perf probe: Show all cached probes

perf probe --list shows all cached probes when --cache is given. Each
caches are shown with on which binary that probed. E.g.:

  -----
  # perf probe --cache vfs_read \$params
  # perf probe --cache -x /lib64/libc-2.17.so getaddrinfo \$params
  # perf probe --cache --list
  [kernel.kallsyms] (1466a0a250b5d0070c6d0f03c5fed30b237970a1):
  vfs_read $params
  /usr/lib64/libc-2.17.so (c31ffe7942bfd77b2fca8f9bd5709d387a86d3bc):
  getaddrinfo $params
  -----

Note that $params requires debuginfo.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
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/146736020674.27797.13488316780383460180.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Documentation/perf-probe.txt

@@ -67,7 +67,10 @@ OPTIONS
 
 -l::
 --list[=[GROUP:]EVENT]::
-	List up current probe events. This can also accept filtering patterns of event names.
+	List up current probe events. This can also accept filtering patterns of
+	event names.
+	When this is used with --cache, perf shows all cached probes instead of
+	the live probes.
 
 -L::
 --line=::
@@ -110,8 +113,9 @@ OPTIONS
 	adding and removal operations.
 
 --cache::
-	Cache the probes (with --add option). Any events which successfully added
+	(With --add) Cache the probes. Any events which successfully added
 	are also stored in the cache file.
+	(With --list) Show cached probes.
 
 --max-probes=NUM::
 	Set the maximum number of probe points for an event. Default is 128.

tools/perf/builtin-probe.c

@@ -44,7 +44,7 @@
 
 #define DEFAULT_VAR_FILTER "!__k???tab_* & !__crc_*"
 #define DEFAULT_FUNC_FILTER "!_*"
-#define DEFAULT_LIST_FILTER "*:*"
+#define DEFAULT_LIST_FILTER "*"
 
 /* Session management structure */
 static struct {

tools/perf/util/build-id.c

@@ -165,8 +165,7 @@ char *build_id_cache__kallsyms_path(const char *sbuild_id, char *bf,
 	return NULL;
 }
 
-static char *build_id_cache__linkname(const char *sbuild_id, char *bf,
-				      size_t size)
+char *build_id_cache__linkname(const char *sbuild_id, char *bf, size_t size)
 {
 	char *tmp = bf;
 	int ret = asnprintf(&bf, size, "%s/.build-id/%.2s/%s", buildid_dir,
@@ -176,6 +175,36 @@ static char *build_id_cache__linkname(const char *sbuild_id, char *bf,
 	return bf;
 }
 
+char *build_id_cache__origname(const char *sbuild_id)
+{
+	char *linkname;
+	char buf[PATH_MAX];
+	char *ret = NULL, *p;
+	size_t offs = 5;	/* == strlen("../..") */
+
+	linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
+	if (!linkname)
+		return NULL;
+
+	if (readlink(linkname, buf, PATH_MAX) < 0)
+		goto out;
+	/* The link should be "../..<origpath>/<sbuild_id>" */
+	p = strrchr(buf, '/');	/* Cut off the "/<sbuild_id>" */
+	if (p && (p > buf + offs)) {
+		*p = '\0';
+		if (buf[offs + 1] == '[')
+			offs++;	/*
+				 * This is a DSO name, like [kernel.kallsyms].
+				 * Skip the first '/', since this is not the
+				 * cache of a regular file.
+				 */
+		ret = strdup(buf + offs);	/* Skip "../..[/]" */
+	}
+out:
+	free(linkname);
+	return ret;
+}
+
 static const char *build_id_cache__basename(bool is_kallsyms, bool is_vdso)
 {
 	return is_kallsyms ? "kallsyms" : (is_vdso ? "vdso" : "elf");
@@ -387,6 +416,81 @@ void disable_buildid_cache(void)
 	no_buildid_cache = true;
 }
 
+static bool lsdir_bid_head_filter(const char *name __maybe_unused,
+				  struct dirent *d __maybe_unused)
+{
+	return (strlen(d->d_name) == 2) &&
+		isxdigit(d->d_name[0]) && isxdigit(d->d_name[1]);
+}
+
+static bool lsdir_bid_tail_filter(const char *name __maybe_unused,
+				  struct dirent *d __maybe_unused)
+{
+	int i = 0;
+	while (isxdigit(d->d_name[i]) && i < SBUILD_ID_SIZE - 3)
+		i++;
+	return (i == SBUILD_ID_SIZE - 3) && (d->d_name[i] == '\0');
+}
+
+struct strlist *build_id_cache__list_all(void)
+{
+	struct strlist *toplist, *linklist = NULL, *bidlist;
+	struct str_node *nd, *nd2;
+	char *topdir, *linkdir = NULL;
+	char sbuild_id[SBUILD_ID_SIZE];
+
+	/* Open the top-level directory */
+	if (asprintf(&topdir, "%s/.build-id/", buildid_dir) < 0)
+		return NULL;
+
+	bidlist = strlist__new(NULL, NULL);
+	if (!bidlist)
+		goto out;
+
+	toplist = lsdir(topdir, lsdir_bid_head_filter);
+	if (!toplist) {
+		pr_debug("Error in lsdir(%s): %d\n", topdir, errno);
+		/* If there is no buildid cache, return an empty list */
+		if (errno == ENOENT)
+			goto out;
+		goto err_out;
+	}
+
+	strlist__for_each_entry(nd, toplist) {
+		if (asprintf(&linkdir, "%s/%s", topdir, nd->s) < 0)
+			goto err_out;
+		/* Open the lower-level directory */
+		linklist = lsdir(linkdir, lsdir_bid_tail_filter);
+		if (!linklist) {
+			pr_debug("Error in lsdir(%s): %d\n", linkdir, errno);
+			goto err_out;
+		}
+		strlist__for_each_entry(nd2, linklist) {
+			if (snprintf(sbuild_id, SBUILD_ID_SIZE, "%s%s",
+				     nd->s, nd2->s) != SBUILD_ID_SIZE - 1)
+				goto err_out;
+			if (strlist__add(bidlist, sbuild_id) < 0)
+				goto err_out;
+		}
+		strlist__delete(linklist);
+		zfree(&linkdir);
+	}
+
+out_free:
+	strlist__delete(toplist);
+out:
+	free(topdir);
+
+	return bidlist;
+
+err_out:
+	strlist__delete(linklist);
+	zfree(&linkdir);
+	strlist__delete(bidlist);
+	bidlist = NULL;
+	goto out_free;
+}
+
 char *build_id_cache__cachedir(const char *sbuild_id, const char *name,
 			       bool is_kallsyms, bool is_vdso)
 {

