as all array accesses should be within the actual bounds. Also,
* types should be compatible (see bpf_core_fields_are_compat for details).
* 3. It is supported and expected that there might be multiple flavors
* matching the spec. As long as all the specs resolve to the same set of
* offsets across all candidates, there is no error. If there is any
* ambiguity, CO-RE relocation will fail. This is necessary to accomodate
* imprefection of BTF deduplication, which can cause slight duplication of
* the same BTF type, if some directly or indirectly referenced (by
* pointer) type gets resolved to different actual types in different
* object files. If such situation occurs, deduplicated BTF will end up
* with two (or more) structurally identical types, which differ only in
* types they refer to through pointer. This should be OK in most cases and
* is not an error.
* 4. Candidate types search is performed by linearly scanning through all
* types in target BTF. It is anticipated that this is overall more
* efficient memory-wise and not significantly worse (if not better)
* CPU-wise compared to prebuilding a map from all local type names to
* a list of candidate type names. It's also sped up by caching resolved
* list of matching candidates per each local "root" type ID, that has at
* least one bpf_field_reloc associated with it. This list is shared
* between multiple relocations for the same type ID and is updated as some
* of the candidates are pruned due to structural incompatibility.
*/
static int bpf_core_reloc_field(struct bpf_program *prog,
const struct bpf_field_reloc *relo,
int relo_idx,
const struct btf *local_btf,
const struct btf *targ_btf,
struct hashmap *cand_cache)
{
const char *prog_name = bpf_program__title(prog, false);
struct bpf_core_spec local_spec, cand_spec, targ_spec;
const void *type_key = u32_as_hash_key(relo->type_id);
const struct btf_type *local_type, *cand_type;
const char *local_name, *cand_name;
struct ids_vec *cand_ids;
__u32 local_id, cand_id;
const char *spec_str;
int i, j, err;
local_id = relo->type_id;
local_type = btf__type_by_id(local_btf, local_id);
if (!local_type)
return -EINVAL;
local_name = btf__name_by_offset(local_btf, local_type->name_off);
if (str_is_empty(local_name))
return -EINVAL;
spec_str = btf__name_by_offset(local_btf, relo->access_str_off);
if (str_is_empty(spec_str))
return -EINVAL;
err = bpf_core_spec_parse(local_btf, local_id, spec_str, &local_spec);
if (err) {
pr_warn("prog '%s': relo #%d: parsing [%d] %s + %s failed: %d\n",
prog_name, relo_idx, local_id, local_name, spec_str,
err);
return -EINVAL;
}
pr_debug("prog '%s': relo #%d: kind %d, spec is ", prog_name, relo_idx,
relo->kind);
bpf_core_dump_spec(LIBBPF_DEBUG, &local_spec);
libbpf_print(LIBBPF_DEBUG, "\n");
if (!hashmap__find(cand_cache, type_key, (void **)&cand_ids)) {
cand_ids = bpf_core_find_cands(local_btf, local_id, targ_btf);
if (IS_ERR(cand_ids)) {
pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s: %ld",
prog_name, relo_idx, local_id, local_name,
PTR_ERR(cand_ids));
return PTR_ERR(cand_ids);
}
err = hashmap__set(cand_cache, type_key, cand_ids, NULL, NULL);
if (err) {
bpf_core_free_cands(cand_ids);
return err;
}
}
for (i = 0, j = 0; i < cand_ids->len; i++) {
cand_id = cand_ids->data[i];
cand_type = btf__type_by_id(targ_btf, cand_id);
cand_name = btf__name_by_offset(targ_btf, cand_type->name_off);
err = bpf_core_spec_match(&local_spec, targ_btf,
cand_id, &cand_spec);
pr_debug("prog '%s': relo #%d: matching candidate #%d %s against spec ",
prog_name, relo_idx, i, cand_name);
bpf_core_dump_spec(LIBBPF_DEBUG, &cand_spec);
libbpf_print(LIBBPF_DEBUG, ": %d\n", err);
if (err < 0) {
pr_warn("prog '%s': relo #%d: matching error: %d\n",
prog_name, relo_idx, err);
return err;
}
if (err == 0)
continue;
if (j == 0) {
targ_spec = cand_spec;
} else if (cand_spec.bit_offset != targ_spec.bit_offset) {
/* if there are many candidates, they should all
* resolve to the same bit offset
*/
pr_warn("prog '%s': relo #%d: offset ambiguity: %u != %u\n",
prog_name, relo_idx, cand_spec.bit_offset,
targ_spec.bit_offset);
return -EINVAL;
}
cand_ids->data[j++] = cand_spec.spec[0].type_id;
}
/*
* For BPF_FIELD_EXISTS relo or when relaxed CO-RE reloc mode is
* requested, it's expected that we might not find any candidates.
* In this case, if field wasn't found in any candidate, the list of
* candidates shouldn't change at all, we'll just handle relocating
* appropriately, depending on relo's kind.
*/
if (j > 0)
cand_ids->len = j;
if (j == 0 && !prog->obj->relaxed_core_relocs &&
relo->kind != BPF_FIELD_EXISTS) {
pr_warn("prog '%s': relo #%d: no matching targets found for [%d] %s + %s\n",
prog_name, relo_idx, local_id, local_name, spec_str);
return -ESRCH;
}
/* bpf_core_reloc_insn should know how to handle missing targ_spec */
err = bpf_core_reloc_insn(prog, relo, &local_spec,
j ? &targ_spec : NULL);
if (err) {
pr_warn("prog '%s': relo #%d: failed to patch insn at offset %d: %d\n",
prog_name, relo_idx, relo->insn_off, err);
return -EINVAL;
}
return 0;
}
static int
bpf_core_reloc_fields(struct bpf_object *obj, const char *targ_btf_path)
{
const struct btf_ext_info_sec *sec;
const struct bpf_field_reloc *rec;
const struct btf_ext_info *seg;
struct hashmap_entry *entry;
struct hashmap *cand_cache = NULL;
struct bpf_program *prog;
struct btf *targ_btf;
const char *sec_name;
int i, err = 0;
if (targ_btf_path)
targ_btf = btf__parse_elf(targ_btf_path, NULL);
else
targ_btf = bpf_core_find_kernel_btf();
if (IS_ERR(targ_btf)) {
pr_warn("failed to get target BTF: %ld\n", PTR_ERR(targ_btf));
return PTR_ERR(targ_btf);
}
cand_cache = hashmap__new(bpf_core_hash_fn, bpf_core_equal_fn, NULL);
if (IS_ERR(cand_cache)) {
err = PTR_ERR(cand_cache);
goto out;
}
seg = &obj->btf_ext->field_reloc_info;
for_each_btf_ext_sec(seg, sec) {
sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off);
if (str_is_empty(sec_name)) {
err = -EINVAL;
goto out;
}
prog = bpf_object__find_program_by_title(obj, sec_name);
if (!prog) {
pr_warn("failed to find program '%s' for CO-RE offset relocation\n",
sec_name);
err = -EINVAL;
goto out;
}
pr_debug("prog '%s': performing %d CO-RE offset relocs\n",
sec_name, sec->num_info);
for_each_btf_ext_rec(seg, sec, i, rec) {
err = bpf_core_reloc_field(prog, rec, i, obj->btf,
targ_btf, cand_cache);
if (err) {
pr_warn("prog '%s': relo #%d: failed to relocate: %d\n",
sec_name, i, err);
goto out;
}
}
}
out:
btf__free(targ_btf);
if (!IS_ERR_OR_NULL(cand_cache)) {
hashmap__for_each_entry(cand_cache, entry, i) {
bpf_core_free_cands(entry->value);
}
hashmap__free(cand_cache);
}
return err;
}
static int
bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
{
int err = 0;
if (obj->btf_ext->field_reloc_info.len)
err = bpf_core_reloc_fields(obj, targ_btf_path);
return err;
}
static int
bpf_program__reloc_text(struct bpf_program *prog, struct bpf_object *obj,
struct reloc_desc *relo)
{
struct bpf_insn *insn, *new_insn;
struct bpf_program *text;
size_t new_cnt;
int err;
if (relo->type != RELO_CALL)
return -LIBBPF_ERRNO__RELOC;
if (prog->idx == obj->efile.text_shndx) {
pr_warn("relo in .text insn %d into off %d (insn #%d)\n",
relo->insn_idx, relo->sym_off, relo->sym_off / 8);
return -LIBBPF_ERRNO__RELOC;
}
if (prog->main_prog_cnt == 0) {
text = bpf_object__find_prog_by_idx(obj, obj->efile.text_shndx);
if (!text) {
pr_warn("no .text section found yet relo into text exist\n");
return -LIBBPF_ERRNO__RELOC;
}
new_cnt = prog->insns_cnt + text->insns_cnt;
new_insn = reallocarray(prog->insns, new_cnt, sizeof(*insn));
if (!new_insn) {
pr_warn("oom in prog realloc\n");
return -ENOMEM;
}
prog->insns = new_insn;
if (obj->btf_ext) {
err = bpf_program_reloc_btf_ext(prog, obj,
text->section_name,
prog->insns_cnt);
if (err)
return err;
}
memcpy(new_insn + prog->insns_cnt, text->insns,
text->insns_cnt * sizeof(*insn));
prog->main_prog_cnt = prog->insns_cnt;
prog->insns_cnt = new_cnt;
pr_debug("added %zd insn from %s to prog %s\n",
text->insns_cnt, text->section_name,
prog->section_name);
}
insn = &prog->insns[relo->insn_idx];
insn->imm += relo->sym_off / 8 + prog->main_prog_cnt - relo->insn_idx;
return 0;
}
static int
bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj)
{
int i, err;
if (!prog)
return 0;
if (obj->btf_ext) {
err = bpf_program_reloc_btf_ext(prog, obj,
prog->section_name, 0);
if (err)
return err;
}
if (!prog->reloc_desc)
return 0;
for (i = 0; i < prog->nr_reloc; i++) {
struct reloc_desc *relo = &prog->reloc_desc[i];
if (relo->type == RELO_LD64 || relo->type == RELO_DATA) {
struct bpf_insn *insn = &prog->insns[relo->insn_idx];
if (relo->insn_idx + 1 >= (int)prog->insns_cnt) {
pr_warn("relocation out of range: '%s'\n",
prog->section_name);
return -LIBBPF_ERRNO__RELOC;
}
if (relo->type != RELO_DATA) {
insn[0].src_reg = BPF_PSEUDO_MAP_FD;
} else {
insn[0].src_reg = BPF_PSEUDO_MAP_VALUE;
insn[1].imm = insn[0].imm + relo->sym_off;
}
insn[0].imm = obj->maps[relo->map_idx].fd;
} else if (relo->type == RELO_CALL) {
err = bpf_program__reloc_text(prog, obj, relo);
if (err)
return err;
}
}
zfree(&prog->reloc_desc);
prog->nr_reloc = 0;
return 0;
}
static int
bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path)
{
struct bpf_program *prog;
size_t i;
int err;
if (obj->btf_ext) {
err = bpf_object__relocate_core(obj, targ_btf_path);
if (err) {
pr_warn("failed to perform CO-RE relocations: %d\n",
err);
return err;
}
}
for (i = 0; i < obj->nr_programs; i++) {
prog = &obj->programs[i];
err = bpf_program__relocate(prog, obj);
if (err) {
pr_warn("failed to relocate '%s'\n", prog->section_name);
return err;
}
}
return 0;
}
