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Commit | Line | Data |
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6d5ae0de IM |
1 | /* |
2 | * Contains the CIFS DFS referral mounting routines used for handling | |
3 | * traversal via DFS junction point | |
4 | * | |
5 | * Copyright (c) 2007 Igor Mammedov | |
366781c1 | 6 | * Copyright (C) International Business Machines Corp., 2008 |
6d5ae0de | 7 | * Author(s): Igor Mammedov (niallain@gmail.com) |
366781c1 | 8 | * Steve French (sfrench@us.ibm.com) |
6d5ae0de IM |
9 | * This program is free software; you can redistribute it and/or |
10 | * modify it under the terms of the GNU General Public License | |
11 | * as published by the Free Software Foundation; either version | |
12 | * 2 of the License, or (at your option) any later version. | |
13 | */ | |
14 | ||
15 | #include <linux/dcache.h> | |
16 | #include <linux/mount.h> | |
17 | #include <linux/namei.h> | |
18 | #include <linux/vfs.h> | |
19 | #include <linux/fs.h> | |
20 | #include "cifsglob.h" | |
21 | #include "cifsproto.h" | |
22 | #include "cifsfs.h" | |
23 | #include "dns_resolve.h" | |
24 | #include "cifs_debug.h" | |
25 | ||
8d142137 | 26 | static LIST_HEAD(cifs_dfs_automount_list); |
6d5ae0de IM |
27 | |
28 | /* | |
29 | * DFS functions | |
30 | */ | |
31 | ||
32 | void dfs_shrink_umount_helper(struct vfsmount *vfsmnt) | |
33 | { | |
34 | mark_mounts_for_expiry(&cifs_dfs_automount_list); | |
35 | mark_mounts_for_expiry(&cifs_dfs_automount_list); | |
6d5ae0de IM |
36 | } |
37 | ||
38 | /** | |
39 | * cifs_get_share_name - extracts share name from UNC | |
40 | * @node_name: pointer to UNC string | |
41 | * | |
42 | * Extracts sharename form full UNC. | |
43 | * i.e. strips from UNC trailing path that is not part of share | |
44 | * name and fixup missing '\' in the begining of DFS node refferal | |
45 | * if neccessary. | |
46 | * Returns pointer to share name on success or NULL on error. | |
47 | * Caller is responsible for freeing returned string. | |
48 | */ | |
49 | static char *cifs_get_share_name(const char *node_name) | |
50 | { | |
51 | int len; | |
52 | char *UNC; | |
53 | char *pSep; | |
54 | ||
55 | len = strlen(node_name); | |
56 | UNC = kmalloc(len+2 /*for term null and additional \ if it's missed */, | |
57 | GFP_KERNEL); | |
58 | if (!UNC) | |
59 | return NULL; | |
60 | ||
61 | /* get share name and server name */ | |
62 | if (node_name[1] != '\\') { | |
63 | UNC[0] = '\\'; | |
64 | strncpy(UNC+1, node_name, len); | |
65 | len++; | |
66 | UNC[len] = 0; | |
67 | } else { | |
68 | strncpy(UNC, node_name, len); | |
69 | UNC[len] = 0; | |
70 | } | |
71 | ||
72 | /* find server name end */ | |
73 | pSep = memchr(UNC+2, '\\', len-2); | |
74 | if (!pSep) { | |
75 | cERROR(1, ("%s: no server name end in node name: %s", | |
55f78e17 | 76 | __func__, node_name)); |
6d5ae0de IM |
77 | kfree(UNC); |
78 | return NULL; | |
79 | } | |
80 | ||
81 | /* find sharename end */ | |
82 | pSep++; | |
83 | pSep = memchr(UNC+(pSep-UNC), '\\', len-(pSep-UNC)); | |
84 | if (!pSep) { | |
85 | cERROR(1, ("%s:2 cant find share name in node name: %s", | |
55f78e17 | 86 | __func__, node_name)); |
6d5ae0de IM |
87 | kfree(UNC); |
88 | return NULL; | |
89 | } | |
90 | /* trim path up to sharename end | |
