/* * linux/fs/ioctl.c * * Copyright (C) 1991, 1992 Linus Torvalds */ #include <linux/syscalls.h> #include <linux/mm.h> #include <linux/capability.h> #include <linux/file.h> #include <linux/fs.h> #include <linux/security.h> #include <linux/export.h> #include <linux/uaccess.h> #include <linux/writeback.h> #include <linux/buffer_head.h> #include <linux/falloc.h> #include <asm/ioctls.h> /* So that the fiemap access checks can't overflow on 32 bit machines. */ #define FIEMAP_MAX_EXTENTS (UINT_MAX / sizeof(struct fiemap_extent)) /** * vfs_ioctl - call filesystem specific ioctl methods * @filp: open file to invoke ioctl method on * @cmd: ioctl command to execute * @arg: command-specific argument for ioctl * * Invokes filesystem specific ->unlocked_ioctl, if one exists; otherwise * returns -ENOTTY. * * Returns 0 on success, -errno on error. */ static long vfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) { int error = -ENOTTY; if (!filp->f_op || !filp->f_op->unlocked_ioctl) goto out; error = filp->f_op->unlocked_ioctl(filp, cmd, arg); if (error == -ENOIOCTLCMD) error = -ENOTTY; out: return error; } static int ioctl_fibmap(struct file *filp, int __user *p) { struct address_space *mapping = filp->f_mapping; int res, block; /* do we support this mess? */ if (!mapping->a_ops->bmap) return -EINVAL; if (!capable(CAP_SYS_RAWIO)) return -EPERM; res = get_user(block, p); if (res) return res; res = mapping->a_ops->bmap(mapping, block); return put_user(res, p); } /** * fiemap_fill_next_extent - Fiemap helper function * @fieinfo: Fiemap context passed into ->fiemap * @logical: Extent logical start offset, in bytes * @phys: Extent physical start offset, in bytes * @len: Extent length, in bytes * @flags: FIEMAP_EXTENT flags that describe this extent * * Called from file system ->fiemap callback. Will populate extent * info as passed in via arguments and copy to user memory. On * success, extent count on fieinfo is incremented. * * Returns 0 on success, -errno on error, 1 if this was the last * extent that will fit in user array. */ #define SET_UNKNOWN_FLAGS (FIEMAP_EXTENT_DELALLOC) #define SET_NO_UNMOUNTED_IO_FLAGS (FIEMAP_EXTENT_DATA_ENCRYPTED) #define SET_NOT_ALIGNED_FLAGS (FIEMAP_EXTENT_DATA_TAIL|FIEMAP_EXTENT_DATA_INLINE) int fiemap_fill_next_extent(struct fiemap_extent_info *fieinfo, u64 logical, u64 phys, u64 len, u32 flags) { struct fiemap_extent extent; struct fiemap_extent __user *dest = fieinfo->fi_extents_start; /* only count the extents */ if (fieinfo->fi_extents_max == 0) { fieinfo->fi_extents_mapped++; return (flags & FIEMAP_EXTENT_LAST) ? 1 : 0; } if (fieinfo->fi_extents_mapped >= fieinfo->fi_extents_max) return 1; if (flags & SET_UNKNOWN_FLAGS) flags |= FIEMAP_EXTENT_UNKNOWN; if (flags & SET_NO_UNMOUNTED_IO_FLAGS) flags |= FIEMAP_EXTENT_ENCODED; if (flags & SET_NOT_ALIGNED_FLAGS) flags |= FIEMAP_EXTENT_NOT_ALIGNED; memset(&extent, 0, sizeof(extent)); extent.fe_logical = logical; extent.fe_physical = phys; extent.fe_length = len; extent.fe_flags = flags; dest += fieinfo->fi_extents_mapped; if (copy_to_user(dest, &extent, sizeof(extent))) return -EFAULT; fieinfo->fi_extents_mapped++; if (fieinfo->fi_extents_mapped == fieinfo->fi_extents_max) return 1; return (flags & FIEMAP_EXTENT_LAST) ? 