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490 lines
12 KiB
490 lines
12 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Copyright (C) 2017 Red Hat, Inc. |
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*/ |
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|
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#include "fuse_i.h" |
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|
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#include <linux/uio.h> |
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#include <linux/compat.h> |
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#include <linux/fileattr.h> |
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|
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/* |
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* CUSE servers compiled on 32bit broke on 64bit kernels because the |
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* ABI was defined to be 'struct iovec' which is different on 32bit |
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* and 64bit. Fortunately we can determine which structure the server |
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* used from the size of the reply. |
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*/ |
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static int fuse_copy_ioctl_iovec_old(struct iovec *dst, void *src, |
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size_t transferred, unsigned count, |
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bool is_compat) |
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{ |
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#ifdef CONFIG_COMPAT |
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if (count * sizeof(struct compat_iovec) == transferred) { |
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struct compat_iovec *ciov = src; |
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unsigned i; |
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|
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/* |
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* With this interface a 32bit server cannot support |
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* non-compat (i.e. ones coming from 64bit apps) ioctl |
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* requests |
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*/ |
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if (!is_compat) |
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return -EINVAL; |
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for (i = 0; i < count; i++) { |
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dst[i].iov_base = compat_ptr(ciov[i].iov_base); |
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dst[i].iov_len = ciov[i].iov_len; |
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} |
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return 0; |
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} |
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#endif |
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if (count * sizeof(struct iovec) != transferred) |
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return -EIO; |
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memcpy(dst, src, transferred); |
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return 0; |
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} |
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/* Make sure iov_length() won't overflow */ |
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static int fuse_verify_ioctl_iov(struct fuse_conn *fc, struct iovec *iov, |
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size_t count) |
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{ |
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size_t n; |
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u32 max = fc->max_pages << PAGE_SHIFT; |
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for (n = 0; n < count; n++, iov++) { |
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if (iov->iov_len > (size_t) max) |
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return -ENOMEM; |
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max -= iov->iov_len; |
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} |
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return 0; |
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} |
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static int fuse_copy_ioctl_iovec(struct fuse_conn *fc, struct iovec *dst, |
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void *src, size_t transferred, unsigned count, |
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bool is_compat) |
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{ |
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unsigned i; |
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struct fuse_ioctl_iovec *fiov = src; |
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if (fc->minor < 16) { |
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return fuse_copy_ioctl_iovec_old(dst, src, transferred, |
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count, is_compat); |
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} |
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if (count * sizeof(struct fuse_ioctl_iovec) != transferred) |
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return -EIO; |
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for (i = 0; i < count; i++) { |
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/* Did the server supply an inappropriate value? */ |
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if (fiov[i].base != (unsigned long) fiov[i].base || |
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fiov[i].len != (unsigned long) fiov[i].len) |
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return -EIO; |
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dst[i].iov_base = (void __user *) (unsigned long) fiov[i].base; |
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dst[i].iov_len = (size_t) fiov[i].len; |
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#ifdef CONFIG_COMPAT |
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if (is_compat && |
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(ptr_to_compat(dst[i].iov_base) != fiov[i].base || |
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(compat_size_t) dst[i].iov_len != fiov[i].len)) |
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return -EIO; |
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#endif |
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} |
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return 0; |
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} |
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/* |
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* For ioctls, there is no generic way to determine how much memory |
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* needs to be read and/or written. Furthermore, ioctls are allowed |
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* to dereference the passed pointer, so the parameter requires deep |
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* copying but FUSE has no idea whatsoever about what to copy in or |
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* out. |
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* |
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* This is solved by allowing FUSE server to retry ioctl with |
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* necessary in/out iovecs. Let's assume the ioctl implementation |
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* needs to read in the following structure. |
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* |
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* struct a { |
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* char *buf; |
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* size_t buflen; |
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* } |
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* |
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* On the first callout to FUSE server, inarg->in_size and |
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* inarg->out_size will be NULL; then, the server completes the ioctl |
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* with FUSE_IOCTL_RETRY set in out->flags, out->in_iovs set to 1 and |
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* the actual iov array to |
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* |
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* { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) } } |