91 | * * now we have share name in UNC */ | |
92 | *pSep = 0; | |
93 | ||
94 | return UNC; | |
95 | } | |
96 | ||
97 | ||
98 | /** | |
99 | * compose_mount_options - creates mount options for refferral | |
100 | * @sb_mountdata: parent/root DFS mount options (template) | |
101 | * @ref_unc: refferral server UNC | |
102 | * @devname: pointer for saving device name | |
103 | * | |
104 | * creates mount options for submount based on template options sb_mountdata | |
105 | * and replacing unc,ip,prefixpath options with ones we've got form ref_unc. | |
106 | * | |
107 | * Returns: pointer to new mount options or ERR_PTR. | |
108 | * Caller is responcible for freeing retunrned value if it is not error. | |
109 | */ | |
366781c1 SF |
110 | static char *compose_mount_options(const char *sb_mountdata, |
111 | const char *ref_unc, | |
112 | char **devname) | |
6d5ae0de IM |
113 | { |
114 | int rc; | |
115 | char *mountdata; | |
116 | int md_len; | |
117 | char *tkn_e; | |
118 | char *srvIP = NULL; | |
119 | char sep = ','; | |
120 | int off, noff; | |
121 | ||
122 | if (sb_mountdata == NULL) | |
123 | return ERR_PTR(-EINVAL); | |
124 | ||
125 | *devname = cifs_get_share_name(ref_unc); | |
126 | rc = dns_resolve_server_name_to_ip(*devname, &srvIP); | |
127 | if (rc != 0) { | |
128 | cERROR(1, ("%s: Failed to resolve server part of %s to IP", | |
55f78e17 | 129 | __func__, *devname)); |
6d5ae0de IM |
130 | mountdata = ERR_PTR(rc); |
131 | goto compose_mount_options_out; | |
132 | } | |
133 | md_len = strlen(sb_mountdata) + strlen(srvIP) + strlen(ref_unc) + 3; | |
134 | mountdata = kzalloc(md_len+1, GFP_KERNEL); | |
135 | if (mountdata == NULL) { | |
136 | mountdata = ERR_PTR(-ENOMEM); | |
137 | goto compose_mount_options_out; | |
138 | } | |
139 | ||
140 | /* copy all options except of unc,ip,prefixpath */ | |
141 | off = 0; | |
142 | if (strncmp(sb_mountdata, "sep=", 4) == 0) { | |
143 | sep = sb_mountdata[4]; | |
144 | strncpy(mountdata, sb_mountdata, 5); | |
145 | off += 5; | |
146 | } | |
147 | while ((tkn_e = strchr(sb_mountdata+off, sep))) { | |
148 | noff = (tkn_e - (sb_mountdata+off)) + 1; | |
149 | if (strnicmp(sb_mountdata+off, "unc=", 4) == 0) { | |
150 | off += noff; | |
151 | continue; | |
152 | } | |
153 | if (strnicmp(sb_mountdata+off, "ip=", 3) == 0) { | |
154 | off += noff; | |
155 | continue; | |
156 | } | |
157 | if (strnicmp(sb_mountdata+off, "prefixpath=", 3) == 0) { | |
158 | off += noff; | |
159 | continue; | |
160 | } | |
161 | strncat(mountdata, sb_mountdata+off, noff); | |
162 | off += noff; | |
163 | } | |
164 | strcat(mountdata, sb_mountdata+off); | |
165 | mountdata[md_len] = '\0'; | |
166 | ||
167 | /* copy new IP and ref share name */ | |
168 | strcat(mountdata, ",ip="); | |
169 | strcat(mountdata, srvIP); | |
170 | strcat(mountdata, ",unc="); | |
171 | strcat(mountdata, *devname); | |
172 | ||
173 | /* find & copy prefixpath */ | |
174 | tkn_e = strchr(ref_unc+2, '\\'); | |
175 | if (tkn_e) { | |
176 | tkn_e = strchr(tkn_e+1, '\\'); | |
177 | if (tkn_e) { | |
178 | strcat(mountdata, ",prefixpath="); | |
179 | strcat(mountdata, tkn_e); | |
180 | } | |
181 | } | |
182 | ||
55f78e17 HH |
183 | /*cFYI(1,("%s: parent mountdata: %s", __func__,sb_mountdata));*/ |
