From: Jiri Olsa <jolsa@redhat.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andriin@fb.com>,
dwarves@vger.kernel.org, Networking <netdev@vger.kernel.org>,
bpf <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: Re: [PATCH 1/3] elf_symtab: Add support for SHN_XINDEX index to elf_section_by_name
Date: Wed, 20 Jan 2021 13:20:10 +0100 [thread overview]
Message-ID: <20210120122010.GA1760208@krava> (raw)
In-Reply-To: <CAEf4BzYjTu-NbEQcgCXmKormPuQUQip+Qr4Qzr3X3VXPSwreBQ@mail.gmail.com>
On Tue, Jan 19, 2021 at 05:23:00PM -0800, Andrii Nakryiko wrote:
> On Tue, Jan 19, 2021 at 2:16 PM Jiri Olsa <jolsa@kernel.org> wrote:
> >
> > In case the elf's header e_shstrndx contains SHN_XINDEX,
> > we need to call elf_getshdrstrndx to get the proper
> > string table index.
> >
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > ---
> > dutil.c | 8 ++++++--
> > 1 file changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/dutil.c b/dutil.c
> > index 7b667647420f..321f4be6669e 100644
> > --- a/dutil.c
> > +++ b/dutil.c
> > @@ -179,13 +179,17 @@ Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
> > {
> > Elf_Scn *sec = NULL;
> > size_t cnt = 1;
> > + size_t shstrndx = ep->e_shstrndx;
> > +
> > + if (shstrndx == SHN_XINDEX && elf_getshdrstrndx(elf, &shstrndx))
> > + return NULL;
> >
>
> see comment for patch #3, no need for SHN_XINDEX checks,
> elf_getshdrstrndx() handles this transparently
ok, will change
jirka
>
> > while ((sec = elf_nextscn(elf, sec)) != NULL) {
> > char *str;
> >
> > gelf_getshdr(sec, shp);
> > - str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
> > - if (!strcmp(name, str)) {
> > + str = elf_strptr(elf, shstrndx, shp->sh_name);
> > + if (str && !strcmp(name, str)) {
> > if (index)
> > *index = cnt;
> > break;
> > --
> > 2.27.0
> >
>
next prev parent reply other threads:[~2021-01-20 12:40 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
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 1/3] elf_symtab: Add support for SHN_XINDEX index to elf_section_by_name Jiri Olsa
2021-01-20 1:23 ` Andrii Nakryiko
2021-01-20 12:20 ` Jiri Olsa [this message]
2021-01-19 22:12 ` [PATCH 2/3] bpf_encoder: Translate SHN_XINDEX in symbol's st_shndx values Jiri Olsa
2021-01-20 2:03 ` Andrii Nakryiko
2021-01-20 12:25 ` 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
2021-01-19 23:17 ` [PATCH 0/3] dwarves,libbpf: Add support to use optional extended section index table Joe Lawrence
2021-01-21 20:22 [PATCHv2 " 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
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