From 3c333937ee3be114b181c4861188cfe8f6a59697 Mon Sep 17 00:00:00 2001 From: Ulrich Drepper Date: Fri, 25 Jul 2008 22:32:13 -0400 Subject: [PATCH] [PATCH] dup3 fix Al Viro notice one cornercase that the new dup3() code. The dup2() function, as a special case, handles dup-ing to the same file descriptor. In this case the current dup3() code does nothing at all. I.e., it ingnores the flags parameter. This shouldn't happen, the close-on-exec flag should be set if requested. In case the O_CLOEXEC bit in the flags parameter is not set the dup3() function should behave in this respect identical to dup2(). This means dup3(fd, fd, 0) should not actively reset the c-o-e flag. The patch below implements this minor change. [AV: credits to Artur Grabowski for bringing that up as potential subtle point in dup2() behaviour] Signed-off-by: Ulrich Drepper Signed-off-by: Al Viro --- fs/fcntl.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/fcntl.c b/fs/fcntl.c index 9679fcbdeaa0..ce12a6885115 100644 --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -139,8 +139,13 @@ asmlinkage long sys_dup3(unsigned int oldfd, unsigned int newfd, int flags) if (!(file = fcheck(oldfd))) goto out_unlock; err = newfd; - if (newfd == oldfd) + if (unlikely(newfd == oldfd)) { + if (flags & O_CLOEXEC) { + fdt = files_fdtable(files); + FD_SET(newfd, fdt->close_on_exec); + } goto out_unlock; + } err = -EBADF; if (newfd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur) goto out_unlock; -- 2.20.1