184 | /*cFYI(1, ("%s: submount mountdata: %s", __func__, mountdata ));*/ | |
6d5ae0de IM |
185 | |
186 | compose_mount_options_out: | |
187 | kfree(srvIP); | |
188 | return mountdata; | |
189 | } | |
190 | ||
191 | ||
366781c1 | 192 | static struct vfsmount *cifs_dfs_do_refmount(const struct vfsmount *mnt_parent, |
6d5ae0de IM |
193 | struct dentry *dentry, char *ref_unc) |
194 | { | |
195 | struct cifs_sb_info *cifs_sb; | |
196 | struct vfsmount *mnt; | |
197 | char *mountdata; | |
366781c1 | 198 | char *devname = NULL; |
6d5ae0de IM |
199 | |
200 | cifs_sb = CIFS_SB(dentry->d_inode->i_sb); | |
201 | mountdata = compose_mount_options(cifs_sb->mountdata, | |
202 | ref_unc, &devname); | |
203 | ||
204 | if (IS_ERR(mountdata)) | |
205 | return (struct vfsmount *)mountdata; | |
206 | ||
207 | mnt = vfs_kern_mount(&cifs_fs_type, 0, devname, mountdata); | |
208 | kfree(mountdata); | |
209 | kfree(devname); | |
210 | return mnt; | |
211 | ||
212 | } | |
213 | ||
214 | static char *build_full_dfs_path_from_dentry(struct dentry *dentry) | |
215 | { | |
216 | char *full_path = NULL; | |
217 | char *search_path; | |
218 | char *tmp_path; | |
219 | size_t l_max_len; | |
220 | struct cifs_sb_info *cifs_sb; | |
221 | ||
222 | if (dentry->d_inode == NULL) | |
223 | return NULL; | |
224 | ||
225 | cifs_sb = CIFS_SB(dentry->d_inode->i_sb); | |
226 | ||
227 | if (cifs_sb->tcon == NULL) | |
228 | return NULL; | |
229 | ||
230 | search_path = build_path_from_dentry(dentry); | |
231 | if (search_path == NULL) | |
232 | return NULL; | |
233 | ||
234 | if (cifs_sb->tcon->Flags & SMB_SHARE_IS_IN_DFS) { | |
235 | /* we should use full path name to correct working with DFS */ | |
236 | l_max_len = strnlen(cifs_sb->tcon->treeName, MAX_TREE_SIZE+1) + | |
237 | strnlen(search_path, MAX_PATHCONF) + 1; | |
238 | tmp_path = kmalloc(l_max_len, GFP_KERNEL); | |
239 | if (tmp_path == NULL) { | |
240 | kfree(search_path); | |
241 | return NULL; | |
242 | } | |
243 | strncpy(tmp_path, cifs_sb->tcon->treeName, l_max_len); | |
244 | strcat(tmp_path, search_path); | |
245 | tmp_path[l_max_len-1] = 0; | |
246 | full_path = tmp_path; | |
247 | kfree(search_path); | |
248 | } else { | |
249 | full_path = search_path; | |
250 | } | |
251 | return full_path; | |
252 | } | |
253 | ||
254 | static int add_mount_helper(struct vfsmount *newmnt, struct nameidata *nd, | |
255 | struct list_head *mntlist) | |
256 | { | |
257 | /* stolen from afs code */ | |
258 | int err; | |
259 | ||
260 | mntget(newmnt); | |
4ac91378 | 261 | err = do_add_mount(newmnt, nd, nd->path.mnt->mnt_flags, mntlist); |
6d5ae0de IM |
262 | switch (err) { |
263 | case 0: | |
4ac91378 JB |
264 | dput(nd->path.dentry); |
265 | mntput(nd->path.mnt); | |
266 | nd->path.mnt = newmnt; | |
267 | nd->path.dentry = dget(newmnt->mnt_root); | |
6d5ae0de IM |
268 | break; |
269 | case -EBUSY: | |
270 | /* someone else made a mount here whilst we were busy */ | |
4ac91378 JB |
271 | while (d_mountpoint(nd->path.dentry) && |
272 | follow_down(&nd->path.mnt, &nd->path.dentry)) | |
6d5ae0de IM |
273 | ; |
274 | err = 0; | |
275 | default: | |
276 | mntput(newmnt); | |
277 | break; | |
278 | } | |
279 | return err; | |
280 | } | |
281 | ||
366781c1 | 282 | static void dump_referral(const struct dfs_info3_param *ref) |
6d5ae0de IM |