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* |
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* which tells FUSE to copy in the requested area and retry the ioctl. |
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* On the second round, the server has access to the structure and |
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* from that it can tell what to look for next, so on the invocation, |
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* it sets FUSE_IOCTL_RETRY, out->in_iovs to 2 and iov array to |
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* |
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* { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) }, |
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* { .iov_base = a.buf, .iov_len = a.buflen } } |
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* |
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* FUSE will copy both struct a and the pointed buffer from the |
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* process doing the ioctl and retry ioctl with both struct a and the |
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* buffer. |
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* |
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* This time, FUSE server has everything it needs and completes ioctl |
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* without FUSE_IOCTL_RETRY which finishes the ioctl call. |
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* |
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* Copying data out works the same way. |
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* |
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* Note that if FUSE_IOCTL_UNRESTRICTED is clear, the kernel |
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* automatically initializes in and out iovs by decoding @cmd with |
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* _IOC_* macros and the server is not allowed to request RETRY. This |
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* limits ioctl data transfers to well-formed ioctls and is the forced |
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* behavior for all FUSE servers. |
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*/ |
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long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg, |
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unsigned int flags) |
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{ |
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struct fuse_file *ff = file->private_data; |
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struct fuse_mount *fm = ff->fm; |
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struct fuse_ioctl_in inarg = { |
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.fh = ff->fh, |
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.cmd = cmd, |
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.arg = arg, |
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.flags = flags |
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}; |
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struct fuse_ioctl_out outarg; |
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struct iovec *iov_page = NULL; |
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struct iovec *in_iov = NULL, *out_iov = NULL; |
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unsigned int in_iovs = 0, out_iovs = 0, max_pages; |
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size_t in_size, out_size, c; |
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ssize_t transferred; |
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int err, i; |
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struct iov_iter ii; |
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struct fuse_args_pages ap = {}; |
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#if BITS_PER_LONG == 32 |
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inarg.flags |= FUSE_IOCTL_32BIT; |
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#else |
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if (flags & FUSE_IOCTL_COMPAT) { |
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inarg.flags |= FUSE_IOCTL_32BIT; |
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#ifdef CONFIG_X86_X32 |
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if (in_x32_syscall()) |
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inarg.flags |= FUSE_IOCTL_COMPAT_X32; |
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#endif |
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} |
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#endif |
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/* assume all the iovs returned by client always fits in a page */ |
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BUILD_BUG_ON(sizeof(struct fuse_ioctl_iovec) * FUSE_IOCTL_MAX_IOV > PAGE_SIZE); |
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err = -ENOMEM; |
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ap.pages = fuse_pages_alloc(fm->fc->max_pages, GFP_KERNEL, &ap.descs); |
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iov_page = (struct iovec *) __get_free_page(GFP_KERNEL); |
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if (!ap.pages || !iov_page) |
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goto out; |
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fuse_page_descs_length_init(ap.descs, 0, fm->fc->max_pages); |
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/* |
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* If restricted, initialize IO parameters as encoded in @cmd. |
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* RETRY from server is not allowed. |
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*/ |
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if (!(flags & FUSE_IOCTL_UNRESTRICTED)) { |
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struct iovec *iov = iov_page; |
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iov->iov_base = (void __user *)arg; |
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iov->iov_len = _IOC_SIZE(cmd); |
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if (_IOC_DIR(cmd) & _IOC_WRITE) { |
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in_iov = iov; |
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in_iovs = 1; |
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} |
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if (_IOC_DIR(cmd) & _IOC_READ) { |
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out_iov = iov; |
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out_iovs = 1; |
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} |
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} |
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retry: |
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inarg.in_size = in_size = iov_length(in_iov, in_iovs); |
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inarg.out_size = out_size = iov_length(out_iov, out_iovs); |
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/* |
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* Out data can be used either for actual out data or iovs, |
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* make sure there always is at least one page. |
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*/ |
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out_size = max_t(size_t, out_size, PAGE_SIZE); |
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max_pages = DIV_ROUND_UP(max(in_size, out_size), PAGE_SIZE); |
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/* make sure there are enough buffer pages and init request with them */ |
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err = -ENOMEM; |
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if (max_pages > fm->fc->max_pages) |
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goto out; |
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while (ap.num_pages < max_pages) { |
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ap.pages[ap.num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM); |
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if (!ap.pages[ap.num_pages]) |
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goto out; |
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ap.num_pages++; |
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} |
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/* okay, let's send it to the client */ |
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ap.args.opcode = FUSE_IOCTL; |
