[PATCH 24/26] perf tools: Add buildid-list --store option

Jiri Olsa
2020-09-13T21:06:26Z

Adding buildid-list --store option to populate
.debug data with build id files.

$ rm -rf ~/.debug/

$ perf buildid-list
1805c738c8f3ec0f47b7ea09080c28f34d18a82b /usr/lib64/ld-2.31.so
d278249792061c6b74d1693ca59513be1def13f2 /usr/lib64/libc-2.31.so

$ perf buildid-list --store

$ find ~/.debug/
.../.debug/
.../.debug/usr
.../.debug/usr/lib64
.../.debug/usr/lib64/ld-2.31.so
.../.debug/usr/lib64/ld-2.31.so/1805c738c8f3ec0f47b7ea09080c28f34d18a82b
.../.debug/usr/lib64/ld-2.31.so/1805c738c8f3ec0f47b7ea09080c28f34d18a82b/elf
.../.debug/usr/lib64/ld-2.31.so/1805c738c8f3ec0f47b7ea09080c28f34d18a82b/debug
.../.debug/usr/lib64/ld-2.31.so/1805c738c8f3ec0f47b7ea09080c28f34d18a82b/probes
.../.debug/usr/lib64/libc-2.31.so
.../.debug/usr/lib64/libc-2.31.so/d278249792061c6b74d1693ca59513be1def13f2
.../.debug/usr/lib64/libc-2.31.so/d278249792061c6b74d1693ca59513be1def13f2/elf
.../.debug/usr/lib64/libc-2.31.so/d278249792061c6b74d1693ca59513be1def13f2/debug
.../.debug/usr/lib64/libc-2.31.so/d278249792061c6b74d1693ca59513be1def13f2/probes
.../.debug/.build-id
.../.debug/.build-id/18
.../.debug/.build-id/18/05c738c8f3ec0f47b7ea09080c28f34d18a82b
.../.debug/.build-id/d2
.../.debug/.build-id/d2/78249792061c6b74d1693ca59513be1def13f2

It's possible to query debuginfod daemon for binaries by defining
DEBUGINFOD_URLS variable with server URL, like:

$ DEBUGINFOD_URLS=http://192.168.122.174:8002 perf buildid-list --store
OK 439fe9bdeaed66af2bb8b8de5e650d5ecc3d8d46 .../.debug/.build-id/43/9fe9bdeaed66af2bb8b8de5e650d5ecc3d8d46/elf
FAIL 23b87f5b0560481043257e82be670bc97786a171 /lib/modules/5.9.0-0.rc3.1.mmap3.fc34.x86_64/kernel/net/ipv4/netfilter/ip_tables.ko.xz
FAIL d2b3be372bcdd4ebc15e479d2ff803657de0fd1e /lib/modules/5.9.0-0.rc3.1.mmap3.fc34.x86_64/kernel/drivers/block/virtio_blk.ko.xz
FAIL 1466a71bcd0ff5c975ee79b72752137c0143d225 /lib/modules/5.9.0-0.rc3.1.mmap3.fc34.x86_64/kernel/fs/xfs/xfs.ko.xz
OK ad60d10b38c93bd8738d5aa594e240f01bb328cd /usr/lib/systemd/systemd
OK 589e403a34f55486bcac848a45e00bcdeedd1ca8 /usr/lib64/libcrypto.so.1.1.1g
OK 3b9b2ef537520303411ad5038b596d5d18e7c2b8 /usr/lib64/libpcre2-8.so.0.10.0

Increasing debug level in util/probe-event.c to get rid
of the sdt probes messages on single verbose level (-v).

