inode.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Squashfs - a compressed read only filesystem for Linux
  4 *
  5 * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
  6 * Phillip Lougher <phillip@squashfs.org.uk>
  7 *
  8 * inode.c
  9 */
 10
 11/*
 12 * This file implements code to create and read inodes from disk.
 13 *
 14 * Inodes in Squashfs are identified by a 48-bit inode which encodes the
 15 * location of the compressed metadata block containing the inode, and the byte
 16 * offset into that block where the inode is placed (<block, offset>).
 17 *
 18 * To maximise compression there are different inodes for each file type
 19 * (regular file, directory, device, etc.), the inode contents and length
 20 * varying with the type.
 21 *
 22 * To further maximise compression, two types of regular file inode and
 23 * directory inode are defined: inodes optimised for frequently occurring
 24 * regular files and directories, and extended types where extra
 25 * information has to be stored.
 26 */
 27
 28#include <linux/fs.h>
 29#include <linux/vfs.h>
 30#include <linux/xattr.h>
 31#include <linux/pagemap.h>
 32
 33#include "squashfs_fs.h"
 34#include "squashfs_fs_sb.h"
 35#include "squashfs_fs_i.h"
 36#include "squashfs.h"
 37#include "xattr.h"
 38
 39/*
 40 * Initialise VFS inode with the base inode information common to all
 41 * Squashfs inode types.  Sqsh_ino contains the unswapped base inode
 42 * off disk.
 43 */
 44static int squashfs_new_inode(struct super_block *sb, struct inode *inode,
 45				struct squashfs_base_inode *sqsh_ino)
 46{
 47	uid_t i_uid;
 48	gid_t i_gid;
 49	int err;
 50
 51	inode->i_ino = le32_to_cpu(sqsh_ino->inode_number);
 52	if (inode->i_ino == 0)
 53		return -EINVAL;
 54
 55	err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->uid), &i_uid);
 56	if (err)
 57		return err;
 58
 59	err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->guid), &i_gid);
 60	if (err)
 61		return err;
 62
 63	i_uid_write(inode, i_uid);
 64	i_gid_write(inode, i_gid);
 65	inode_set_mtime(inode, le32_to_cpu(sqsh_ino->mtime), 0);
 66	inode_set_atime(inode, inode_get_mtime_sec(inode), 0);
 67	inode_set_ctime(inode, inode_get_mtime_sec(inode), 0);
 68	inode->i_mode = le16_to_cpu(sqsh_ino->mode);
 69	inode->i_size = 0;
 70
 71	/* File type must not be set at this moment, for it will later be set by the caller. */
 72	if (inode->i_mode & S_IFMT)
 73		err = -EIO;
 74
 75	return err;
 76}
 77
 78
 79struct inode *squashfs_iget(struct super_block *sb, long long ino,
 80				unsigned int ino_number)
 81{
 82	struct inode *inode = iget_locked(sb, ino_number);
 83	int err;
 84
 85	TRACE("Entered squashfs_iget\n");
 86
 87	if (!inode)
 88		return ERR_PTR(-ENOMEM);
 89	if (!(inode_state_read_once(inode) & I_NEW))
 90		return inode;
 91
 92	err = squashfs_read_inode(inode, ino);
 93	if (err) {
 94		iget_failed(inode);
 95		return ERR_PTR(err);
 96	}
 97
 98	unlock_new_inode(inode);
 99	return inode;
100}
101
102
103/*
104 * Initialise VFS inode by reading inode from inode table (compressed
105 * metadata).  The format and amount of data read depends on type.
106 */
107int squashfs_read_inode(struct inode *inode, long long ino)
108{
109	struct super_block *sb = inode->i_sb;
110	struct squashfs_sb_info *msblk = sb->s_fs_info;
111	u64 block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
112	int err, type, offset = SQUASHFS_INODE_OFFSET(ino);
113	union squashfs_inode squashfs_ino;
114	struct squashfs_base_inode *sqshb_ino = &squashfs_ino.base;
115	int xattr_id = SQUASHFS_INVALID_XATTR;
116
117	TRACE("Entered squashfs_read_inode\n");
118
119	/*
120	 * Read inode base common to all inode types.