283 | { |
284 | cFYI(1, ("DFS: ref path: %s", ref->path_name)); | |
285 | cFYI(1, ("DFS: node path: %s", ref->node_name)); | |
286 | cFYI(1, ("DFS: fl: %hd, srv_type: %hd", ref->flags, ref->server_type)); | |
287 | cFYI(1, ("DFS: ref_flags: %hd, path_consumed: %hd", ref->ref_flag, | |
8aad018b | 288 | ref->path_consumed)); |
6d5ae0de IM |
289 | } |
290 | ||
291 | ||
292 | static void* | |
293 | cifs_dfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd) | |
294 | { | |
295 | struct dfs_info3_param *referrals = NULL; | |
296 | unsigned int num_referrals = 0; | |
297 | struct cifs_sb_info *cifs_sb; | |
298 | struct cifsSesInfo *ses; | |
299 | char *full_path = NULL; | |
300 | int xid, i; | |
301 | int rc = 0; | |
302 | struct vfsmount *mnt = ERR_PTR(-ENOENT); | |
303 | ||
55f78e17 | 304 | cFYI(1, ("in %s", __func__)); |
6d5ae0de IM |
305 | BUG_ON(IS_ROOT(dentry)); |
306 | ||
307 | xid = GetXid(); | |
308 | ||
4ac91378 JB |
309 | dput(nd->path.dentry); |
310 | nd->path.dentry = dget(dentry); | |
6d5ae0de IM |
311 | |
312 | cifs_sb = CIFS_SB(dentry->d_inode->i_sb); | |
313 | ses = cifs_sb->tcon->ses; | |
314 | ||
315 | if (!ses) { | |
316 | rc = -EINVAL; | |
317 | goto out_err; | |
318 | } | |
319 | ||
320 | full_path = build_full_dfs_path_from_dentry(dentry); | |
321 | if (full_path == NULL) { | |
322 | rc = -ENOMEM; | |
323 | goto out_err; | |
324 | } | |
325 | ||
326 | rc = get_dfs_path(xid, ses , full_path, cifs_sb->local_nls, | |
327 | &num_referrals, &referrals, | |
328 | cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR); | |
329 | ||
330 | for (i = 0; i < num_referrals; i++) { | |
331 | dump_referral(referrals+i); | |
332 | /* connect to a storage node */ | |
333 | if (referrals[i].flags & DFSREF_STORAGE_SERVER) { | |
334 | int len; | |
335 | len = strlen(referrals[i].node_name); | |
336 | if (len < 2) { | |
337 | cERROR(1, ("%s: Net Address path too short: %s", | |
55f78e17 | 338 | __func__, referrals[i].node_name)); |
6d5ae0de IM |
339 | rc = -EINVAL; |
340 | goto out_err; | |
341 | } | |
4ac91378 JB |
342 | mnt = cifs_dfs_do_refmount(nd->path.mnt, |
343 | nd->path.dentry, | |
6d5ae0de IM |
344 | referrals[i].node_name); |
345 | cFYI(1, ("%s: cifs_dfs_do_refmount:%s , mnt:%p", | |
55f78e17 | 346 | __func__, |
6d5ae0de IM |
347 | referrals[i].node_name, mnt)); |
348 | ||
349 | /* complete mount procedure if we accured submount */ | |
350 | if (!IS_ERR(mnt)) | |
351 | break; | |
352 | } | |
353 | } | |
354 | ||
355 | /* we need it cause for() above could exit without valid submount */ | |
356 | rc = PTR_ERR(mnt); | |
357 | if (IS_ERR(mnt)) | |
358 | goto out_err; | |
359 | ||
4ac91378 | 360 | nd->path.mnt->mnt_flags |= MNT_SHRINKABLE; |
6d5ae0de IM |
361 | rc = add_mount_helper(mnt, nd, &cifs_dfs_automount_list); |
362 | ||
363 | out: | |
364 | FreeXid(xid); | |
365 | free_dfs_info_array(referrals, num_referrals); | |
366 | kfree(full_path); | |
55f78e17 | 367 | cFYI(1, ("leaving %s" , __func__)); |
6d5ae0de IM |
368 | return ERR_PTR(rc); |
369 | out_err: | |
1d957f9b | 370 | path_put(&nd->path); |
6d5ae0de IM |
371 | goto out; |
372 | } | |
373 | ||
374 | struct inode_operations cifs_dfs_referral_inode_operations = { | |
375 | .follow_link = cifs_dfs_follow_mountpoint, | |
376 | }; | |
377 |