Em Tue, Apr 26, 2016 at 06:02:33PM +0900, Masami Hiramatsu escreveu:
> Fall back to the old style build-id cache
> (~/.debug/<path-to-bin>/<build-id>) if possible.
> Because there is old build-id cache under ~/.debug, perf
> has to check if the old entry is there instead of returning
> an error. Or, user have to remove ~/.debug completely.
So, from the description this seems to address the issues I mentioned in
the previous patch.
Probably it is a good idea not to introduce the problem in the first
place? I.e. combine this and the previous patch, so that we don't have
this bisection break?
- Arnaldo
> This patch introduces fallback code to try using old-style
> buildid caches. To update the cached entry, you just need to
> add a cache. It automatically removes old cache entry and
> make a new one in new style
> (~/.debug/<path-to-bin>/<build-id>/[elf|vdso|kallsyms]).
>
> IOW, without this patch, "perf buildid-cache --add" always
> gets errors when adding existing binaries.
> ----
> # perf buildid-cache -a /usr/lib64/libc-2.20.so,/usr/bin/gcc
> Couldn't add /usr/bin/gcc: Not a directory
> Couldn't add /usr/lib64/libc-2.20.so: Not a directory
> ----
> Moreover, --update option removes only symlink, thus the
> build-id cache is corrupted.
>
> This fixes above issues.
>
> Signed-off-by: Masami Hiramatsu <mhira...@kernel.org>
> ---
> tools/perf/util/build-id.c | 17 ++++++++++++++++-
> tools/perf/util/symbol.c | 13 +++++++++----
> 2 files changed, 25 insertions(+), 5 deletions(-)
>
> diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
> index 46a8bcc..b035483 100644
> --- a/tools/perf/util/build-id.c
> +++ b/tools/perf/util/build-id.c
> @@ -155,6 +155,12 @@ static char *build_id_cache__linkname(const char
> *sbuild_id, char *bf,
> return bf;
> }
>
> +static bool __is_regular_file(const char *pathname)
> +{
> + struct stat sb;
> + return stat(pathname, &sb) == 0 && S_ISREG(sb.st_mode);
> +}
> +
> static const char *build_id_cache__basename(bool is_kallsyms, bool is_vdso)
> {
> return is_kallsyms ? "kallsyms" : (is_vdso ? "vdso" : "elf");
> @@ -177,7 +183,11 @@ char *dso__build_id_filename(const struct dso *dso, char
> *bf, size_t size)
> if (!linkname)
> return NULL;
>
> - ret = asnprintf(&bf, size, "%s/%s", linkname,
> + /* Check if old style build_id cache */
> + if (__is_regular_file(linkname))
> + ret = asnprintf(&bf, size, "%s", linkname);
> + else
> + ret = asnprintf(&bf, size, "%s/%s", linkname,
> build_id_cache__basename(is_kallsyms, is_vdso));
> if (ret < 0 || (!alloc && size < (unsigned int)ret))
> bf = NULL;
> @@ -445,6 +455,11 @@ int build_id_cache__add_s(const char *sbuild_id, const
> char *name,
> if (!dir_name)
> goto out_free;
>
> + /* Remove old style build-id cache */
> + if (__is_regular_file(dir_name))
> + if (unlink(dir_name))
> + goto out_free;
> +
> if (mkdir_p(dir_name, 0755))
> goto out_free;
>
> diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
> index c57cb47..9463c7d 100644
> --- a/tools/perf/util/symbol.c
> +++ b/tools/perf/util/symbol.c
> @@ -1687,11 +1687,16 @@ static char *dso__find_kallsyms(struct dso *dso,
> struct map *map)
>
> scnprintf(path, sizeof(path), "%s/[kernel.kallsyms]/%s/kallsyms",
> buildid_dir, sbuild_id);
> -
> + /* Try old style kallsyms cache */
> if (access(path, F_OK)) {
> - pr_err("No kallsyms or vmlinux with build-id %s was found\n",
> - sbuild_id);
> - return NULL;
> + scnprintf(path, sizeof(path), "%s/[kernel.kallsyms]/%s",
> + buildid_dir, sbuild_id);
> +
> + if (access(path, F_OK)) {
> + pr_err("No kallsyms or vmlinux with build-id %s was
> found\n",
> + sbuild_id);
> + return NULL;
> + }
> }
>
> return strdup(path);