static int bpf_object__collect_reloc(struct bpf_object *obj)
{
int i, err;
if (!obj_elf_valid(obj)) {
pr_warn("Internal error: elf object is closed\n");
return -LIBBPF_ERRNO__INTERNAL;
}
for (i = 0; i < obj->efile.nr_reloc_sects; i++) {
GElf_Shdr *shdr = &obj->efile.reloc_sects[i].shdr;
Elf_Data *data = obj->efile.reloc_sects[i].data;
int idx = shdr->sh_info;
struct bpf_program *prog;
if (shdr->sh_type != SHT_REL) {
pr_warn("internal error at %d\n", __LINE__);
return -LIBBPF_ERRNO__INTERNAL;
}
prog = bpf_object__find_prog_by_idx(obj, idx);
if (!prog) {
pr_warn("relocation failed: no section(%d)\n", idx);
return -LIBBPF_ERRNO__RELOC;
}
err = bpf_program__collect_reloc(prog, shdr, data, obj);
if (err)
return err;
}
return 0;
}
static int
load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
char *license, __u32 kern_version, int *pfd)
{
struct bpf_load_program_attr load_attr;
char *cp, errmsg[STRERR_BUFSIZE];
int log_buf_size = BPF_LOG_BUF_SIZE;
char *log_buf;
int btf_fd, ret;
if (!insns || !insns_cnt)
return -EINVAL;
memset(&load_attr, 0, sizeof(struct bpf_load_program_attr));
load_attr.prog_type = prog->type;
load_attr.expected_attach_type = prog->expected_attach_type;
if (prog->caps->name)
load_attr.name = prog->name;
load_attr.insns = insns;
load_attr.insns_cnt = insns_cnt;
load_attr.license = license;
if (prog->type == BPF_PROG_TYPE_TRACING) {
load_attr.attach_prog_fd = prog->attach_prog_fd;
load_attr.attach_btf_id = prog->attach_btf_id;
} else {
load_attr.kern_version = kern_version;
load_attr.prog_ifindex = prog->prog_ifindex;
}
/* if .BTF.ext was loaded, kernel supports associated BTF for prog */
if (prog->obj->btf_ext)
btf_fd = bpf_object__btf_fd(prog->obj);
else
btf_fd = -1;
load_attr.prog_btf_fd = btf_fd >= 0 ? btf_fd : 0;
load_attr.func_info = prog->func_info;
load_attr.func_info_rec_size = prog->func_info_rec_size;
load_attr.func_info_cnt = prog->func_info_cnt;
load_attr.line_info = prog->line_info;
load_attr.line_info_rec_size = prog->line_info_rec_size;
load_attr.line_info_cnt = prog->line_info_cnt;
load_attr.log_level = prog->log_level;
load_attr.prog_flags = prog->prog_flags;
retry_load:
log_buf = malloc(log_buf_size);
if (!log_buf)
pr_warn("Alloc log buffer for bpf loader error, continue without log\n");
ret = bpf_load_program_xattr(&load_attr, log_buf, log_buf_size);
if (ret >= 0) {
if (load_attr.log_level)
pr_debug("verifier log:\n%s", log_buf);
*pfd = ret;
ret = 0;
goto out;
}
if (errno == ENOSPC) {
log_buf_size <<= 1;
free(log_buf);
goto retry_load;
}
ret = -errno;
cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
pr_warn("load bpf program failed: %s\n", cp);
if (log_buf && log_buf[0] != '\0') {
ret = -LIBBPF_ERRNO__VERIFY;
pr_warn("-- BEGIN DUMP LOG ---\n");
pr_warn("\n%s\n", log_buf);
pr_warn("-- END LOG --\n");
} else if (load_attr.insns_cnt >= BPF_MAXINSNS) {
pr_warn("Program too large (%zu insns), at most %d insns\n",
load_attr.insns_cnt, BPF_MAXINSNS);
ret = -LIBBPF_ERRNO__PROG2BIG;
} else if (load_attr.prog_type != BPF_PROG_TYPE_KPROBE) {
/* Wrong program type? */
int fd;
load_attr.prog_type = BPF_PROG_TYPE_KPROBE;
load_attr.expected_attach_type = 0;
fd = bpf_load_program_xattr(&load_attr, NULL, 0);
if (fd >= 0) {
close(fd);
ret = -LIBBPF_ERRNO__PROGTYPE;
goto out;
}
}
out:
free(log_buf);
return ret;
}
int
bpf_program__load(struct bpf_program *prog,
char *license, __u32 kern_version)
{
int err = 0, fd, i;
if (prog->instances.nr < 0 || !prog->instances.fds) {
if (prog->preprocessor) {
pr_warn("Internal error: can't load program '%s'\n",
prog->section_name);
return -LIBBPF_ERRNO__INTERNAL;
}
prog->instances.fds = malloc(sizeof(int));
if (!prog->instances.fds) {
pr_warn("Not enough memory for BPF fds\n");
return -ENOMEM;
}
prog->instances.nr = 1;
prog->instances.fds[0] = -1;
}
if (!prog->preprocessor) {
if (prog->instances.nr != 1) {
pr_warn("Program '%s' is inconsistent: nr(%d) != 1\n",
prog->section_name, prog->instances.nr);
}
err = load_program(prog, prog->insns, prog->insns_cnt,
license, kern_version, &fd);
if (!err)
prog->instances.fds[0] = fd;
goto out;
}
for (i = 0; i < prog->instances.nr; i++) {
struct bpf_prog_prep_result result;
bpf_program_prep_t preprocessor = prog->preprocessor;
memset(&result, 0, sizeof(result));
err = preprocessor(prog, i, prog->insns,
prog->insns_cnt, &result);
if (err) {
pr_warn("Preprocessing the %dth instance of program '%s' failed\n",
i, prog->section_name);
goto out;
}
if (!result.new_insn_ptr || !result.new_insn_cnt) {
pr_debug("Skip loading the %dth instance of program '%s'\n",
i, prog->section_name);
prog->instances.fds[i] = -1;
if (result.pfd)
*result.pfd = -1;
continue;
}
err = load_program(prog, result.new_insn_ptr,
result.new_insn_cnt,
license, kern_version, &fd);
if (err) {
pr_warn("Loading the %dth instance of program '%s' failed\n",
i, prog->section_name);
goto out;
}
if (result.pfd)
*result.pfd = fd;
prog->instances.fds[i] = fd;
}
out:
if (err)
pr_warn("failed to load program '%s'\n", prog->section_name);
zfree(&prog->insns);
prog->insns_cnt = 0;
return err;
}
static bool bpf_program__is_function_storage(const struct bpf_program *prog,
const struct bpf_object *obj)
{
return prog->idx == obj->efile.text_shndx && obj->has_pseudo_calls;
}
static int
bpf_object__load_progs(struct bpf_object *obj, int log_level)
{
size_t i;
int err;
for (i = 0; i < obj->nr_programs; i++) {
if (bpf_program__is_function_storage(&obj->programs[i], obj))
continue;
obj->programs[i].log_level |= log_level;
err = bpf_program__load(&obj->programs[i],
obj->license,
obj->kern_version);
if (err)
return err;
}
return 0;
}
static int libbpf_find_attach_btf_id(const char *name,
enum bpf_attach_type attach_type,
__u32 attach_prog_fd);
static struct bpf_object *
__bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
struct bpf_object_open_opts *opts)
{
const char *pin_root_path;
struct bpf_program *prog;
struct bpf_object *obj;
const char *obj_name;
char tmp_name[64];
bool relaxed_maps;
__u32 attach_prog_fd;
int err;
if (elf_version(EV_CURRENT) == EV_NONE) {
pr_warn("failed to init libelf for %s\n",
path ? : "(mem buf)");
return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
}
if (!OPTS_VALID(opts, bpf_object_open_opts))
return ERR_PTR(-EINVAL);
obj_name = OPTS_GET(opts, object_name, NULL);
if (obj_buf) {
if (!obj_name) {
snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx",
(unsigned long)obj_buf,
(unsigned long)obj_buf_sz);
obj_name = tmp_name;
}
path = obj_name;
pr_debug("loading object '%s' from buffer\n", obj_name);
}
obj = bpf_object__new(path, obj_buf, obj_buf_sz, obj_name);
if (IS_ERR(obj))
return obj;
obj->relaxed_core_relocs = OPTS_GET(opts, relaxed_core_relocs, false);
relaxed_maps = OPTS_GET(opts, relaxed_maps, false);
pin_root_path = OPTS_GET(opts, pin_root_path, NULL);
attach_prog_fd = OPTS_GET(opts, attach_prog_fd, 0);
CHECK_ERR(bpf_object__elf_init(obj), err, out);
CHECK_ERR(bpf_object__check_endianness(obj), err, out);
CHECK_ERR(bpf_object__probe_caps(obj), err, out);
CHECK_ERR(bpf_object__elf_collect(obj, relaxed_maps, pin_root_path),
err, out);
CHECK_ERR(bpf_object__collect_reloc(obj), err, out);
bpf_object__elf_finish(obj);
bpf_object__for_each_program(prog, obj) {
enum bpf_prog_type prog_type;
enum bpf_attach_type attach_type;
err = libbpf_prog_type_by_name(prog->section_name, &prog_type,
&attach_type);
if (err == -ESRCH)
/* couldn't guess, but user might manually specify */
continue;
if (err)
goto out;
bpf_program__set_type(prog, prog_type);
bpf_program__set_expected_attach_type(prog, attach_type);
if (prog_type == BPF_PROG_TYPE_TRACING) {
err = libbpf_find_attach_btf_id(prog->section_name,
attach_type,
attach_prog_fd);
if (err <= 0)
goto out;
prog->attach_btf_id = err;
prog->attach_prog_fd = attach_prog_fd;
}
}
return obj;
out:
bpf_object__close(obj);
return ERR_PTR(err);
}
static struct bpf_object *
__bpf_object__open_xattr(struct bpf_object_open_attr *attr, int flags)
{
DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts,
.relaxed_maps = flags & MAPS_RELAX_COMPAT,
);
/* param validation */
if (!attr->file)
return NULL;
pr_debug("loading %s\n", attr->file);
return __bpf_object__open(attr->file, NULL, 0, &opts);
}
struct bpf_object *bpf_object__open_xattr(struct bpf_object_open_attr *attr)
{
return __bpf_object__open_xattr(attr, 0);
}
struct bpf_object *bpf_object__open(const char *path)
{
struct bpf_object_open_attr attr = {
.file = path,
.prog_type = BPF_PROG_TYPE_UNSPEC,
};
return bpf_object__open_xattr(&attr);
}
struct bpf_object *
bpf_object__open_file(const char *path, struct bpf_object_open_opts *opts)
{
if (!path)
return ERR_PTR(-EINVAL);
pr_debug("loading %s\n", path);
return __bpf_object__open(path, NULL, 0, opts);
}
struct bpf_object *
bpf_object__open_mem(const void *obj_buf, size_t obj_buf_sz,
struct bpf_object_open_opts *opts)
{
if (!obj_buf || obj_buf_sz == 0)
return ERR_PTR(-EINVAL);
return __bpf_object__open(NULL, obj_buf, obj_buf_sz, opts);
}
struct bpf_object *
bpf_object__open_buffer(const void *obj_buf, size_t obj_buf_sz,
const char *name)
{
DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts,
.object_name = name,
/* wrong default, but backwards-compatible */
.relaxed_maps = true,
);
/* returning NULL is wrong, but backwards-compatible */
if (!obj_buf || obj_buf_sz == 0)
return NULL;
return bpf_object__open_mem(obj_buf, obj_buf_sz, &opts);
}
int bpf_object__unload(struct bpf_object *obj)
{
size_t i;
if (!obj)
return -EINVAL;
for (i = 0; i < obj->nr_maps; i++)
zclose(obj->maps[i].fd);
for (i = 0; i < obj->nr_programs; i++)
bpf_program__unload(&obj->programs[i]);
return 0;
