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OpenCloudOS-Kernel/tools/bpf/bpftool/btf_dumper.c

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// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/* Copyright (c) 2018 Facebook */
#include <ctype.h>
#include <stdio.h> /* for (FILE *) used by json_writer */
#include <string.h>
#include <unistd.h>
#include <asm/byteorder.h>
#include <linux/bitops.h>
#include <linux/btf.h>
#include <linux/err.h>
#include <bpf/btf.h>
#include <bpf/bpf.h>
#include "json_writer.h"
#include "main.h"
#define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
#define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
#define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
#define BITS_ROUNDUP_BYTES(bits) \
(BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
static int btf_dumper_do_type(const struct btf_dumper *d, __u32 type_id,
__u8 bit_offset, const void *data);
static int btf_dump_func(const struct btf *btf, char *func_sig,
const struct btf_type *func_proto,
const struct btf_type *func, int pos, int size);
static int dump_prog_id_as_func_ptr(const struct btf_dumper *d,
const struct btf_type *func_proto,
__u32 prog_id)
{
const struct btf_type *func_type;
int prog_fd = -1, func_sig_len;
struct bpf_prog_info info = {};
__u32 info_len = sizeof(info);
const char *prog_name = NULL;
struct btf *prog_btf = NULL;
struct bpf_func_info finfo;
__u32 finfo_rec_size;
char prog_str[1024];
int err;
/* Get the ptr's func_proto */
func_sig_len = btf_dump_func(d->btf, prog_str, func_proto, NULL, 0,
sizeof(prog_str));
if (func_sig_len == -1)
return -1;
if (!prog_id)
goto print;
/* Get the bpf_prog's name. Obtain from func_info. */
prog_fd = bpf_prog_get_fd_by_id(prog_id);
if (prog_fd < 0)
goto print;
err = bpf_prog_get_info_by_fd(prog_fd, &info, &info_len);
if (err)
goto print;
if (!info.btf_id || !info.nr_func_info)
goto print;
finfo_rec_size = info.func_info_rec_size;
memset(&info, 0, sizeof(info));
info.nr_func_info = 1;
info.func_info_rec_size = finfo_rec_size;
info.func_info = ptr_to_u64(&finfo);
err = bpf_prog_get_info_by_fd(prog_fd, &info, &info_len);
if (err)
goto print;
prog_btf = btf__load_from_kernel_by_id(info.btf_id);
if (!prog_btf)
goto print;
func_type = btf__type_by_id(prog_btf, finfo.type_id);
if (!func_type || !btf_is_func(func_type))
goto print;
prog_name = btf__name_by_offset(prog_btf, func_type->name_off);
print:
if (!prog_id)
snprintf(&prog_str[func_sig_len],
sizeof(prog_str) - func_sig_len, " 0");
else if (prog_name)
snprintf(&prog_str[func_sig_len],
sizeof(prog_str) - func_sig_len,
" %s/prog_id:%u", prog_name, prog_id);
else
snprintf(&prog_str[func_sig_len],
sizeof(prog_str) - func_sig_len,
" <unknown_prog_name>/prog_id:%u", prog_id);
prog_str[sizeof(prog_str) - 1] = '\0';
jsonw_string(d->jw, prog_str);
btf__free(prog_btf);
if (prog_fd >= 0)
close(prog_fd);
return 0;
}
static void btf_dumper_ptr(const struct btf_dumper *d,
const struct btf_type *t,
const void *data)
{
unsigned long value = *(unsigned long *)data;
const struct btf_type *ptr_type;
__s32 ptr_type_id;
if (!d->prog_id_as_func_ptr || value > UINT32_MAX)
goto print_ptr_value;
ptr_type_id = btf__resolve_type(d->btf, t->type);