1 : 0; } EXPORT_SYMBOL(fiemap_fill_next_extent); /** * fiemap_check_flags - check validity of requested flags for fiemap * @fieinfo: Fiemap context passed into ->fiemap * @fs_flags: Set of fiemap flags that the file system understands * * Called from file system ->fiemap callback. This will compute the * intersection of valid fiemap flags and those that the fs supports. That * value is then compared against the user supplied flags. In case of bad user * flags, the invalid values will be written into the fieinfo structure, and * -EBADR is returned, which tells ioctl_fiemap() to return those values to * userspace. For this reason, a return code of -EBADR should be preserved. * * Returns 0 on success, -EBADR on bad flags. */ int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags) { u32 incompat_flags; incompat_flags = fieinfo->fi_flags & ~(FIEMAP_FLAGS_COMPAT & fs_flags); if (incompat_flags) { fieinfo->fi_flags = incompat_flags; return -EBADR; } return 0; } EXPORT_SYMBOL(fiemap_check_flags); static int fiemap_check_ranges(struct super_block *sb, u64 start, u64 len, u64 *new_len) { u64 maxbytes = (u64) sb->s_maxbytes; *new_len = len; if (len == 0) return -EINVAL; if (start > maxbytes) return -EFBIG; /* * Shrink request scope to what the fs can actually handle. */ if (len > maxbytes || (maxbytes - len) < start) *new_len = maxbytes - start; return 0; } static int ioctl_fiemap(struct file *filp, unsigned long arg) { struct fiemap fiemap; struct fiemap __user *ufiemap = (struct fiemap __user *) arg; struct fiemap_extent_info fieinfo = { 0, }; struct inode *inode = filp->f_path.dentry->d_inode; struct super_block *sb = inode->i_sb; u64 len; int error; if (!inode->i_op->fiemap) return -EOPNOTSUPP; if (copy_from_user(&fiemap, ufiemap, sizeof(fiemap))) return -EFAULT; if (fiemap.fm_extent_count > FIEMAP_MAX_EXTENTS) return -EINVAL; error = fiemap_check_ranges(sb, fiemap.fm_start, fiemap.fm_length, &len); if (error) return error; fieinfo.fi_flags = fiemap.fm_flags; fieinfo.fi_extents_max = fiemap.fm_extent_count; fieinfo.fi_extents_start = ufiemap->fm_extents; if (fiemap.fm_extent_count != 0 && !access_ok(VERIFY_WRITE, fieinfo.fi_extents_start, fieinfo.fi_extents_max * sizeof(struct fiemap_extent))) return -EFAULT; if (fieinfo.fi_flags & FIEMAP_FLAG_SYNC) filemap_write_and_wait(inode->i_mapping); error = inode->i_op->fiemap(inode, &fieinfo, fiemap.fm_start, len); fiemap.fm_flags = fieinfo.fi_flags; fiemap.fm_mapped_extents = fieinfo.fi_extents_mapped; if (copy_to_user(ufiemap, &fiemap, sizeof(fiemap))) error = -EFAULT; return error; } #ifdef CONFIG_BLOCK static inline sector_t logical_to_blk(struct inode *inode, loff_t offset) { return (offset >> inode->i_blkbits); } static inline loff_t blk_to_logical(struct inode *inode, sector_t blk) { return (blk << inode->i_blkbits); } /** * __generic_block_fiemap - FIEMAP for block based inodes (no locking) * @inode: the inode to map * @fieinfo: the fiemap info struct that will be passed back to userspace * @start: where to start mapping in the inode * @len: how much space to map * @get_block: the fs's get_block function * * This does FIEMAP for block based inodes. Basically it will just loop * through get_block until we hit the number of extents we want to map, or we * go past the end of the file and hit a hole. * * If it is possible to have data blocks beyond a hole past @inode->i_size, then * please do not use this function, it will stop at the first unmapped block * beyond i_size. * * If you use this function directly, you need to do your own locking. Use * generic_block_fiemap if you want the locking done for you. */ int __generic_block_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, loff_t start, loff_t len, get_block_t *get_block) { struct buffer_head map_bh; sector_t start_blk, last_blk; loff_t isize = i_size_read(inode); u64 logical = 0, phys = 0, size = 0; u32 flags = FIEMAP_EXTENT_MERGED; bool past_eof = false, whole_file = false; int ret = 0; ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC); if (ret) return ret; /* * Either the i_mutex or other appropriate locking needs to be held * since we expect isize to not change at all through the duration of * this call. */ if (len >= isize) { whole_file = true; len = isize; } /* * Some filesystems can't deal with being asked to map less than * blocksize, so make sure our len is at least block length. */ if (logical_to_blk(inode, len) == 0) len = blk_to_logical(inode, 1); start_blk = logical_to_blk(inode, start); last_blk = logical_to_blk(inode, start + len - 1); do { /* * we set b_size to the total size we want so it will map as * many contiguous blocks as possible at once */ memset(&map_bh, 0, sizeof(struct buffer_head)); map_bh.b_size = len; ret = get_block(inode, start_blk, &map_bh, 0); if (ret) break; /* HOLE */ if (!buffer_mapped(&map_bh)) { start_blk++; /* * We want to handle the case where there is an * allocated block at the front of the file, and then * nothing but holes up to the end of the file properly, * to make sure that extent at the front gets properly * marked with FIEMAP_EXTENT_LAST */ if (!past_eof && blk_to_logical(inode, start_blk) >= isize) past_eof = 1; /* * First hole after going past the EOF, this is our * last extent */ if (past_eof && size) { flags = FIEMAP_EXTENT_MERGED|FIEMAP_EXTENT_LAST; ret = fiemap_fill_next_extent(fieinfo, logical, phys, size, flags); } else if (size) { ret = fiemap_fill_next_extent(fieinfo, logical, phys, size, flags); size = 0; } /* if we have holes up to/past EOF then we're done */ if (start_blk > last_blk || past_eof || ret) break; } else { /* * We have gone over the length of what we wanted to * map, and it wasn't the entire file, so add the extent * we got last time and exit. * * This is for the case where say we want to map all the * way up to the second to the last block in a file, but * the last block is a hole, making the second to last * block FIEMAP_EXTENT_LAST. In this case we want to * see if there is a hole after the second to last block * so we can mark it properly. If we found data after * we exceeded the length we were requesting, then we * are good to go, just add the extent to the fieinfo * and break */ if (start_blk > last_blk && !whole_file) { ret = fiemap_fill_next_extent(fieinfo, logical, phys, size, flags); break; } /* * if size != 0 then we know we already have an extent * to add, so add it. */ if (size) { ret = fiemap_fill_next_extent(fieinfo, logical, phys, size, flags); if (ret) break; } logical = blk_to_logical(inode, start_blk); phys = blk_to_logical(inode, map_bh.b_blocknr); size = map_bh.b_size; flags = FIEMAP_EXTENT_MERGED; start_blk += logical_to_blk(inode, size); /* * If we are past the EOF, then we need to make sure as * soon as we find a hole that the last extent we found * is marked with FIEMAP_EXTENT_LAST */ if (!past_eof && logical + size >= isize) past_eof = true; } cond_resched(); } while (1); /* If ret is 1 then we just hit the end of the extent array */ if (ret == 1) ret = 0; return ret; } EXPORT_SYMBOL(__generic_block_fiemap); /** * generic_block_fiemap - FIEMAP for block based inodes * @inode: The inode to map * @fieinfo: The mapping information * @start: The initial block to map * @len: The length of the extect to attempt to map * @get_block: The block mapping function for the fs * * Calls __generic_block_fiemap to map the inode, after taking * the inode's mutex lock. */ int generic_block_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, u64 start, u64 len, get_block_t *get_block) { int ret; mutex_lock(&inode->i_mutex); ret = __generic_block_fiemap(inode, fieinfo, start, len, get_block); mutex_unlock(&inode->i_mutex); return ret; } EXPORT_SYMBOL(generic_block_fiemap); #endif /* CONFIG_BLOCK */ /* * This provides compatibility with legacy XFS pre-allocation ioctls * which predate the fallocate syscall. * * Only the l_start, l_len and l_whence fields of the 'struct space_resv' * are used here, rest are ignored. */ int ioctl_preallocate(struct