}
int bpf_object__load_xattr(struct bpf_object_load_attr *attr)
{
struct bpf_object *obj;
int err, i;
if (!attr)
return -EINVAL;
obj = attr->obj;
if (!obj)
return -EINVAL;
if (obj->loaded) {
pr_warn("object should not be loaded twice\n");
return -EINVAL;
}
obj->loaded = true;
CHECK_ERR(bpf_object__create_maps(obj), err, out);
CHECK_ERR(bpf_object__relocate(obj, attr->target_btf_path), err, out);
CHECK_ERR(bpf_object__load_progs(obj, attr->log_level), err, out);
return 0;
out:
/* unpin any maps that were auto-pinned during load */
for (i = 0; i < obj->nr_maps; i++)
if (obj->maps[i].pinned && !obj->maps[i].reused)
bpf_map__unpin(&obj->maps[i], NULL);
bpf_object__unload(obj);
pr_warn("failed to load object '%s'\n", obj->path);
return err;
}
int bpf_object__load(struct bpf_object *obj)
{
struct bpf_object_load_attr attr = {
.obj = obj,
};
return bpf_object__load_xattr(&attr);
}
static int make_parent_dir(const char *path)
{
char *cp, errmsg[STRERR_BUFSIZE];
char *dname, *dir;
int err = 0;
dname = strdup(path);
if (dname == NULL)
return -ENOMEM;
dir = dirname(dname);
if (mkdir(dir, 0700) && errno != EEXIST)
err = -errno;
free(dname);
if (err) {
cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg));
pr_warn("failed to mkdir %s: %s\n", path, cp);
}
return err;
}
static int check_path(const char *path)
{
char *cp, errmsg[STRERR_BUFSIZE];
struct statfs st_fs;
char *dname, *dir;
int err = 0;
if (path == NULL)
return -EINVAL;
dname = strdup(path);
if (dname == NULL)
return -ENOMEM;
dir = dirname(dname);
if (statfs(dir, &st_fs)) {
cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
pr_warn("failed to statfs %s: %s\n", dir, cp);
err = -errno;
}
free(dname);
if (!err && st_fs.f_type != BPF_FS_MAGIC) {
pr_warn("specified path %s is not on BPF FS\n", path);
err = -EINVAL;
}
return err;
}
int bpf_program__pin_instance(struct bpf_program *prog, const char *path,
int instance)
{
char *cp, errmsg[STRERR_BUFSIZE];
int err;
err = make_parent_dir(path);
if (err)
return err;
err = check_path(path);
if (err)
return err;
if (prog == NULL) {
pr_warn("invalid program pointer\n");
return -EINVAL;
}
if (instance < 0 || instance >= prog->instances.nr) {
pr_warn("invalid prog instance %d of prog %s (max %d)\n",
instance, prog->section_name, prog->instances.nr);
return -EINVAL;
}
if (bpf_obj_pin(prog->instances.fds[instance], path)) {
cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
pr_warn("failed to pin program: %s\n", cp);
return -errno;
}
pr_debug("pinned program '%s'\n", path);
return 0;
}
int bpf_program__unpin_instance(struct bpf_program *prog, const char *path,
int instance)
{
int err;
err = check_path(path);
if (err)
return err;
if (prog == NULL) {
pr_warn("invalid program pointer\n");
return -EINVAL;
}
if (instance < 0 || instance >= prog->instances.nr) {
pr_warn("invalid prog instance %d of prog %s (max %d)\n",
instance, prog->section_name, prog->instances.nr);
return -EINVAL;
}
err = unlink(path);
if (err != 0)
return -errno;
pr_debug("unpinned program '%s'\n", path);
return 0;
}
int bpf_program__pin(struct bpf_program *prog, const char *path)
{
int i, err;
err = make_parent_dir(path);
if (err)
return err;
err = check_path(path);
if (err)
return err;
if (prog == NULL) {
pr_warn("invalid program pointer\n");
return -EINVAL;
}
if (prog->instances.nr <= 0) {
pr_warn("no instances of prog %s to pin\n",
prog->section_name);
return -EINVAL;
}
if (prog->instances.nr == 1) {
/* don't create subdirs when pinning single instance */
return bpf_program__pin_instance(prog, path, 0);
}
for (i = 0; i < prog->instances.nr; i++) {
char buf[PATH_MAX];
int len;
len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
if (len < 0) {
err = -EINVAL;
goto err_unpin;
} else if (len >= PATH_MAX) {
err = -ENAMETOOLONG;
goto err_unpin;
}
err = bpf_program__pin_instance(prog, buf, i);
if (err)
goto err_unpin;
}
return 0;
err_unpin:
for (i = i - 1; i >= 0; i--) {
char buf[PATH_MAX];
int len;
len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
if (len < 0)
continue;
else if (len >= PATH_MAX)
continue;
bpf_program__unpin_instance(prog, buf, i);
}
rmdir(path);
return err;
}
int bpf_program__unpin(struct bpf_program *prog, const char *path)
{
int i, err;
err = check_path(path);
if (err)
return err;
if (prog == NULL) {
pr_warn("invalid program pointer\n");
return -EINVAL;
}
if (prog->instances.nr <= 0) {
pr_warn("no instances of prog %s to pin\n",
prog->section_name);
return -EINVAL;
}
if (prog->instances.nr == 1) {
/* don't create subdirs when pinning single instance */
return bpf_program__unpin_instance(prog, path, 0);
}
for (i = 0; i < prog->instances.nr; i++) {
char buf[PATH_MAX];
int len;
len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
if (len < 0)
return -EINVAL;
else if (len >= PATH_MAX)
return -ENAMETOOLONG;
err = bpf_program__unpin_instance(prog, buf, i);
if (err)
return err;
}
err = rmdir(path);
if (err)
return -errno;
return 0;
}
int bpf_map__pin(struct bpf_map *map, const char *path)
{
char *cp, errmsg[STRERR_BUFSIZE];
int err;
if (map == NULL) {
pr_warn("invalid map pointer\n");
return -EINVAL;
}
if (map->pin_path) {
if (path && strcmp(path, map->pin_path)) {
pr_warn("map '%s' already has pin path '%s' different from '%s'\n",
bpf_map__name(map), map->pin_path, path);
return -EINVAL;
} else if (map->pinned) {
pr_debug("map '%s' already pinned at '%s'; not re-pinning\n",
bpf_map__name(map), map->pin_path);
return 0;
}
} else {
if (!path) {
pr_warn("missing a path to pin map '%s' at\n",
bpf_map__name(map));
return -EINVAL;
} else if (map->pinned) {
pr_warn("map '%s' already pinned\n", bpf_map__name(map));
return -EEXIST;
}
map->pin_path = strdup(path);
if (!map->pin_path) {
err = -errno;
goto out_err;
}
}
err = make_parent_dir(map->pin_path);
if (err)
return err;
err = check_path(map->pin_path);
if (err)
return err;
if (bpf_obj_pin(map->fd, map->pin_path)) {
err = -errno;
goto out_err;
}
map->pinned = true;
pr_debug("pinned map '%s'\n", map->pin_path);
return 0;
out_err:
cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg));
pr_warn("failed to pin map: %s\n", cp);
return err;
}
int bpf_map__unpin(struct bpf_map *map, const char *path)
{
int err;
if (map == NULL) {
pr_warn("invalid map pointer\n");
return -EINVAL;
}
if (map->pin_path) {
if (path && strcmp(path, map->pin_path)) {
pr_warn("map '%s' already has pin path '%s' different from '%s'\n",
bpf_map__name(map), map->pin_path, path);
return -EINVAL;
}
path = map->pin_path;
} else if (!path) {
pr_warn("no path to unpin map '%s' from\n",
bpf_map__name(map));
return -EINVAL;
}
err = check_path(path);
if (err)
return err;
err = unlink(path);
if (err != 0)
return -errno;
map->pinned = false;
pr_debug("unpinned map '%s' from '%s'\n", bpf_map__name(map), path);
return 0;
}
int bpf_map__set_pin_path(struct bpf_map *map, const char *path)
{
char *new = NULL;
if (path) {
new = strdup(path);
if (!new)
return -errno;
}
free(map->pin_path);
map->pin_path = new;
return 0;
}
const char *bpf_map__get_pin_path(const struct bpf_map *map)
{
return map->pin_path;
}
bool bpf_map__is_pinned(const struct bpf_map *map)
{
return map->pinned;
}
int bpf_object__pin_maps(struct bpf_object *obj, const char *path)
{
struct bpf_map *map;
int err;
if (!obj)
return -ENOENT;
if (!obj->loaded) {
pr_warn("object not yet loaded; load it first\n");
return -ENOENT;
}
bpf_object__for_each_map(map, obj) {
char *pin_path = NULL;
char buf[PATH_MAX];
if (path) {
int len;
len = snprintf(buf, PATH_MAX, "%s/%s", path,
bpf_map__name(map));
if (len < 0) {
err = -EINVAL;
goto err_unpin_maps;
} else if (len >= PATH_MAX) {
err = -ENAMETOOLONG;
goto err_unpin_maps;
}
pin_path = buf;
} else if (!map->pin_path) {
continue;
}
err = bpf_map__pin(map, pin_path);
if (err)
goto err_unpin_maps;
}
return 0;
err_unpin_maps:
while ((map = bpf_map__prev(map, obj))) {
if (!map->pin_path)
continue;
bpf_map__unpin(map, NULL);
}
return err;
}
int bpf_object__unpin_maps(struct bpf_object *obj, const char *path)
{
struct bpf_map *map;
int err;
if (!obj)
return -ENOENT;
bpf_object__for_each_map(map, obj) {
char *pin_path = NULL;
char buf[PATH_MAX];
if (path) {
int len;
len = snprintf(buf, PATH_MAX, "%s/%s", path,
bpf_map__name(map));
if (len < 0)
return -EINVAL;
else if (len >= PATH_MAX)
return -ENAMETOOLONG;
pin_path = buf;
} else if (!map->pin_path) {
continue;
}
err = bpf_map__unpin(map, pin_path);
if (err)
return err;
}
return 0;
}
int bpf_object__pin_programs(struct bpf_object *obj, const char *path)
{
struct bpf_program *prog;
int err;
if (!obj)
return -ENOENT;
if (!obj->loaded) {
pr_warn("object not yet loaded; load it first\n");
return -ENOENT;
}
bpf_object__for_each_program(prog, obj) {
char buf[PATH_MAX];
int len;
len = snprintf(buf, PATH_MAX, "%s/%s", path,
prog->pin_name);
if (len < 0) {
err = -EINVAL;
goto err_unpin_programs;
} else if (len >= PATH_MAX) {
err = -ENAMETOOLONG;
goto err_unpin_programs;
}
err = bpf_program__pin(prog, buf);
if (err)
goto err_unpin_programs;
}
return 0;
err_unpin_programs:
while ((prog = bpf_program__prev(prog, obj))) {
char buf[PATH_MAX];
int len;
len = snprintf(buf, PATH_MAX, "%s/%s", path,
prog->pin_name);
if (len < 0)
continue;
else if (len >= PATH_MAX)
continue;
bpf_program__unpin(prog, buf);
}
return err;
}
int bpf_object__unpin_programs(struct bpf_object *obj, const char *path)
{
struct bpf_program *prog;
int err;
if (!obj)
return -ENOENT;
bpf_object__for_each_program(prog, obj) {
char buf[PATH_MAX];
int len;
len = snprintf(buf, PATH_MAX, "%s/%s", path,
prog->pin_name);
if (len < 0)
return -EINVAL;
else if (len >= PATH_MAX)
return -ENAMETOOLONG;