if (ptr_type_id < 0)
goto print_ptr_value;
ptr_type = btf__type_by_id(d->btf, ptr_type_id);
if (!ptr_type || !btf_is_func_proto(ptr_type))
goto print_ptr_value;
if (!dump_prog_id_as_func_ptr(d, ptr_type, value))
return;
print_ptr_value:
if (d->is_plain_text)
jsonw_printf(d->jw, "%p", (void *)value);
else
jsonw_printf(d->jw, "%lu", value);
}
static int btf_dumper_modifier(const struct btf_dumper *d, __u32 type_id,
__u8 bit_offset, const void *data)
{
int actual_type_id;
actual_type_id = btf__resolve_type(d->btf, type_id);
if (actual_type_id < 0)
return actual_type_id;
return btf_dumper_do_type(d, actual_type_id, bit_offset, data);
}
static int btf_dumper_enum(const struct btf_dumper *d,
const struct btf_type *t,
const void *data)
{
const struct btf_enum *enums = btf_enum(t);
__s64 value;
__u16 i;
switch (t->size) {
case 8:
value = *(__s64 *)data;
break;
case 4:
value = *(__s32 *)data;
break;
case 2:
value = *(__s16 *)data;
break;
case 1:
value = *(__s8 *)data;
break;
default:
return -EINVAL;
}
for (i = 0; i < btf_vlen(t); i++) {
if (value == enums[i].val) {
jsonw_string(d->jw,
btf__name_by_offset(d->btf,
enums[i].name_off));
return 0;
}
}
jsonw_int(d->jw, value);
return 0;
}
static int btf_dumper_enum64(const struct btf_dumper *d,
const struct btf_type *t,
const void *data)
{
const struct btf_enum64 *enums = btf_enum64(t);
__u32 val_lo32, val_hi32;
__u64 value;
__u16 i;
value = *(__u64 *)data;
val_lo32 = (__u32)value;
val_hi32 = value >> 32;
for (i = 0; i < btf_vlen(t); i++) {
if (val_lo32 == enums[i].val_lo32 && val_hi32 == enums[i].val_hi32) {
jsonw_string(d->jw,
btf__name_by_offset(d->btf,
enums[i].name_off));
return 0;
}
}
jsonw_int(d->jw, value);
return 0;
}
static bool is_str_array(const struct btf *btf, const struct btf_array *arr,
const char *s)
{
const struct btf_type *elem_type;
const char *end_s;
if (!arr->nelems)
return false;
elem_type = btf__type_by_id(btf, arr->type);
/* Not skipping typedef. typedef to char does not count as
* a string now.
*/
while (elem_type && btf_is_mod(elem_type))
elem_type = btf__type_by_id(btf, elem_type->type);
if (!elem_type || !btf_is_int(elem_type) || elem_type->size != 1)
return false;
if (btf_int_encoding(elem_type) != BTF_INT_CHAR &&
strcmp("char", btf__name_by_offset(btf, elem_type->name_off)))
return false;
end_s = s + arr->nelems;
while (s < end_s) {
if (!*s)
return true;
if (*s <= 0x1f || *s >= 0x7f)
return false;
s++;
}
/* '\0' is not found */
return false;
}
static int btf_dumper_array(const struct btf_dumper *d, __u32 type_id,
const void *data)
{
const struct btf_type *t = btf__type_by_id(d->btf, type_id);
struct btf_array *arr = (struct btf_array *)(t + 1);
long long elem_size;
int ret = 0;
__u32 i;
if (is_str_array(d->btf, arr, data)) {
jsonw_string(d->jw, data);
return 0;
}
elem_size = btf__resolve_size(d->btf, arr->type);
if (elem_size < 0)
return elem_size;
jsonw_start_array(d->jw);
for (i = 0; i < arr->nelems; i++) {
ret = btf_dumper_do_type(d, arr->type, 0,
data + i * elem_size);
if (ret)
break;
}
jsonw_end_array(d->jw);
return ret;
}
static void btf_int128_print(json_writer_t *jw, const void *data,
bool is_plain_text)
{
/* data points to a __int128 number.
