[PATCH bpf-next 3/3] libbpf: Use string table index from index table if needed
flat view
STALE2094d
From: Jiri Olsa <jolsa@kernel.org>
Date: 2021-01-19 22:13:46
Also in:
bpf
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [library] (libbpf), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
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. In such case we need to call elf_getshdrstrndx to get the proper string table index. Signed-off-by: Jiri Olsa <jolsa@kernel.org> --- tools/lib/bpf/btf.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 3c3f2bc6c652..4fe987846bc0 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c@@ -863,6 +863,7 @@ 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);
@@ -887,7 +888,16 @@ 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)) { + + /* + * Get string table index from extended section index + * table if needed. + */ + shstrndx = ehdr.e_shstrndx; + if (shstrndx == SHN_XINDEX && elf_getshdrstrndx(elf, &shstrndx)) + goto done; + + if (!elf_rawdata(elf_getscn(elf, shstrndx), NULL)) { pr_warn("failed to get e_shstrndx from %s\n", path); goto done; }
@@ -902,7 +912,7 @@ 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);
--
2.27.0