adjust posix_spawn dup2 action behavior to match future requirements

[musl] / src / process / posix_spawn.c

diff --git a/src/process/posix_spawn.c b/src/process/posix_spawn.c
index 0849c71..93fb155 100644 (file)
--- a/src/process/posix_spawn.c
+++ b/src/process/posix_spawn.c
@@ -27,12 +27,7 @@ static int __sys_dup2(int old, int new)
 #ifdef SYS_dup2
        return __syscall(SYS_dup2, old, new);
 #else
-       if (old==new) {
-               int r = __syscall(SYS_fcntl, old, F_GETFD);
-               return r<0 ? r : old;
-       } else {
-               return __syscall(SYS_dup3, old, new, 0);
-       }
+       return __syscall(SYS_dup3, old, new, 0);
 #endif
 }
 
@@ -109,8 +104,17 @@ static int child(void *args_vp)
                                __syscall(SYS_close, op->fd);
                                break;
                        case FDOP_DUP2:
-                               if ((ret=__sys_dup2(op->srcfd, op->fd))<0)
-                                       goto fail;
+                               fd = op->srcfd;
+                               if (fd != op->fd) {
+                                       if ((ret=__sys_dup2(fd, op->fd))<0)
+                                               goto fail;
+                               } else {
+                                       ret = __syscall(SYS_fcntl, fd, F_GETFD);
+                                       ret = __syscall(SYS_fcntl, fd, F_SETFD,
+                                                       ret & ~FD_CLOEXEC);
+                                       if (ret<0)
+                                               goto fail;
+                               }
                                break;
                        case FDOP_OPEN:
                                fd = __sys_open(op->path, op->oflag, op->mode);