* Suppose
* int128_num = *(__int128 *)data;
* The below formulas shows what upper_num and lower_num represents:
* upper_num = int128_num >> 64;
* lower_num = int128_num & 0xffffffffFFFFFFFFULL;
*/
__u64 upper_num, lower_num;
#ifdef __BIG_ENDIAN_BITFIELD
upper_num = *(__u64 *)data;
lower_num = *(__u64 *)(data + 8);
#else
upper_num = *(__u64 *)(data + 8);
lower_num = *(__u64 *)data;
#endif
if (is_plain_text) {
if (upper_num == 0)
jsonw_printf(jw, "0x%llx", lower_num);
else
jsonw_printf(jw, "0x%llx%016llx", upper_num, lower_num);
} else {
if (upper_num == 0)
jsonw_printf(jw, "\"0x%llx\"", lower_num);
else
jsonw_printf(jw, "\"0x%llx%016llx\"", upper_num, lower_num);
}
}
static void btf_int128_shift(__u64 *print_num, __u16 left_shift_bits,
__u16 right_shift_bits)
{
__u64 upper_num, lower_num;
#ifdef __BIG_ENDIAN_BITFIELD
upper_num = print_num[0];
lower_num = print_num[1];
#else
upper_num = print_num[1];
lower_num = print_num[0];
#endif
/* shake out un-needed bits by shift/or operations */
if (left_shift_bits >= 64) {
upper_num = lower_num << (left_shift_bits - 64);
lower_num = 0;
} else {
upper_num = (upper_num << left_shift_bits) |
(lower_num >> (64 - left_shift_bits));
lower_num = lower_num << left_shift_bits;
}
if (right_shift_bits >= 64) {
lower_num = upper_num >> (right_shift_bits - 64);
upper_num = 0;
} else {
lower_num = (lower_num >> right_shift_bits) |
(upper_num << (64 - right_shift_bits));
upper_num = upper_num >> right_shift_bits;
}
#ifdef __BIG_ENDIAN_BITFIELD
print_num[0] = upper_num;
print_num[1] = lower_num;
#else
print_num[0] = lower_num;
print_num[1] = upper_num;
#endif
}
static void btf_dumper_bitfield(__u32 nr_bits, __u8 bit_offset,
const void *data, json_writer_t *jw,
bool is_plain_text)
{
int left_shift_bits, right_shift_bits;
__u64 print_num[2] = {};
int bytes_to_copy;
int bits_to_copy;
bits_to_copy = bit_offset + nr_bits;
bytes_to_copy = BITS_ROUNDUP_BYTES(bits_to_copy);
memcpy(print_num, data, bytes_to_copy);
#if defined(__BIG_ENDIAN_BITFIELD)
left_shift_bits = bit_offset;
#elif defined(__LITTLE_ENDIAN_BITFIELD)
left_shift_bits = 128 - bits_to_copy;
#else
#error neither big nor little endian
#endif
right_shift_bits = 128 - nr_bits;
btf_int128_shift(print_num, left_shift_bits, right_shift_bits);
btf_int128_print(jw, print_num, is_plain_text);
}
static void btf_dumper_int_bits(__u32 int_type, __u8 bit_offset,
const void *data, json_writer_t *jw,
bool is_plain_text)
{
int nr_bits = BTF_INT_BITS(int_type);
int total_bits_offset;
/* bits_offset is at most 7.
* BTF_INT_OFFSET() cannot exceed 128 bits.
