Unverified Commit 03ba0fe4 authored by Christian Brauner's avatar Christian Brauner
Browse files

file: simplify logic in __close_range() 



It never looked too pleasant and it doesn't really buy us anything
anymore now that CLOSE_RANGE_CLOEXEC exists and we need to retake the
current maximum under the lock for it anyway. This also makes the logic
easier to follow.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Giuseppe Scrivano <gscrivan@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: default avatarChristian Brauner <christian.brauner@ubuntu.com>
parent f49fd6d3

fs/file.c

+14 −17
Original line number Diff line number Diff line
@@ -701,7 +701,6 @@ static inline void __range_close(struct files_struct *cur_fds, unsigned int fd, 
 */

int __close_range(unsigned fd, unsigned max_fd, unsigned int flags)

{

	unsigned int cur_max;

	struct task_struct *me = current;

	struct files_struct *cur_fds = me->files, *fds = NULL;
@@ -711,26 +710,26 @@ int __close_range(unsigned fd, unsigned max_fd, unsigned int flags) 
	if (fd > max_fd)

		return -EINVAL;



	rcu_read_lock();

	cur_max = files_fdtable(cur_fds)->max_fds;

	rcu_read_unlock();



	/* cap to last valid index into fdtable */

	cur_max--;



	if (flags & CLOSE_RANGE_UNSHARE) {

		int ret;

		unsigned int max_unshare_fds = NR_OPEN_MAX;



		/*

		 * If the requested range is greater than the current maximum,

		 * we're closing everything so only copy all file descriptors

		 * beneath the lowest file descriptor.

		 * If the caller requested all fds to be made cloexec copy all

		 * of the file descriptors since they still want to use them.

		 * If the caller requested all fds to be made cloexec we always

		 * copy all of the file descriptors since they still want to

		 * use them.

		 */

		if (!(flags & CLOSE_RANGE_CLOEXEC)) {

			/*

			 * If the requested range is greater than the current

			 * maximum, we're closing everything so only copy all

			 * file descriptors beneath the lowest file descriptor.

			 */

		if (!(flags & CLOSE_RANGE_CLOEXEC) && (max_fd >= cur_max))

			rcu_read_lock();

			if (max_fd >= last_fd(files_fdtable(cur_fds)))

				max_unshare_fds = fd;

			rcu_read_unlock();

		}



		ret = unshare_fd(CLONE_FILES, max_unshare_fds, &fds);

		if (ret)
@@ -744,8 +743,6 @@ int __close_range(unsigned fd, unsigned max_fd, unsigned int flags) 
			swap(cur_fds, fds);

	}



	max_fd = min(max_fd, cur_max);



	if (flags & CLOSE_RANGE_CLOEXEC)

		__range_cloexec(cur_fds, fd, max_fd);

	else