libbpf: Use string table index from index table if needed

For very large ELF objects (with many sections), we could
get special value SHN_XINDEX (65535) for elf object's string
table index - e_shstrndx.

Call elf_getshdrstrndx to get the proper string table index,
instead of reading it directly from ELF header.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210121202203.9346-4-jolsa@kernel.org
This commit is contained in:
Jiri Olsa 2021-01-21 21:22:03 +01:00 committed by Andrii Nakryiko
parent b452ee005a
commit 6095d5a271

View File

@ -858,6 +858,7 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf,
Elf_Scn *scn = NULL;
Elf *elf = NULL;
GElf_Ehdr ehdr;
size_t shstrndx;
if (elf_version(EV_CURRENT) == EV_NONE) {
pr_warn("failed to init libelf for %s\n", path);
@ -882,7 +883,14 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf,
pr_warn("failed to get EHDR from %s\n", path);
goto done;
}
if (!elf_rawdata(elf_getscn(elf, ehdr.e_shstrndx), NULL)) {
if (elf_getshdrstrndx(elf, &shstrndx)) {
pr_warn("failed to get section names section index for %s\n",
path);
goto done;
}
if (!elf_rawdata(elf_getscn(elf, shstrndx), NULL)) {
pr_warn("failed to get e_shstrndx from %s\n", path);
goto done;
}
@ -897,7 +905,7 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf,
idx, path);
goto done;
}
name = elf_strptr(elf, ehdr.e_shstrndx, sh.sh_name);
name = elf_strptr(elf, shstrndx, sh.sh_name);
if (!name) {
pr_warn("failed to get section(%d) name from %s\n",
idx, path);