*/
total_bits_offset = bit_offset + BTF_INT_OFFSET(int_type);
data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
bit_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
btf_dumper_bitfield(nr_bits, bit_offset, data, jw,
is_plain_text);
}
static int btf_dumper_int(const struct btf_type *t, __u8 bit_offset,
const void *data, json_writer_t *jw,
bool is_plain_text)
{
__u32 *int_type;
__u32 nr_bits;
int_type = (__u32 *)(t + 1);
nr_bits = BTF_INT_BITS(*int_type);
/* if this is bit field */
if (bit_offset || BTF_INT_OFFSET(*int_type) ||
BITS_PER_BYTE_MASKED(nr_bits)) {
btf_dumper_int_bits(*int_type, bit_offset, data, jw,
is_plain_text);
return 0;
}
if (nr_bits == 128) {
btf_int128_print(jw, data, is_plain_text);
return 0;
}
switch (BTF_INT_ENCODING(*int_type)) {
case 0:
if (BTF_INT_BITS(*int_type) == 64)
jsonw_printf(jw, "%llu", *(__u64 *)data);
else if (BTF_INT_BITS(*int_type) == 32)
jsonw_printf(jw, "%u", *(__u32 *)data);
else if (BTF_INT_BITS(*int_type) == 16)
jsonw_printf(jw, "%hu", *(__u16 *)data);
else if (BTF_INT_BITS(*int_type) == 8)
jsonw_printf(jw, "%hhu", *(__u8 *)data);
else
btf_dumper_int_bits(*int_type, bit_offset, data, jw,
is_plain_text);
break;
case BTF_INT_SIGNED:
if (BTF_INT_BITS(*int_type) == 64)
jsonw_printf(jw, "%lld", *(long long *)data);
else if (BTF_INT_BITS(*int_type) == 32)
jsonw_printf(jw, "%d", *(int *)data);
else if (BTF_INT_BITS(*int_type) == 16)
jsonw_printf(jw, "%hd", *(short *)data);
else if (BTF_INT_BITS(*int_type) == 8)
jsonw_printf(jw, "%hhd", *(char *)data);
else
btf_dumper_int_bits(*int_type, bit_offset, data, jw,
is_plain_text);
break;
case BTF_INT_CHAR:
if (isprint(*(char *)data))
jsonw_printf(jw, "\"%c\"", *(char *)data);
else
if (is_plain_text)
jsonw_printf(jw, "0x%hhx", *(char *)data);
else
jsonw_printf(jw, "\"\\u00%02hhx\"",
*(char *)data);
break;
case BTF_INT_BOOL:
jsonw_bool(jw, *(bool *)data);
break;
default:
/* shouldn't happen */
return -EINVAL;
}
return 0;
}
static int btf_dumper_struct(const struct btf_dumper *d, __u32 type_id,
const void *data)
{
const struct btf_type *t;
struct btf_member *m;
const void *data_off;
int kind_flag;
int ret = 0;
int i, vlen;
t = btf__type_by_id(d->btf, type_id);
if (!t)
return -EINVAL;
kind_flag = BTF_INFO_KFLAG(t->info);
vlen = BTF_INFO_VLEN(t->info);
jsonw_start_object(d->jw);
m = (struct btf_member *)(t + 1);
for (i = 0; i < vlen; i++) {
__u32 bit_offset = m[i].offset;
__u32 bitfield_size = 0;
if (kind_flag) {
bitfield_size = BTF_MEMBER_BITFIELD_SIZE(bit_offset);
bit_offset = BTF_MEMBER_BIT_OFFSET(bit_offset);
}
jsonw_name(d->jw, btf__name_by_offset(d->btf, m[i].name_off));
data_off = data + BITS_ROUNDDOWN_BYTES(bit_offset);
if (bitfield_size) {
btf_dumper_bitfield(bitfield_size,
BITS_PER_BYTE_MASKED(bit_offset),
data_off, d->jw, d->is_plain_text);
} else {
ret = btf_dumper_do_type(d, m[i].type,
BITS_PER_BYTE_MASKED(bit_offset),
data_off);
if (ret)
break;
}
}
jsonw_end_object(d->jw);
return ret;
}
static int btf_dumper_var(const struct btf_dumper *d, __u32 type_id,
