Commit 628ff7c1 authored by Roland Dreier's avatar Roland Dreier Committed by Al Viro
Browse files

anonfd: Allow making anon files read-only 



It seems a couple places such as arch/ia64/kernel/perfmon.c and
drivers/infiniband/core/uverbs_main.c could use anon_inode_getfile()
instead of a private pseudo-fs + alloc_file(), if only there were a way
to get a read-only file.  So provide this by having anon_inode_getfile()
create a read-only file if we pass O_RDONLY in flags.

Signed-off-by: default avatarRoland Dreier <rolandd@cisco.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent ed261758

fs/anon_inodes.c

+10 −2
Original line number Diff line number Diff line
@@ -89,11 +89,19 @@ struct file *anon_inode_getfile(const char *name, 
	struct qstr this;

	struct path path;

	struct file *file;

	fmode_t mode;

	int error;



	if (IS_ERR(anon_inode_inode))

		return ERR_PTR(-ENODEV);



	switch (flags & O_ACCMODE) {

	case O_RDONLY: mode = FMODE_READ;		break;

	case O_WRONLY: mode = FMODE_WRITE;		break;

	case O_RDWR:   mode = FMODE_READ | FMODE_WRITE;	break;

	default:       return ERR_PTR(-EINVAL);

	}



	if (fops->owner && !try_module_get(fops->owner))

		return ERR_PTR(-ENOENT);
@@ -121,13 +129,13 @@ struct file *anon_inode_getfile(const char *name, 
	d_instantiate(path.dentry, anon_inode_inode);



	error = -ENFILE;

	file = alloc_file(&path, FMODE_READ | FMODE_WRITE, fops);

	file = alloc_file(&path, mode, fops);

	if (!file)

		goto err_dput;

	file->f_mapping = anon_inode_inode->i_mapping;



	file->f_pos = 0;

	file->f_flags = O_RDWR | (flags & O_NONBLOCK);

	file->f_flags = flags & (O_ACCMODE | O_NONBLOCK);

	file->f_version = 0;

	file->private_data = priv;

fs/eventfd.c

+1 −1
Original line number Diff line number Diff line
@@ -339,7 +339,7 @@ struct file *eventfd_file_create(unsigned int count, int flags) 
	ctx->flags = flags;



	file = anon_inode_getfile("[eventfd]", &eventfd_fops, ctx,

				  flags & EFD_SHARED_FCNTL_FLAGS);

				  O_RDWR | (flags & EFD_SHARED_FCNTL_FLAGS));

	if (IS_ERR(file))

		eventfd_free_ctx(ctx);

fs/eventpoll.c

+1 −1
Original line number Diff line number Diff line
@@ -1206,7 +1206,7 @@ SYSCALL_DEFINE1(epoll_create1, int, flags) 
	 * a file structure and a free file descriptor.

	 */

	error = anon_inode_getfd("[eventpoll]", &eventpoll_fops, ep,

				 flags & O_CLOEXEC);

				 O_RDWR | (flags & O_CLOEXEC));

	if (error < 0)

		ep_free(ep);

fs/signalfd.c

+1 −1
Original line number Diff line number Diff line
@@ -236,7 +236,7 @@ SYSCALL_DEFINE4(signalfd4, int, ufd, sigset_t __user *, user_mask, 
		 * anon_inode_getfd() will install the fd.

		 */

		ufd = anon_inode_getfd("[signalfd]", &signalfd_fops, ctx,

				       flags & (O_CLOEXEC | O_NONBLOCK));

				       O_RDWR | (flags & (O_CLOEXEC | O_NONBLOCK)));

		if (ufd < 0)

			kfree(ctx);

	} else {

fs/timerfd.c

+1 −1
Original line number Diff line number Diff line
@@ -200,7 +200,7 @@ SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags) 
	hrtimer_init(&ctx->tmr, clockid, HRTIMER_MODE_ABS);



	ufd = anon_inode_getfd("[timerfd]", &timerfd_fops, ctx,

			       flags & TFD_SHARED_FCNTL_FLAGS);

			       O_RDWR | (flags & TFD_SHARED_FCNTL_FLAGS));

	if (ufd < 0)

		kfree(ctx);

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