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

[Masami Hiramatsu]

Oops, I missed to fix the SEGV bug. 
I'll fix it and resend as 5.1.

Thanks,

On Thu, 28 Apr 2016 03:39:17 +0900
Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote:

> 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@xxxxxxxxxx>
> ---
>  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,
> 


-- 
Masami Hiramatsu <mhiramat@xxxxxxxxxx>