__u8 bit_offset, const void *data)
{
const struct btf_type *t = btf__type_by_id(d->btf, type_id);
int ret;
jsonw_start_object(d->jw);
jsonw_name(d->jw, btf__name_by_offset(d->btf, t->name_off));
ret = btf_dumper_do_type(d, t->type, bit_offset, data);
jsonw_end_object(d->jw);
return ret;
}
static int btf_dumper_datasec(const struct btf_dumper *d, __u32 type_id,
const void *data)
{
struct btf_var_secinfo *vsi;
const struct btf_type *t;
int ret = 0, i, vlen;
t = btf__type_by_id(d->btf, type_id);
if (!t)
return -EINVAL;
vlen = BTF_INFO_VLEN(t->info);
vsi = (struct btf_var_secinfo *)(t + 1);
jsonw_start_object(d->jw);
jsonw_name(d->jw, btf__name_by_offset(d->btf, t->name_off));
jsonw_start_array(d->jw);
for (i = 0; i < vlen; i++) {
ret = btf_dumper_do_type(d, vsi[i].type, 0, data + vsi[i].offset);
if (ret)
break;
}
jsonw_end_array(d->jw);
jsonw_end_object(d->jw);
return ret;
}
static int btf_dumper_do_type(const struct btf_dumper *d, __u32 type_id,
__u8 bit_offset, const void *data)
{
const struct btf_type *t = btf__type_by_id(d->btf, type_id);
switch (BTF_INFO_KIND(t->info)) {
case BTF_KIND_INT:
return btf_dumper_int(t, bit_offset, data, d->jw,
d->is_plain_text);
case BTF_KIND_STRUCT:
case BTF_KIND_UNION:
return btf_dumper_struct(d, type_id, data);
case BTF_KIND_ARRAY:
return btf_dumper_array(d, type_id, data);
case BTF_KIND_ENUM:
return btf_dumper_enum(d, t, data);
case BTF_KIND_ENUM64:
return btf_dumper_enum64(d, t, data);
case BTF_KIND_PTR:
btf_dumper_ptr(d, t, data);
return 0;
case BTF_KIND_UNKN:
jsonw_printf(d->jw, "(unknown)");
return 0;
case BTF_KIND_FWD:
/* map key or value can't be forward */
jsonw_printf(d->jw, "(fwd-kind-invalid)");
return -EINVAL;
case BTF_KIND_TYPEDEF:
case BTF_KIND_VOLATILE:
case BTF_KIND_CONST:
case BTF_KIND_RESTRICT:
return btf_dumper_modifier(d, type_id, bit_offset, data);
case BTF_KIND_VAR:
return btf_dumper_var(d, type_id, bit_offset, data);
case BTF_KIND_DATASEC:
return btf_dumper_datasec(d, type_id, data);
default:
jsonw_printf(d->jw, "(unsupported-kind");
return -EINVAL;
}
}
int btf_dumper_type(const struct btf_dumper *d, __u32 type_id,
const void *data)
{
return btf_dumper_do_type(d, type_id, 0, data);
}
#define BTF_PRINT_ARG(...) \
do { \
pos += snprintf(func_sig + pos, size - pos, \
__VA_ARGS__); \
if (pos >= size) \
return -1; \
} while (0)
#define BTF_PRINT_TYPE(type) \
do { \
pos = __btf_dumper_type_only(btf, type, func_sig, \
pos, size); \
if (pos == -1) \
return -1; \
} while (0)
static int __btf_dumper_type_only(const struct btf *btf, __u32 type_id,
char *func_sig, int pos, int size)
{
const struct btf_type *proto_type;
const struct btf_array *array;
const struct btf_var *var;
const struct btf_type *t;
if (!type_id) {
BTF_PRINT_ARG("void ");
return pos;
}
t = btf__type_by_id(btf, type_id);
switch (BTF_INFO_KIND(t->info)) {
case BTF_KIND_INT:
case BTF_KIND_TYPEDEF:
case BTF_KIND_FLOAT:
BTF_PRINT_ARG("%s ", btf__name_by_offset(btf, t->name_off));
break;
case BTF_KIND_STRUCT:
BTF_PRINT_ARG("struct %s ",
btf__name_by_offset(btf, t->name_off));
