blob: 1b2a8c97199541ace5dc9aba230780d7bcf5cca4 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * fs/cifs/link.c
3 *
Steve French366781c2008-01-25 10:12:41 +00004 * Copyright (C) International Business Machines Corp., 2002,2008
Linus Torvalds1da177e2005-04-16 15:20:36 -07005 * Author(s): Steve French (sfrench@us.ibm.com)
6 *
7 * This library is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU Lesser General Public License as published
9 * by the Free Software Foundation; either version 2.1 of the License, or
10 * (at your option) any later version.
11 *
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
15 * the GNU Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public License
18 * along with this library; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21#include <linux/fs.h>
22#include <linux/stat.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090023#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070024#include <linux/namei.h>
25#include "cifsfs.h"
26#include "cifspdu.h"
27#include "cifsglob.h"
28#include "cifsproto.h"
29#include "cifs_debug.h"
30#include "cifs_fs_sb.h"
Stefan Metzmacherc69c1b62010-07-31 09:14:16 +020031#include "md5.h"
32
33#define CIFS_MF_SYMLINK_LEN_OFFSET (4+1)
34#define CIFS_MF_SYMLINK_MD5_OFFSET (CIFS_MF_SYMLINK_LEN_OFFSET+(4+1))
35#define CIFS_MF_SYMLINK_LINK_OFFSET (CIFS_MF_SYMLINK_MD5_OFFSET+(32+1))
36#define CIFS_MF_SYMLINK_LINK_MAXLEN (1024)
37#define CIFS_MF_SYMLINK_FILE_SIZE \
38 (CIFS_MF_SYMLINK_LINK_OFFSET + CIFS_MF_SYMLINK_LINK_MAXLEN)
39
40#define CIFS_MF_SYMLINK_LEN_FORMAT "XSym\n%04u\n"
41#define CIFS_MF_SYMLINK_MD5_FORMAT \
42 "%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x\n"
43#define CIFS_MF_SYMLINK_MD5_ARGS(md5_hash) \
44 md5_hash[0], md5_hash[1], md5_hash[2], md5_hash[3], \
45 md5_hash[4], md5_hash[5], md5_hash[6], md5_hash[7], \
46 md5_hash[8], md5_hash[9], md5_hash[10], md5_hash[11],\
47 md5_hash[12], md5_hash[13], md5_hash[14], md5_hash[15]
48
49static int
50CIFSParseMFSymlink(const u8 *buf,
51 unsigned int buf_len,
52 unsigned int *_link_len,
53 char **_link_str)
54{
55 int rc;
56 unsigned int link_len;
57 const char *md5_str1;
58 const char *link_str;
59 struct MD5Context md5_ctx;
60 u8 md5_hash[16];
61 char md5_str2[34];
62
63 if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
64 return -EINVAL;
65
66 md5_str1 = (const char *)&buf[CIFS_MF_SYMLINK_MD5_OFFSET];
67 link_str = (const char *)&buf[CIFS_MF_SYMLINK_LINK_OFFSET];
68
69 rc = sscanf(buf, CIFS_MF_SYMLINK_LEN_FORMAT, &link_len);
70 if (rc != 1)
71 return -EINVAL;
72
73 cifs_MD5_init(&md5_ctx);
74 cifs_MD5_update(&md5_ctx, (const u8 *)link_str, link_len);
75 cifs_MD5_final(md5_hash, &md5_ctx);
76
77 snprintf(md5_str2, sizeof(md5_str2),
78 CIFS_MF_SYMLINK_MD5_FORMAT,
79 CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
80
81 if (strncmp(md5_str1, md5_str2, 17) != 0)
82 return -EINVAL;
83
84 if (_link_str) {
85 *_link_str = kstrndup(link_str, link_len, GFP_KERNEL);
86 if (!*_link_str)
87 return -ENOMEM;
88 }
89
90 *_link_len = link_len;
91 return 0;
92}
Linus Torvalds1da177e2005-04-16 15:20:36 -070093
Stefan Metzmacher0fd43ae2010-08-05 21:13:44 +020094static int
Stefan Metzmacher18bddd12010-08-03 11:24:22 +020095CIFSFormatMFSymlink(u8 *buf, unsigned int buf_len, const char *link_str)