err = bpf_program__unpin(prog, buf);
if (err)
return err;
}
return 0;
}
int bpf_object__pin(struct bpf_object *obj, const char *path)
{
int err;
err = bpf_object__pin_maps(obj, path);
if (err)
return err;
err = bpf_object__pin_programs(obj, path);
if (err) {
bpf_object__unpin_maps(obj, path);
return err;
}
return 0;
}
void bpf_object__close(struct bpf_object *obj)
{
size_t i;
if (!obj)
return;
if (obj->clear_priv)
obj->clear_priv(obj, obj->priv);
bpf_object__elf_finish(obj);
bpf_object__unload(obj);
btf__free(obj->btf);
btf_ext__free(obj->btf_ext);
for (i = 0; i < obj->nr_maps; i++) {
zfree(&obj->maps[i].name);
zfree(&obj->maps[i].pin_path);
if (obj->maps[i].clear_priv)
obj->maps[i].clear_priv(&obj->maps[i],
obj->maps[i].priv);
obj->maps[i].priv = NULL;
obj->maps[i].clear_priv = NULL;
}
zfree(&obj->sections.rodata);
zfree(&obj->sections.data);
zfree(&obj->maps);
obj->nr_maps = 0;
if (obj->programs && obj->nr_programs) {
for (i = 0; i < obj->nr_programs; i++)
bpf_program__exit(&obj->programs[i]);
}
zfree(&obj->programs);
list_del(&obj->list);
free(obj);
}
struct bpf_object *
bpf_object__next(struct bpf_object *prev)
{
struct bpf_object *next;
if (!prev)
next = list_first_entry(&bpf_objects_list,
struct bpf_object,
list);
else
next = list_next_entry(prev, list);
/* Empty list is noticed here so don't need checking on entry. */
if (&next->list == &bpf_objects_list)
return NULL;
return next;
}
const char *bpf_object__name(const struct bpf_object *obj)
{
return obj ? obj->name : ERR_PTR(-EINVAL);
}
unsigned int bpf_object__kversion(const struct bpf_object *obj)
{
return obj ? obj->kern_version : 0;
}
struct btf *bpf_object__btf(const struct bpf_object *obj)
{
return obj ? obj->btf : NULL;
}
int bpf_object__btf_fd(const struct bpf_object *obj)
{
return obj->btf ? btf__fd(obj->btf) : -1;
}
int bpf_object__set_priv(struct bpf_object *obj, void *priv,
bpf_object_clear_priv_t clear_priv)
{
if (obj->priv && obj->clear_priv)
obj->clear_priv(obj, obj->priv);
obj->priv = priv;
obj->clear_priv = clear_priv;
return 0;
}
void *bpf_object__priv(const struct bpf_object *obj)
{
return obj ? obj->priv : ERR_PTR(-EINVAL);
}
static struct bpf_program *
__bpf_program__iter(const struct bpf_program *p, const struct bpf_object *obj,
bool forward)
{
size_t nr_programs = obj->nr_programs;
ssize_t idx;
if (!nr_programs)
return NULL;
if (!p)
/* Iter from the beginning */
return forward ? &obj->programs[0] :
&obj->programs[nr_programs - 1];
if (p->obj != obj) {
pr_warn("error: program handler doesn't match object\n");
return NULL;
}
idx = (p - obj->programs) + (forward ? 1 : -1);
if (idx >= obj->nr_programs || idx < 0)
return NULL;
return &obj->programs[idx];
}
struct bpf_program *
bpf_program__next(struct bpf_program *prev, const struct bpf_object *obj)
{
struct bpf_program *prog = prev;
do {
prog = __bpf_program__iter(prog, obj, true);
} while (prog && bpf_program__is_function_storage(prog, obj));
return prog;
}
struct bpf_program *
bpf_program__prev(struct bpf_program *next, const struct bpf_object *obj)
{
struct bpf_program *prog = next;
do {
prog = __bpf_program__iter(prog, obj, false);
} while (prog && bpf_program__is_function_storage(prog, obj));
return prog;
}
int bpf_program__set_priv(struct bpf_program *prog, void *priv,
bpf_program_clear_priv_t clear_priv)
{
if (prog->priv && prog->clear_priv)
prog->clear_priv(prog, prog->priv);
prog->priv = priv;
prog->clear_priv = clear_priv;
return 0;
}
void *bpf_program__priv(const struct bpf_program *prog)
{
return prog ? prog->priv : ERR_PTR(-EINVAL);
}
void bpf_program__set_ifindex(struct bpf_program *prog, __u32 ifindex)
{
prog->prog_ifindex = ifindex;
}
const char *bpf_program__title(const struct bpf_program *prog, bool needs_copy)
{
const char *title;
title = prog->section_name;
if (needs_copy) {
title = strdup(title);
if (!title) {
pr_warn("failed to strdup program title\n");
return ERR_PTR(-ENOMEM);
}
}
return title;
}
int bpf_program__fd(const struct bpf_program *prog)
{
return bpf_program__nth_fd(prog, 0);
}
size_t bpf_program__size(const struct bpf_program *prog)
{
return prog->insns_cnt * sizeof(struct bpf_insn);
}
int bpf_program__set_prep(struct bpf_program *prog, int nr_instances,
bpf_program_prep_t prep)
{
int *instances_fds;
if (nr_instances <= 0 || !prep)
return -EINVAL;
if (prog->instances.nr > 0 || prog->instances.fds) {
pr_warn("Can't set pre-processor after loading\n");
return -EINVAL;
}
instances_fds = malloc(sizeof(int) * nr_instances);
if (!instances_fds) {
pr_warn("alloc memory failed for fds\n");
return -ENOMEM;
}
/* fill all fd with -1 */
memset(instances_fds, -1, sizeof(int) * nr_instances);
prog->instances.nr = nr_instances;
prog->instances.fds = instances_fds;
prog->preprocessor = prep;
return 0;
}
int bpf_program__nth_fd(const struct bpf_program *prog, int n)
{
int fd;
if (!prog)
return -EINVAL;
if (n >= prog->instances.nr || n < 0) {
pr_warn("Can't get the %dth fd from program %s: only %d instances\n",
n, prog->section_name, prog->instances.nr);
return -EINVAL;
}
fd = prog->instances.fds[n];
if (fd < 0) {
pr_warn("%dth instance of program '%s' is invalid\n",
n, prog->section_name);
return -ENOENT;
}
return fd;
}
enum bpf_prog_type bpf_program__get_type(struct bpf_program *prog)
{
return prog->type;
}
void bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type)
{
prog->type = type;
}
static bool bpf_program__is_type(const struct bpf_program *prog,
enum bpf_prog_type type)
{
return prog ? (prog->type == type) : false;
}
#define BPF_PROG_TYPE_FNS(NAME, TYPE) \
int bpf_program__set_##NAME(struct bpf_program *prog) \
{ \
if (!prog) \
return -EINVAL; \
bpf_program__set_type(prog, TYPE); \
return 0; \
} \
\
bool bpf_program__is_##NAME(const struct bpf_program *prog) \
{ \
return bpf_program__is_type(prog, TYPE); \
} \
BPF_PROG_TYPE_FNS(socket_filter, BPF_PROG_TYPE_SOCKET_FILTER);
BPF_PROG_TYPE_FNS(kprobe, BPF_PROG_TYPE_KPROBE);
BPF_PROG_TYPE_FNS(sched_cls, BPF_PROG_TYPE_SCHED_CLS);
BPF_PROG_TYPE_FNS(sched_act, BPF_PROG_TYPE_SCHED_ACT);
BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT);
BPF_PROG_TYPE_FNS(raw_tracepoint, BPF_PROG_TYPE_RAW_TRACEPOINT);
BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP);
BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT);
BPF_PROG_TYPE_FNS(tracing, BPF_PROG_TYPE_TRACING);
enum bpf_attach_type
bpf_program__get_expected_attach_type(struct bpf_program *prog)
{
return prog->expected_attach_type;
}
void bpf_program__set_expected_attach_type(struct bpf_program *prog,
enum bpf_attach_type type)
{
prog->expected_attach_type = type;
}
#define BPF_PROG_SEC_IMPL(string, ptype, eatype, is_attachable, btf, atype) \
{ string, sizeof(string) - 1, ptype, eatype, is_attachable, btf, atype }
/* Programs that can NOT be attached. */
#define BPF_PROG_SEC(string, ptype) BPF_PROG_SEC_IMPL(string, ptype, 0, 0, 0, 0)
/* Programs that can be attached. */
#define BPF_APROG_SEC(string, ptype, atype) \
BPF_PROG_SEC_IMPL(string, ptype, 0, 1, 0, atype)
/* Programs that must specify expected attach type at load time. */
#define BPF_EAPROG_SEC(string, ptype, eatype) \
BPF_PROG_SEC_IMPL(string, ptype, eatype, 1, 0, eatype)
/* Programs that use BTF to identify attach point */
#define BPF_PROG_BTF(string, ptype, eatype) \
BPF_PROG_SEC_IMPL(string, ptype, eatype, 0, 1, 0)
/* Programs that can be attached but attach type can't be identified by section
* name. Kept for backward compatibility.
*/
#define BPF_APROG_COMPAT(string, ptype) BPF_PROG_SEC(string, ptype)
static const struct {
const char *sec;
size_t len;
enum bpf_prog_type prog_type;
enum bpf_attach_type expected_attach_type;
bool is_attachable;
bool is_attach_btf;
enum bpf_attach_type attach_type;
} section_names[] = {
BPF_PROG_SEC("socket", BPF_PROG_TYPE_SOCKET_FILTER),
BPF_PROG_SEC("kprobe/", BPF_PROG_TYPE_KPROBE),
BPF_PROG_SEC("uprobe/", BPF_PROG_TYPE_KPROBE),
BPF_PROG_SEC("kretprobe/", BPF_PROG_TYPE_KPROBE),
BPF_PROG_SEC("uretprobe/", BPF_PROG_TYPE_KPROBE),
BPF_PROG_SEC("classifier", BPF_PROG_TYPE_SCHED_CLS),
BPF_PROG_SEC("action", BPF_PROG_TYPE_SCHED_ACT),
BPF_PROG_SEC("tracepoint/", BPF_PROG_TYPE_TRACEPOINT),
BPF_PROG_SEC("tp/", BPF_PROG_TYPE_TRACEPOINT),
BPF_PROG_SEC("raw_tracepoint/", BPF_PROG_TYPE_RAW_TRACEPOINT),
BPF_PROG_SEC("raw_tp/", BPF_PROG_TYPE_RAW_TRACEPOINT),
BPF_PROG_BTF("tp_btf/", BPF_PROG_TYPE_TRACING,
BPF_TRACE_RAW_TP),
BPF_PROG_BTF("fentry/", BPF_PROG_TYPE_TRACING,
BPF_TRACE_FENTRY),
BPF_PROG_BTF("fexit/", BPF_PROG_TYPE_TRACING,
BPF_TRACE_FEXIT),
BPF_PROG_SEC("xdp", BPF_PROG_TYPE_XDP),
BPF_PROG_SEC("perf_event", BPF_PROG_TYPE_PERF_EVENT),
BPF_PROG_SEC("lwt_in", BPF_PROG_TYPE_LWT_IN),
BPF_PROG_SEC("lwt_out", BPF_PROG_TYPE_LWT_OUT),
BPF_PROG_SEC("lwt_xmit", BPF_PROG_TYPE_LWT_XMIT),
BPF_PROG_SEC("lwt_seg6local", BPF_PROG_TYPE_LWT_SEG6LOCAL),
BPF_APROG_SEC("cgroup_skb/ingress", BPF_PROG_TYPE_CGROUP_SKB,
BPF_CGROUP_INET_INGRESS),
BPF_APROG_SEC("cgroup_skb/egress", BPF_PROG_TYPE_CGROUP_SKB,
BPF_CGROUP_INET_EGRESS),
BPF_APROG_COMPAT("cgroup/skb", BPF_PROG_TYPE_CGROUP_SKB),
BPF_APROG_SEC("cgroup/sock", BPF_PROG_TYPE_CGROUP_SOCK,
BPF_CGROUP_INET_SOCK_CREATE),
BPF_EAPROG_SEC("cgroup/post_bind4", BPF_PROG_TYPE_CGROUP_SOCK,
BPF_CGROUP_INET4_POST_BIND),
BPF_EAPROG_SEC("cgroup/post_bind6", BPF_PROG_TYPE_CGROUP_SOCK,
BPF_CGROUP_INET6_POST_BIND),
BPF_APROG_SEC("cgroup/dev", BPF_PROG_TYPE_CGROUP_DEVICE,
BPF_CGROUP_DEVICE),
BPF_APROG_SEC("sockops", BPF_PROG_TYPE_SOCK_OPS,
BPF_CGROUP_SOCK_OPS),
BPF_APROG_SEC("sk_skb/stream_parser", BPF_PROG_TYPE_SK_SKB,
BPF_SK_SKB_STREAM_PARSER),
BPF_APROG_SEC("sk_skb/stream_verdict", BPF_PROG_TYPE_SK_SKB,
BPF_SK_SKB_STREAM_VERDICT),
