libbpf: cleanup after partial failure in bpf_object__pin

bpftool will use bpf_object__pin in the next commits to pin all programs
and maps from the file; in case of a partial failure, we need to get
back to the clean state (undo previous program/map pins).

As part of a cleanup, I've added and exported separate routines to
pin all maps (bpf_object__pin_maps) and progs (bpf_object__pin_programs)
of an object.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Stanislav Fomichev 2018-11-09 08:21:41 -08:00 committed by Alexei Starovoitov
parent 108d50a976
commit 0c19a9fbc9
2 changed files with 319 additions and 23 deletions

View File

@ -1699,6 +1699,34 @@ int bpf_program__pin_instance(struct bpf_program *prog, const char *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_warning("invalid program pointer\n");
return -EINVAL;
}
if (instance < 0 || instance >= prog->instances.nr) {
pr_warning("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;
}
static int make_dir(const char *path)
{
char *cp, errmsg[STRERR_BUFSIZE];
@ -1737,6 +1765,64 @@ int bpf_program__pin(struct bpf_program *prog, const char *path)
if (err)
return err;
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_warning("invalid program pointer\n");
return -EINVAL;
}
if (prog->instances.nr <= 0) {
pr_warning("no instances of prog %s to pin\n",
prog->section_name);
return -EINVAL;
}
for (i = 0; i < prog->instances.nr; i++) {
char buf[PATH_MAX];
int len;
@ -1747,11 +1833,15 @@ int bpf_program__pin(struct bpf_program *prog, const char *path)
else if (len >= PATH_MAX)
return -ENAMETOOLONG;
err = bpf_program__pin_instance(prog, buf, i);
err = bpf_program__unpin_instance(prog, buf, i);
if (err)
return err;
}
err = rmdir(path);
if (err)
return -errno;
return 0;
}
@ -1776,12 +1866,33 @@ int bpf_map__pin(struct bpf_map *map, const char *path)
}
pr_debug("pinned map '%s'\n", path);
return 0;
}
int bpf_object__pin(struct bpf_object *obj, const char *path)
int bpf_map__unpin(struct bpf_map *map, const char *path)
{
int err;
err = check_path(path);
if (err)
return err;
if (map == NULL) {
pr_warning("invalid map pointer\n");
return -EINVAL;
}
err = unlink(path);
if (err != 0)
return -errno;
pr_debug("unpinned map '%s'\n", path);
return 0;
}
int bpf_object__pin_maps(struct bpf_object *obj, const char *path)
{
struct bpf_program *prog;
struct bpf_map *map;
int err;
@ -1797,6 +1908,53 @@ int bpf_object__pin(struct bpf_object *obj, const char *path)
if (err)
return err;
bpf_map__for_each(map, obj) {
char buf[PATH_MAX];
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;
}
err = bpf_map__pin(map, buf);
if (err)
goto err_unpin_maps;
}
return 0;
err_unpin_maps:
while ((map = bpf_map__prev(map, obj))) {
char buf[PATH_MAX];
int len;
len = snprintf(buf, PATH_MAX, "%s/%s", path,
bpf_map__name(map));
if (len < 0)
continue;
else if (len >= PATH_MAX)
continue;
bpf_map__unpin(map, buf);
}
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_map__for_each(map, obj) {
char buf[PATH_MAX];
int len;
@ -1808,11 +1966,78 @@ int bpf_object__pin(struct bpf_object *obj, const char *path)
else if (len >= PATH_MAX)
return -ENAMETOOLONG;
err = bpf_map__pin(map, buf);
err = bpf_map__unpin(map, buf);
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_warning("object not yet loaded; load it first\n");
return -ENOENT;
}
err = make_dir(path);
if (err)
return err;
bpf_object__for_each_program(prog, obj) {
char buf[PATH_MAX];
int len;
len = snprintf(buf, PATH_MAX, "%s/%s", path,
prog->section_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->section_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;
@ -1824,7 +2049,7 @@ int bpf_object__pin(struct bpf_object *obj, const char *path)
else if (len >= PATH_MAX)
return -ENAMETOOLONG;
err = bpf_program__pin(prog, buf);
err = bpf_program__unpin(prog, buf);
if (err)
return err;
}
@ -1832,6 +2057,23 @@ int bpf_object__pin(struct bpf_object *obj, const char *path)
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;
@ -1918,23 +2160,20 @@ void *bpf_object__priv(struct bpf_object *obj)
}
static struct bpf_program *
__bpf_program__next(struct bpf_program *prev, struct bpf_object *obj)
__bpf_program__iter(struct bpf_program *p, struct bpf_object *obj, int i)
{
size_t idx;
ssize_t idx;
if (!obj->programs)
return NULL;
/* First handler */
if (prev == NULL)
return &obj->programs[0];
if (prev->obj != obj) {
if (p->obj != obj) {
pr_warning("error: program handler doesn't match object\n");
return NULL;
}
idx = (prev - obj->programs) + 1;
if (idx >= obj->nr_programs)
idx = (p - obj->programs) + i;
if (idx >= obj->nr_programs || idx < 0)
return NULL;
return &obj->programs[idx];
}
@ -1944,8 +2183,29 @@ bpf_program__next(struct bpf_program *prev, struct bpf_object *obj)
{
struct bpf_program *prog = prev;
if (prev == NULL)
return obj->programs;
do {
prog = __bpf_program__next(prog, obj);
prog = __bpf_program__iter(prog, obj, 1);
} while (prog && bpf_program__is_function_storage(prog, obj));
return prog;
}
struct bpf_program *
bpf_program__prev(struct bpf_program *next, struct bpf_object *obj)
{
struct bpf_program *prog = next;
if (next == NULL) {
if (!obj->nr_programs)
return NULL;
return obj->programs + obj->nr_programs - 1;
}
do {
prog = __bpf_program__iter(prog, obj, -1);
} while (prog && bpf_program__is_function_storage(prog, obj));
return prog;
@ -2272,10 +2532,10 @@ void bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex)
map->map_ifindex = ifindex;
}
struct bpf_map *
bpf_map__next(struct bpf_map *prev, struct bpf_object *obj)
static struct bpf_map *
__bpf_map__iter(struct bpf_map *m, struct bpf_object *obj, int i)
{
size_t idx;
ssize_t idx;
struct bpf_map *s, *e;
if (!obj || !obj->maps)
@ -2284,21 +2544,39 @@ bpf_map__next(struct bpf_map *prev, struct bpf_object *obj)
s = obj->maps;
e = obj->maps + obj->nr_maps;
if (prev == NULL)
return s;
if ((prev < s) || (prev >= e)) {
if ((m < s) || (m >= e)) {
pr_warning("error in %s: map handler doesn't belong to object\n",
__func__);
return NULL;
}
idx = (prev - obj->maps) + 1;
if (idx >= obj->nr_maps)
idx = (m - obj->maps) + i;
if (idx >= obj->nr_maps || idx < 0)
return NULL;
return &obj->maps[idx];
}
struct bpf_map *
bpf_map__next(struct bpf_map *prev, struct bpf_object *obj)
{
if (prev == NULL)
return obj->maps;
return __bpf_map__iter(prev, obj, 1);
}
struct bpf_map *
bpf_map__prev(struct bpf_map *next, 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(struct bpf_object *obj, const char *name)
{