96{
97 unsigned int link_len;
98 unsigned int ofs;
99 struct MD5Context md5_ctx;
100 u8 md5_hash[16];
101
102 if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
103 return -EINVAL;
104
105 link_len = strlen(link_str);
106
107 if (link_len > CIFS_MF_SYMLINK_LINK_MAXLEN)
108 return -ENAMETOOLONG;
109
110 cifs_MD5_init(&md5_ctx);
111 cifs_MD5_update(&md5_ctx, (const u8 *)link_str, link_len);
112 cifs_MD5_final(md5_hash, &md5_ctx);
113
114 snprintf(buf, buf_len,
115 CIFS_MF_SYMLINK_LEN_FORMAT CIFS_MF_SYMLINK_MD5_FORMAT,
116 link_len,
117 CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
118
119 ofs = CIFS_MF_SYMLINK_LINK_OFFSET;
120 memcpy(buf + ofs, link_str, link_len);
121
122 ofs += link_len;
123 if (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
124 buf[ofs] = '\n';
125 ofs++;
126 }
127
128 while (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
129 buf[ofs] = ' ';
130 ofs++;
131 }
132
133 return 0;
134}
135
Stefan Metzmacher8713d012010-08-05 21:15:22 +0200136static int
137CIFSCreateMFSymLink(const int xid, struct cifsTconInfo *tcon,
138 const char *fromName, const char *toName,
139 const struct nls_table *nls_codepage, int remap)
140{
141 int rc;
142 int oplock = 0;
143 __u16 netfid = 0;
144 u8 *buf;
145 unsigned int bytes_written = 0;
146
147 buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
148 if (!buf)
149 return -ENOMEM;
150
151 rc = CIFSFormatMFSymlink(buf, CIFS_MF_SYMLINK_FILE_SIZE, toName);
152 if (rc != 0) {
153 kfree(buf);
154 return rc;
155 }
156
157 rc = CIFSSMBOpen(xid, tcon, fromName, FILE_CREATE, GENERIC_WRITE,
158 CREATE_NOT_DIR, &netfid, &oplock, NULL,
159 nls_codepage, remap);
160 if (rc != 0) {
161 kfree(buf);
162 return rc;
163 }
164
165 rc = CIFSSMBWrite(xid, tcon, netfid,
166 CIFS_MF_SYMLINK_FILE_SIZE /* length */,
167 0 /* offset */,
168 &bytes_written, buf, NULL, 0);
169 CIFSSMBClose(xid, tcon, netfid);
170 kfree(buf);
171 if (rc != 0)
172 return rc;
173
174 if (bytes_written != CIFS_MF_SYMLINK_FILE_SIZE)
175 return -EIO;
176
177 return 0;
178}
179
180static int
Stefan Metzmacher0fd43ae2010-08-05 21:13:44 +0200181CIFSQueryMFSymLink(const int xid, struct cifsTconInfo *tcon,
182 const unsigned char *searchName, char **symlinkinfo,
183 const struct nls_table *nls_codepage, int remap)
184{
185 int rc;
186 int oplock = 0;
187 __u16 netfid = 0;
188 u8 *buf;
189 char *pbuf;
190 unsigned int bytes_read = 0;
191 int buf_type = CIFS_NO_BUFFER;
192 unsigned int link_len = 0;
193 FILE_ALL_INFO file_info;
194
195 rc = CIFSSMBOpen(xid, tcon, searchName, FILE_OPEN, GENERIC_READ,
196 CREATE_NOT_DIR, &netfid, &oplock, &file_info,
197 nls_codepage, remap);
198 if (rc != 0)
199 return rc;
200
201 if (file_info.EndOfFile != CIFS_MF_SYMLINK_FILE_SIZE) {
202 CIFSSMBClose(xid, tcon, netfid);
203 /* it's not a symlink */
204 return -EINVAL;
205 }
206
207 buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
208 if (!buf)
209 return -ENOMEM;
210 pbuf = buf;
211
212 rc = CIFSSMBRead(xid, tcon, netfid,
213 CIFS_MF_SYMLINK_FILE_SIZE /* length */,
214 0 /* offset */,
215 &bytes_read, &pbuf, &buf_type);
216 CIFSSMBClose(xid, tcon, netfid);
217 if (rc != 0) {
218 kfree(buf);
219 return rc;
220 }
221
222 rc = CIFSParseMFSymlink(buf, bytes_read, &link_len, symlinkinfo);
223 kfree(buf);
