perf probe: Allow wildcard for cached events

Allo glob wildcard for reusing cached/SDT events. E.g.

  # perf probe -x /usr/lib64/libc-2.20.so -a %sdt_libc:\*

This example adds probes for all SDT in libc.
Note that the SDTs must have been scanned by perf buildid-cache.

Committer note:

Using it to check what of those SDT probes would take place when doing
a cargo run (rust):

  # trace --no-sys --event sdt_libc:* cargo run
     0.000 sdt_libc:setjmp:(7f326b69c4d1))
    28.423 sdt_libc:setjmp:(7f4b0a5364d1))
    29.000 sdt_libc:setjmp:(7f4b0a5364d1))
    88.597 sdt_libc:setjmp:(7fc01fd414d1))
    89.220 sdt_libc:setjmp:(7fc01fd414d1))
    95.501 sdt_libc:setjmp:(7f326b69c4d1))
     Running `target/debug/hello_world`
    97.110 sdt_libc:setjmp:(7f95e09234d1))
  Hello, world!
  #

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/146831791813.17065.17846564230840594888.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 32 insertions, 6 deletions

diff --git a/tools/perf/util/probe-file.c b/tools/perf/util/probe-file.c
index abfb05cf135b..9aed9c332da6 100644
--- a/tools/perf/util/probe-file.c
+++ b/tools/perf/util/probe-file.c
@@ -362,13 +362,38 @@ probe_cache_entry__new(struct perf_probe_event *pev)
 	return entry;
 }
 
-/* For the kernel probe caches, pass target = NULL */
+int probe_cache_entry__get_event(struct probe_cache_entry *entry,
+				 struct probe_trace_event **tevs)
+{
+	struct probe_trace_event *tev;
+	struct str_node *node;
+	int ret, i;
+
+	ret = strlist__nr_entries(entry->tevlist);
+	if (ret > probe_conf.max_probes)
+		return -E2BIG;
+
+	*tevs = zalloc(ret * sizeof(*tev));
+	if (!*tevs)
+		return -ENOMEM;
+
+	i = 0;
+	strlist__for_each_entry(node, entry->tevlist) {
+		tev = &(*tevs)[i++];
+		ret = parse_probe_trace_command(node->s, tev);
+		if (ret < 0)
+			break;
+	}
+	return i;
+}
+
+/* For the kernel probe caches, pass target = NULL or DSO__NAME_KALLSYMS */
 static int probe_cache__open(struct probe_cache *pcache, const char *target)
 {
 	char cpath[PATH_MAX];
 	char sbuildid[SBUILD_ID_SIZE];
 	char *dir_name = NULL;
-	bool is_kallsyms = !target;
+	bool is_kallsyms = false;
 	int ret, fd;
 
 	if (target && build_id_cache__cached(target)) {
@@ -378,12 +403,13 @@ static int probe_cache__open(struct probe_cache *pcache, const char *target)
 		goto found;
 	}
 
-	if (target)
-		ret = filename__sprintf_build_id(target, sbuildid);
-	else {
+	if (!target || !strcmp(target, DSO__NAME_KALLSYMS)) {
 		target = DSO__NAME_KALLSYMS;
+		is_kallsyms = true;
 		ret = sysfs__sprintf_build_id("/", sbuildid);
-	}
+	} else
+		ret = filename__sprintf_build_id(target, sbuildid);
+
 	if (ret < 0) {
 		pr_debug("Failed to get build-id from %s.\n", target);
 		return ret;