BPF_APROG_COMPAT("sk_skb", BPF_PROG_TYPE_SK_SKB),
BPF_APROG_SEC("sk_msg", BPF_PROG_TYPE_SK_MSG,
BPF_SK_MSG_VERDICT),
BPF_APROG_SEC("lirc_mode2", BPF_PROG_TYPE_LIRC_MODE2,
BPF_LIRC_MODE2),
BPF_APROG_SEC("flow_dissector", BPF_PROG_TYPE_FLOW_DISSECTOR,
BPF_FLOW_DISSECTOR),
BPF_EAPROG_SEC("cgroup/bind4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_INET4_BIND),
BPF_EAPROG_SEC("cgroup/bind6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_INET6_BIND),
BPF_EAPROG_SEC("cgroup/connect4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_INET4_CONNECT),
BPF_EAPROG_SEC("cgroup/connect6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_INET6_CONNECT),
BPF_EAPROG_SEC("cgroup/sendmsg4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_UDP4_SENDMSG),
BPF_EAPROG_SEC("cgroup/sendmsg6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_UDP6_SENDMSG),
BPF_EAPROG_SEC("cgroup/recvmsg4", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_UDP4_RECVMSG),
BPF_EAPROG_SEC("cgroup/recvmsg6", BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_CGROUP_UDP6_RECVMSG),
BPF_EAPROG_SEC("cgroup/sysctl", BPF_PROG_TYPE_CGROUP_SYSCTL,
BPF_CGROUP_SYSCTL),
BPF_EAPROG_SEC("cgroup/getsockopt", BPF_PROG_TYPE_CGROUP_SOCKOPT,
BPF_CGROUP_GETSOCKOPT),
BPF_EAPROG_SEC("cgroup/setsockopt", BPF_PROG_TYPE_CGROUP_SOCKOPT,
BPF_CGROUP_SETSOCKOPT),
};
#undef BPF_PROG_SEC_IMPL
#undef BPF_PROG_SEC
#undef BPF_APROG_SEC
#undef BPF_EAPROG_SEC
#undef BPF_APROG_COMPAT
#define MAX_TYPE_NAME_SIZE 32
static char *libbpf_get_type_names(bool attach_type)
{
int i, len = ARRAY_SIZE(section_names) * MAX_TYPE_NAME_SIZE;
char *buf;
buf = malloc(len);
if (!buf)
return NULL;
buf[0] = '\0';
/* Forge string buf with all available names */
for (i = 0; i < ARRAY_SIZE(section_names); i++) {
if (attach_type && !section_names[i].is_attachable)
continue;
if (strlen(buf) + strlen(section_names[i].sec) + 2 > len) {
free(buf);
return NULL;
}
strcat(buf, " ");
strcat(buf, section_names[i].sec);
}
return buf;
}
int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
enum bpf_attach_type *expected_attach_type)
{
char *type_names;
int i;
if (!name)
return -EINVAL;
for (i = 0; i < ARRAY_SIZE(section_names); i++) {
if (strncmp(name, section_names[i].sec, section_names[i].len))
continue;
*prog_type = section_names[i].prog_type;
*expected_attach_type = section_names[i].expected_attach_type;
return 0;
}
pr_warn("failed to guess program type from ELF section '%s'\n", name);
type_names = libbpf_get_type_names(false);
if (type_names != NULL) {
pr_info("supported section(type) names are:%s\n", type_names);
free(type_names);
}
return -ESRCH;
}
#define BTF_PREFIX "btf_trace_"
int libbpf_find_vmlinux_btf_id(const char *name,
enum bpf_attach_type attach_type)
{
struct btf *btf = bpf_core_find_kernel_btf();
char raw_tp_btf[128] = BTF_PREFIX;
char *dst = raw_tp_btf + sizeof(BTF_PREFIX) - 1;
const char *btf_name;
int err = -EINVAL;
__u32 kind;
if (IS_ERR(btf)) {
pr_warn("vmlinux BTF is not found\n");
return -EINVAL;
}
if (attach_type == BPF_TRACE_RAW_TP) {
/* prepend "btf_trace_" prefix per kernel convention */
strncat(dst, name, sizeof(raw_tp_btf) - sizeof(BTF_PREFIX));
btf_name = raw_tp_btf;
kind = BTF_KIND_TYPEDEF;
} else {
btf_name = name;
kind = BTF_KIND_FUNC;
}
err = btf__find_by_name_kind(btf, btf_name, kind);
btf__free(btf);
return err;
}
static int libbpf_find_prog_btf_id(const char *name, __u32 attach_prog_fd)
{
struct bpf_prog_info_linear *info_linear;
struct bpf_prog_info *info;
struct btf *btf = NULL;
int err = -EINVAL;
info_linear = bpf_program__get_prog_info_linear(attach_prog_fd, 0);
if (IS_ERR_OR_NULL(info_linear)) {
pr_warn("failed get_prog_info_linear for FD %d\n",
attach_prog_fd);
return -EINVAL;
}
info = &info_linear->info;
if (!info->btf_id) {
pr_warn("The target program doesn't have BTF\n");
goto out;
}
if (btf__get_from_id(info->btf_id, &btf)) {
pr_warn("Failed to get BTF of the program\n");
goto out;
}
err = btf__find_by_name_kind(btf, name, BTF_KIND_FUNC);
btf__free(btf);
if (err <= 0) {
pr_warn("%s is not found in prog's BTF\n", name);
goto out;
}
out:
free(info_linear);
return err;
}
static int libbpf_find_attach_btf_id(const char *name,
enum bpf_attach_type attach_type,
__u32 attach_prog_fd)
{
int i, err;
if (!name)
return -EINVAL;
for (i = 0; i < ARRAY_SIZE(section_names); i++) {
if (!section_names[i].is_attach_btf)
continue;
if (strncmp(name, section_names[i].sec, section_names[i].len))
continue;
if (attach_prog_fd)
err = libbpf_find_prog_btf_id(name + section_names[i].len,
attach_prog_fd);
else
err = libbpf_find_vmlinux_btf_id(name + section_names[i].len,
attach_type);
if (err <= 0)
pr_warn("%s is not found in vmlinux BTF\n", name);
return err;
}
pr_warn("failed to identify btf_id based on ELF section name '%s'\n", name);
return -ESRCH;
}
int libbpf_attach_type_by_name(const char *name,
enum bpf_attach_type *attach_type)
{
char *type_names;
int i;
if (!name)
return -EINVAL;
for (i = 0; i < ARRAY_SIZE(section_names); i++) {
if (strncmp(name, section_names[i].sec, section_names[i].len))
continue;
if (!section_names[i].is_attachable)
return -EINVAL;
*attach_type = section_names[i].attach_type;
return 0;
}
pr_warn("failed to guess attach type based on ELF section name '%s'\n", name);
type_names = libbpf_get_type_names(true);
if (type_names != NULL) {
pr_info("attachable section(type) names are:%s\n", type_names);
free(type_names);
}
return -EINVAL;
}
int bpf_map__fd(const struct bpf_map *map)
{
return map ? map->fd : -EINVAL;
}
const struct bpf_map_def *bpf_map__def(const struct bpf_map *map)
{
return map ? &map->def : ERR_PTR(-EINVAL);
}
const char *bpf_map__name(const struct bpf_map *map)
{
return map ? map->name : NULL;
}
__u32 bpf_map__btf_key_type_id(const struct bpf_map *map)
{
return map ? map->btf_key_type_id : 0;
}
__u32 bpf_map__btf_value_type_id(const struct bpf_map *map)
{
return map ? map->btf_value_type_id : 0;
}
int bpf_map__set_priv(struct bpf_map *map, void *priv,
bpf_map_clear_priv_t clear_priv)
{
if (!map)
return -EINVAL;
if (map->priv) {
if (map->clear_priv)
map->clear_priv(map, map->priv);
}
map->priv = priv;
map->clear_priv = clear_priv;
return 0;
}
void *bpf_map__priv(const struct bpf_map *map)
{
return map ? map->priv : ERR_PTR(-EINVAL);
}
bool bpf_map__is_offload_neutral(const struct bpf_map *map)
{
return map->def.type == BPF_MAP_TYPE_PERF_EVENT_ARRAY;
}
bool bpf_map__is_internal(const struct bpf_map *map)
{
return map->libbpf_type != LIBBPF_MAP_UNSPEC;
}
void bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex)
{
map->map_ifindex = ifindex;
}
int bpf_map__set_inner_map_fd(struct bpf_map *map, int fd)
{
if (!bpf_map_type__is_map_in_map(map->def.type)) {
pr_warn("error: unsupported map type\n");
return -EINVAL;
}
if (map->inner_map_fd != -1) {
pr_warn("error: inner_map_fd already specified\n");
return -EINVAL;
}
map->inner_map_fd = fd;
return 0;
}
static struct bpf_map *
__bpf_map__iter(const struct bpf_map *m, const struct bpf_object *obj, int i)
{
ssize_t idx;
struct bpf_map *s, *e;
if (!obj || !obj->maps)
return NULL;
s = obj->maps;
e = obj->maps + obj->nr_maps;
if ((m < s) || (m >= e)) {
pr_warn("error in %s: map handler doesn't belong to object\n",
__func__);
return NULL;
}
idx = (m - obj->maps) + i;
if (idx >= obj->nr_maps || idx < 0)
return NULL;
return &obj->maps[idx];
}
struct bpf_map *
bpf_map__next(const struct bpf_map *prev, const struct bpf_object *obj)
{
if (prev == NULL)
return obj->maps;
return __bpf_map__iter(prev, obj, 1);
}
struct bpf_map *
bpf_map__prev(const struct bpf_map *next, const struct bpf_object *obj)
{
if (next == NULL) {
if (!obj->nr_maps)
return NULL;
return obj->maps + obj->nr_maps - 1;
}
return __bpf_map__iter(next, obj, -1);
}
struct bpf_map *
bpf_object__find_map_by_name(const struct bpf_object *obj, const char *name)
{
struct bpf_map *pos;
bpf_object__for_each_map(pos, obj) {
if (pos->name && !strcmp(pos->name, name))
return pos;
}
return NULL;
}
int
bpf_object__find_map_fd_by_name(const struct bpf_object *obj, const char *name)
{
return bpf_map__fd(bpf_object__find_map_by_name(obj, name));
}
struct bpf_map *
bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset)
{
return ERR_PTR(-ENOTSUP);
}
long libbpf_get_error(const void *ptr)
{
return PTR_ERR_OR_ZERO(ptr);
}
int bpf_prog_load(const char *file, enum bpf_prog_type type,
struct bpf_object **pobj, int *prog_fd)
{
struct bpf_prog_load_attr attr;
memset(&attr, 0, sizeof(struct bpf_prog_load_attr));
attr.file = file;
attr.prog_type = type;
attr.expected_attach_type = 0;
return bpf_prog_load_xattr(&attr, pobj, prog_fd);
}
int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr,
struct bpf_object **pobj, int *prog_fd)
{
struct bpf_object_open_attr open_attr = {};
struct bpf_program *prog, *first_prog = NULL;
struct bpf_object *obj;
struct bpf_map *map;
int err;
if (!attr)
return -EINVAL;
if (!attr->file)
return -EINVAL;
open_attr.file = attr->file;
open_attr.prog_type = attr->prog_type;
obj = bpf_object__open_xattr(&open_attr);
if (IS_ERR_OR_NULL(obj))
return -ENOENT;
bpf_object__for_each_program(prog, obj) {
enum bpf_attach_type attach_type = attr->expected_attach_type;
/*
* to preserve backwards compatibility, bpf_prog_load treats
* attr->prog_type, if specified, as an override to whatever
* bpf_object__open guessed
*/
if (attr->prog_type != BPF_PROG_TYPE_UNSPEC) {
bpf_program__set_type(prog, attr->prog_type);
bpf_program__set_expected_attach_type(prog,
attach_type);
}
if (bpf_program__get_type(prog) == BPF_PROG_TYPE_UNSPEC) {
/*
* we haven't guessed from section name and user
* didn't provide a fallback type, too bad...