224 if (rc != 0)
225 return rc;
226
227 return 0;
228}
229
Stefan Metzmacher8bfb50a2010-07-31 09:15:10 +0200230bool
231CIFSCouldBeMFSymlink(const struct cifs_fattr *fattr)
232{
233 if (!(fattr->cf_mode & S_IFREG))
234 /* it's not a symlink */
235 return false;
236
237 if (fattr->cf_eof != CIFS_MF_SYMLINK_FILE_SIZE)
238 /* it's not a symlink */
239 return false;
240
241 return true;
242}
243
244int
245CIFSCheckMFSymlink(struct cifs_fattr *fattr,
246 const unsigned char *path,
247 struct cifs_sb_info *cifs_sb, int xid)
248{
249 int rc;
250 int oplock = 0;
251 __u16 netfid = 0;
252 struct cifsTconInfo *pTcon = cifs_sb->tcon;
253 u8 *buf;
254 char *pbuf;
255 unsigned int bytes_read = 0;
256 int buf_type = CIFS_NO_BUFFER;
257 unsigned int link_len = 0;
258 FILE_ALL_INFO file_info;
259
260 if (!CIFSCouldBeMFSymlink(fattr))
261 /* it's not a symlink */
262 return 0;
263
264 rc = CIFSSMBOpen(xid, pTcon, path, FILE_OPEN, GENERIC_READ,
265 CREATE_NOT_DIR, &netfid, &oplock, &file_info,
266 cifs_sb->local_nls,
267 cifs_sb->mnt_cifs_flags &
268 CIFS_MOUNT_MAP_SPECIAL_CHR);
269 if (rc != 0)
270 return rc;
271
272 if (file_info.EndOfFile != CIFS_MF_SYMLINK_FILE_SIZE) {
273 CIFSSMBClose(xid, pTcon, netfid);
274 /* it's not a symlink */
275 return 0;
276 }
277
278 buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
279 if (!buf)
280 return -ENOMEM;
281 pbuf = buf;
282
283 rc = CIFSSMBRead(xid, pTcon, netfid,
284 CIFS_MF_SYMLINK_FILE_SIZE /* length */,
285 0 /* offset */,
286 &bytes_read, &pbuf, &buf_type);
287 CIFSSMBClose(xid, pTcon, netfid);
288 if (rc != 0) {
289 kfree(buf);
290 return rc;
291 }
292
293 rc = CIFSParseMFSymlink(buf, bytes_read, &link_len, NULL);
294 kfree(buf);
295 if (rc == -EINVAL)
296 /* it's not a symlink */
297 return 0;
298 if (rc != 0)
299 return rc;
300
301 /* it is a symlink */
302 fattr->cf_eof = link_len;
303 fattr->cf_mode &= ~S_IFMT;
304 fattr->cf_mode |= S_IFLNK | S_IRWXU | S_IRWXG | S_IRWXO;
305 fattr->cf_dtype = DT_LNK;
306 return 0;
307}
308
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309int
310cifs_hardlink(struct dentry *old_file, struct inode *inode,
311 struct dentry *direntry)
312{
313 int rc = -EACCES;
314 int xid;
315 char *fromName = NULL;
316 char *toName = NULL;
317 struct cifs_sb_info *cifs_sb_target;
318 struct cifsTconInfo *pTcon;
319 struct cifsInodeInfo *cifsInode;
320
321 xid = GetXid();
322
323 cifs_sb_target = CIFS_SB(inode->i_sb);
324 pTcon = cifs_sb_target->tcon;
325
326/* No need to check for cross device links since server will do that
327 BB note DFS case in future though (when we may have to check) */
328
Steve French7f573562005-08-30 11:32:14 -0700329 fromName = build_path_from_dentry(old_file);
330 toName = build_path_from_dentry(direntry);
Steve Frenchfb8c4b12007-07-10 01:16:18 +0000331 if ((fromName == NULL) || (toName == NULL)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700332 rc = -ENOMEM;
333 goto cifs_hl_exit;
334 }
335
Steve Frenchc18c8422007-07-18 23:21:09 +0000336/* if (cifs_sb_target->tcon->ses->capabilities & CAP_UNIX)*/
337 if (pTcon->unix_ext)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338 rc = CIFSUnixCreateHardLink(xid, pTcon, fromName, toName,
Steve Frenchfb8c4b12007-07-10 01:16:18 +0000339 cifs_sb_target->local_nls,
