[PATCH perf/core v5 14/15] perf probe: Allow wildcard for cached events

Masami Hiramatsu
2016-04-27T18:39:26Z

Allo glob wildcard for reusing cached/SDT events. This also
automatically find the target binaries, e.g.

# perf probe -a %sdt_libc:\*

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

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
tools/perf/util/probe-event.c | 153 ++++++++++++++++++++++++++++++++++++++++-
tools/perf/util/probe-event.h | 1
tools/perf/util/probe-file.c | 33 ++++++++-
tools/perf/util/probe-file.h | 5 +
4 files changed, 183 insertions(+), 9 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 1a9ea2b..9ca8392 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -236,7 +236,7 @@ static void clear_perf_probe_point(struct perf_probe_point *pp)
free(pp->lazy_line);
}

-static void clear_probe_trace_events(struct probe_trace_event *tevs, int ntevs)
+void clear_probe_trace_events(struct probe_trace_event *tevs, int ntevs)
{
int i;

@@ -1206,7 +1206,7 @@ static int parse_perf_probe_event_name(char **arg, struct perf_probe_event *pev)
ptr = strchr(*arg, ':');
if (ptr) {
*ptr = '\0';
- if (!is_c_func_name(*arg))
+ if (!pev->sdt && !is_c_func_name(*arg))
goto ng_name;
pev->group = strdup(*arg);
if (!pev->group)
@@ -1214,7 +1214,7 @@ static int parse_perf_probe_event_name(char **arg, struct perf_probe_event *pev)
*arg = ptr + 1;
} else
pev->group = NULL;
- if (!is_c_func_name(*arg)) {
+ if (!pev->sdt && !is_c_func_name(*arg)) {
ng_name:
semantic_error("%s is bad for event name -it must "
"follow C symbol-naming rule.\n", *arg);
@@ -1640,6 +1640,11 @@ int parse_probe_trace_command(const char *cmd, struct probe_trace_event *tev)
p = strchr(argv[1], ':');
if (p) {
tp->module = strndup(argv[1], p - argv[1]);
+ if (!tp->module) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ tev->uprobes = (tp->module[0] == '/');
p++;
} else
p = argv[1];
@@ -2485,7 +2490,7 @@ static int probe_trace_event__set_name(struct probe_trace_event *tev,
int ret;

/* If probe_event or trace_event already have the name, reuse it */
- if (pev->event)
+ if (pev->event && !pev->sdt)
event = pev->event;
else if (tev->event)
event = tev->event;
@@ -2498,7 +2503,7 @@ static int probe_trace_event__set_name(struct probe_trace_event *tev,
else
event = tev->point.realname;
}
- if (pev->group)
+ if (pev->group && !pev->sdt)
group = pev->group;
else if (tev->group)
group = tev->group;
@@ -2860,6 +2865,137 @@ errout:

bool __weak arch__prefers_symtab(void) { return false; }

+/* Concatinate two arrays */
+static void *memcat(void *a, size_t sz_a, void *b, size_t sz_b)
+{
+ void *ret;
+
+ ret = malloc(sz_a + sz_b);
+ if (ret) {
+ memcpy(ret, a, sz_a);
+ memcpy(ret + sz_a, b, sz_b);
+ }
+ return ret;
+}
+
+static int
+concat_probe_trace_events(struct probe_trace_event **tevs, int *ntevs,
+ struct probe_trace_event **tevs2, int ntevs2)
+{
+ struct probe_trace_event *new_tevs;
+ int ret = 0;
+
+ if (ntevs == 0) {
+ *tevs = *tevs2;
+ *ntevs = ntevs2;
+ *tevs2 = NULL;
+ return 0;
+ }
+
+ if (*ntevs + ntevs2 > probe_conf.max_probes)
+ ret = -E2BIG;
+ else {
+ /* Concatinate the array of probe_trace_event */
+ new_tevs = memcat(*tevs, (*ntevs) * sizeof(**tevs),
+ *tevs2, ntevs2 * sizeof(**tevs2));
+ if (!new_tevs)
+ ret = -ENOMEM;
+ else {
+ free(*tevs);
+ *tevs = new_tevs;
+ *ntevs += ntevs2;
+ }
+ }
+ if (ret < 0)
+ clear_probe_trace_events(*tevs2, ntevs2);
+ zfree(tevs2);
+
+ return ret;
+}
+
+/* Try to find probe_trace_event from given probe caches */
+static int find_cached_events(struct perf_probe_event *pev,
+ struct probe_trace_event **tevs,
+ const char *target)
+{
+ struct probe_cache *cache;
+ struct probe_cache_entry *entry;
+ struct probe_trace_event *tmp_tevs = NULL;
+ int ntevs = 0;
+ int ret = 0;
+
+ cache = probe_cache__new(target);
+ if (!cache)
+ return -ENOENT;
+
+ for_each_probe_cache_entry(entry, cache) {
+ /* Skip the cache entry which has no name */
+ if (!entry->pev.event || !entry->pev.group)
+ continue;
+ if (strglobmatch(entry->pev.group, pev->group) &&
+ strglobmatch(entry->pev.event, pev->event)) {
+ ret = probe_cache_entry__get_event(entry, &tmp_tevs);
+ if (ret > 0)
+ ret = concat_probe_trace_events(tevs, &ntevs,
+ &tmp_tevs, ret);
+ if (ret < 0)
+ break;
+ }
+ }
+ probe_cache__delete(cache);
+ if (ret < 0) {
+ clear_probe_trace_events(*tevs, ntevs);
+ zfree(tevs);
+ } else {
+ ret = ntevs;
+ if (target[0] == '/')
+ pev->uprobes = true;
+ }
+
+ return ret;
+}
+
+/* Try to find probe_trace_event from all probe caches */
+static int find_cached_events_all(struct perf_probe_event *pev,
+ struct probe_trace_event **tevs)
+{
+ struct probe_trace_event *tmp_tevs = NULL;
+ struct strlist *bidlist;
+ struct str_node *nd;
+ char *pathname;
+ int ntevs = 0;
+ int ret;
+
+ /* Get the buildid list of all valid caches */
+ ret = build_id_cache__list_all(&bidlist, true);
+ if (ret < 0) {
+ pr_debug("Failed to get buildids: %d\n", ret);
+ return ret;
+ }
+
+ ret = 0;
+ strlist__for_each(nd, bidlist) {
+ pathname = build_id_cache__origname(nd->s);
+ ret = find_cached_events(pev, &tmp_tevs, pathname);
+ if (ret > 0)
+ ret = concat_probe_trace_events(tevs, &ntevs,
+ &tmp_tevs, ret);
+ /* In the case of cnt == 0, we just skip it */
+ free(pathname);
+ if (ret < 0)
+ break;
+ }
+ strlist__delete(bidlist);
+
+ if (ret < 0) {
+ clear_probe_trace_events(*tevs, ntevs);
+ zfree(tevs);
+ } else
+ ret = ntevs;
+
+ return ret;
+}
+
static int find_probe_trace_events_from_cache(struct perf_probe_event *pev,
struct probe_trace_event **tevs)
{
@@ -2869,6 +3005,13 @@ static int find_probe_trace_events_from_cache(struct perf_probe_event *pev,
struct str_node *node;
int ret, i;

