Commit 6095d5a2 authored by Jiri Olsa's avatar Jiri Olsa Committed by Andrii Nakryiko
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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: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210121202203.9346-4-jolsa@kernel.org
parent b452ee00

tools/lib/bpf/btf.c

+10 −2
Original line number Diff line number Diff line
@@ -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);