121	 */
122	err = squashfs_read_metadata(sb, sqshb_ino, &block,
123				&offset, sizeof(*sqshb_ino));
124	if (err < 0)
125		goto failed_read;
126
127	err = squashfs_new_inode(sb, inode, sqshb_ino);
128	if (err)
129		goto failed_read;
130
131	block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
132	offset = SQUASHFS_INODE_OFFSET(ino);
133
134	type = le16_to_cpu(sqshb_ino->inode_type);
135	switch (type) {
136	case SQUASHFS_REG_TYPE: {
137		unsigned int frag_offset, frag;
138		int frag_size;
139		u64 frag_blk;
140		struct squashfs_reg_inode *sqsh_ino = &squashfs_ino.reg;
141
142		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
143							sizeof(*sqsh_ino));
144		if (err < 0)
145			goto failed_read;
146
147		inode->i_size = le32_to_cpu(sqsh_ino->file_size);
148		frag = le32_to_cpu(sqsh_ino->fragment);
149		if (frag != SQUASHFS_INVALID_FRAG) {
150			/*
151			 * the file cannot have a fragment (tailend) and have a
152			 * file size a multiple of the block size
153			 */
154			if ((inode->i_size & (msblk->block_size - 1)) == 0) {
155				err = -EINVAL;
156				goto failed_read;
157			}
158			frag_offset = le32_to_cpu(sqsh_ino->offset);
159			frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
160			if (frag_size < 0) {
161				err = frag_size;
162				goto failed_read;
163			}
164		} else {
165			frag_blk = SQUASHFS_INVALID_BLK;
166			frag_size = 0;
167			frag_offset = 0;
168		}
169
170		set_nlink(inode, 1);
171		inode->i_fop = &squashfs_file_operations;
172		inode->i_mode |= S_IFREG;
173		inode->i_blocks = ((inode->i_size - 1) >> 9) + 1;
174		squashfs_i(inode)->fragment_block = frag_blk;
175		squashfs_i(inode)->fragment_size = frag_size;
176		squashfs_i(inode)->fragment_offset = frag_offset;
177		squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
178		squashfs_i(inode)->block_list_start = block;
179		squashfs_i(inode)->offset = offset;
180		squashfs_i(inode)->parent = 0;
181		inode->i_data.a_ops = &squashfs_aops;
182
183		TRACE("File inode %x:%x, start_block %llx, block_list_start "
184			"%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
185			offset, squashfs_i(inode)->start, block, offset);
186		break;
187	}
188	case SQUASHFS_LREG_TYPE: {
189		unsigned int frag_offset, frag;
190		int frag_size;
191		u64 frag_blk;
192		struct squashfs_lreg_inode *sqsh_ino = &squashfs_ino.lreg;
193
194		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
195							sizeof(*sqsh_ino));
196		if (err < 0)
197			goto failed_read;
198
199		inode->i_size = le64_to_cpu(sqsh_ino->file_size);
200		if (inode->i_size < 0) {
201			err = -EINVAL;
202			goto failed_read;
203		}
204		frag = le32_to_cpu(sqsh_ino->fragment);
205		if (frag != SQUASHFS_INVALID_FRAG) {
206			/*
207			 * the file cannot have a fragment (tailend) and have a
208			 * file size a multiple of the block size
209			 */
210			if ((inode->i_size & (msblk->block_size - 1)) == 0) {
211				err = -EINVAL;
212				goto failed_read;
213			}
214			frag_offset = le32_to_cpu(sqsh_ino->offset);
215			frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
216			if (frag_size < 0) {
217				err = frag_size;
218				goto failed_read;
219			}
220		} else {
221			frag_blk = SQUASHFS_INVALID_BLK;
222			frag_size = 0;
223			frag_offset = 0;
224		}
225
226		xattr_id = le32_to_cpu(sqsh_ino->xattr);
227		set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
228		inode->i_op = &squashfs_inode_ops;
229		inode->i_fop = &squashfs_file_operations;
230		inode->i_mode |= S_IFREG;
231		inode->i_blocks = (inode->i_size -
232				le64_to_cpu(sqsh_ino->sparse) + 511) >> 9;
233
234		squashfs_i(inode)->fragment_block = frag_blk;
