remove spurious lock in popen
authorRich Felker <dalias@aerifal.cx>
Tue, 20 Apr 2021 18:52:08 +0000 (14:52 -0400)
committerRich Felker <dalias@aerifal.cx>
Tue, 20 Apr 2021 18:52:08 +0000 (14:52 -0400)
the newly allocated FILE * has not yet leaked to the application and
is only visible to stdio internals until popen returns. since we do
not change any fields of the structure observed by libc internals,
only the pipe_pid member, locking is not necessary.

src/stdio/popen.c

index b53a557..19bbe7c 100644 (file)
@@ -31,7 +31,6 @@ FILE *popen(const char *cmd, const char *mode)
                __syscall(SYS_close, p[1]);
                return NULL;
        }
-       FLOCK(f);
 
        e = ENOMEM;
        if (!posix_spawn_file_actions_init(&fa)) {
@@ -43,7 +42,6 @@ FILE *popen(const char *cmd, const char *mode)
                                if (!strchr(mode, 'e'))
                                        fcntl(p[op], F_SETFD, 0);
                                __syscall(SYS_close, p[1-op]);
-                               FUNLOCK(f);
                                return f;
                        }
                }