+ if (pev->sdt) {
+ /* For SDT/cached events, we use special search functions */
+ if (!pev->target)
+ return find_cached_events_all(pev, tevs);
+ else
+ return find_cached_events(pev, tevs, pev->target);
+ }
cache = probe_cache__new(pev->target);
if (!cache)
return 0;
diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
index 2a23efe..39b5a35 100644
--- a/tools/perf/util/probe-event.h
+++ b/tools/perf/util/probe-event.h
@@ -134,6 +134,7 @@ bool perf_probe_event_need_dwarf(struct perf_probe_event *pev);
/* Release event contents */
void clear_perf_probe_event(struct perf_probe_event *pev);
void clear_probe_trace_event(struct probe_trace_event *tev);
+void clear_probe_trace_events(struct probe_trace_event *tevs, int ntevs);

/* Command string to line-range */
int parse_line_range_desc(const char *cmd, struct line_range *lr);
diff --git a/tools/perf/util/probe-file.c b/tools/perf/util/probe-file.c
index 2437b48..896d645 100644
--- a/tools/perf/util/probe-file.c
+++ b/tools/perf/util/probe-file.c
@@ -360,6 +360,31 @@ probe_cache_entry__new(struct perf_probe_event *pev)
return ret;
}

+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(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 */
static int probe_cache__open(struct probe_cache *pcache, const char *target)
{
@@ -528,7 +553,7 @@ probe_cache__find(struct probe_cache *pcache, struct perf_probe_event *pev)
if (!cmd)
return NULL;

- list_for_each_entry(entry, &pcache->list, list) {
+ for_each_probe_cache_entry(entry, pcache) {
if (pev->sdt) {
if (entry->pev.event &&
streql(entry->pev.event, pev->event) &&
@@ -558,7 +583,7 @@ probe_cache__find_by_name(struct probe_cache *pcache,
{
struct probe_cache_entry *entry = NULL;

- list_for_each_entry(entry, &pcache->list, list) {
+ for_each_probe_cache_entry(entry, pcache) {
/* Hit if same event name or same command-string */
if (streql(entry->pev.group, group) &&
streql(entry->pev.event, event))
@@ -711,7 +736,7 @@ int probe_cache__commit(struct probe_cache *pcache)
if (ret < 0)
goto out;

- list_for_each_entry(entry, &pcache->list, list) {
+ for_each_probe_cache_entry(entry, pcache) {
ret = probe_cache_entry__write(entry, pcache->fd);
pr_debug("Cache committed: %d\n", ret);
if (ret < 0)
@@ -750,7 +775,7 @@ static int probe_cache__show_entries(struct probe_cache *pcache,
{
struct probe_cache_entry *entry;

- list_for_each_entry(entry, &pcache->list, list) {
+ for_each_probe_cache_entry(entry, pcache) {
if (probe_cache_entry__compare(entry, filter))
printf("%s\n", entry->spev);
}
diff --git a/tools/perf/util/probe-file.h b/tools/perf/util/probe-file.h
index ce98162..0faf083 100644
--- a/tools/perf/util/probe-file.h
+++ b/tools/perf/util/probe-file.h
@@ -21,6 +21,8 @@ struct probe_cache {

#define PF_FL_UPROBE 1
#define PF_FL_RW 2
+#define for_each_probe_cache_entry(entry, pcache) \
+ list_for_each_entry(entry, &pcache->list, list)

/* probe-file.c depends on libelf */
#ifdef HAVE_LIBELF_SUPPORT
@@ -34,6 +36,9 @@ int probe_file__get_events(int fd, struct strfilter *filter,
struct strlist *plist);
int probe_file__del_strlist(int fd, struct strlist *namelist);

+int probe_cache_entry__get_event(struct probe_cache_entry *entry,
+ struct probe_trace_event **tevs);
+
struct probe_cache *probe_cache__new(const char *target);
int probe_cache__add_entry(struct probe_cache *pcache,
struct perf_probe_event *pev,