[PATCH 24/37] perf tools: Make perf_exec_path() always return malloc'd string

From: Arnaldo Carvalho de Melo
Date: Thu Nov 19 2015 - 12:58:43 EST


From: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>

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

This may cause a memory leak because the caller can not unconditionally
free the returned string.

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

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Link: http://lkml.kernel.org/r/20151119060453.14210.65666.stgit@xxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/util/exec_cmd.c | 21 +++++++++++----------
tools/perf/util/exec_cmd.h | 5 +++--
tools/perf/util/help.c | 6 ++++--
3 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/tools/perf/util/exec_cmd.c b/tools/perf/util/exec_cmd.c
index 7adf4ad15d8f..1099e92f5ee1 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)
@@ -52,17 +52,16 @@ 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;
- }
+ if (env && *env)
+ return strdup(env);

return system_path(PERF_EXEC_PATH);
}
@@ -83,9 +82,11 @@ 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 bc4b915963f5..48b4175f1e11 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 86c37c472263..fa1fc4acb8a4 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) {
--
2.1.0

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