From 00c570f4ba43ae73b41fa0a2269c3b0ac20386ef Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Wed, 1 Jul 2015 16:26:08 +0200 Subject: fuse: device fd clone Allow an open fuse device to be "cloned". Userspace can create a clone by: newfd = open("/dev/fuse", O_RDWR) ioctl(newfd, FUSE_DEV_IOC_CLONE, &oldfd); At this point newfd will refer to the same fuse connection as oldfd. Signed-off-by: Miklos Szeredi Reviewed-by: Ashish Samant --- fs/fuse/dev.c | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) (limited to 'fs') diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index dcfc87172a47..d405c1fa4618 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -2197,6 +2197,44 @@ static int fuse_dev_fasync(int fd, struct file *file, int on) return fasync_helper(fd, file, on, &fc->iq.fasync); } +static int fuse_device_clone(struct fuse_conn *fc, struct file *new) +{ + if (new->private_data) + return -EINVAL; + + new->private_data = fuse_conn_get(fc); + + return 0; +} + +static long fuse_dev_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + int err = -ENOTTY; + + if (cmd == FUSE_DEV_IOC_CLONE) { + int oldfd; + + err = -EFAULT; + if (!get_user(oldfd, (__u32 __user *) arg)) { + struct file *old = fget(oldfd); + + err = -EINVAL; + if (old) { + struct fuse_conn *fc = fuse_get_conn(old); + + if (fc) { + mutex_lock(&fuse_mutex); + err = fuse_device_clone(fc, file); + mutex_unlock(&fuse_mutex); + } + fput(old); + } + } + } + return err; +} + const struct file_operations fuse_dev_operations = { .owner = THIS_MODULE, .open = fuse_dev_open, @@ -2208,6 +2246,8 @@ const struct file_operations fuse_dev_operations = { .poll = fuse_dev_poll, .release = fuse_dev_release, .fasync = fuse_dev_fasync, + .unlocked_ioctl = fuse_dev_ioctl, + .compat_ioctl = fuse_dev_ioctl, }; EXPORT_SYMBOL_GPL(fuse_dev_operations); -- cgit v1.2.3-59-g8ed1b