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fs/ioctl.c
15.7 KB
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/* * linux/fs/ioctl.c * * Copyright (C) 1991, 1992 Linus Torvalds */ |
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#include <linux/syscalls.h> #include <linux/mm.h> #include <linux/smp_lock.h> |
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#include <linux/capability.h> |
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#include <linux/file.h> #include <linux/fs.h> #include <linux/security.h> #include <linux/module.h> |
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#include <linux/uaccess.h> |
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#include <linux/writeback.h> #include <linux/buffer_head.h> |
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#include <linux/falloc.h> |
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#include <asm/ioctls.h> |
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/* So that the fiemap access checks can't overflow on 32 bit machines. */ #define FIEMAP_MAX_EXTENTS (UINT_MAX / sizeof(struct fiemap_extent)) |
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/** * vfs_ioctl - call filesystem specific ioctl methods |
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* @filp: open file to invoke ioctl method on * @cmd: ioctl command to execute * @arg: command-specific argument for ioctl |
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* * Invokes filesystem specific ->unlocked_ioctl, if one exists; otherwise |
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* returns -ENOTTY. * * Returns 0 on success, -errno on error. */ |
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static long vfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) |
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{ int error = -ENOTTY; |
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if (!filp->f_op || !filp->f_op->unlocked_ioctl) |
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goto out; |
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error = filp->f_op->unlocked_ioctl(filp, cmd, arg); if (error == -ENOIOCTLCMD) error = -EINVAL; |
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out: return error; } |
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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; |
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res = mapping->a_ops->bmap(mapping, block); |
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return put_user(res, p); } |
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/** * 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 *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) { |
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u64 maxbytes = (u64) sb->s_maxbytes; |
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*new_len = len; if (len == 0) return -EINVAL; |
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if (start > maxbytes) |
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return -EFBIG; /* * Shrink request scope to what the fs can actually handle. */ |
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if (len > maxbytes || (maxbytes - len) < start) *new_len = maxbytes - start; |
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return 0; } static int ioctl_fiemap(struct file *filp, unsigned long arg) { struct fiemap fiemap; 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, (struct fiemap __user *)arg, sizeof(struct 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 = (struct fiemap_extent *)(arg + sizeof(fiemap)); 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((char *)arg, &fiemap, sizeof(fiemap))) error = -EFAULT; return error; } |
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#ifdef CONFIG_BLOCK |
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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); } |
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/** * __generic_block_fiemap - FIEMAP for block based inodes (no locking) |
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* @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 |
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* * 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 |
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* 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. |
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*/ |
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int __generic_block_fiemap(struct inode *inode, |
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struct fiemap_extent_info *fieinfo, loff_t start, loff_t len, get_block_t *get_block) |
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{ |
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struct buffer_head map_bh; sector_t start_blk, last_blk; loff_t isize = i_size_read(inode); |
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u64 logical = 0, phys = 0, size = 0; u32 flags = FIEMAP_EXTENT_MERGED; |
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bool past_eof = false, whole_file = false; int ret = 0; |
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ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC); if (ret) |
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return ret; |
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/* * 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; } |
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start_blk = logical_to_blk(inode, start); last_blk = logical_to_blk(inode, start + len - 1); |
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do { /* * we set b_size to the total size we want so it will map as * many contiguous blocks as possible at once */ |
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memset(&map_bh, 0, sizeof(struct buffer_head)); map_bh.b_size = len; |
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ret = get_block(inode, start_blk, &map_bh, 0); |
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if (ret) break; /* HOLE */ |
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if (!buffer_mapped(&map_bh)) { |
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start_blk++; /* |
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* We want to handle the case where there is an |
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* 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 && |
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blk_to_logical(inode, start_blk) >= isize) |
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past_eof = 1; |
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/* |
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* First hole after going past the EOF, this is our |
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* last extent */ |
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if (past_eof && size) { |
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flags = FIEMAP_EXTENT_MERGED|FIEMAP_EXTENT_LAST; ret = fiemap_fill_next_extent(fieinfo, logical, phys, size, flags); |
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} else if (size) { ret = fiemap_fill_next_extent(fieinfo, logical, phys, size, flags); size = 0; |
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} |
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/* if we have holes up to/past EOF then we're done */ |
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if (start_blk > last_blk || past_eof || ret) |
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break; |
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} else { |
