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From: Jiri Olsa <olsajiri@gmail.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Alexei Starovoitov <ast@kernel.org>,
	Andrii Nakryiko <andrii@kernel.org>, Hao Luo <haoluo@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Matthew Wilcox <willy@infradead.org>,
	bpf@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-perf-users@vger.kernel.org, Martin KaFai Lau <kafai@fb.com>,
	Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@chromium.org>,
	Stanislav Fomichev <sdf@google.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Namhyung Kim <namhyung@gmail.com>
Subject: Re: [PATCH RFC v2 bpf-next 5/9] selftests/bpf: Add read_buildid function
Date: Wed, 8 Mar 2023 14:49:57 +0100	[thread overview]
Message-ID: <ZAiShb3hVRlnGam0@krava> (raw)
In-Reply-To: <CAEf4BzZsOvvPJRt69vj+YCAJ1DAXgLSD0E3rfoMOLo3c6mSKiQ@mail.gmail.com>

On Tue, Mar 07, 2023 at 05:22:51PM -0800, Andrii Nakryiko wrote:
> On Tue, Feb 28, 2023 at 1:33 AM Jiri Olsa <jolsa@kernel.org> wrote:
> >
> > Adding read_build_id function that parses out build id from
> > specified binary.
> >
> > It will replace extract_build_id and also be used in following
> > changes.
> >
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > ---
> >  tools/testing/selftests/bpf/trace_helpers.c | 98 +++++++++++++++++++++
> >  tools/testing/selftests/bpf/trace_helpers.h |  5 ++
> >  2 files changed, 103 insertions(+)
> >
> > diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c
> > index 09a16a77bae4..c10e16626cd3 100644
> > --- a/tools/testing/selftests/bpf/trace_helpers.c
> > +++ b/tools/testing/selftests/bpf/trace_helpers.c
> > @@ -11,6 +11,9 @@
> >  #include <linux/perf_event.h>
> >  #include <sys/mman.h>
> >  #include "trace_helpers.h"
> > +#include <linux/limits.h>
> > +#include <libelf.h>
> > +#include <gelf.h>
> >
> >  #define DEBUGFS "/sys/kernel/debug/tracing/"
> >
> > @@ -230,3 +233,98 @@ ssize_t get_rel_offset(uintptr_t addr)
> >         fclose(f);
> >         return -EINVAL;
> >  }
> > +
> > +static int
> > +parse_build_id_buf(const void *note_start, Elf32_Word note_size,
> > +                  char *build_id)
> > +{
> > +       Elf32_Word note_offs = 0, new_offs;
> > +
> > +       while (note_offs + sizeof(Elf32_Nhdr) < note_size) {
> > +               Elf32_Nhdr *nhdr = (Elf32_Nhdr *)(note_start + note_offs);
> > +
> > +               if (nhdr->n_type == 3 &&
> > +                   nhdr->n_namesz == sizeof("GNU") &&
> > +                   !strcmp((char *)(nhdr + 1), "GNU") &&
> > +                   nhdr->n_descsz > 0 &&
> > +                   nhdr->n_descsz <= BPF_BUILD_ID_SIZE) {
> > +                       memcpy(build_id, note_start + note_offs +
> > +                              ALIGN(sizeof("GNU"), 4) + sizeof(Elf32_Nhdr),
> > +                              nhdr->n_descsz);
> > +                       memset(build_id + nhdr->n_descsz, 0,
> > +                              BPF_BUILD_ID_SIZE - nhdr->n_descsz);
> 
> I won't count :) but if something fits within 100 characters, please
> keep it on single line

copy&paste from kernel code ;-) I'll reformat that

SNIP

> > diff --git a/tools/testing/selftests/bpf/trace_helpers.h b/tools/testing/selftests/bpf/trace_helpers.h
> > index 53efde0e2998..50b2cc498ba7 100644
> > --- a/tools/testing/selftests/bpf/trace_helpers.h
> > +++ b/tools/testing/selftests/bpf/trace_helpers.h
> > @@ -4,6 +4,9 @@
> >
> >  #include <bpf/libbpf.h>
> >
> > +#define ALIGN(x, a)            __ALIGN_MASK(x, (typeof(x))(a)-1)
> > +#define __ALIGN_MASK(x, mask)  (((x)+(mask))&~(mask))
> 
> nit: I know these are macros, but why would you first use __ALIGN_MASK
> and then #define it? swap them?

same reason as above, I'll swap that

thanks,
jirka

  reply	other threads:[~2023-03-08 13:50 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-28  9:31 [RFC v2 bpf-next 0/9] mm/bpf/perf: Store build id in inode object Jiri Olsa
2023-02-28  9:31 ` [PATCH RFC v2 bpf-next 1/9] mm: " Jiri Olsa
2023-02-28 19:13   ` Andrew Morton
2023-03-01  8:16     ` Jiri Olsa
2023-02-28  9:31 ` [PATCH RFC v2 bpf-next 2/9] bpf: Use file's inode object build id in stackmap Jiri Olsa
2023-02-28  9:32 ` [PATCH RFC v2 bpf-next 3/9] perf: Use file object build id in perf_event_mmap_event Jiri Olsa
2023-02-28  9:32 ` [PATCH RFC v2 bpf-next 4/9] libbpf: Allow to resolve binary path in current directory Jiri Olsa
2023-03-08  1:19   ` Andrii Nakryiko
2023-03-08 13:48     ` Jiri Olsa
2023-02-28  9:32 ` [PATCH RFC v2 bpf-next 5/9] selftests/bpf: Add read_buildid function Jiri Olsa
2023-03-08  1:22   ` Andrii Nakryiko
2023-03-08 13:49     ` Jiri Olsa [this message]
2023-02-28  9:32 ` [PATCH RFC v2 bpf-next 6/9] selftests/bpf: Add err.h header Jiri Olsa
2023-02-28  9:32 ` [PATCH RFC v2 bpf-next 7/9] selftests/bpf: Replace extract_build_id with read_build_id Jiri Olsa
2023-03-08  1:26   ` Andrii Nakryiko
2023-03-08 13:51     ` Jiri Olsa
2023-02-28  9:32 ` [PATCH RFC v2 bpf-next 8/9] selftests/bpf: Add inode_build_id test Jiri Olsa
2023-02-28  9:32 ` [PATCH RFC v2 bpf-next 9/9] selftests/bpf: Add iter_task_vma_buildid test Jiri Olsa
2023-03-08  1:32   ` Andrii Nakryiko
2023-03-08 14:00     ` Jiri Olsa
2023-02-28 22:07 ` [RFC v2 bpf-next 0/9] mm/bpf/perf: Store build id in inode object Dave Chinner
2023-03-01 15:41   ` Arnaldo Carvalho de Melo
2023-03-02  8:41     ` Jiri Olsa
2023-03-02  8:35   ` Jiri Olsa

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