perf probe: Make --list show only available cached events

Make "perf probe --cache --list" show only available cached events by
checking build-id validity.

E.g. without this patch:
  ----
  $ ./perf probe --cache --add oldevent=cmd_probe
  $ make #(to update ./perf)
  $ ./perf probe --cache --add newevent=cmd_probe
  $ ./perf probe --cache --list
  /home/mhiramat/ksrc/linux/tools/perf/perf (061e90539bac69
  probe_perf:newevent=cmd_probe
  /home/mhiramat/ksrc/linux/tools/perf/perf (c2e44d614e33e1
  probe_perf:oldevent=cmd_probe
  ----
It shows both of old and new events but user can not use old one.
With this;
  ----
  $ ./perf probe --cache -l
  /home/mhiramat/ksrc/linux/tools/perf/perf (061e90539bac69
  probe_perf:newevent=cmd_probe
  ----

This shows only new events which are on the existing binary.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.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/146831789417.17065.17896487479879669610.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-probe.c

@@ -370,7 +370,7 @@ static int del_perf_probe_caches(struct strfilter *filter)
 	struct str_node *nd;
 	int ret;
 
-	bidlist = build_id_cache__list_all();
+	bidlist = build_id_cache__list_all(false);
 	if (!bidlist) {
 		ret = -errno;
 		pr_debug("Failed to get buildids: %d\n", ret);

tools/perf/util/build-id.c

@@ -206,6 +206,31 @@ out:
 	return ret;
 }
 
+/* Check if the given build_id cache is valid on current running system */
+static bool build_id_cache__valid_id(char *sbuild_id)
+{
+	char real_sbuild_id[SBUILD_ID_SIZE] = "";
+	char *pathname;
+	int ret = 0;
+	bool result = false;
+
+	pathname = build_id_cache__origname(sbuild_id);
+	if (!pathname)
+		return false;
+
+	if (!strcmp(pathname, DSO__NAME_KALLSYMS))
+		ret = sysfs__sprintf_build_id("/", real_sbuild_id);
+	else if (pathname[0] == '/')
+		ret = filename__sprintf_build_id(pathname, real_sbuild_id);
+	else
+		ret = -EINVAL;	/* Should we support other special DSO cache? */
+	if (ret >= 0)
+		result = (strcmp(sbuild_id, real_sbuild_id) == 0);
+	free(pathname);
+
+	return result;
+}
+
 static const char *build_id_cache__basename(bool is_kallsyms, bool is_vdso)
 {
 	return is_kallsyms ? "kallsyms" : (is_vdso ? "vdso" : "elf");
@@ -433,13 +458,17 @@ static bool lsdir_bid_tail_filter(const char *name __maybe_unused,
 	return (i == SBUILD_ID_SIZE - 3) && (d->d_name[i] == '\0');
 }
 
-struct strlist *build_id_cache__list_all(void)
+struct strlist *build_id_cache__list_all(bool validonly)
 {
 	struct strlist *toplist, *linklist = NULL, *bidlist;
 	struct str_node *nd, *nd2;
 	char *topdir, *linkdir = NULL;
 	char sbuild_id[SBUILD_ID_SIZE];
 
+	/* for filename__ functions */
+	if (validonly)
+		symbol__init(NULL);
+
 	/* Open the top-level directory */
 	if (asprintf(&topdir, "%s/.build-id/", buildid_dir) < 0)
 		return NULL;
@@ -470,6 +499,8 @@ struct strlist *build_id_cache__list_all(void)
 			if (snprintf(sbuild_id, SBUILD_ID_SIZE, "%s%s",
 				     nd->s, nd2->s) != SBUILD_ID_SIZE - 1)
 				goto err_out;
+			if (validonly && !build_id_cache__valid_id(sbuild_id))
+				continue;
 			if (strlist__add(bidlist, sbuild_id) < 0)
 				goto err_out;
 		}

tools/perf/util/build-id.h

@@ -34,7 +34,7 @@ char *build_id_cache__origname(const char *sbuild_id);
 char *build_id_cache__linkname(const char *sbuild_id, char *bf, size_t size);
 char *build_id_cache__cachedir(const char *sbuild_id, const char *name,
 			       bool is_kallsyms, bool is_vdso);
-struct strlist *build_id_cache__list_all(void);
+struct strlist *build_id_cache__list_all(bool validonly);
 int build_id_cache__list_build_ids(const char *pathname,
 				   struct strlist **result);
 bool build_id_cache__cached(const char *sbuild_id);

tools/perf/util/probe-file.c

@@ -808,7 +808,7 @@ int probe_cache__show_all_caches(struct strfilter *filter)
 	pr_debug("list cache with filter: %s\n", buf);
 	free(buf);
 
-	bidlist = build_id_cache__list_all();
+	bidlist = build_id_cache__list_all(true);
 	if (!bidlist) {
 		pr_debug("Failed to get buildids: %d\n", errno);
 		return -EINVAL;