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