View File

@ -71,6 +71,13 @@ struct bpf_object *__bpf_object__open_xattr(struct bpf_object_open_attr *attr,
LIBBPF_API struct bpf_object *bpf_object__open_buffer(void *obj_buf,
size_t obj_buf_sz,
const char *name);
LIBBPF_API int bpf_object__pin_maps(struct bpf_object *obj, const char *path);
LIBBPF_API int bpf_object__unpin_maps(struct bpf_object *obj,
const char *path);
LIBBPF_API int bpf_object__pin_programs(struct bpf_object *obj,
const char *path);
LIBBPF_API int bpf_object__unpin_programs(struct bpf_object *obj,
const char *path);
LIBBPF_API int bpf_object__pin(struct bpf_object *object, const char *path);
LIBBPF_API void bpf_object__close(struct bpf_object *object);
@ -112,6 +119,9 @@ LIBBPF_API struct bpf_program *bpf_program__next(struct bpf_program *prog,
(pos) != NULL; \
(pos) = bpf_program__next((pos), (obj)))
LIBBPF_API struct bpf_program *bpf_program__prev(struct bpf_program *prog,
struct bpf_object *obj);
typedef void (*bpf_program_clear_priv_t)(struct bpf_program *,
void *);
@ -131,7 +141,11 @@ LIBBPF_API int bpf_program__fd(struct bpf_program *prog);
LIBBPF_API int bpf_program__pin_instance(struct bpf_program *prog,
const char *path,
int instance);
LIBBPF_API int bpf_program__unpin_instance(struct bpf_program *prog,
const char *path,
int instance);
LIBBPF_API int bpf_program__pin(struct bpf_program *prog, const char *path);
LIBBPF_API int bpf_program__unpin(struct bpf_program *prog, const char *path);
LIBBPF_API void bpf_program__unload(struct bpf_program *prog);
struct bpf_insn;
@ -260,6 +274,9 @@ bpf_map__next(struct bpf_map *map, struct bpf_object *obj);
(pos) != NULL; \
(pos) = bpf_map__next((pos), (obj)))
LIBBPF_API struct bpf_map *
bpf_map__prev(struct bpf_map *map, struct bpf_object *obj);
LIBBPF_API int bpf_map__fd(struct bpf_map *map);
LIBBPF_API const struct bpf_map_def *bpf_map__def(struct bpf_map *map);
LIBBPF_API const char *bpf_map__name(struct bpf_map *map);
@ -274,6 +291,7 @@ LIBBPF_API int bpf_map__reuse_fd(struct bpf_map *map, int fd);
LIBBPF_API bool bpf_map__is_offload_neutral(struct bpf_map *map);
LIBBPF_API void bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex);
LIBBPF_API int bpf_map__pin(struct bpf_map *map, const char *path);
LIBBPF_API int bpf_map__unpin(struct bpf_map *map, const char *path);
LIBBPF_API long libbpf_get_error(const void *ptr);