perf tools: Get debug info of DSO properly

The dso__debuginfo() just used the path name to open the file but it may
be outdated.  It should check build-ID and use the file in the build-ID
cache if available rather than just using the path name.

Let's factor out dso__get_filename() to avoid code duplicate.

Fixes: 53a61a6 ("perf annotate: Add dso__debuginfo() helper")
Reviewed-by: Ian Rogers <[email protected]>
Signed-off-by: Namhyung Kim <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: James Clark <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Author: namhyung

tools/perf/util/dso.c

@@ -112,7 +112,7 @@ bool dso__is_object_file(const struct dso *dso)
 
 int dso__read_binary_type_filename(const struct dso *dso,
 				   enum dso_binary_type type,
-				   char *root_dir, char *filename, size_t size)
+				   const char *root_dir, char *filename, size_t size)
 {
 	char build_id_hex[SBUILD_ID_SIZE];
 	int ret = 0;
@@ -561,20 +561,15 @@ char *dso__filename_with_chroot(const struct dso *dso, const char *filename)
 	return filename_with_chroot(nsinfo__pid(dso__nsinfo_const(dso)), filename);
 }
 
-static int __open_dso(struct dso *dso, struct machine *machine)
-	EXCLUSIVE_LOCKS_REQUIRED(_dso__data_open_lock)
+static char *dso__get_filename(struct dso *dso, const char *root_dir,
+			       bool *decomp)
 {
-	int fd = -EINVAL;
-	char *root_dir = (char *)"";
 	char *name = malloc(PATH_MAX);
-	bool decomp = false;
 
-	if (!name)
-		return -ENOMEM;
+	*decomp = false;
 
-	mutex_lock(dso__lock(dso));
-	if (machine)
-		root_dir = machine->root_dir;
+	if (name == NULL)
+		return NULL;
 
 	if (dso__read_binary_type_filename(dso, dso__binary_type(dso),
 					    root_dir, name, PATH_MAX))
@@ -599,20 +594,38 @@ static int __open_dso(struct dso *dso, struct machine *machine)
 		size_t len = sizeof(newpath);
 
 		if (dso__decompress_kmodule_path(dso, name, newpath, len) < 0) {
-			fd = -(*dso__load_errno(dso));
+			errno = *dso__load_errno(dso);
 			goto out;
 		}
 
-		decomp = true;
+		*decomp = true;
 		strcpy(name, newpath);
 	}
+	return name;
+
+out:
+	free(name);
+	return NULL;
+}
 
-	fd = do_open(name);
+static int __open_dso(struct dso *dso, struct machine *machine)
+	EXCLUSIVE_LOCKS_REQUIRED(_dso__data_open_lock)
+{
+	int fd = -EINVAL;
+	char *name;
+	bool decomp = false;
+
+	mutex_lock(dso__lock(dso));
+
+	name = dso__get_filename(dso, machine ? machine->root_dir : "", &decomp);
+	if (name)
+		fd = do_open(name);
+	else
+		fd = -errno;
 
 	if (decomp)
 		unlink(name);
 
-out:
 	mutex_unlock(dso__lock(dso));
 	free(name);
 	return fd;
@@ -1916,3 +1929,23 @@ const u8 *dso__read_symbol(struct dso *dso, const char *symfs_filename,
 	return __dso__read_symbol(dso, symfs_filename, start, len,
 				  out_buf, out_buf_len, is_64bit);
 }
+
+struct debuginfo *dso__debuginfo(struct dso *dso)
+{
+	char *name;
+	bool decomp = false;
+	struct debuginfo *dinfo = NULL;
+
+	mutex_lock(dso__lock(dso));
+
+	name = dso__get_filename(dso, "", &decomp);
+	if (name)
+		dinfo = debuginfo__new(name);
+
+	if (decomp)
+		unlink(name);
+
+	mutex_unlock(dso__lock(dso));
+	free(name);
+	return dinfo;
+}

tools/perf/util/dso.h

@@ -784,7 +784,7 @@ int dso__kernel_module_get_build_id(struct dso *dso, const char *root_dir);
 
 char dso__symtab_origin(const struct dso *dso);
 int dso__read_binary_type_filename(const struct dso *dso, enum dso_binary_type type,
-				   char *root_dir, char *filename, size_t size);
+				   const char *root_dir, char *filename, size_t size);
 bool is_kernel_module(const char *pathname, int cpumode);
 bool dso__needs_decompress(struct dso *dso);
 int dso__decompress_kmodule_fd(struct dso *dso, const char *name);
@@ -933,14 +933,7 @@ u64 dso__findnew_global_type(struct dso *dso, u64 addr, u64 offset);
 bool perf_pid_map_tid(const char *dso_name, int *tid);
 bool is_perf_pid_map_name(const char *dso_name);
 
-/*
- * In the future, we may get debuginfo using build-ID (w/o path).
- * Add this helper is for the smooth conversion.
- */
-static inline struct debuginfo *dso__debuginfo(struct dso *dso)
-{
-	return debuginfo__new(dso__long_name(dso));
-}
+struct debuginfo *dso__debuginfo(struct dso *dso);
 
 const u8 *dso__read_symbol(struct dso *dso, const char *symfs_filename,
 			   const struct map *map, const struct symbol *sym,