tools/perf/util/build-id.h

@@ -30,8 +30,11 @@ bool perf_session__read_build_ids(struct perf_session *session, bool with_hits);
 int perf_session__write_buildid_table(struct perf_session *session, int fd);
 int perf_session__cache_build_ids(struct perf_session *session);
 
+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);
 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-event.c

@@ -2366,6 +2366,9 @@ int show_perf_probe_events(struct strfilter *filter)
 
 	setup_pager();
 
+	if (probe_conf.cache)
+		return probe_cache__show_all_caches(filter);
+
 	ret = init_probe_symbol_maps(false);
 	if (ret < 0)
 		return ret;

tools/perf/util/probe-file.c

@@ -367,10 +367,17 @@ static int probe_cache__open(struct probe_cache *pcache, const char *target)
 {
 	char cpath[PATH_MAX];
 	char sbuildid[SBUILD_ID_SIZE];
-	char *dir_name;
+	char *dir_name = NULL;
 	bool is_kallsyms = !target;
 	int ret, fd;
 
+	if (target && build_id_cache__cached(target)) {
+		/* This is a cached buildid */
+		strncpy(sbuildid, target, SBUILD_ID_SIZE);
+		dir_name = build_id_cache__linkname(sbuildid, NULL, 0);
+		goto found;
+	}
+
 	if (target)
 		ret = filename__sprintf_build_id(target, sbuildid);
 	else {
@@ -394,8 +401,11 @@ static int probe_cache__open(struct probe_cache *pcache, const char *target)
 
 	dir_name = build_id_cache__cachedir(sbuildid, target, is_kallsyms,
 					    false);
-	if (!dir_name)
+found:
+	if (!dir_name) {
+		pr_debug("Failed to get cache from %s\n", target);
 		return -ENOMEM;
+	}
 
 	snprintf(cpath, PATH_MAX, "%s/probes", dir_name);
 	fd = open(cpath, O_CREAT | O_RDWR, 0644);
@@ -673,3 +683,55 @@ int probe_cache__commit(struct probe_cache *pcache)
 out:
 	return ret;
 }
+
+static int probe_cache__show_entries(struct probe_cache *pcache,
+				     struct strfilter *filter)
+{
+	struct probe_cache_entry *entry;
+	char buf[128], *ptr;
+
+	list_for_each_entry(entry, &pcache->entries, node) {
+		if (entry->pev.event) {
+			ptr = buf;
+			snprintf(buf, 128, "%s:%s",
+				 entry->pev.group, entry->pev.event);
+		} else
+			ptr = entry->spev;
+		if (strfilter__compare(filter, ptr))
+			printf("%s\n", entry->spev);
+	}
+	return 0;
+}
+
+/* Show all cached probes */
+int probe_cache__show_all_caches(struct strfilter *filter)
+{
+	struct probe_cache *pcache;
+	struct strlist *bidlist;
+	struct str_node *nd;
+	char *buf = strfilter__string(filter);
+
+	pr_debug("list cache with filter: %s\n", buf);
+	free(buf);
+
+	bidlist = build_id_cache__list_all();
+	if (!bidlist) {
+		pr_debug("Failed to get buildids: %d\n", errno);
+		return -EINVAL;
+	}
+	strlist__for_each_entry(nd, bidlist) {
+		pcache = probe_cache__new(nd->s);
+		if (!pcache)
+			continue;
+		if (!list_empty(&pcache->entries)) {
+			buf = build_id_cache__origname(nd->s);
+			printf("%s (%s):\n", buf, nd->s);
+			free(buf);
+			probe_cache__show_entries(pcache, filter);
+		}
+		probe_cache__delete(pcache);
+	}
+	strlist__delete(bidlist);
+
+	return 0;
+}

tools/perf/util/probe-file.h

@@ -42,4 +42,5 @@ struct probe_cache_entry *probe_cache__find(struct probe_cache *pcache,
 					    struct perf_probe_event *pev);
 struct probe_cache_entry *probe_cache__find_by_name(struct probe_cache *pcache,
 					const char *group, const char *event);
+int probe_cache__show_all_caches(struct strfilter *filter);
 #endif