Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-25 21:51:40 +00:00
Code Issues Packages Projects Releases Wiki Activity

libbpf: Reject static maps

Browse Source 
Static maps never really worked with libbpf, because all such maps were always
silently resolved to the very first map. Detect static maps (both legacy and
BTF-defined) and report user-friendly error.

Tested locally by switching few maps (legacy and BTF-defined) in selftests to
static ones and verifying that now libbpf rejects them loudly.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210513233643.194711-2-andrii@kernel.org
This commit is contained in:
Andrii Nakryiko 2021-05-13 16:36:43 -07:00 committed by Alexei Starovoitov
parent 9e9b451593
commit c1cccec9c6
1 changed files with 19 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
tools/lib/bpf/libbpf.c
View File

@ -1795,7 +1795,6 @@ static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
if (!symbols)
return -EINVAL;
scn = elf_sec_by_idx(obj, obj->efile.maps_shndx);
data = elf_sec_data(obj, scn);
if (!scn || !data) {
@ -1855,6 +1854,12 @@ static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
return -LIBBPF_ERRNO__FORMAT;
}
if (GELF_ST_TYPE(sym.st_info) == STT_SECTION
|| GELF_ST_BIND(sym.st_info) == STB_LOCAL) {
pr_warn("map '%s' (legacy): static maps are not supported\n", map_name);
return -ENOTSUP;
}
map->libbpf_type = LIBBPF_MAP_UNSPEC;
map->sec_idx = sym.st_shndx;
map->sec_offset = sym.st_value;
@ -2262,6 +2267,16 @@ static void fill_map_from_def(struct bpf_map *map, const struct btf_map_def *def
pr_debug("map '%s': found inner map definition.\n", map->name);
}
static const char *btf_var_linkage_str(__u32 linkage)
{
switch (linkage) {
case BTF_VAR_STATIC: return "static";
case BTF_VAR_GLOBAL_ALLOCATED: return "global";
case BTF_VAR_GLOBAL_EXTERN: return "extern";
default: return "unknown";
}
}
static int bpf_object__init_user_btf_map(struct bpf_object *obj,
const struct btf_type *sec,
int var_idx, int sec_idx,
@ -2294,10 +2309,9 @@ static int bpf_object__init_user_btf_map(struct bpf_object *obj,
map_name, btf_kind_str(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);
if (var_extra->linkage != BTF_VAR_GLOBAL_ALLOCATED) {
pr_warn("map '%s': unsupported map linkage %s.\n",
map_name, btf_var_linkage_str(var_extra->linkage));
return -EOPNOTSUPP;
}