[PATCH perf/core v5 15/15] perf probe: Support @BUILDID or @FILE suffix for SDT events

Masami Hiramatsu
2016-04-27T18:39:34Z

Support @BUILDID or @FILE suffix for SDT events. This allows
perf to add probes on SDTs/pre-cached events on given FILE
or the file which has given BUILDID (also, this complements
BUILDID.)
For example, both gcc and libstdc++ has same SDTs as below.
If you would like to add a probe on sdt_libstdcxx:catch on gcc,
you can do as below.

----
# perf list sdt | tail -n 6
sdt_libstdcxx:catch@/usr/bin/gcc(0cc207fc4b27) [SDT event]
sdt_libstdcxx:catch@/usr/lib64/libstdc++.so.6.0.20(91c7a88fdf49)
sdt_libstdcxx:rethrow@/usr/bin/gcc(0cc207fc4b27) [SDT event]
sdt_libstdcxx:rethrow@/usr/lib64/libstdc++.so.6.0.20(91c7a88fdf49)
sdt_libstdcxx:throw@/usr/bin/gcc(0cc207fc4b27) [SDT event]
sdt_libstdcxx:throw@/usr/lib64/libstdc++.so.6.0.20(91c7a88fdf49)
# perf probe -a sdt_libstdcxx:catch@0cc
Added new event:
sdt_libstdcxx:catch (on %catch in /usr/bin/gcc)

You can now use it in all perf tools, such as:

perf record -e sdt_libstdcxx:catch -aR sleep 1
----

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
tools/perf/util/build-id.c | 40 ++++++++++++++++++++++++++++++++++++++++
tools/perf/util/build-id.h | 1 +
tools/perf/util/probe-event.c | 17 +++++++++++++++--
3 files changed, 56 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
index c849253..4fec09e 100644
--- a/tools/perf/util/build-id.c
+++ b/tools/perf/util/build-id.c
@@ -472,6 +472,46 @@ out:
return ret;
}

+static bool str_is_build_id(const char *maybe_sbuild_id, size_t len)
+{
+ size_t i;
+
+ for (i = 0; i < len; i++) {
+ if (!isxdigit(maybe_sbuild_id[i]))
+ return false;
+ }
+ return true;
+}
+
+/* Return the valid complete build-id */
+char *build_id_cache__complement(const char *incomplete_sbuild_id)
+{
+ struct strlist *list;
+ struct str_node *nd, *cand = NULL;
+ char *sbuild_id = NULL;
+ size_t len = strlen(incomplete_sbuild_id);
+
+ if (len >= SBUILD_ID_SIZE ||
+ !str_is_build_id(incomplete_sbuild_id, len) ||
+ build_id_cache__list_all(&list, true) < 0)
+ return NULL;
+
+ strlist__for_each(nd, list) {
+ if (strncmp(nd->s, incomplete_sbuild_id, len) != 0)
+ continue;
+ if (cand) { /* Error: There are more than 2 candidates. */
+ cand = NULL;
+ break;
+ }
+ cand = nd;
+ }
+ if (cand)
+ sbuild_id = strdup(cand->s);
+ strlist__delete(list);
+
+ return sbuild_id;
+}
+
char *build_id_cache__dirname_from_path(const char *sbuild_id, const char *name,
bool is_kallsyms, bool is_vdso)
{
diff --git a/tools/perf/util/build-id.h b/tools/perf/util/build-id.h
index 5e29cfc..cafab5e 100644
--- a/tools/perf/util/build-id.h
+++ b/tools/perf/util/build-id.h
@@ -33,6 +33,7 @@ char *build_id_cache__linkname(const char *sbuild_id, char *bf, size_t size);
char *build_id_cache__dirname_from_path(const char *sbuild_id, const char *name,
bool is_kallsyms, bool is_vdso);
int build_id_cache__list_all(struct strlist **result, bool validonly);
+char *build_id_cache__complement(const char *incomplete_sbuild_id);
int build_id_cache__list_build_ids(const char *pathname,
struct strlist **result);
bool build_id_cache__cached(const char *sbuild_id);
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 9ca8392..29dc153 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -1253,8 +1253,21 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
ptr = strpbrk(arg, ";=@+%");
if (pev->sdt) {
if (ptr) {
- semantic_error("%s must contain only an SDT event name.\n", arg);
- return -EINVAL;
+ if (*ptr != '@') {
+ semantic_error("%s must contain only an SDT event name.\n", arg);
+ return -EINVAL;
+ }
+ /* This must be a target file name or build id */
+ tmp = build_id_cache__complement(ptr + 1);
+ if (tmp) {
+ pev->target = build_id_cache__origname(tmp);
+ free(tmp);
+ } else
+ pev->target = strdup(ptr + 1);
+ if (!pev->target)
+ return -ENOMEM;
+ pev->uprobes = 1;
+ *ptr = '\0';
}
ret = parse_perf_probe_event_name(&arg, pev);
if (ret == 0) {