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ap.args.nodeid = ff->nodeid; |
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ap.args.in_numargs = 1; |
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ap.args.in_args[0].size = sizeof(inarg); |
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ap.args.in_args[0].value = &inarg; |
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if (in_size) { |
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ap.args.in_numargs++; |
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ap.args.in_args[1].size = in_size; |
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ap.args.in_pages = true; |
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err = -EFAULT; |
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iov_iter_init(&ii, WRITE, in_iov, in_iovs, in_size); |
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for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= ap.num_pages); i++) { |
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c = copy_page_from_iter(ap.pages[i], 0, PAGE_SIZE, &ii); |
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if (c != PAGE_SIZE && iov_iter_count(&ii)) |
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goto out; |
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} |
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} |
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ap.args.out_numargs = 2; |
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ap.args.out_args[0].size = sizeof(outarg); |
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ap.args.out_args[0].value = &outarg; |
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ap.args.out_args[1].size = out_size; |
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ap.args.out_pages = true; |
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ap.args.out_argvar = true; |
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transferred = fuse_simple_request(fm, &ap.args); |
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err = transferred; |
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if (transferred < 0) |
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goto out; |
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/* did it ask for retry? */ |
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if (outarg.flags & FUSE_IOCTL_RETRY) { |
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void *vaddr; |
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/* no retry if in restricted mode */ |
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err = -EIO; |
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if (!(flags & FUSE_IOCTL_UNRESTRICTED)) |
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goto out; |
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in_iovs = outarg.in_iovs; |
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out_iovs = outarg.out_iovs; |
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/* |
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* Make sure things are in boundary, separate checks |
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* are to protect against overflow. |
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*/ |
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err = -ENOMEM; |
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if (in_iovs > FUSE_IOCTL_MAX_IOV || |
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out_iovs > FUSE_IOCTL_MAX_IOV || |
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in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV) |
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goto out; |
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vaddr = kmap_atomic(ap.pages[0]); |
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err = fuse_copy_ioctl_iovec(fm->fc, iov_page, vaddr, |
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transferred, in_iovs + out_iovs, |
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(flags & FUSE_IOCTL_COMPAT) != 0); |
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kunmap_atomic(vaddr); |
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if (err) |
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goto out; |
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in_iov = iov_page; |
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out_iov = in_iov + in_iovs; |
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err = fuse_verify_ioctl_iov(fm->fc, in_iov, in_iovs); |
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if (err) |
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goto out; |
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err = fuse_verify_ioctl_iov(fm->fc, out_iov, out_iovs); |
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if (err) |
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goto out; |
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goto retry; |
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} |
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err = -EIO; |
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if (transferred > inarg.out_size) |
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goto out; |
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err = -EFAULT; |
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iov_iter_init(&ii, READ, out_iov, out_iovs, transferred); |
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for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= ap.num_pages); i++) { |
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c = copy_page_to_iter(ap.pages[i], 0, PAGE_SIZE, &ii); |
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if (c != PAGE_SIZE && iov_iter_count(&ii)) |
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goto out; |
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} |
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err = 0; |
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out: |
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free_page((unsigned long) iov_page); |
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while (ap.num_pages) |
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__free_page(ap.pages[--ap.num_pages]); |
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kfree(ap.pages); |
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return err ? err : outarg.result; |
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} |
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EXPORT_SYMBOL_GPL(fuse_do_ioctl); |
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long fuse_ioctl_common(struct file *file, unsigned int cmd, |
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unsigned long arg, unsigned int flags) |
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{ |
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struct inode *inode = file_inode(file); |
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struct fuse_conn *fc = get_fuse_conn(inode); |
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if (!fuse_allow_current_process(fc)) |
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return -EACCES; |
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if (fuse_is_bad(inode)) |
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return -EIO; |
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return fuse_do_ioctl(file, cmd, arg, flags); |
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} |
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long fuse_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
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{ |
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return fuse_ioctl_common(file, cmd, arg, 0); |
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} |
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long fuse_file_compat_ioctl(struct file *file, unsigned int cmd, |
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unsigned long arg) |
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{ |
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return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_COMPAT); |
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} |
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static int fuse_priv_ioctl(struct inode *inode, struct fuse_file *ff, |
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unsigned int cmd, void *ptr, size_t size) |
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{ |
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struct fuse_mount *fm = ff->fm; |
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struct fuse_ioctl_in inarg; |
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struct fuse_ioctl_out outarg; |
