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Diffstat (limited to 'tools/lib/bpf/libbpf.c')
-rw-r--r--tools/lib/bpf/libbpf.c146
1 files changed, 138 insertions, 8 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index fa15f3b315ba..7aa2a2a22cef 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1093,10 +1093,32 @@ static bool get_map_field_int(const char *map_name, const struct btf *btf,
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 Elf_Data *data, bool strict,
+ const char *pin_root_path)
{
const struct btf_type *var, *def, *t;
const struct btf_var_secinfo *vi;
@@ -1271,6 +1293,30 @@ static int bpf_object__init_user_btf_map(struct bpf_object *obj,
}
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",
@@ -1290,7 +1336,8 @@ static int bpf_object__init_user_btf_map(struct bpf_object *obj,
return 0;
}
-static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict)
+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;
@@ -1332,7 +1379,7 @@ static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict)
for (i = 0; i < vlen; i++) {
err = bpf_object__init_user_btf_map(obj, sec, i,
obj->efile.btf_maps_shndx,
- data, strict);
+ data, strict, pin_root_path);
if (err)
return err;
}
@@ -1340,7 +1387,8 @@ static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict)
return 0;
}
-static int bpf_object__init_maps(struct bpf_object *obj, bool relaxed_maps)
+static int bpf_object__init_maps(struct bpf_object *obj, bool relaxed_maps,
+ const char *pin_root_path)
{
bool strict = !relaxed_maps;
int err;
@@ -1349,7 +1397,7 @@ static int bpf_object__init_maps(struct bpf_object *obj, bool relaxed_maps)
if (err)
return err;
- err = bpf_object__init_user_btf_maps(obj, strict);
+ err = bpf_object__init_user_btf_maps(obj, strict, pin_root_path);
if (err)
return err;
@@ -1538,7 +1586,8 @@ static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj)
return 0;
}
-static int bpf_object__elf_collect(struct bpf_object *obj, bool relaxed_maps)
+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;
@@ -1673,7 +1722,7 @@ static int bpf_object__elf_collect(struct bpf_object *obj, bool relaxed_maps)
}
err = bpf_object__init_btf(obj, btf_data, btf_ext_data);
if (!err)
- err = bpf_object__init_maps(obj, relaxed_maps);
+ err = bpf_object__init_maps(obj, relaxed_maps, pin_root_path);
if (!err)
err = bpf_object__sanitize_and_load_btf(obj);
if (!err)
@@ -2129,6 +2178,66 @@ bpf_object__probe_caps(struct bpf_object *obj)
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)
{
@@ -2171,6 +2280,15 @@ bpf_object__create_maps(struct bpf_object *obj)
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);
@@ -2249,6 +2367,15 @@ 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);
}
@@ -3623,6 +3750,7 @@ 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;
@@ -3657,11 +3785,13 @@ __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
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);
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), 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);
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-13 04:20:29 +0000