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/* |
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* We have gone over the length of what we wanted to |
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* 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 */ |
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if (start_blk > last_blk && !whole_file) { |
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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) { |
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ret = fiemap_fill_next_extent(fieinfo, logical, phys, size, flags); if (ret) break; } logical = blk_to_logical(inode, start_blk); |
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phys = blk_to_logical(inode, map_bh.b_blocknr); size = map_bh.b_size; |
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flags = FIEMAP_EXTENT_MERGED; |
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start_blk += logical_to_blk(inode, size); /* |
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* 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 |
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*/ |
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if (!past_eof && logical + size >= isize) past_eof = true; |
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} cond_resched(); } while (1); |
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/* If ret is 1 then we just hit the end of the extent array */ |
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if (ret == 1) ret = 0; return ret; } |
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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; } |
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EXPORT_SYMBOL(generic_block_fiemap); |
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#endif /* CONFIG_BLOCK */ |
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/* * 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); } |
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static int file_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) { |
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struct inode *inode = filp->f_path.dentry->d_inode; |
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int __user *p = (int __user *)arg; switch (cmd) { |
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case FIBMAP: |
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return ioctl_fibmap(filp, p); |
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case FIONREAD: return put_user(i_size_read(inode) - filp->f_pos, p); |
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case FS_IOC_RESVSP: case FS_IOC_RESVSP64: return ioctl_preallocate(filp, p); |
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} |
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return vfs_ioctl(filp, cmd, arg); |
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} |
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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 |
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spin_lock(&filp->f_lock); |
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if (on) filp->f_flags |= flag; else filp->f_flags &= ~flag; |
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spin_unlock(&filp->f_lock); |
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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) { |
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if (filp->f_op && filp->f_op->fasync) |
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/* fasync() adjusts filp->f_flags */ |
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error = filp->f_op->fasync(fd, filp, on); |
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else |
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error = -ENOTTY; } |
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return error < 0 ? error : 0; |
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} |
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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; |
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/* Freeze */ |
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return freeze_super(sb); |
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} 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; |
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/* Thaw */ |
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return thaw_super(sb); |
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} |
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/* * When you add any new common ioctls to the switches above and below * please update compat_sys_ioctl() too. * |
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* do_vfs_ioctl() is not for drivers and not intended to be EXPORT_SYMBOL()'d. |
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* It's just a simple helper for sys_ioctl and compat_sys_ioctl. */ |
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int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd, unsigned long arg) |
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{ |
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int error = 0; int __user *argp = (int __user *)arg; |
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switch (cmd) { |
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case FIOCLEX: set_close_on_exec(fd, 1); break; |
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case FIONCLEX: set_close_on_exec(fd, 0); break; |
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case FIONBIO: |
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error = ioctl_fionbio(filp, argp); |
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break; case FIOASYNC: |
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error = ioctl_fioasync(fd, filp, argp); |
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break; case FIOQSIZE: if (S_ISDIR(filp->f_path.dentry->d_inode->i_mode) || S_ISREG(filp->f_path.dentry->d_inode->i_mode) || S_ISLNK(filp->f_path.dentry->d_inode->i_mode)) { loff_t res = inode_get_bytes(filp->f_path.dentry->d_inode); error = copy_to_user((loff_t __user *)arg, &res, sizeof(res)) ? -EFAULT : 0; } else error = -ENOTTY; break; |
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case FIFREEZE: error = ioctl_fsfreeze(filp); break; case FITHAW: error = ioctl_fsthaw(filp); break; |
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case FS_IOC_FIEMAP: return ioctl_fiemap(filp, arg); case FIGETBSZ: { struct inode *inode = filp->f_path.dentry->d_inode; int __user *p = (int __user *)arg; return put_user(inode->i_sb->s_blocksize, p); } |
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default: if (S_ISREG(filp->f_path.dentry->d_inode->i_mode)) error = file_ioctl(filp, cmd, arg); else |
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error = vfs_ioctl(filp, cmd, arg); |
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break; |
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} return error; } |
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SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg) |
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{ |
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struct file *filp; |
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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; |
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588 |
error = do_vfs_ioctl(filp, fd, cmd, arg); |
1da177e4c
|
589 590 591 592 593 |
out_fput: fput_light(filp, fput_needed); out: return error; } |