[PATCH perf/core 02/13] perf: Make perf_exec_path always returns malloc'd string

From: Masami Hiramatsu
Date: Wed Nov 18 2015 - 01:50:27 EST


Since system_path() returns malloc'd string if given path is
not an absolute path, perf_exec_path sometimes returns static
string and sometimes returns malloc'd string depends on the
environment variables or command options.

This causes a memory leak because caller can not free the
returned string.

This fixes perf_exec_path and system_path to always return
malloc'd string, so caller can always free it.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
---
tools/perf/util/exec_cmd.c | 20 ++++++++++++--------
tools/perf/util/exec_cmd.h | 5 +++--
tools/perf/util/help.c | 6 ++++--
3 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/tools/perf/util/exec_cmd.c b/tools/perf/util/exec_cmd.c
index 7adf4ad..7031ffc 100644
--- a/tools/perf/util/exec_cmd.c
+++ b/tools/perf/util/exec_cmd.c
@@ -9,17 +9,17 @@
static const char *argv_exec_path;
static const char *argv0_path;

-const char *system_path(const char *path)
+char *system_path(const char *path)
{
static const char *prefix = PREFIX;
struct strbuf d = STRBUF_INIT;

if (is_absolute_path(path))
- return path;
+ return strdup(path);

strbuf_addf(&d, "%s/%s", prefix, path);
path = strbuf_detach(&d, NULL);
- return path;
+ return (char *)path;
}

const char *perf_extract_argv0_path(const char *argv0)
@@ -52,16 +52,18 @@ void perf_set_argv_exec_path(const char *exec_path)


/* Returns the highest-priority, location to look for perf programs. */
-const char *perf_exec_path(void)
+char *perf_exec_path(void)
{
- const char *env;
+ char *env;

if (argv_exec_path)
- return argv_exec_path;
+ return strdup(argv_exec_path);

env = getenv(EXEC_PATH_ENVIRONMENT);
if (env && *env) {
- return env;
+ env = strdup(env);
+ if (env)
+ return env;
}

return system_path(PERF_EXEC_PATH);
@@ -83,9 +85,11 @@ void setup_path(void)
{
const char *old_path = getenv("PATH");
struct strbuf new_path = STRBUF_INIT;
+ char *tmp = perf_exec_path();

- add_path(&new_path, perf_exec_path());
+ add_path(&new_path, tmp);
add_path(&new_path, argv0_path);
+ free(tmp);

if (old_path)
strbuf_addstr(&new_path, old_path);
diff --git a/tools/perf/util/exec_cmd.h b/tools/perf/util/exec_cmd.h
index bc4b915..48b4175 100644
--- a/tools/perf/util/exec_cmd.h
+++ b/tools/perf/util/exec_cmd.h
@@ -3,10 +3,11 @@

extern void perf_set_argv_exec_path(const char *exec_path);
extern const char *perf_extract_argv0_path(const char *path);
-extern const char *perf_exec_path(void);
extern void setup_path(void);
extern int execv_perf_cmd(const char **argv); /* NULL terminated */
extern int execl_perf_cmd(const char *cmd, ...);
-extern const char *system_path(const char *path);
+/* perf_exec_path and system_path return malloc'd string, caller must free it */
+extern char *perf_exec_path(void);
+extern char *system_path(const char *path);

#endif /* __PERF_EXEC_CMD_H */
diff --git a/tools/perf/util/help.c b/tools/perf/util/help.c
index 86c37c4..fa1fc4a 100644
--- a/tools/perf/util/help.c
+++ b/tools/perf/util/help.c
@@ -159,7 +159,7 @@ void load_command_list(const char *prefix,
struct cmdnames *other_cmds)
{
const char *env_path = getenv("PATH");
- const char *exec_path = perf_exec_path();
+ char *exec_path = perf_exec_path();

if (exec_path) {
list_commands_in_dir(main_cmds, exec_path, prefix);
@@ -187,6 +187,7 @@ void load_command_list(const char *prefix,
sizeof(*other_cmds->names), cmdname_compare);
uniq(other_cmds);
}
+ free(exec_path);
exclude_cmds(other_cmds, main_cmds);
}

@@ -203,13 +204,14 @@ void list_commands(const char *title, struct cmdnames *main_cmds,
longest = other_cmds->names[i]->len;

if (main_cmds->cnt) {
- const char *exec_path = perf_exec_path();
+ char *exec_path = perf_exec_path();
printf("available %s in '%s'\n", title, exec_path);
printf("----------------");
mput_char('-', strlen(title) + strlen(exec_path));
putchar('\n');
pretty_print_string_list(main_cmds, longest);
putchar('\n');
+ free(exec_path);
}

if (other_cmds->cnt) {

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