file *filp, void __user *argp) { struct inode *inode = filp->f_path.dentry->d_inode; struct space_resv sr; if (copy_from_user(&sr, argp, sizeof(sr))) return -EFAULT; switch (sr.l_whence) { case SEEK_SET: break; case SEEK_CUR: sr.l_start += filp->f_pos; break; case SEEK_END: sr.l_start += i_size_read(inode); break; default: return -EINVAL; } return do_fallocate(filp, FALLOC_FL_KEEP_SIZE, sr.l_start, sr.l_len); } static int file_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) { struct inode *inode = filp->f_path.dentry->d_inode; int __user *p = (int __user *)arg; switch (cmd) { case FIBMAP: return ioctl_fibmap(filp, p); case FIONREAD: return put_user(i_size_read(inode) - filp->f_pos, p); case FS_IOC_RESVSP: case FS_IOC_RESVSP64: return ioctl_preallocate(filp, p); } return vfs_ioctl(filp, cmd, arg); } static int ioctl_fionbio(struct file *filp, int __user *argp) { unsigned int flag; int on, error; error = get_user(on, argp); if (error) return error; flag = O_NONBLOCK; #ifdef __sparc__ /* SunOS compatibility item. */ if (O_NONBLOCK != O_NDELAY) flag |= O_NDELAY; #endif spin_lock(&filp->f_lock); if (on) filp->f_flags |= flag; else filp->f_flags &= ~flag; spin_unlock(&filp->f_lock); return error; } static int ioctl_fioasync(unsigned int fd, struct file *filp, int __user *argp) { unsigned int flag; int on, error; error = get_user(on, argp); if (error) return error; flag = on ? FASYNC : 0; /* Did FASYNC state change ? */ if ((flag ^ filp->f_flags) & FASYNC) { if (filp->f_op && filp->f_op->fasync) /* fasync() adjusts filp->f_flags */ error = filp->f_op->fasync(fd, filp, on); else error = -ENOTTY; } return error < 0 ? error : 0; } static int ioctl_fsfreeze(struct file *filp) { struct super_block *sb = filp->f_path.dentry->d_inode->i_sb; if (!capable(CAP_SYS_ADMIN)) return -EPERM; /* If filesystem doesn't support freeze feature, return. */ if (sb->s_op->freeze_fs == NULL) return -EOPNOTSUPP; /* Freeze */ return freeze_super(sb); } static int ioctl_fsthaw(struct file *filp) { struct super_block *sb = filp->f_path.dentry->d_inode->i_sb; if (!capable(CAP_SYS_ADMIN)) return -EPERM; /* Thaw */ return thaw_super(sb); } /* * When you add any new common ioctls to the switches above and below * please update compat_sys_ioctl() too. * * do_vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d. * It's just a simple helper for sys_ioctl and compat_sys_ioctl. */ int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd, unsigned long arg) { int error = 0; int __user *argp = (int __user *)arg; struct inode *inode = filp->f_path.dentry->d_inode; switch (cmd) { case FIOCLEX: set_close_on_exec(fd, 1); break; case FIONCLEX: set_close_on_exec(fd, 0); break; case FIONBIO: error = ioctl_fionbio(filp, argp); break; case FIOASYNC: error = ioctl_fioasync(fd, filp, argp); break; case FIOQSIZE: if (S_ISDIR(inode->i_mode) || S_ISREG(inode->i_mode) || S_ISLNK(inode->i_mode)) { loff_t res = inode_get_bytes(inode); error = copy_to_user(argp, &res, sizeof(res)) ? -EFAULT : 0; } else error = -ENOTTY; break; case FIFREEZE: error = ioctl_fsfreeze(filp); break; case FITHAW: error = ioctl_fsthaw(filp); break; case FS_IOC_FIEMAP: return ioctl_fiemap(filp, arg); case FIGETBSZ: return put_user(inode->i_sb->s_blocksize, argp); default: if (S_ISREG(inode->i_mode)) error = file_ioctl(filp, cmd, arg); else error = vfs_ioctl(filp, cmd, arg); break; } return error; } SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg) { struct file *filp; int error = -EBADF; int fput_needed; filp = fget_light(fd, &fput_needed); if (!filp) goto out; error = security_file_ioctl(filp, cmd, arg); if (error) goto out_fput; error = do_vfs_ioctl(filp, fd, cmd, arg); out_fput: fput_light(filp, fput_needed); out: return error; }