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Commit 4bb11d01 authored by Namhyung Kim's avatar Namhyung Kim Committed by Arnaldo Carvalho de Melo
Browse files

perf tools: Add dso__data_get/put_fd() 



Using dso__data_fd() in multi-thread environment is not safe since
returned fd can be closed and/or reused anytime.

So convert it to the dso__data_get/put_fd() pair to protect the access
with lock.

The original dso__data_fd() is deprecated and kept only for testing.

Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
Acked-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1432137821-10853-3-git-send-email-namhyung@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent e840238d

tools/perf/tests/dso-data.c

+11 −0
Original line number Diff line number Diff line
@@ -99,6 +99,17 @@ struct test_data_offset offsets[] = { 
	},

};



/* move it from util/dso.c for compatibility */

static int dso__data_fd(struct dso *dso, struct machine *machine)

{

	int fd = dso__data_get_fd(dso, machine);



	if (fd >= 0)

		dso__data_put_fd(dso);



	return fd;

}



int test__dso_data(void)

{

	struct machine machine;

tools/perf/util/dso.c

+22 −9
Original line number Diff line number Diff line
@@ -473,25 +473,35 @@ static void try_to_open_dso(struct dso *dso, struct machine *machine) 
}



/**

 * dso__data_fd - Get dso's data file descriptor

 * dso__data_get_fd - Get dso's data file descriptor

 * @dso: dso object

 * @machine: machine object

 *

 * External interface to find dso's file, open it and

 * returns file descriptor.

 * returns file descriptor.  It should be paired with

 * dso__data_put_fd() if it returns non-negative value.

 */

int dso__data_fd(struct dso *dso, struct machine *machine)

int dso__data_get_fd(struct dso *dso, struct machine *machine)

{

	if (dso->data.status == DSO_DATA_STATUS_ERROR)

		return -1;



	pthread_mutex_lock(&dso__data_open_lock);

	if (pthread_mutex_lock(&dso__data_open_lock) < 0)

		return -1;



	try_to_open_dso(dso, machine);



	if (dso->data.fd < 0)

		pthread_mutex_unlock(&dso__data_open_lock);



	return dso->data.fd;

}



void dso__data_put_fd(struct dso *dso __maybe_unused)

{

	pthread_mutex_unlock(&dso__data_open_lock);

}



bool dso__data_status_seen(struct dso *dso, enum dso_data_status_seen by)

{

	u32 flag = 1 << by;
@@ -1199,12 +1209,15 @@ size_t dso__fprintf(struct dso *dso, enum map_type type, FILE *fp) 
enum dso_type dso__type(struct dso *dso, struct machine *machine)

{

	int fd;

	enum dso_type type = DSO__TYPE_UNKNOWN;



	fd = dso__data_fd(dso, machine);

	if (fd < 0)

		return DSO__TYPE_UNKNOWN;

	fd = dso__data_get_fd(dso, machine);

	if (fd >= 0) {

		type = dso__type_fd(fd);

		dso__data_put_fd(dso);

	}



	return dso__type_fd(fd);

	return type;

}



int dso__strerror_load(struct dso *dso, char *buf, size_t buflen)

tools/perf/util/dso.h

+9 −4
Original line number Diff line number Diff line
@@ -240,7 +240,8 @@ int __kmod_path__parse(struct kmod_path *m, const char *path, 


/*

 * The dso__data_* external interface provides following functions:

 *   dso__data_fd

 *   dso__data_get_fd

 *   dso__data_put_fd

 *   dso__data_close

 *   dso__data_size

 *   dso__data_read_offset
@@ -257,8 +258,11 @@ int __kmod_path__parse(struct kmod_path *m, const char *path, 
 * The current usage of the dso__data_* interface is as follows:

 *

 * Get DSO's fd:

 *   int fd = dso__data_fd(dso, machine);

 *   int fd = dso__data_get_fd(dso, machine);

 *   if (fd >= 0) {

 *       USE 'fd' SOMEHOW

 *       dso__data_put_fd(dso);

 *   }

 *

 * Read DSO's data:

 *   n = dso__data_read_offset(dso_0, &machine, 0, buf, BUFSIZE);
@@ -277,7 +281,8 @@ int __kmod_path__parse(struct kmod_path *m, const char *path, 
 *

 * TODO

*/

int dso__data_fd(struct dso *dso, struct machine *machine);

int dso__data_get_fd(struct dso *dso, struct machine *machine);

void dso__data_put_fd(struct dso *dso __maybe_unused);

void dso__data_close(struct dso *dso);



off_t dso__data_size(struct dso *dso, struct machine *machine);

tools/perf/util/unwind-libunwind.c

+8 −3
Original line number Diff line number Diff line
@@ -269,13 +269,14 @@ static int read_unwind_spec_eh_frame(struct dso *dso, struct machine *machine, 
	u64 offset = dso->data.eh_frame_hdr_offset;



	if (offset == 0) {

		fd = dso__data_fd(dso, machine);

		fd = dso__data_get_fd(dso, machine);

		if (fd < 0)

			return -EINVAL;



		/* Check the .eh_frame section for unwinding info */

		offset = elf_section_offset(fd, ".eh_frame_hdr");

		dso->data.eh_frame_hdr_offset = offset;

		dso__data_put_fd(dso);

	}



	if (offset)
@@ -294,13 +295,14 @@ static int read_unwind_spec_debug_frame(struct dso *dso, 
	u64 ofs = dso->data.debug_frame_offset;



	if (ofs == 0) {

		fd = dso__data_fd(dso, machine);

		fd = dso__data_get_fd(dso, machine);

		if (fd < 0)

			return -EINVAL;



		/* Check the .debug_frame section for unwinding info */

		ofs = elf_section_offset(fd, ".debug_frame");

		dso->data.debug_frame_offset = ofs;

		dso__data_put_fd(dso);

	}



	*offset = ofs;
@@ -353,10 +355,13 @@ find_proc_info(unw_addr_space_t as, unw_word_t ip, unw_proc_info_t *pi, 
#ifndef NO_LIBUNWIND_DEBUG_FRAME

	/* Check the .debug_frame section for unwinding info */

	if (!read_unwind_spec_debug_frame(map->dso, ui->machine, &segbase)) {

		int fd = dso__data_fd(map->dso, ui->machine);

		int fd = dso__data_get_fd(map->dso, ui->machine);

		int is_exec = elf_is_exec(fd, map->dso->name);

		unw_word_t base = is_exec ? 0 : map->start;



		if (fd >= 0)

			dso__data_put_fd(dso);



		memset(&di, 0, sizeof(di));

		if (dwarf_find_debug_frame(0, &di, ip, base, map->dso->name,

					   map->start, map->end))