Steve French737b7582005-04-28 22:41:06 -0700340 cifs_sb_target->mnt_cifs_flags &
341 CIFS_MOUNT_MAP_SPECIAL_CHR);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342 else {
343 rc = CIFSCreateHardLink(xid, pTcon, fromName, toName,
Steve Frenchfb8c4b12007-07-10 01:16:18 +0000344 cifs_sb_target->local_nls,
Steve French737b7582005-04-28 22:41:06 -0700345 cifs_sb_target->mnt_cifs_flags &
346 CIFS_MOUNT_MAP_SPECIAL_CHR);
Steve Frenchfb8c4b12007-07-10 01:16:18 +0000347 if ((rc == -EIO) || (rc == -EINVAL))
348 rc = -EOPNOTSUPP;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 }
350
Steve French31ec35d2006-11-16 20:54:20 +0000351 d_drop(direntry); /* force new lookup from server of target */
352
353 /* if source file is cached (oplocked) revalidate will not go to server
354 until the file is closed or oplock broken so update nlinks locally */
Steve Frenchfb8c4b12007-07-10 01:16:18 +0000355 if (old_file->d_inode) {
Steve French31ec35d2006-11-16 20:54:20 +0000356 cifsInode = CIFS_I(old_file->d_inode);
Steve Frenchfb8c4b12007-07-10 01:16:18 +0000357 if (rc == 0) {
Steve French31ec35d2006-11-16 20:54:20 +0000358 old_file->d_inode->i_nlink++;
Steve French1b2b2122007-02-17 04:30:54 +0000359/* BB should we make this contingent on superblock flag NOATIME? */
360/* old_file->d_inode->i_ctime = CURRENT_TIME;*/
Steve French31ec35d2006-11-16 20:54:20 +0000361 /* parent dir timestamps will update from srv
362 within a second, would it really be worth it
363 to set the parent dir cifs inode time to zero
364 to force revalidate (faster) for it too? */
365 }
Steve Frenchfb8c4b12007-07-10 01:16:18 +0000366 /* if not oplocked will force revalidate to get info
Steve French31ec35d2006-11-16 20:54:20 +0000367 on source file from srv */
368 cifsInode->time = 0;
369
Steve Frenchfb8c4b12007-07-10 01:16:18 +0000370 /* Will update parent dir timestamps from srv within a second.
Steve French31ec35d2006-11-16 20:54:20 +0000371 Would it really be worth it to set the parent dir (cifs
372 inode) time field to zero to force revalidate on parent
Steve Frenchfb8c4b12007-07-10 01:16:18 +0000373 directory faster ie
Steve French31ec35d2006-11-16 20:54:20 +0000374 CIFS_I(inode)->time = 0; */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700376
377cifs_hl_exit:
Jesper Juhlf99d49a2005-11-07 01:01:34 -0800378 kfree(fromName);
379 kfree(toName);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 FreeXid(xid);
381 return rc;
382}
383
Linus Torvaldscc314ee2005-08-19 18:02:56 -0700384void *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
386{
387 struct inode *inode = direntry->d_inode;
Jeff Layton8b6427a2009-05-19 09:57:03 -0400388 int rc = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389 int xid;
390 char *full_path = NULL;
Jeff Layton8b6427a2009-05-19 09:57:03 -0400391 char *target_path = NULL;
392 struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
393 struct cifsTconInfo *tcon = cifs_sb->tcon;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394
395 xid = GetXid();
396
Jeff Layton8b6427a2009-05-19 09:57:03 -0400397 /*
398 * For now, we just handle symlinks with unix extensions enabled.
399 * Eventually we should handle NTFS reparse points, and MacOS
400 * symlink support. For instance...
401 *
402 * rc = CIFSSMBQueryReparseLinkInfo(...)