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
.../perf/Documentation/perf-buildid-list.txt | 12 ++
tools/perf/builtin-buildid-list.c | 169 +++++++++++++++++-
tools/perf/util/probe-event.c | 6 +-
3 files changed, 181 insertions(+), 6 deletions(-)

diff --git a/tools/perf/Documentation/perf-buildid-list.txt b/tools/perf/Documentation/perf-buildid-list.txt
index 25c52efcc7f0..9bb8948e2e75 100644
--- a/tools/perf/Documentation/perf-buildid-list.txt
+++ b/tools/perf/Documentation/perf-buildid-list.txt
@@ -33,6 +33,18 @@ OPTIONS
-k::
--kernel::
Show running kernel build id.
+
+--store::
+ Store DSOs into .debug cache.
+
+ The option goes through all build ids and try to locate related binary,
+ if found, it's stored in the build id database (~/.debug).
+
+ It's possible to query debuginfod daemon for binaries by defining
+ DEBUGINFOD_URLS variable with server URL, like:
+
+ $ DEBUGINFOD_URLS=http://192.168.122.174:8002 perf buildid-list --store
+
-v::
--verbose::
Be more verbose.
diff --git a/tools/perf/builtin-buildid-list.c b/tools/perf/builtin-buildid-list.c
index adcc64478ec1..af326e7b5c44 100644
--- a/tools/perf/builtin-buildid-list.c
+++ b/tools/perf/builtin-buildid-list.c
@@ -17,8 +17,15 @@
#include "util/session.h"
#include "util/symbol.h"
#include "util/data.h"
+#include "util/namespaces.h"
#include <errno.h>
#include <linux/err.h>
+#include <linux/zalloc.h>
+#ifdef HAVE_DEBUGINFOD_SUPPORT
+#include <elfutils/debuginfod.h>
+#endif
+#include <unistd.h>
+#include <sys/stat.h>

static int sysfs__fprintf_build_id(FILE *fp)
{
@@ -49,7 +56,155 @@ static bool dso__skip_buildid(struct dso *dso, int with_hits)
return with_hits && !dso->hit;
}

-static int perf_session__list_build_ids(bool force, bool with_hits)
+#ifdef HAVE_DEBUGINFOD_SUPPORT
+static int get_executable(const char *sbuild_id, char **path)
+{
+ debuginfod_client *c;
+ int fd;
+
+ c = debuginfod_begin();
+ if (c == NULL)
+ return -1;
+
+ pr_debug("trying debuginfod for executable <%s> ... ", sbuild_id);
+
+ fd = debuginfod_find_executable(c, (const unsigned char *) sbuild_id,
+ 0, path);
+ if (fd >= 0)
+ close(fd); /* retaining reference by realname */
+
+ debuginfod_end(c);
+ pr_debug("%s%s\n", *path ? "OK " : "FAILED", *path ? *path : "");
+ return *path ? 0 : -1;
+}
+#else
+static int get_executable(const char *sbuild_id __maybe_unused,
+ char **path __maybe_unused)
+{
+ return -1;
+}
+#endif
+
+struct dso_store_data {
+ bool with_hits;
+};
+
+static int dso__store(struct dso *dso, struct machine *machine __maybe_unused, void *priv)
+{
+ struct dso_store_data *data = priv;
+ char sbuild_id[SBUILD_ID_SIZE];
+ u8 bid[BUILD_ID_SIZE];
+ char *path = NULL;
+ bool is_kallsyms;
+ int err = -1;
+
+ if (!dso->has_build_id ||
+ !build_id__is_defined(dso->build_id))
+ return 0;
+
+ if (data->with_hits && !dso->hit)
+ return 0;
+
+ /*
+ * The storing process is:
+ * - get build id of the dso
+ * - check if it matches provided build id from mmap3 event
+ * - if not, try debuginfod to download the binary
+ * - store binary to build id database
+ */
+ is_kallsyms = !strcmp(machine->mmap_name, dso->short_name);
+ build_id__sprintf(dso->build_id, sizeof(dso->build_id), sbuild_id);
+
+ if (is_kallsyms) {
+ /*
+ * Find out if we are on the same kernel as perf.data
+ * and keel kallsyms in that case.
+ */
+ path = strdup(dso->long_name);
+ if (!path)
+ goto out_err;
+
+ err = sysfs__read_build_id("/sys/kernel/notes", &bid, sizeof(bid));
+ if (err < 0)
+ goto out_err;
+ } else {
+ struct stat st;
+
+ /*
+ * Does the file exists in the first place, if it does,
+ * resolve path and read the build id.
+ */
+ if (stat(dso->long_name, &st)) {
+ zfree(&path);
+ goto try_download;
+ }
+
+ path = nsinfo__realpath(dso->long_name, dso->nsinfo);
+ if (!path)
+ goto out_err;
+
+ err = filename__read_build_id(path, &bid, sizeof(bid));
+ if (err != sizeof(bid))
+ goto out_err;
+ }
+
+ /*
+ * If we match then we want in mmap3 event,
+ * is what we got in the binary, so we're happy.
+ */
+ if (memcmp(&bid, dso->build_id, BUILD_ID_SIZE)) {
+ char sbid[SBUILD_ID_SIZE];
+
+ build_id__sprintf(bid, sizeof(bid), sbid);
+ pr_debug("mmap build id <%s> does not match for %s <%s>\n",
+ sbuild_id, path, sbid);
+ zfree(&path);
+ }
+
+try_download:
+ /*
+ * We did not match build id or did not find the
+ * binary - try debuginfod as last resort.
+ */
+ if (!path) {
+ char *tmp = NULL;
+
+ /*
+ * The debuginfo retrieval is handled within
+ * build_id_cache__add function.
+ */
+ if (get_executable(sbuild_id, &tmp)) {
+ err = -1;
+ goto out_err;
+ }
+
+ path = tmp;
+
+ /*
+ * The kernel dso is now elf binary, so disable is_kallsyms
+ * so build_id_cache__add can prepare proper file names.
+ */
+ is_kallsyms = false;
+ }
+
+ pr_debug("linking %s %s <%s>\n", dso->short_name, path, sbuild_id);
+
+ err = build_id_cache__add(sbuild_id, path, path,
+ dso->nsinfo, is_kallsyms, false);
+out_err:
+ free(path);
+ fprintf(stderr, "%s %s %s\n", err ? "FAIL" : "OK ", sbuild_id, dso->long_name);
+ return 0;
+}
+
+static int perf_session__store(struct perf_session *session, bool with_hits)
+{
+ struct dso_store_data data = { .with_hits = with_hits, };
+
+ return __perf_session__cache_build_ids(session, dso__store, &data);
+}
+
+static int perf_session__list_build_ids(bool force, bool with_hits, bool store)
{
struct perf_session *session;
struct perf_data data = {
@@ -94,7 +249,13 @@ static int perf_session__list_build_ids(bool force, bool with_hits)
if (with_hits || perf_data__is_pipe(&data))
perf_session__process_events(session);