*/
bpf_object__close(obj);
return -EINVAL;
}
prog->prog_ifindex = attr->ifindex;
prog->log_level = attr->log_level;
prog->prog_flags = attr->prog_flags;
if (!first_prog)
first_prog = prog;
}
bpf_object__for_each_map(map, obj) {
if (!bpf_map__is_offload_neutral(map))
map->map_ifindex = attr->ifindex;
}
if (!first_prog) {
pr_warn("object file doesn't contain bpf program\n");
bpf_object__close(obj);
return -ENOENT;
}
err = bpf_object__load(obj);
if (err) {
bpf_object__close(obj);
return -EINVAL;
}
*pobj = obj;
*prog_fd = bpf_program__fd(first_prog);
return 0;
}
struct bpf_link {
int (*destroy)(struct bpf_link *link);
};
int bpf_link__destroy(struct bpf_link *link)
{
int err;
if (!link)
return 0;
err = link->destroy(link);
free(link);
return err;
}
struct bpf_link_fd {
struct bpf_link link; /* has to be at the top of struct */
int fd; /* hook FD */
};
static int bpf_link__destroy_perf_event(struct bpf_link *link)
{
struct bpf_link_fd *l = (void *)link;
int err;
err = ioctl(l->fd, PERF_EVENT_IOC_DISABLE, 0);
if (err)
err = -errno;
close(l->fd);
return err;
}
struct bpf_link *bpf_program__attach_perf_event(struct bpf_program *prog,
int pfd)
{
char errmsg[STRERR_BUFSIZE];
struct bpf_link_fd *link;
int prog_fd, err;
if (pfd < 0) {
pr_warn("program '%s': invalid perf event FD %d\n",
bpf_program__title(prog, false), pfd);
return ERR_PTR(-EINVAL);
}
prog_fd = bpf_program__fd(prog);
if (prog_fd < 0) {
pr_warn("program '%s': can't attach BPF program w/o FD (did you load it?)\n",
bpf_program__title(prog, false));
return ERR_PTR(-EINVAL);
}
link = malloc(sizeof(*link));
if (!link)
return ERR_PTR(-ENOMEM);
link->link.destroy = &bpf_link__destroy_perf_event;
link->fd = pfd;
if (ioctl(pfd, PERF_EVENT_IOC_SET_BPF, prog_fd) < 0) {
err = -errno;
free(link);
pr_warn("program '%s': failed to attach to pfd %d: %s\n",
bpf_program__title(prog, false), pfd,
libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
return ERR_PTR(err);
}
if (ioctl(pfd, PERF_EVENT_IOC_ENABLE, 0) < 0) {
err = -errno;
free(link);
pr_warn("program '%s': failed to enable pfd %d: %s\n",
bpf_program__title(prog, false), pfd,
libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
return ERR_PTR(err);
}
return (struct bpf_link *)link;
}
/*
* this function is expected to parse integer in the range of [0, 2^31-1] from
* given file using scanf format string fmt. If actual parsed value is
* negative, the result might be indistinguishable from error
*/
static int parse_uint_from_file(const char *file, const char *fmt)
{
char buf[STRERR_BUFSIZE];
int err, ret;
FILE *f;
f = fopen(file, "r");
if (!f) {
err = -errno;
pr_debug("failed to open '%s': %s\n", file,
libbpf_strerror_r(err, buf, sizeof(buf)));
return err;
}
err = fscanf(f, fmt, &ret);
if (err != 1) {
err = err == EOF ? -EIO : -errno;
pr_debug("failed to parse '%s': %s\n", file,
libbpf_strerror_r(err, buf, sizeof(buf)));
fclose(f);
return err;
}
fclose(f);
return ret;
}
static int determine_kprobe_perf_type(void)
{
const char *file = "/sys/bus/event_source/devices/kprobe/type";
return parse_uint_from_file(file, "%d\n");
}
static int determine_uprobe_perf_type(void)
{
const char *file = "/sys/bus/event_source/devices/uprobe/type";
return parse_uint_from_file(file, "%d\n");
}
static int determine_kprobe_retprobe_bit(void)
{
const char *file = "/sys/bus/event_source/devices/kprobe/format/retprobe";
return parse_uint_from_file(file, "config:%d\n");
}
static int determine_uprobe_retprobe_bit(void)
{
const char *file = "/sys/bus/event_source/devices/uprobe/format/retprobe";
return parse_uint_from_file(file, "config:%d\n");
}
static int perf_event_open_probe(bool uprobe, bool retprobe, const char *name,
uint64_t offset, int pid)
{
struct perf_event_attr attr = {};
char errmsg[STRERR_BUFSIZE];
int type, pfd, err;
type = uprobe ? determine_uprobe_perf_type()
: determine_kprobe_perf_type();
if (type < 0) {
pr_warn("failed to determine %s perf type: %s\n",
uprobe ? "uprobe" : "kprobe",
libbpf_strerror_r(type, errmsg, sizeof(errmsg)));
return type;
}
if (retprobe) {
int bit = uprobe ? determine_uprobe_retprobe_bit()
: determine_kprobe_retprobe_bit();
if (bit < 0) {
pr_warn("failed to determine %s retprobe bit: %s\n",
uprobe ? "uprobe" : "kprobe",
libbpf_strerror_r(bit, errmsg, sizeof(errmsg)));
return bit;
}
attr.config |= 1 << bit;
}
attr.size = sizeof(attr);
attr.type = type;
attr.config1 = ptr_to_u64(name); /* kprobe_func or uprobe_path */
attr.config2 = offset; /* kprobe_addr or probe_offset */
/* pid filter is meaningful only for uprobes */
pfd = syscall(__NR_perf_event_open, &attr,
pid < 0 ? -1 : pid /* pid */,
pid == -1 ? 0 : -1 /* cpu */,
-1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
if (pfd < 0) {
err = -errno;
pr_warn("%s perf_event_open() failed: %s\n",
uprobe ? "uprobe" : "kprobe",
libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
return err;
}
return pfd;
}
struct bpf_link *bpf_program__attach_kprobe(struct bpf_program *prog,
bool retprobe,
const char *func_name)
{
char errmsg[STRERR_BUFSIZE];
struct bpf_link *link;
int pfd, err;
pfd = perf_event_open_probe(false /* uprobe */, retprobe, func_name,
0 /* offset */, -1 /* pid */);
if (pfd < 0) {
pr_warn("program '%s': failed to create %s '%s' perf event: %s\n",
bpf_program__title(prog, false),
retprobe ? "kretprobe" : "kprobe", func_name,
libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
return ERR_PTR(pfd);
}
link = bpf_program__attach_perf_event(prog, pfd);
if (IS_ERR(link)) {
close(pfd);
err = PTR_ERR(link);
pr_warn("program '%s': failed to attach to %s '%s': %s\n",
bpf_program__title(prog, false),
retprobe ? "kretprobe" : "kprobe", func_name,
libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
return link;
}
return link;
}
struct bpf_link *bpf_program__attach_uprobe(struct bpf_program *prog,
bool retprobe, pid_t pid,
const char *binary_path,
size_t func_offset)
{
char errmsg[STRERR_BUFSIZE];
struct bpf_link *link;
int pfd, err;
pfd = perf_event_open_probe(true /* uprobe */, retprobe,
binary_path, func_offset, pid);
if (pfd < 0) {
pr_warn("program '%s': failed to create %s '%s:0x%zx' perf event: %s\n",
bpf_program__title(prog, false),
retprobe ? "uretprobe" : "uprobe",
binary_path, func_offset,
libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
return ERR_PTR(pfd);
}
link = bpf_program__attach_perf_event(prog, pfd);
if (IS_ERR(link)) {
close(pfd);
err = PTR_ERR(link);
pr_warn("program '%s': failed to attach to %s '%s:0x%zx': %s\n",
bpf_program__title(prog, false),
retprobe ? "uretprobe" : "uprobe",
binary_path, func_offset,
libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
return link;
}
return link;
}
static int determine_tracepoint_id(const char *tp_category,
const char *tp_name)
{
char file[PATH_MAX];
int ret;
ret = snprintf(file, sizeof(file),
"/sys/kernel/debug/tracing/events/%s/%s/id",
tp_category, tp_name);
if (ret < 0)
return -errno;
if (ret >= sizeof(file)) {
pr_debug("tracepoint %s/%s path is too long\n",
tp_category, tp_name);
return -E2BIG;
}
return parse_uint_from_file(file, "%d\n");
}
static int perf_event_open_tracepoint(const char *tp_category,
const char *tp_name)
{
struct perf_event_attr attr = {};
char errmsg[STRERR_BUFSIZE];
int tp_id, pfd, err;
tp_id = determine_tracepoint_id(tp_category, tp_name);
if (tp_id < 0) {
pr_warn("failed to determine tracepoint '%s/%s' perf event ID: %s\n",
tp_category, tp_name,
libbpf_strerror_r(tp_id, errmsg, sizeof(errmsg)));
return tp_id;
}
attr.type = PERF_TYPE_TRACEPOINT;
attr.size = sizeof(attr);
attr.config = tp_id;
pfd = syscall(__NR_perf_event_open, &attr, -1 /* pid */, 0 /* cpu */,
-1 /* group_fd */, PERF_FLAG_FD_CLOEXEC);
if (pfd < 0) {
err = -errno;
pr_warn("tracepoint '%s/%s' perf_event_open() failed: %s\n",
tp_category, tp_name,
libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
return err;
}
return pfd;
}
struct bpf_link *bpf_program__attach_tracepoint(struct bpf_program *prog,
const char *tp_category,
const char *tp_name)
{
char errmsg[STRERR_BUFSIZE];
struct bpf_link *link;
int pfd, err;
pfd = perf_event_open_tracepoint(tp_category, tp_name);
if (pfd < 0) {
pr_warn("program '%s': failed to create tracepoint '%s/%s' perf event: %s\n",
bpf_program__title(prog, false),
tp_category, tp_name,
libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
return ERR_PTR(pfd);
}
link = bpf_program__attach_perf_event(prog, pfd);
if (IS_ERR(link)) {
close(pfd);
err = PTR_ERR(link);
pr_warn("program '%s': failed to attach to tracepoint '%s/%s': %s\n",
bpf_program__title(prog, false),
tp_category, tp_name,
libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
return link;
}
return link;
}
static int bpf_link__destroy_fd(struct bpf_link *link)
{
struct bpf_link_fd *l = (void *)link;
return close(l->fd);
}
struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog,
const char *tp_name)
{
char errmsg[STRERR_BUFSIZE];
struct bpf_link_fd *link;
int prog_fd, pfd;
prog_fd = bpf_program__fd(prog);
if (prog_fd < 0) {
pr_warn("program '%s': can't attach before loaded\n",
bpf_program__title(prog, false));
return ERR_PTR(-EINVAL);
}
link = malloc(sizeof(*link));
if (!link)
return ERR_PTR(-ENOMEM);
link->link.destroy = &bpf_link__destroy_fd;
