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-rw-r--r--tools/lib/bpf/libbpf.c142
1 files changed, 98 insertions, 44 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index b699aea9a025..96a2b2ff1212 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -185,6 +185,7 @@ struct bpf_program {
struct bpf_map {
int fd;
char *name;
+ size_t offset;
struct bpf_map_def def;
void *priv;
bpf_map_clear_priv_t clear_priv;
@@ -513,57 +514,106 @@ bpf_object__init_kversion(struct bpf_object *obj,
}
static int
-bpf_object__init_maps(struct bpf_object *obj, void *data,
- size_t size)
+bpf_object__validate_maps(struct bpf_object *obj)
{
- size_t nr_maps;
int i;
- nr_maps = size / sizeof(struct bpf_map_def);
- if (!data || !nr_maps) {
- pr_debug("%s doesn't need map definition\n",
- obj->path);
+ /*
+ * If there's only 1 map, the only error case should have been
+ * catched in bpf_object__init_maps().
+ */
+ if (!obj->maps || !obj->nr_maps || (obj->nr_maps == 1))
return 0;
- }
- pr_debug("maps in %s: %zd bytes\n", obj->path, size);
+ for (i = 1; i < obj->nr_maps; i++) {
+ const struct bpf_map *a = &obj->maps[i - 1];
+ const struct bpf_map *b = &obj->maps[i];
- obj->maps = calloc(nr_maps, sizeof(obj->maps[0]));
- if (!obj->maps) {
- pr_warning("alloc maps for object failed\n");
- return -ENOMEM;
+ if (b->offset - a->offset < sizeof(struct bpf_map_def)) {
+ pr_warning("corrupted map section in %s: map \"%s\" too small\n",
+ obj->path, a->name);
+ return -EINVAL;
+ }
}
- obj->nr_maps = nr_maps;
-
- for (i = 0; i < nr_maps; i++) {
- struct bpf_map_def *def = &obj->maps[i].def;
+ return 0;
+}
- /*
- * fill all fd with -1 so won't close incorrect
- * fd (fd=0 is stdin) when failure (zclose won't close
- * negative fd)).
- */
- obj->maps[i].fd = -1;
+static int compare_bpf_map(const void *_a, const void *_b)
+{
+ const struct bpf_map *a = _a;
+ const struct bpf_map *b = _b;
- /* Save map definition into obj->maps */
- *def = ((struct bpf_map_def *)data)[i];
- }
- return 0;
+ return a->offset - b->offset;
}
static int
-bpf_object__init_maps_name(struct bpf_object *obj)
+bpf_object__init_maps(struct bpf_object *obj)
{
- int i;
+ int i, map_idx, nr_maps = 0;
+ Elf_Scn *scn;
+ Elf_Data *data;
Elf_Data *symbols = obj->efile.symbols;
- if (!symbols || obj->efile.maps_shndx < 0)
+ if (obj->efile.maps_shndx < 0)
+ return -EINVAL;
+ 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_warning("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.
+ */
for (i = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
GElf_Sym sym;
- size_t map_idx;
+
+ if (!gelf_getsym(symbols, i, &sym))
+ continue;
+ if (sym.st_shndx != obj->efile.maps_shndx)
+ continue;
+ nr_maps++;
+ }
+
+ /* Alloc obj->maps and fill nr_maps. */
+ pr_debug("maps in %s: %d maps in %zd bytes\n", obj->path,
+ nr_maps, data->d_size);
+
+ if (!nr_maps)
+ return 0;
+
+ obj->maps = calloc(nr_maps, sizeof(obj->maps[0]));
+ if (!obj->maps) {
+ pr_warning("alloc maps for object failed\n");
+ return -ENOMEM;
+ }
+ obj->nr_maps = nr_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 = 0; i < nr_maps; i++)
+ obj->maps[i].fd = -1;
+
+ /*
+ * Fill obj->maps using data in "maps" section.
+ */
+ for (i = 0, map_idx = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
+ GElf_Sym sym;
const char *map_name;
+ struct bpf_map_def *def;
if (!gelf_getsym(symbols, i, &sym))
continue;
@@ -573,21 +623,27 @@ bpf_object__init_maps_name(struct bpf_object *obj)
map_name = elf_strptr(obj->efile.elf,
obj->efile.strtabidx,
sym.st_name);
- map_idx = sym.st_value / sizeof(struct bpf_map_def);
- if (map_idx >= obj->nr_maps) {
- pr_warning("index of map \"%s\" is buggy: %zu > %zu\n",
- map_name, map_idx, obj->nr_maps);
- continue;
+ obj->maps[map_idx].offset = sym.st_value;
+ if (sym.st_value + sizeof(struct bpf_map_def) > data->d_size) {
+ pr_warning("corrupted maps section in %s: last map \"%s\" too small\n",
+ obj->path, map_name);
+ return -EINVAL;
}
+
obj->maps[map_idx].name = strdup(map_name);
if (!obj->maps[map_idx].name) {
pr_warning("failed to alloc map name\n");
return -ENOMEM;
}
- pr_debug("map %zu is \"%s\"\n", map_idx,
+ pr_debug("map %d is \"%s\"\n", map_idx,
obj->maps[map_idx].name);
+ def = (struct bpf_map_def *)(data->d_buf + sym.st_value);
+ obj->maps[map_idx].def = *def;
+ map_idx++;
}
- return 0;
+
+ qsort(obj->maps, obj->nr_maps, sizeof(obj->maps[0]), compare_bpf_map);
+ return bpf_object__validate_maps(obj);
}
static int bpf_object__elf_collect(struct bpf_object *obj)
@@ -645,11 +701,9 @@ static int bpf_object__elf_collect(struct bpf_object *obj)
err = bpf_object__init_kversion(obj,
data->d_buf,
data->d_size);
- else if (strcmp(name, "maps") == 0) {
- err = bpf_object__init_maps(obj, data->d_buf,
- data->d_size);
+ else if (strcmp(name, "maps") == 0)
obj->efile.maps_shndx = idx;
- } else if (sh.sh_type == SHT_SYMTAB) {
+ else if (sh.sh_type == SHT_SYMTAB) {
if (obj->efile.symbols) {
pr_warning("bpf: multiple SYMTAB in %s\n",
obj->path);
@@ -698,7 +752,7 @@ static int bpf_object__elf_collect(struct bpf_object *obj)
return LIBBPF_ERRNO__FORMAT;
}
if (obj->efile.maps_shndx >= 0)
- err = bpf_object__init_maps_name(obj);
+ err = bpf_object__init_maps(obj);
out:
return err;
}
@@ -807,7 +861,7 @@ bpf_object__create_maps(struct bpf_object *obj)
zclose(obj->maps[j].fd);
return err;
}
- pr_debug("create map: fd=%d\n", *pfd);
+ pr_debug("create map %s: fd=%d\n", obj->maps[i].name, *pfd);
}
return 0;
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-30 15:59:33 +0000