- perf_session__fprintf_dsos_buildid(session, stdout, dso__skip_buildid, with_hits);
+ if (store) {
+ perf_session__store(session, with_hits);
+ } else {
+ perf_session__fprintf_dsos_buildid(session, stdout, dso__skip_buildid,
+ with_hits);
+ }
+
perf_session__delete(session);
out:
return 0;
@@ -105,11 +266,13 @@ int cmd_buildid_list(int argc, const char **argv)
bool show_kernel = false;
bool with_hits = false;
bool force = false;
+ bool store = false;
const struct option options[] = {
OPT_BOOLEAN('H', "with-hits", &with_hits, "Show only DSOs with hits"),
OPT_STRING('i', "input", &input_name, "file", "input file name"),
OPT_BOOLEAN('f', "force", &force, "don't complain, do it"),
OPT_BOOLEAN('k', "kernel", &show_kernel, "Show current kernel build id"),
+ OPT_BOOLEAN(0, "store", &store, "Store build id dsos in .debug cache"),
OPT_INCR('v', "verbose", &verbose, "be more verbose"),
OPT_END()
};
@@ -124,5 +287,5 @@ int cmd_buildid_list(int argc, const char **argv)
if (show_kernel)
return !(sysfs__fprintf_build_id(stdout) > 0);

- return perf_session__list_build_ids(force, with_hits);
+ return perf_session__list_build_ids(force, with_hits, store);
}
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 99d36ac77c08..a7d7ebffd005 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -1555,9 +1555,9 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
return -EINVAL;
}

- pr_debug("symbol:%s file:%s line:%d offset:%lu return:%d lazy:%s\n",
- pp->function, pp->file, pp->line, pp->offset, pp->retprobe,
- pp->lazy_line);
+ pr_debug2("symbol:%s file:%s line:%d offset:%lu return:%d lazy:%s\n",
+ pp->function, pp->file, pp->line, pp->offset, pp->retprobe,
+ pp->lazy_line);
return 0;
}

--
2.26.2