235		squashfs_i(inode)->fragment_size = frag_size;
236		squashfs_i(inode)->fragment_offset = frag_offset;
237		squashfs_i(inode)->start = le64_to_cpu(sqsh_ino->start_block);
238		squashfs_i(inode)->block_list_start = block;
239		squashfs_i(inode)->offset = offset;
240		squashfs_i(inode)->parent = 0;
241		inode->i_data.a_ops = &squashfs_aops;
242
243		TRACE("File inode %x:%x, start_block %llx, block_list_start "
244			"%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
245			offset, squashfs_i(inode)->start, block, offset);
246		break;
247	}
248	case SQUASHFS_DIR_TYPE: {
249		struct squashfs_dir_inode *sqsh_ino = &squashfs_ino.dir;
250
251		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
252				sizeof(*sqsh_ino));
253		if (err < 0)
254			goto failed_read;
255
256		set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
257		inode->i_size = le16_to_cpu(sqsh_ino->file_size);
258		inode->i_op = &squashfs_dir_inode_ops;
259		inode->i_fop = &squashfs_dir_ops;
260		inode->i_mode |= S_IFDIR;
261		squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
262		squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
263		squashfs_i(inode)->dir_idx_cnt = 0;
264		squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
265
266		TRACE("Directory inode %x:%x, start_block %llx, offset %x\n",
267				SQUASHFS_INODE_BLK(ino), offset,
268				squashfs_i(inode)->start,
269				le16_to_cpu(sqsh_ino->offset));
270		break;
271	}
272	case SQUASHFS_LDIR_TYPE: {
273		struct squashfs_ldir_inode *sqsh_ino = &squashfs_ino.ldir;
274
275		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
276				sizeof(*sqsh_ino));
277		if (err < 0)
278			goto failed_read;
279
280		xattr_id = le32_to_cpu(sqsh_ino->xattr);
281		set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
282		inode->i_size = le32_to_cpu(sqsh_ino->file_size);
283		inode->i_op = &squashfs_dir_inode_ops;
284		inode->i_fop = &squashfs_dir_ops;
285		inode->i_mode |= S_IFDIR;
286		squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
287		squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
288		squashfs_i(inode)->dir_idx_start = block;
289		squashfs_i(inode)->dir_idx_offset = offset;
290		squashfs_i(inode)->dir_idx_cnt = le16_to_cpu(sqsh_ino->i_count);
291		squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
292
293		TRACE("Long directory inode %x:%x, start_block %llx, offset "
294				"%x\n", SQUASHFS_INODE_BLK(ino), offset,
295				squashfs_i(inode)->start,
296				le16_to_cpu(sqsh_ino->offset));
297		break;
298	}
299	case SQUASHFS_SYMLINK_TYPE:
300	case SQUASHFS_LSYMLINK_TYPE: {
301		struct squashfs_symlink_inode *sqsh_ino = &squashfs_ino.symlink;
302
303		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
304				sizeof(*sqsh_ino));
305		if (err < 0)
306			goto failed_read;
307
308		inode->i_size = le32_to_cpu(sqsh_ino->symlink_size);
309		if (inode->i_size > PAGE_SIZE) {
310			ERROR("Corrupted symlink\n");
311			return -EINVAL;
312		}
313
314		set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
315		inode->i_op = &squashfs_symlink_inode_ops;
316		inode_nohighmem(inode);
317		inode->i_data.a_ops = &squashfs_symlink_aops;
318		inode->i_mode |= S_IFLNK;
319		squashfs_i(inode)->start = block;
320		squashfs_i(inode)->offset = offset;
321		squashfs_i(inode)->parent = 0;
322
323		if (type == SQUASHFS_LSYMLINK_TYPE) {
324			__le32 xattr;
325
326			err = squashfs_read_metadata(sb, NULL, &block,
327						&offset, inode->i_size);
328			if (err < 0)
329				goto failed_read;
330			err = squashfs_read_metadata(sb, &xattr, &block,
331						&offset, sizeof(xattr));
332			if (err < 0)
333				goto failed_read;