break;
case BTF_KIND_UNION:
BTF_PRINT_ARG("union %s ",
btf__name_by_offset(btf, t->name_off));
break;
case BTF_KIND_ENUM:
case BTF_KIND_ENUM64:
BTF_PRINT_ARG("enum %s ",
btf__name_by_offset(btf, t->name_off));
break;
case BTF_KIND_ARRAY:
array = (struct btf_array *)(t + 1);
BTF_PRINT_TYPE(array->type);
BTF_PRINT_ARG("[%d]", array->nelems);
break;
case BTF_KIND_PTR:
BTF_PRINT_TYPE(t->type);
BTF_PRINT_ARG("* ");
break;
case BTF_KIND_FWD:
BTF_PRINT_ARG("%s %s ",
BTF_INFO_KFLAG(t->info) ? "union" : "struct",
btf__name_by_offset(btf, t->name_off));
break;
case BTF_KIND_VOLATILE:
BTF_PRINT_ARG("volatile ");
BTF_PRINT_TYPE(t->type);
break;
case BTF_KIND_CONST:
BTF_PRINT_ARG("const ");
BTF_PRINT_TYPE(t->type);
break;
case BTF_KIND_RESTRICT:
BTF_PRINT_ARG("restrict ");
BTF_PRINT_TYPE(t->type);
break;
case BTF_KIND_FUNC_PROTO:
pos = btf_dump_func(btf, func_sig, t, NULL, pos, size);
if (pos == -1)
return -1;
break;
case BTF_KIND_FUNC:
proto_type = btf__type_by_id(btf, t->type);
pos = btf_dump_func(btf, func_sig, proto_type, t, pos, size);
if (pos == -1)
return -1;
break;
case BTF_KIND_VAR:
var = (struct btf_var *)(t + 1);
if (var->linkage == BTF_VAR_STATIC)
BTF_PRINT_ARG("static ");
BTF_PRINT_TYPE(t->type);
BTF_PRINT_ARG(" %s",
btf__name_by_offset(btf, t->name_off));
break;
case BTF_KIND_DATASEC:
BTF_PRINT_ARG("section (\"%s\") ",
btf__name_by_offset(btf, t->name_off));
break;
case BTF_KIND_UNKN:
default:
return -1;
}
return pos;
}
static int btf_dump_func(const struct btf *btf, char *func_sig,
const struct btf_type *func_proto,
const struct btf_type *func, int pos, int size)
{
int i, vlen;
BTF_PRINT_TYPE(func_proto->type);
if (func)
BTF_PRINT_ARG("%s(", btf__name_by_offset(btf, func->name_off));
else
BTF_PRINT_ARG("(");
vlen = BTF_INFO_VLEN(func_proto->info);
for (i = 0; i < vlen; i++) {
struct btf_param *arg = &((struct btf_param *)(func_proto + 1))[i];
if (i)
BTF_PRINT_ARG(", ");
if (arg->type) {
BTF_PRINT_TYPE(arg->type);
if (arg->name_off)
BTF_PRINT_ARG("%s",
btf__name_by_offset(btf, arg->name_off));
else if (pos && func_sig[pos - 1] == ' ')
/* Remove unnecessary space for
* FUNC_PROTO that does not have
* arg->name_off
*/
func_sig[--pos] = '\0';
} else {
BTF_PRINT_ARG("...");
}
}
BTF_PRINT_ARG(")");
return pos;
}
void btf_dumper_type_only(const struct btf *btf, __u32 type_id, char *func_sig,
int size)
{
int err;
func_sig[0] = '\0';
if (!btf)
return;
err = __btf_dumper_type_only(btf, type_id, func_sig, 0, size);
if (err < 0)
func_sig[0] = '\0';
}
static const char *ltrim(const char *s)
{
while (isspace(*s))
s++;
return s;
}
void btf_dump_linfo_plain(const struct btf *btf,
const struct bpf_line_info *linfo,
const char *prefix, bool linum)
{
const char *line = btf__name_by_offset(btf, linfo->line_off);
if (!line)
return;
line = ltrim(line);
if (!prefix)
prefix = "";
if (linum) {
const char *file = btf__name_by_offset(btf, linfo->file_name_off);
/* More forgiving on file because linum option is
* expected to provide more info than the already
* available src line.