403 *
404 * For now, just return -EACCES when the server doesn't support posix
405 * extensions. Note that we still allow querying symlinks when posix
406 * extensions are manually disabled. We could disable these as well
407 * but there doesn't seem to be any harm in allowing the client to
408 * read them.
409 */
410 if (!(tcon->ses->capabilities & CAP_UNIX)) {
411 rc = -EACCES;
412 goto out;
413 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414
Jeff Layton8b6427a2009-05-19 09:57:03 -0400415 full_path = build_path_from_dentry(direntry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416 if (!full_path)
Jeff Layton460b9692009-04-30 07:17:56 -0400417 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418
Joe Perchesb6b38f72010-04-21 03:50:45 +0000419 cFYI(1, "Full path: %s inode = 0x%p", full_path, inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420
Jeff Layton8b6427a2009-05-19 09:57:03 -0400421 rc = CIFSSMBUnixQuerySymLink(xid, tcon, full_path, &target_path,
422 cifs_sb->local_nls);
423 kfree(full_path);
424out:
Jeff Layton460b9692009-04-30 07:17:56 -0400425 if (rc != 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426 kfree(target_path);
427 target_path = ERR_PTR(rc);
428 }
429
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430 FreeXid(xid);
431 nd_set_link(nd, target_path);
Jeff Layton460b9692009-04-30 07:17:56 -0400432 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433}
434
435int
436cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
437{
438 int rc = -EOPNOTSUPP;
439 int xid;
440 struct cifs_sb_info *cifs_sb;
441 struct cifsTconInfo *pTcon;
442 char *full_path = NULL;
443 struct inode *newinode = NULL;
444
445 xid = GetXid();
446
447 cifs_sb = CIFS_SB(inode->i_sb);
448 pTcon = cifs_sb->tcon;
449
Steve French7f573562005-08-30 11:32:14 -0700450 full_path = build_path_from_dentry(direntry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451
Steve Frenchfb8c4b12007-07-10 01:16:18 +0000452 if (full_path == NULL) {
Suresh Jayaraman0f3bc092009-06-25 18:12:34 +0530453 rc = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454 FreeXid(xid);
Suresh Jayaraman0f3bc092009-06-25 18:12:34 +0530455 return rc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456 }
457
Joe Perchesb6b38f72010-04-21 03:50:45 +0000458 cFYI(1, "Full path: %s", full_path);
459 cFYI(1, "symname is %s", symname);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700460
461 /* BB what if DFS and this volume is on different share? BB */
Steve Frenchc18c8422007-07-18 23:21:09 +0000462 if (pTcon->unix_ext)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463 rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
464 cifs_sb->local_nls);
465 /* else
Steve Frenchfb8c4b12007-07-10 01:16:18 +0000466 rc = CIFSCreateReparseSymLink(xid, pTcon, fromName, toName,
467 cifs_sb_target->local_nls); */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468
469 if (rc == 0) {
Steve Frenchc18c8422007-07-18 23:21:09 +0000470 if (pTcon->unix_ext)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471 rc = cifs_get_inode_info_unix(&newinode, full_path,
Steve Frenchfb8c4b12007-07-10 01:16:18 +0000472 inode->i_sb, xid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473 else
474 rc = cifs_get_inode_info(&newinode, full_path, NULL,
Steve French8b1327f2008-03-14 22:37:16 +0000475 inode->i_sb, xid, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476
477 if (rc != 0) {
Joe Perchesb6b38f72010-04-21 03:50:45 +0000478 cFYI(1, "Create symlink ok, getinodeinfo fail rc = %d",
479 rc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480 } else {
Steve Frenchb92327f2005-08-22 20:09:43 -0700481 if (pTcon->nocase)
482 direntry->d_op = &cifs_ci_dentry_ops;
483 else
484 direntry->d_op = &cifs_dentry_ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485 d_instantiate(direntry, newinode);
486 }
487 }
488
Jesper Juhlf99d49a2005-11-07 01:01:34 -0800489 kfree(full_path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490 FreeXid(xid);
491 return rc;
492}
493
Linus Torvaldscc314ee2005-08-19 18:02:56 -0700494void cifs_put_link(struct dentry *direntry, struct nameidata *nd, void *cookie)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495{
496 char *p = nd_get_link(nd);
497 if (!IS_ERR(p))
498 kfree(p);
499}