From: Jiri Olsa <jolsa@kernel.org>
To: Arnaldo Carvalho de Melo <acme@kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andriin@fb.com>
Cc: dwarves@vger.kernel.org, netdev@vger.kernel.org,
bpf@vger.kernel.org, Yonghong Song <yhs@fb.com>,
Hao Luo <haoluo@google.com>, Martin KaFai Lau <kafai@fb.com>,
Song Liu <songliubraving@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@chromium.org>,
Joe Lawrence <joe.lawrence@redhat.com>,
Mark Wielaard <mjw@redhat.com>
Subject: [PATCH bpf-next 3/3] libbpf: Use string table index from index table if needed
Date: Thu, 21 Jan 2021 21:22:03 +0100 [thread overview]
Message-ID: <20210121202203.9346-4-jolsa@kernel.org> (raw)
In-Reply-To: <20210121202203.9346-1-jolsa@kernel.org>
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>
---
tools/lib/bpf/btf.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 9970a288dda5..d9c10830d749 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -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);
--
2.27.0
next prev parent reply other threads:[~2021-01-21 20:35 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-21 20:22 [PATCHv2 0/3] dwarves,libbpf: Add support to use optional extended section index table Jiri Olsa
2021-01-21 20:22 ` [PATCH 1/3] elf_symtab: Add support for SHN_XINDEX index to elf_section_by_name Jiri Olsa
2021-01-21 23:10 ` Andrii Nakryiko
2021-01-21 23:34 ` Jiri Olsa
2021-01-21 20:22 ` [PATCH 2/3] bpf_encoder: Translate SHN_XINDEX in symbol's st_shndx values Jiri Olsa
2021-01-21 23:32 ` Andrii Nakryiko
2021-01-22 9:32 ` Jiri Olsa
2021-01-22 20:46 ` Jiri Olsa
2021-01-22 22:55 ` Andrii Nakryiko
2021-01-23 18:51 ` Jiri Olsa
2021-01-23 20:07 ` Andrii Nakryiko
2021-01-23 20:21 ` Mark Wielaard
2021-01-23 20:08 ` Mark Wielaard
2021-01-23 20:15 ` Jiri Olsa
2021-01-23 21:23 ` Jiri Olsa
2021-01-24 6:08 ` Andrii Nakryiko
2021-01-21 20:22 ` Jiri Olsa [this message]
2021-01-21 23:46 ` [PATCH bpf-next 3/3] libbpf: Use string table index from index table if needed Andrii Nakryiko
-- strict thread matches above, loose matches on Subject: below --
2021-01-19 22:12 [PATCH 0/3] dwarves,libbpf: Add support to use optional extended section index table Jiri Olsa
2021-01-19 22:12 ` [PATCH bpf-next 3/3] libbpf: Use string table index from index table if needed Jiri Olsa
2021-01-20 1:22 ` Andrii Nakryiko
2021-01-20 11:12 ` Arnaldo Carvalho de Melo
2021-01-20 12:26 ` Jiri Olsa
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