pfd = bpf_raw_tracepoint_open(tp_name, prog_fd);
if (pfd < 0) {
pfd = -errno;
free(link);
pr_warn("program '%s': failed to attach to raw tracepoint '%s': %s\n",
bpf_program__title(prog, false), tp_name,
libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
return ERR_PTR(pfd);
}
link->fd = pfd;
return (struct bpf_link *)link;
}
struct bpf_link *bpf_program__attach_trace(struct bpf_program *prog)
{
char errmsg[STRERR_BUFSIZE];
struct bpf_link_fd *link;
int prog_fd, pfd;
prog_fd = bpf_program__fd(prog);
if (prog_fd < 0) {
pr_warn("program '%s': can't attach before loaded\n",
bpf_program__title(prog, false));
return ERR_PTR(-EINVAL);
}
link = malloc(sizeof(*link));
if (!link)
return ERR_PTR(-ENOMEM);
link->link.destroy = &bpf_link__destroy_fd;
pfd = bpf_raw_tracepoint_open(NULL, prog_fd);
if (pfd < 0) {
pfd = -errno;
free(link);
pr_warn("program '%s': failed to attach to trace: %s\n",
bpf_program__title(prog, false),
libbpf_strerror_r(pfd, errmsg, sizeof(errmsg)));
return ERR_PTR(pfd);
}
link->fd = pfd;
return (struct bpf_link *)link;
}
enum bpf_perf_event_ret
bpf_perf_event_read_simple(void *mmap_mem, size_t mmap_size, size_t page_size,
void **copy_mem, size_t *copy_size,
bpf_perf_event_print_t fn, void *private_data)
{
struct perf_event_mmap_page *header = mmap_mem;
__u64 data_head = ring_buffer_read_head(header);
__u64 data_tail = header->data_tail;
void *base = ((__u8 *)header) + page_size;
int ret = LIBBPF_PERF_EVENT_CONT;
struct perf_event_header *ehdr;
size_t ehdr_size;
while (data_head != data_tail) {
ehdr = base + (data_tail & (mmap_size - 1));
ehdr_size = ehdr->size;
if (((void *)ehdr) + ehdr_size > base + mmap_size) {
void *copy_start = ehdr;
size_t len_first = base + mmap_size - copy_start;
size_t len_secnd = ehdr_size - len_first;
if (*copy_size < ehdr_size) {
free(*copy_mem);
*copy_mem = malloc(ehdr_size);
if (!*copy_mem) {
*copy_size = 0;
ret = LIBBPF_PERF_EVENT_ERROR;
break;
}
*copy_size = ehdr_size;
}
memcpy(*copy_mem, copy_start, len_first);
memcpy(*copy_mem + len_first, base, len_secnd);
ehdr = *copy_mem;
}
ret = fn(ehdr, private_data);
data_tail += ehdr_size;
if (ret != LIBBPF_PERF_EVENT_CONT)
break;
}
ring_buffer_write_tail(header, data_tail);
return ret;
}
struct perf_buffer;
struct perf_buffer_params {
struct perf_event_attr *attr;
/* if event_cb is specified, it takes precendence */
perf_buffer_event_fn event_cb;
/* sample_cb and lost_cb are higher-level common-case callbacks */
perf_buffer_sample_fn sample_cb;
perf_buffer_lost_fn lost_cb;
void *ctx;
int cpu_cnt;
int *cpus;
int *map_keys;
};
struct perf_cpu_buf {
struct perf_buffer *pb;
void *base; /* mmap()'ed memory */
void *buf; /* for reconstructing segmented data */
size_t buf_size;
int fd;
int cpu;
int map_key;
};
struct perf_buffer {
perf_buffer_event_fn event_cb;
perf_buffer_sample_fn sample_cb;
perf_buffer_lost_fn lost_cb;
void *ctx; /* passed into callbacks */
size_t page_size;
size_t mmap_size;
struct perf_cpu_buf **cpu_bufs;
struct epoll_event *events;
int cpu_cnt;
int epoll_fd; /* perf event FD */
int map_fd; /* BPF_MAP_TYPE_PERF_EVENT_ARRAY BPF map FD */
};
static void perf_buffer__free_cpu_buf(struct perf_buffer *pb,
struct perf_cpu_buf *cpu_buf)
{
if (!cpu_buf)
return;
if (cpu_buf->base &&
munmap(cpu_buf->base, pb->mmap_size + pb->page_size))
pr_warn("failed to munmap cpu_buf #%d\n", cpu_buf->cpu);
if (cpu_buf->fd >= 0) {
ioctl(cpu_buf->fd, PERF_EVENT_IOC_DISABLE, 0);
close(cpu_buf->fd);
}
free(cpu_buf->buf);
free(cpu_buf);
}
void perf_buffer__free(struct perf_buffer *pb)
{
int i;
if (!pb)
return;
if (pb->cpu_bufs) {
for (i = 0; i < pb->cpu_cnt && pb->cpu_bufs[i]; i++) {
struct perf_cpu_buf *cpu_buf = pb->cpu_bufs[i];
bpf_map_delete_elem(pb->map_fd, &cpu_buf->map_key);
perf_buffer__free_cpu_buf(pb, cpu_buf);
}
free(pb->cpu_bufs);
}
if (pb->epoll_fd >= 0)
close(pb->epoll_fd);
free(pb->events);
free(pb);
}
static struct perf_cpu_buf *
perf_buffer__open_cpu_buf(struct perf_buffer *pb, struct perf_event_attr *attr,
int cpu, int map_key)
{
struct perf_cpu_buf *cpu_buf;
char msg[STRERR_BUFSIZE];
int err;
cpu_buf = calloc(1, sizeof(*cpu_buf));
if (!cpu_buf)
return ERR_PTR(-ENOMEM);
cpu_buf->pb = pb;
cpu_buf->cpu = cpu;
cpu_buf->map_key = map_key;
cpu_buf->fd = syscall(__NR_perf_event_open, attr, -1 /* pid */, cpu,
-1, PERF_FLAG_FD_CLOEXEC);
if (cpu_buf->fd < 0) {
err = -errno;
pr_warn("failed to open perf buffer event on cpu #%d: %s\n",
cpu, libbpf_strerror_r(err, msg, sizeof(msg)));
goto error;
}
cpu_buf->base = mmap(NULL, pb->mmap_size + pb->page_size,
PROT_READ | PROT_WRITE, MAP_SHARED,
cpu_buf->fd, 0);
if (cpu_buf->base == MAP_FAILED) {
cpu_buf->base = NULL;
err = -errno;
pr_warn("failed to mmap perf buffer on cpu #%d: %s\n",
cpu, libbpf_strerror_r(err, msg, sizeof(msg)));
goto error;
}
if (ioctl(cpu_buf->fd, PERF_EVENT_IOC_ENABLE, 0) < 0) {
err = -errno;
pr_warn("failed to enable perf buffer event on cpu #%d: %s\n",
cpu, libbpf_strerror_r(err, msg, sizeof(msg)));
goto error;
}
return cpu_buf;
error:
perf_buffer__free_cpu_buf(pb, cpu_buf);
return (struct perf_cpu_buf *)ERR_PTR(err);
}
static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt,
struct perf_buffer_params *p);
struct perf_buffer *perf_buffer__new(int map_fd, size_t page_cnt,
const struct perf_buffer_opts *opts)
{
struct perf_buffer_params p = {};
struct perf_event_attr attr = { 0, };
attr.config = PERF_COUNT_SW_BPF_OUTPUT,
attr.type = PERF_TYPE_SOFTWARE;
attr.sample_type = PERF_SAMPLE_RAW;
attr.sample_period = 1;
attr.wakeup_events = 1;
p.attr = &attr;
p.sample_cb = opts ? opts->sample_cb : NULL;
p.lost_cb = opts ? opts->lost_cb : NULL;
p.ctx = opts ? opts->ctx : NULL;
return __perf_buffer__new(map_fd, page_cnt, &p);
}
struct perf_buffer *
perf_buffer__new_raw(int map_fd, size_t page_cnt,
const struct perf_buffer_raw_opts *opts)
{
struct perf_buffer_params p = {};
p.attr = opts->attr;
p.event_cb = opts->event_cb;
p.ctx = opts->ctx;
p.cpu_cnt = opts->cpu_cnt;
p.cpus = opts->cpus;
p.map_keys = opts->map_keys;
return __perf_buffer__new(map_fd, page_cnt, &p);
}
static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt,
struct perf_buffer_params *p)
{
struct bpf_map_info map = {};
char msg[STRERR_BUFSIZE];
struct perf_buffer *pb;
__u32 map_info_len;
int err, i;
if (page_cnt & (page_cnt - 1)) {
pr_warn("page count should be power of two, but is %zu\n",
page_cnt);
return ERR_PTR(-EINVAL);
}
map_info_len = sizeof(map);
err = bpf_obj_get_info_by_fd(map_fd, &map, &map_info_len);
if (err) {
err = -errno;
pr_warn("failed to get map info for map FD %d: %s\n",
map_fd, libbpf_strerror_r(err, msg, sizeof(msg)));
return ERR_PTR(err);
}
if (map.type != BPF_MAP_TYPE_PERF_EVENT_ARRAY) {
pr_warn("map '%s' should be BPF_MAP_TYPE_PERF_EVENT_ARRAY\n",
map.name);
return ERR_PTR(-EINVAL);
}
pb = calloc(1, sizeof(*pb));
if (!pb)
return ERR_PTR(-ENOMEM);
pb->event_cb = p->event_cb;
pb->sample_cb = p->sample_cb;
pb->lost_cb = p->lost_cb;
pb->ctx = p->ctx;
pb->page_size = getpagesize();
pb->mmap_size = pb->page_size * page_cnt;
pb->map_fd = map_fd;
pb->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
if (pb->epoll_fd < 0) {
err = -errno;
pr_warn("failed to create epoll instance: %s\n",
libbpf_strerror_r(err, msg, sizeof(msg)));
goto error;
}
if (p->cpu_cnt > 0) {
pb->cpu_cnt = p->cpu_cnt;
} else {
pb->cpu_cnt = libbpf_num_possible_cpus();
if (pb->cpu_cnt < 0) {
err = pb->cpu_cnt;
goto error;
}
if (map.max_entries < pb->cpu_cnt)
pb->cpu_cnt = map.max_entries;
}
pb->events = calloc(pb->cpu_cnt, sizeof(*pb->events));
if (!pb->events) {
err = -ENOMEM;
pr_warn("failed to allocate events: out of memory\n");
goto error;
}
pb->cpu_bufs = calloc(pb->cpu_cnt, sizeof(*pb->cpu_bufs));
if (!pb->cpu_bufs) {
err = -ENOMEM;
pr_warn("failed to allocate buffers: out of memory\n");
goto error;
}
for (i = 0; i < pb->cpu_cnt; i++) {
struct perf_cpu_buf *cpu_buf;
int cpu, map_key;
cpu = p->cpu_cnt > 0 ? p->cpus[i] : i;
map_key = p->cpu_cnt > 0 ? p->map_keys[i] : i;
cpu_buf = perf_buffer__open_cpu_buf(pb, p->attr, cpu, map_key);
if (IS_ERR(cpu_buf)) {
err = PTR_ERR(cpu_buf);
goto error;
}
pb->cpu_bufs[i] = cpu_buf;
err = bpf_map_update_elem(pb->map_fd, &map_key,
&cpu_buf->fd, 0);
if (err) {
err = -errno;
pr_warn("failed to set cpu #%d, key %d -> perf FD %d: %s\n",
cpu, map_key, cpu_buf->fd,
libbpf_strerror_r(err, msg, sizeof(msg)));
goto error;
}
pb->events[i].events = EPOLLIN;
pb->events[i].data.ptr = cpu_buf;
if (epoll_ctl(pb->epoll_fd, EPOLL_CTL_ADD, cpu_buf->fd,
&pb->events[i]) < 0) {
err = -errno;
pr_warn("failed to epoll_ctl cpu #%d perf FD %d: %s\n",
cpu, cpu_buf->fd,
libbpf_strerror_r(err, msg, sizeof(msg)));
goto error;
}
}
return pb;
error:
if (pb)
perf_buffer__free(pb);
return ERR_PTR(err);
}
struct perf_sample_raw {
struct perf_event_header header;
uint32_t size;
char data[0];
};
struct perf_sample_lost {
struct perf_event_header header;
uint64_t id;
uint64_t lost;
uint64_t sample_id;
};
static enum bpf_perf_event_ret
perf_buffer__process_record(struct perf_event_header *e, void *ctx)
{
struct perf_cpu_buf *cpu_buf = ctx;
struct perf_buffer *pb = cpu_buf->pb;
void *data = e;
/* user wants full control over parsing perf event */