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FUSE_ARGS(args); |
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int err; |
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memset(&inarg, 0, sizeof(inarg)); |
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inarg.fh = ff->fh; |
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inarg.cmd = cmd; |
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#if BITS_PER_LONG == 32 |
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inarg.flags |= FUSE_IOCTL_32BIT; |
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#endif |
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if (S_ISDIR(inode->i_mode)) |
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inarg.flags |= FUSE_IOCTL_DIR; |
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if (_IOC_DIR(cmd) & _IOC_READ) |
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inarg.out_size = size; |
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if (_IOC_DIR(cmd) & _IOC_WRITE) |
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inarg.in_size = size; |
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args.opcode = FUSE_IOCTL; |
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args.nodeid = ff->nodeid; |
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args.in_numargs = 2; |
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args.in_args[0].size = sizeof(inarg); |
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args.in_args[0].value = &inarg; |
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args.in_args[1].size = inarg.in_size; |
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args.in_args[1].value = ptr; |
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args.out_numargs = 2; |
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args.out_args[0].size = sizeof(outarg); |
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args.out_args[0].value = &outarg; |
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args.out_args[1].size = inarg.out_size; |
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args.out_args[1].value = ptr; |
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err = fuse_simple_request(fm, &args); |
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if (!err && outarg.flags & FUSE_IOCTL_RETRY) |
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err = -EIO; |
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return err; |
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} |
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static struct fuse_file *fuse_priv_ioctl_prepare(struct inode *inode) |
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{ |
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struct fuse_mount *fm = get_fuse_mount(inode); |
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bool isdir = S_ISDIR(inode->i_mode); |
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if (!S_ISREG(inode->i_mode) && !isdir) |
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return ERR_PTR(-ENOTTY); |
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return fuse_file_open(fm, get_node_id(inode), O_RDONLY, isdir); |
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} |
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static void fuse_priv_ioctl_cleanup(struct inode *inode, struct fuse_file *ff) |
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{ |
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fuse_file_release(inode, ff, O_RDONLY, NULL, S_ISDIR(inode->i_mode)); |
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} |
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int fuse_fileattr_get(struct dentry *dentry, struct fileattr *fa) |
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{ |
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struct inode *inode = d_inode(dentry); |
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struct fuse_file *ff; |
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unsigned int flags; |
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struct fsxattr xfa; |
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int err; |
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ff = fuse_priv_ioctl_prepare(inode); |
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if (IS_ERR(ff)) |
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return PTR_ERR(ff); |
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if (fa->flags_valid) { |
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err = fuse_priv_ioctl(inode, ff, FS_IOC_GETFLAGS, |
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&flags, sizeof(flags)); |
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if (err) |
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goto cleanup; |
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fileattr_fill_flags(fa, flags); |
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} else { |
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err = fuse_priv_ioctl(inode, ff, FS_IOC_FSGETXATTR, |
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&xfa, sizeof(xfa)); |
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if (err) |
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goto cleanup; |
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fileattr_fill_xflags(fa, xfa.fsx_xflags); |
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fa->fsx_extsize = xfa.fsx_extsize; |
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fa->fsx_nextents = xfa.fsx_nextents; |
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fa->fsx_projid = xfa.fsx_projid; |
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fa->fsx_cowextsize = xfa.fsx_cowextsize; |
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} |
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cleanup: |
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fuse_priv_ioctl_cleanup(inode, ff); |
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return err; |
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} |
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int fuse_fileattr_set(struct user_namespace *mnt_userns, |
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struct dentry *dentry, struct fileattr *fa) |
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{ |
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struct inode *inode = d_inode(dentry); |
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struct fuse_file *ff; |
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unsigned int flags = fa->flags; |
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struct fsxattr xfa; |
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int err; |
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|
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ff = fuse_priv_ioctl_prepare(inode); |
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if (IS_ERR(ff)) |
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return PTR_ERR(ff); |
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|
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if (fa->flags_valid) { |
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err = fuse_priv_ioctl(inode, ff, FS_IOC_SETFLAGS, |
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&flags, sizeof(flags)); |
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if (err) |
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goto cleanup; |
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} else { |
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memset(&xfa, 0, sizeof(xfa)); |
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xfa.fsx_xflags = fa->fsx_xflags; |
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xfa.fsx_extsize = fa->fsx_extsize; |
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xfa.fsx_nextents = fa->fsx_nextents; |
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xfa.fsx_projid = fa->fsx_projid; |
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xfa.fsx_cowextsize = fa->fsx_cowextsize; |
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|
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err = fuse_priv_ioctl(inode, ff, FS_IOC_FSSETXATTR, |
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&xfa, sizeof(xfa)); |
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} |
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|
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cleanup: |
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fuse_priv_ioctl_cleanup(inode, ff); |
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|
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return err; |
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}
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