perf tools: Pass build id object to sysfs__read_build_id()

Passing build id object to sysfs__read_build_id function, so it can
populate the size of the build_id object.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20201013192441.1299447-4-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/build-id.c

@@ -113,7 +113,7 @@ int build_id__sprintf(const u8 *build_id, int len, char *bf)
 int sysfs__sprintf_build_id(const char *root_dir, char *sbuild_id)
 {
 	char notes[PATH_MAX];
-	u8 build_id[BUILD_ID_SIZE];
+	struct build_id bid;
 	int ret;
 
 	if (!root_dir)
@@ -121,11 +121,11 @@ int sysfs__sprintf_build_id(const char *root_dir, char *sbuild_id)
 
 	scnprintf(notes, sizeof(notes), "%s/sys/kernel/notes", root_dir);
 
-	ret = sysfs__read_build_id(notes, build_id, sizeof(build_id));
+	ret = sysfs__read_build_id(notes, &bid);
 	if (ret < 0)
 		return ret;
 
-	return build_id__sprintf(build_id, sizeof(build_id), sbuild_id);
+	return build_id__sprintf(bid.data, sizeof(bid.data), sbuild_id);
 }
 
 int filename__sprintf_build_id(const char *pathname, char *sbuild_id)

tools/perf/util/dso.c

@@ -1346,8 +1346,7 @@ void dso__read_running_kernel_build_id(struct dso *dso, struct machine *machine)
 	if (machine__is_default_guest(machine))
 		return;
 	sprintf(path, "%s/sys/kernel/notes", machine->root_dir);
-	if (sysfs__read_build_id(path, dso->bid.data,
-				 sizeof(dso->bid.data)) == 0)
+	if (sysfs__read_build_id(path, &dso->bid) == 0)
 		dso->has_build_id = true;
 }
 
@@ -1365,8 +1364,7 @@ int dso__kernel_module_get_build_id(struct dso *dso,
 		 "%s/sys/module/%.*s/notes/.note.gnu.build-id",
 		 root_dir, (int)strlen(name) - 1, name);
 
-	if (sysfs__read_build_id(filename, dso->bid.data,
-				 sizeof(dso->bid.data)) == 0)
+	if (sysfs__read_build_id(filename, &dso->bid) == 0)
 		dso->has_build_id = true;
 
 	return 0;

tools/perf/util/symbol-elf.c

@@ -595,13 +595,11 @@ int filename__read_build_id(const char *filename, struct build_id *bid)
 
 #endif // HAVE_LIBBFD_BUILDID_SUPPORT
 
-int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
+int sysfs__read_build_id(const char *filename, struct build_id *bid)
 {
+	size_t size = sizeof(bid->data);
 	int fd, err = -1;
 
-	if (size < BUILD_ID_SIZE)
-		goto out;
-
 	fd = open(filename, O_RDONLY);
 	if (fd < 0)
 		goto out;
@@ -622,8 +620,9 @@ int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
 				break;
 			if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
 				size_t sz = min(descsz, size);
-				if (read(fd, build_id, sz) == (ssize_t)sz) {
-					memset(build_id + sz, 0, size - sz);
+				if (read(fd, bid->data, sz) == (ssize_t)sz) {
+					memset(bid->data + sz, 0, size - sz);
+					bid->size = sz;
 					err = 0;
 					break;
 				}

tools/perf/util/symbol-minimal.c

@@ -222,9 +222,8 @@ int filename__read_build_id(const char *filename, struct build_id *bid)
 	return ret;
 }
 
-int sysfs__read_build_id(const char *filename, void *build_id, size_t size __maybe_unused)
+int sysfs__read_build_id(const char *filename, struct build_id *bid)
 {
-	struct build_id bid;
 	int fd;
 	int ret = -1;
 	struct stat stbuf;
@@ -246,9 +245,7 @@ int sysfs__read_build_id(const char *filename, void *build_id, size_t size __may
 	if (read(fd, buf, buf_size) != (ssize_t) buf_size)
 		goto out_free;
 
-	ret = read_build_id(buf, buf_size, &bid, false);
-	if (ret > 0)
-		memcpy(build_id, bid.data, bid.size);
+	ret = read_build_id(buf, buf_size, bid, false);
 out_free:
 	free(buf);
 out:

tools/perf/util/symbol.c

@@ -2122,7 +2122,7 @@ static bool filename__readable(const char *file)
 
 static char *dso__find_kallsyms(struct dso *dso, struct map *map)
 {
-	u8 host_build_id[BUILD_ID_SIZE];
+	struct build_id bid;
 	char sbuild_id[SBUILD_ID_SIZE];
 	bool is_host = false;
 	char path[PATH_MAX];
@@ -2135,9 +2135,8 @@ static char *dso__find_kallsyms(struct dso *dso, struct map *map)
 		goto proc_kallsyms;
 	}
 
-	if (sysfs__read_build_id("/sys/kernel/notes", host_build_id,
-				 sizeof(host_build_id)) == 0)
-		is_host = dso__build_id_equal(dso, host_build_id);
+	if (sysfs__read_build_id("/sys/kernel/notes", &bid) == 0)
+		is_host = dso__build_id_equal(dso, bid.data);
 
 	/* Try a fast path for /proc/kallsyms if possible */
 	if (is_host) {

tools/perf/util/symbol.h

@@ -144,7 +144,7 @@ struct symbol *dso__next_symbol(struct symbol *sym);
 enum dso_type dso__type_fd(int fd);
 
 int filename__read_build_id(const char *filename, struct build_id *id);
-int sysfs__read_build_id(const char *filename, void *bf, size_t size);
+int sysfs__read_build_id(const char *filename, struct build_id *bid);
 int modules__parse(const char *filename, void *arg,
 		   int (*process_module)(void *arg, const char *name,
 					 u64 start, u64 size));