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Subject[PATCH perf/core v8 14/16] perf probe: Allow wildcard for cached events
Date
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>
---
Changes in v7:
- Continue to search caches if a build-id cache has no probe cache.
- Make probe_cache__open() to accept DSO__NAME_KALLSYMS for kernel.
- Fix to add probes correctly when a wildcard matchs both of
uprobes and kprobes.
Changes in v5.1:
- Fix a SEGV bug when a group name is omitted. (Thanks Hemant!)
---
tools/perf/util/probe-event.c | 211 +++++++++++++++++++++++++++++++++++++----
tools/perf/util/probe-event.h | 1
tools/perf/util/probe-file.c | 46 +++++++--
tools/perf/util/probe-file.h | 5 +
4 files changed, 232 insertions(+), 31 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 5ec98b2..0019a22 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];
@@ -2514,7 +2519,7 @@ 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;
@@ -2527,7 +2532,7 @@ 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;
@@ -2552,41 +2557,60 @@ static int probe_trace_event__set_name(struct probe_trace_event *tev,
return 0;
}

-static int __add_probe_trace_events(struct perf_probe_event *pev,
- struct probe_trace_event *tevs,
- int ntevs, bool allow_suffix)
+static int __open_probe_file_and_namelist(bool uprobe,
+ struct strlist **namelist)
{
- int i, fd, ret;
- struct probe_trace_event *tev = NULL;
- struct probe_cache *cache = NULL;
- struct strlist *namelist;
+ int fd;

- fd = probe_file__open(PF_FL_RW | (pev->uprobes ? PF_FL_UPROBE : 0));
+ fd = probe_file__open(PF_FL_RW | (uprobe ? PF_FL_UPROBE : 0));
if (fd < 0)
return fd;

/* Get current event names */
- namelist = probe_file__get_namelist(fd);
- if (!namelist) {
+ *namelist = probe_file__get_namelist(fd);
+ if (!(*namelist)) {
pr_debug("Failed to get current event list.\n");
- ret = -ENOMEM;
- goto close_out;
+ close(fd);
+ return -ENOMEM;
}
+ return fd;
+}
+
+static int __add_probe_trace_events(struct perf_probe_event *pev,
+ struct probe_trace_event *tevs,
+ int ntevs, bool allow_suffix)
+{
+ int i, fd[2] = {-1, -1}, up, ret;
+ struct probe_trace_event *tev = NULL;
+ struct probe_cache *cache = NULL;
+ struct strlist *namelist[2] = {NULL, NULL};
+
+ up = pev->uprobes ? 1 : 0;
+ fd[up] = __open_probe_file_and_namelist(up, &namelist[up]);
+ if (fd[up] < 0)
+ return fd[up];

ret = 0;
for (i = 0; i < ntevs; i++) {
tev = &tevs[i];
+ up = tev->uprobes ? 1 : 0;
+ if (fd[up] == -1) { /* Open the kprobe/uprobe_events */
+ fd[up] = __open_probe_file_and_namelist(up,
+ &namelist[up]);
+ if (fd[up] < 0)
+ goto close_out;
+ }
/* Skip if the symbol is out of .text or blacklisted */
if (!tev->point.symbol && !pev->uprobes)
continue;

/* Set new name for tev (and update namelist) */
- ret = probe_trace_event__set_name(tev, pev, namelist,
+ ret = probe_trace_event__set_name(tev, pev, namelist[up],
allow_suffix);
if (ret < 0)
break;

- ret = probe_file__add_event(fd, tev);
+ ret = probe_file__add_event(fd[up], tev);
if (ret < 0)
break;

@@ -2609,9 +2633,12 @@ static int __add_probe_trace_events(struct perf_probe_event *pev,
}
}

- strlist__delete(namelist);
close_out:
- close(fd);
+ for (up = 0; up < 2; up++) {
+ strlist__delete(namelist[up]);
+ if (fd[up] >= 0)
+ close(fd[up]);
+ }
return ret;
}

@@ -2890,6 +2917,141 @@ 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. Return the number
+ * of cached events found, if an error occurs return the error.
+ */
+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);
+ /* Return 0 ("not found") if the target has no probe cache. */
+ if (!cache)
+ return 0;
+
+ for_each_probe_cache_entry(entry, cache) {
+ /* Skip the cache entry which has no name */
+ if (!entry->pev.event || !entry->pev.group)
+ continue;
+ if ((!pev->group || 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 (ntevs > 0 && 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);
+ /* In the case of cnt == 0, we just skip it */
+ if (ret > 0)
+ ret = concat_probe_trace_events(tevs, &ntevs,
+ &tmp_tevs, ret);
+ 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)
{
@@ -2899,6 +3061,13 @@ 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 e18ea9f..a027bfe 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 c4104c4..4d25882 100644
--- a/tools/perf/util/probe-file.c
+++ b/tools/perf/util/probe-file.c
@@ -360,13 +360,38 @@ probe_cache_entry__new(struct perf_probe_event *pev)
return ret;
}

-/* 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(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)) {
@@ -376,12 +401,13 @@ 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;
@@ -537,7 +563,7 @@ 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) &&
@@ -567,7 +593,7 @@ 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))
@@ -720,7 +746,7 @@ 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)
@@ -759,7 +785,7 @@ 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,
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