if (pb->event_cb)
return pb->event_cb(pb->ctx, cpu_buf->cpu, e);
switch (e->type) {
case PERF_RECORD_SAMPLE: {
struct perf_sample_raw *s = data;
if (pb->sample_cb)
pb->sample_cb(pb->ctx, cpu_buf->cpu, s->data, s->size);
break;
}
case PERF_RECORD_LOST: {
struct perf_sample_lost *s = data;
if (pb->lost_cb)
pb->lost_cb(pb->ctx, cpu_buf->cpu, s->lost);
break;
}
default:
pr_warn("unknown perf sample type %d\n", e->type);
return LIBBPF_PERF_EVENT_ERROR;
}
return LIBBPF_PERF_EVENT_CONT;
}
static int perf_buffer__process_records(struct perf_buffer *pb,
struct perf_cpu_buf *cpu_buf)
{
enum bpf_perf_event_ret ret;
ret = bpf_perf_event_read_simple(cpu_buf->base, pb->mmap_size,
pb->page_size, &cpu_buf->buf,
&cpu_buf->buf_size,
perf_buffer__process_record, cpu_buf);
if (ret != LIBBPF_PERF_EVENT_CONT)
return ret;
return 0;
}
int perf_buffer__poll(struct perf_buffer *pb, int timeout_ms)
{
int i, cnt, err;
cnt = epoll_wait(pb->epoll_fd, pb->events, pb->cpu_cnt, timeout_ms);
for (i = 0; i < cnt; i++) {
struct perf_cpu_buf *cpu_buf = pb->events[i].data.ptr;
err = perf_buffer__process_records(pb, cpu_buf);
if (err) {
pr_warn("error while processing records: %d\n", err);
return err;
}
}
return cnt < 0 ? -errno : cnt;
}
struct bpf_prog_info_array_desc {
int array_offset; /* e.g. offset of jited_prog_insns */
int count_offset; /* e.g. offset of jited_prog_len */
int size_offset; /* > 0: offset of rec size,
* < 0: fix size of -size_offset
*/
};
static struct bpf_prog_info_array_desc bpf_prog_info_array_desc[] = {
[BPF_PROG_INFO_JITED_INSNS] = {
offsetof(struct bpf_prog_info, jited_prog_insns),
offsetof(struct bpf_prog_info, jited_prog_len),
-1,
},
[BPF_PROG_INFO_XLATED_INSNS] = {
offsetof(struct bpf_prog_info, xlated_prog_insns),
offsetof(struct bpf_prog_info, xlated_prog_len),
-1,
},
[BPF_PROG_INFO_MAP_IDS] = {
offsetof(struct bpf_prog_info, map_ids),
offsetof(struct bpf_prog_info, nr_map_ids),
-(int)sizeof(__u32),
},
[BPF_PROG_INFO_JITED_KSYMS] = {
offsetof(struct bpf_prog_info, jited_ksyms),
offsetof(struct bpf_prog_info, nr_jited_ksyms),
-(int)sizeof(__u64),
},
[BPF_PROG_INFO_JITED_FUNC_LENS] = {
offsetof(struct bpf_prog_info, jited_func_lens),
offsetof(struct bpf_prog_info, nr_jited_func_lens),
-(int)sizeof(__u32),
},
[BPF_PROG_INFO_FUNC_INFO] = {
offsetof(struct bpf_prog_info, func_info),
offsetof(struct bpf_prog_info, nr_func_info),
offsetof(struct bpf_prog_info, func_info_rec_size),
},
[BPF_PROG_INFO_LINE_INFO] = {
offsetof(struct bpf_prog_info, line_info),
offsetof(struct bpf_prog_info, nr_line_info),
offsetof(struct bpf_prog_info, line_info_rec_size),
},
[BPF_PROG_INFO_JITED_LINE_INFO] = {
offsetof(struct bpf_prog_info, jited_line_info),
offsetof(struct bpf_prog_info, nr_jited_line_info),
offsetof(struct bpf_prog_info, jited_line_info_rec_size),
},
[BPF_PROG_INFO_PROG_TAGS] = {
offsetof(struct bpf_prog_info, prog_tags),
offsetof(struct bpf_prog_info, nr_prog_tags),
-(int)sizeof(__u8) * BPF_TAG_SIZE,
},
};
static __u32 bpf_prog_info_read_offset_u32(struct bpf_prog_info *info,
int offset)
{
__u32 *array = (__u32 *)info;
if (offset >= 0)
return array[offset / sizeof(__u32)];
return -(int)offset;
}
static __u64 bpf_prog_info_read_offset_u64(struct bpf_prog_info *info,
int offset)
{
__u64 *array = (__u64 *)info;
if (offset >= 0)
return array[offset / sizeof(__u64)];
return -(int)offset;
}
static void bpf_prog_info_set_offset_u32(struct bpf_prog_info *info, int offset,
__u32 val)
{
__u32 *array = (__u32 *)info;
if (offset >= 0)
array[offset / sizeof(__u32)] = val;
}
static void bpf_prog_info_set_offset_u64(struct bpf_prog_info *info, int offset,
__u64 val)
{
__u64 *array = (__u64 *)info;
if (offset >= 0)
array[offset / sizeof(__u64)] = val;
}
struct bpf_prog_info_linear *
bpf_program__get_prog_info_linear(int fd, __u64 arrays)
{
struct bpf_prog_info_linear *info_linear;
struct bpf_prog_info info = {};
__u32 info_len = sizeof(info);
__u32 data_len = 0;
int i, err;
void *ptr;
if (arrays >> BPF_PROG_INFO_LAST_ARRAY)
return ERR_PTR(-EINVAL);
/* step 1: get array dimensions */
err = bpf_obj_get_info_by_fd(fd, &info, &info_len);
if (err) {
pr_debug("can't get prog info: %s", strerror(errno));
return ERR_PTR(-EFAULT);
}
/* step 2: calculate total size of all arrays */
for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
bool include_array = (arrays & (1UL << i)) > 0;
struct bpf_prog_info_array_desc *desc;
__u32 count, size;
desc = bpf_prog_info_array_desc + i;
/* kernel is too old to support this field */
if (info_len < desc->array_offset + sizeof(__u32) ||
info_len < desc->count_offset + sizeof(__u32) ||
(desc->size_offset > 0 && info_len < desc->size_offset))
include_array = false;
if (!include_array) {
arrays &= ~(1UL << i); /* clear the bit */
continue;
}
count = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
size = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
data_len += count * size;
}
/* step 3: allocate continuous memory */
data_len = roundup(data_len, sizeof(__u64));
info_linear = malloc(sizeof(struct bpf_prog_info_linear) + data_len);
if (!info_linear)
return ERR_PTR(-ENOMEM);
/* step 4: fill data to info_linear->info */
info_linear->arrays = arrays;
memset(&info_linear->info, 0, sizeof(info));
ptr = info_linear->data;
for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
struct bpf_prog_info_array_desc *desc;
__u32 count, size;
if ((arrays & (1UL << i)) == 0)
continue;
desc = bpf_prog_info_array_desc + i;
count = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
size = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
bpf_prog_info_set_offset_u32(&info_linear->info,
desc->count_offset, count);
bpf_prog_info_set_offset_u32(&info_linear->info,
desc->size_offset, size);
bpf_prog_info_set_offset_u64(&info_linear->info,
desc->array_offset,
ptr_to_u64(ptr));
ptr += count * size;
}
/* step 5: call syscall again to get required arrays */
err = bpf_obj_get_info_by_fd(fd, &info_linear->info, &info_len);
if (err) {
pr_debug("can't get prog info: %s", strerror(errno));
free(info_linear);
return ERR_PTR(-EFAULT);
}
/* step 6: verify the data */
for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
struct bpf_prog_info_array_desc *desc;
__u32 v1, v2;
if ((arrays & (1UL << i)) == 0)
continue;
desc = bpf_prog_info_array_desc + i;
v1 = bpf_prog_info_read_offset_u32(&info, desc->count_offset);
v2 = bpf_prog_info_read_offset_u32(&info_linear->info,
desc->count_offset);
if (v1 != v2)
pr_warn("%s: mismatch in element count\n", __func__);
v1 = bpf_prog_info_read_offset_u32(&info, desc->size_offset);
v2 = bpf_prog_info_read_offset_u32(&info_linear->info,
desc->size_offset);
if (v1 != v2)
pr_warn("%s: mismatch in rec size\n", __func__);
}
/* step 7: update info_len and data_len */
info_linear->info_len = sizeof(struct bpf_prog_info);
info_linear->data_len = data_len;
return info_linear;
}
void bpf_program__bpil_addr_to_offs(struct bpf_prog_info_linear *info_linear)
{
int i;
for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
struct bpf_prog_info_array_desc *desc;
__u64 addr, offs;
if ((info_linear->arrays & (1UL << i)) == 0)
continue;
desc = bpf_prog_info_array_desc + i;
addr = bpf_prog_info_read_offset_u64(&info_linear->info,
desc->array_offset);
offs = addr - ptr_to_u64(info_linear->data);
bpf_prog_info_set_offset_u64(&info_linear->info,
desc->array_offset, offs);
}
}
void bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear)
{
int i;
for (i = BPF_PROG_INFO_FIRST_ARRAY; i < BPF_PROG_INFO_LAST_ARRAY; ++i) {
struct bpf_prog_info_array_desc *desc;
__u64 addr, offs;
if ((info_linear->arrays & (1UL << i)) == 0)
continue;
desc = bpf_prog_info_array_desc + i;
offs = bpf_prog_info_read_offset_u64(&info_linear->info,
desc->array_offset);
addr = offs + ptr_to_u64(info_linear->data);
bpf_prog_info_set_offset_u64(&info_linear->info,
desc->array_offset, addr);
}
}
int libbpf_num_possible_cpus(void)
{
static const char *fcpu = "/sys/devices/system/cpu/possible";
int len = 0, n = 0, il = 0, ir = 0;
unsigned int start = 0, end = 0;
int tmp_cpus = 0;
static int cpus;
char buf[128];
int error = 0;
int fd = -1;
tmp_cpus = READ_ONCE(cpus);
if (tmp_cpus > 0)
return tmp_cpus;
fd = open(fcpu, O_RDONLY);
if (fd < 0) {
error = errno;
pr_warn("Failed to open file %s: %s\n", fcpu, strerror(error));
return -error;
}
len = read(fd, buf, sizeof(buf));
close(fd);
if (len <= 0) {
error = len ? errno : EINVAL;
pr_warn("Failed to read # of possible cpus from %s: %s\n",
fcpu, strerror(error));
return -error;
}
if (len == sizeof(buf)) {
pr_warn("File %s size overflow\n", fcpu);
return -EOVERFLOW;
}
buf[len] = '\0';
for (ir = 0, tmp_cpus = 0; ir <= len; ir++) {
/* Each sub string separated by ',' has format \d+-\d+ or \d+ */
if (buf[ir] == ',' || buf[ir] == '\0') {
buf[ir] = '\0';
n = sscanf(&buf[il], "%u-%u", &start, &end);
if (n <= 0) {
pr_warn("Failed to get # CPUs from %s\n",
&buf[il]);
return -EINVAL;
} else if (n == 1) {
end = start;
}
tmp_cpus += end - start + 1;
il = ir + 1;
}
}
if (tmp_cpus <= 0) {
pr_warn("Invalid #CPUs %d from %s\n", tmp_cpus, fcpu);
return -EINVAL;
}
WRITE_ONCE(cpus, tmp_cpus);
return tmp_cpus;
}
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