[PATCH 09/25] perf tools: Add support to read build id from compressed elf

Jiri Olsa
2020-11-26T17:01:30Z

Adding support to decompress file before reading build id.

Adding filename__read_build_id and change its current
versions to read_build_id.

Shutting down stderr output of perf list in the shell test:
82: Check open filename arg using perf trace + vfs_getname : Ok

because with decompression code in the place we the
filename__read_build_id function is more verbose in case
of error and the test did not account for that.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
.../tests/shell/trace+probe_vfs_getname.sh | 2 +-
tools/perf/util/symbol-elf.c | 37 ++++++++++++++++++-
2 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/tools/perf/tests/shell/trace+probe_vfs_getname.sh b/tools/perf/tests/shell/trace+probe_vfs_getname.sh
index 11cc2af13f2b..3660fcc02fef 100755
--- a/tools/perf/tests/shell/trace+probe_vfs_getname.sh
+++ b/tools/perf/tests/shell/trace+probe_vfs_getname.sh
@@ -20,7 +20,7 @@ skip_if_no_perf_trace || exit 2
file=$(mktemp /tmp/temporary_file.XXXXX)

trace_open_vfs_getname() {
- evts=$(echo $(perf list syscalls:sys_enter_open* 2>&1 | egrep 'open(at)? ' | sed -r 's/.*sys_enter_([a-z]+) +\[.*$/\1/') | sed 's/ /,/')
+ evts=$(echo $(perf list syscalls:sys_enter_open* >&1 2>/dev/nul | egrep 'open(at)? ' | sed -r 's/.*sys_enter_([a-z]+) +\[.*$/\1/') | sed 's/ /,/')
perf trace -e $evts touch $file 2>&1 | \
egrep " +[0-9]+\.[0-9]+ +\( +[0-9]+\.[0-9]+ ms\): +touch\/[0-9]+ open(at)?\((dfd: +CWD, +)?filename: +${file}, +flags: CREAT\|NOCTTY\|NONBLOCK\|WRONLY, +mode: +IRUGO\|IWUGO\) += +[0-9]+$"
}
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 44dd86a4f25f..f3577f7d72fe 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -534,7 +534,7 @@ static int elf_read_build_id(Elf *elf, void *bf, size_t size)

#ifdef HAVE_LIBBFD_BUILDID_SUPPORT

-int filename__read_build_id(const char *filename, struct build_id *bid)
+static int read_build_id(const char *filename, struct build_id *bid)
{
size_t size = sizeof(bid->data);
int err = -1;
@@ -563,7 +563,7 @@ int filename__read_build_id(const char *filename, struct build_id *bid)

#else // HAVE_LIBBFD_BUILDID_SUPPORT

-int filename__read_build_id(const char *filename, struct build_id *bid)
+static int read_build_id(const char *filename, struct build_id *bid)
{
size_t size = sizeof(bid->data);
int fd, err = -1;
@@ -595,6 +595,39 @@ int filename__read_build_id(const char *filename, struct build_id *bid)

#endif // HAVE_LIBBFD_BUILDID_SUPPORT

+int filename__read_build_id(const char *filename, struct build_id *bid)
+{
+ struct kmod_path m = { .name = NULL, };
+ char path[PATH_MAX];
+ int err;
+
+ if (!filename)
+ return -EFAULT;
+
+ err = kmod_path__parse(&m, filename);
+ if (err)
+ return -1;
+
+ if (m.comp) {
+ int error = 0, fd;
+
+ fd = filename__decompress(filename, path, sizeof(path), m.comp, &error);
+ if (fd < 0) {
+ pr_debug("Failed to decompress (error %d) %s\n",
+ error, filename);
+ return -1;
+ }
+ close(fd);
+ filename = path;
+ }
+
+ err = read_build_id(filename, bid);
+
+ if (m.comp)
+ unlink(filename);
+ return err;
+}
+
int sysfs__read_build_id(const char *filename, struct build_id *bid)
{
size_t size = sizeof(bid->data);
--
2.26.2