Re: [PATCH 1/4] perf buildid-cache: Don't skip 16-byte build-ids

From: Jiri Olsa
Date: Mon Feb 15 2021 - 09:33:44 EST


On Wed, Feb 10, 2021 at 02:17:25PM -0500, Nicholas Fraser wrote:
> lsdir_bid_tail_filter() ignored any build-id that wasn't exactly 20
> bytes. This worked only for SHA-1 build-ids. The build-id for a PE file
> is always a 16-byte GUID and ELF files can also have MD5 or UUID
> build-ids.
>
> This fix changes the filter to allow build-ids between 16 and 20 bytes.

hi,
there's tests/shell/buildid.sh test for this, please add
testcase for this.. looks like perf buildid-cacle -l will
end up calling this function

thanks,
jirka

>
> Signed-off-by: Nicholas Fraser <nfraser@xxxxxxxxxxxxxxx>
> ---
> tools/perf/util/build-id.c | 5 +++--
> tools/perf/util/build-id.h | 4 +++-
> 2 files changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
> index 02df36b30ac5..e32e8f2ff3bd 100644
> --- a/tools/perf/util/build-id.c
> +++ b/tools/perf/util/build-id.c
> @@ -448,7 +448,8 @@ static bool lsdir_bid_tail_filter(const char *name __maybe_unused,
> int i = 0;
> while (isxdigit(d->d_name[i]) && i < SBUILD_ID_SIZE - 3)
> i++;
> - return (i == SBUILD_ID_SIZE - 3) && (d->d_name[i] == '\0');
> + return (i >= SBUILD_ID_MIN_SIZE - 3) && (i <= SBUILD_ID_SIZE - 3) &&
> + (d->d_name[i] == '\0');
> }
>
> struct strlist *build_id_cache__list_all(bool validonly)
> @@ -490,7 +491,7 @@ struct strlist *build_id_cache__list_all(bool validonly)
> }
> strlist__for_each_entry(nd2, linklist) {
> if (snprintf(sbuild_id, SBUILD_ID_SIZE, "%s%s",
> - nd->s, nd2->s) != SBUILD_ID_SIZE - 1)
> + nd->s, nd2->s) > SBUILD_ID_SIZE - 1)
> goto err_out;
> if (validonly && !build_id_cache__valid_id(sbuild_id))
> continue;
> diff --git a/tools/perf/util/build-id.h b/tools/perf/util/build-id.h
> index 02613f4b2c29..c19617151670 100644
> --- a/tools/perf/util/build-id.h
> +++ b/tools/perf/util/build-id.h
> @@ -2,8 +2,10 @@
> #ifndef PERF_BUILD_ID_H_
> #define PERF_BUILD_ID_H_ 1
>
> -#define BUILD_ID_SIZE 20
> +#define BUILD_ID_SIZE 20 /* SHA-1 length in bytes */
> +#define BUILD_ID_MIN_SIZE 16 /* MD5/UUID/GUID length in bytes */
> #define SBUILD_ID_SIZE (BUILD_ID_SIZE * 2 + 1)
> +#define SBUILD_ID_MIN_SIZE (BUILD_ID_MIN_SIZE * 2 + 1)
>
> #include "machine.h"
> #include "tool.h"
> --
> 2.30.0
>