*/
if (!file)
file = "";
printf("%s%s [file:%s line_num:%u line_col:%u]\n",
prefix, line, file,
BPF_LINE_INFO_LINE_NUM(linfo->line_col),
BPF_LINE_INFO_LINE_COL(linfo->line_col));
} else {
printf("%s%s\n", prefix, line);
}
}
void btf_dump_linfo_json(const struct btf *btf,
const struct bpf_line_info *linfo, bool linum)
{
const char *line = btf__name_by_offset(btf, linfo->line_off);
if (line)
jsonw_string_field(json_wtr, "src", ltrim(line));
if (linum) {
const char *file = btf__name_by_offset(btf, linfo->file_name_off);
if (file)
jsonw_string_field(json_wtr, "file", file);
if (BPF_LINE_INFO_LINE_NUM(linfo->line_col))
jsonw_int_field(json_wtr, "line_num",
BPF_LINE_INFO_LINE_NUM(linfo->line_col));
if (BPF_LINE_INFO_LINE_COL(linfo->line_col))
jsonw_int_field(json_wtr, "line_col",
BPF_LINE_INFO_LINE_COL(linfo->line_col));
}
}
static void dotlabel_puts(const char *s)
{
for (; *s; ++s) {
switch (*s) {
case '\\':
case '"':
case '{':
case '}':
case '<':
case '>':
case '|':
case ' ':
putchar('\\');
fallthrough;
default:
putchar(*s);
}
}
}
static const char *shorten_path(const char *path)
{
const unsigned int MAX_PATH_LEN = 32;
size_t len = strlen(path);
const char *shortpath;
if (len <= MAX_PATH_LEN)
return path;
/* Search for last '/' under the MAX_PATH_LEN limit */
shortpath = strchr(path + len - MAX_PATH_LEN, '/');
if (shortpath) {
if (shortpath < path + strlen("..."))
/* We removed a very short prefix, e.g. "/w", and we'll
* make the path longer by prefixing with the ellipsis.
* Not worth it, keep initial path.
*/
return path;
return shortpath;
}
/* File base name length is > MAX_PATH_LEN, search for last '/' */
shortpath = strrchr(path, '/');
if (shortpath)
return shortpath;
return path;
}
void btf_dump_linfo_dotlabel(const struct btf *btf,
const struct bpf_line_info *linfo, bool linum)
{
const char *line = btf__name_by_offset(btf, linfo->line_off);
if (!line || !strlen(line))
return;
line = ltrim(line);
if (linum) {
const char *file = btf__name_by_offset(btf, linfo->file_name_off);
const char *shortfile;
/* More forgiving on file because linum option is
* expected to provide more info than the already
* available src line.
*/
if (!file)
shortfile = "";
else
shortfile = shorten_path(file);
printf("; [%s", shortfile > file ? "..." : "");
dotlabel_puts(shortfile);
printf(" line:%u col:%u]\\l\\\n",
BPF_LINE_INFO_LINE_NUM(linfo->line_col),
BPF_LINE_INFO_LINE_COL(linfo->line_col));
}
printf("; ");
dotlabel_puts(line);
printf("\\l\\\n");
}
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