334			xattr_id = le32_to_cpu(xattr);
335		}
336
337		TRACE("Symbolic link inode %x:%x, start_block %llx, offset "
338				"%x\n", SQUASHFS_INODE_BLK(ino), offset,
339				block, offset);
340		break;
341	}
342	case SQUASHFS_BLKDEV_TYPE:
343	case SQUASHFS_CHRDEV_TYPE: {
344		struct squashfs_dev_inode *sqsh_ino = &squashfs_ino.dev;
345		unsigned int rdev;
346
347		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
348				sizeof(*sqsh_ino));
349		if (err < 0)
350			goto failed_read;
351
352		if (type == SQUASHFS_CHRDEV_TYPE)
353			inode->i_mode |= S_IFCHR;
354		else
355			inode->i_mode |= S_IFBLK;
356		set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
357		rdev = le32_to_cpu(sqsh_ino->rdev);
358		init_special_inode(inode, inode->i_mode, new_decode_dev(rdev));
359		squashfs_i(inode)->parent = 0;
360
361		TRACE("Device inode %x:%x, rdev %x\n",
362				SQUASHFS_INODE_BLK(ino), offset, rdev);
363		break;
364	}
365	case SQUASHFS_LBLKDEV_TYPE:
366	case SQUASHFS_LCHRDEV_TYPE: {
367		struct squashfs_ldev_inode *sqsh_ino = &squashfs_ino.ldev;
368		unsigned int rdev;
369
370		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
371				sizeof(*sqsh_ino));
372		if (err < 0)
373			goto failed_read;
374
375		if (type == SQUASHFS_LCHRDEV_TYPE)
376			inode->i_mode |= S_IFCHR;
377		else
378			inode->i_mode |= S_IFBLK;
379		xattr_id = le32_to_cpu(sqsh_ino->xattr);
380		inode->i_op = &squashfs_inode_ops;
381		set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
382		rdev = le32_to_cpu(sqsh_ino->rdev);
383		init_special_inode(inode, inode->i_mode, new_decode_dev(rdev));
384		squashfs_i(inode)->parent = 0;
385
386		TRACE("Device inode %x:%x, rdev %x\n",
387				SQUASHFS_INODE_BLK(ino), offset, rdev);
388		break;
389	}
390	case SQUASHFS_FIFO_TYPE:
391	case SQUASHFS_SOCKET_TYPE: {
392		struct squashfs_ipc_inode *sqsh_ino = &squashfs_ino.ipc;
393
394		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
395				sizeof(*sqsh_ino));
396		if (err < 0)
397			goto failed_read;
398
399		if (type == SQUASHFS_FIFO_TYPE)
400			inode->i_mode |= S_IFIFO;
401		else
402			inode->i_mode |= S_IFSOCK;
403		set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
404		init_special_inode(inode, inode->i_mode, 0);
405		squashfs_i(inode)->parent = 0;
406		break;
407	}
408	case SQUASHFS_LFIFO_TYPE:
409	case SQUASHFS_LSOCKET_TYPE: {
410		struct squashfs_lipc_inode *sqsh_ino = &squashfs_ino.lipc;
411
412		err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
413				sizeof(*sqsh_ino));
414		if (err < 0)
415			goto failed_read;
416
417		if (type == SQUASHFS_LFIFO_TYPE)
418			inode->i_mode |= S_IFIFO;
419		else
420			inode->i_mode |= S_IFSOCK;
421		xattr_id = le32_to_cpu(sqsh_ino->xattr);
422		inode->i_op = &squashfs_inode_ops;
423		set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
424		init_special_inode(inode, inode->i_mode, 0);
425		squashfs_i(inode)->parent = 0;
426		break;
427	}
428	default:
429		ERROR("Unknown inode type %d in squashfs_iget!\n", type);
430		return -EINVAL;
431	}
432
433	if (xattr_id != SQUASHFS_INVALID_XATTR && msblk->xattr_id_table) {
434		err = squashfs_xattr_lookup(sb, xattr_id,
435					&squashfs_i(inode)->xattr_count,
436					&squashfs_i(inode)->xattr_size,
437					&squashfs_i(inode)->xattr);
438		if (err < 0)
439			goto failed_read;
440		inode->i_blocks += ((squashfs_i(inode)->xattr_size - 1) >> 9)
441				+ 1;
442	} else
443		squashfs_i(inode)->xattr_count = 0;
444
445	return 0;
446
447failed_read:
448	ERROR("Unable to read inode 0x%llx\n", ino);
449	return err;
450}
451
452
453const struct inode_operations squashfs_inode_ops = {
454	.listxattr = squashfs_listxattr
455};
456