[CIFS] cifs: replace remaining __FUNCTION__ occurrences
[sfrench/cifs-2.6.git] / fs / cifs / cifs_dfs_ref.c
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
6  *   Copyright (C) International Business Machines  Corp., 2008
7  *   Author(s): Igor Mammedov (niallain@gmail.com)
8  *              Steve French (sfrench@us.ibm.com)
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                         __func__, 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                         __func__, 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  */
111 static char *compose_mount_options(const char *sb_mountdata,
112                                    const char *ref_unc,
113                                    char **devname)
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                           __func__, *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", __func__,sb_mountdata));*/
185         /*cFYI(1, ("%s: submount mountdata: %s", __func__, mountdata ));*/
186
187 compose_mount_options_out:
188         kfree(srvIP);
189         return mountdata;
190 }
191
192
193 static struct vfsmount *cifs_dfs_do_refmount(const struct vfsmount *mnt_parent,
194                 struct dentry *dentry, char *ref_unc)
195 {
196         struct cifs_sb_info *cifs_sb;
197         struct vfsmount *mnt;
198         char *mountdata;
199         char *devname = NULL;
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->path.mnt->mnt_flags, mntlist);
263         switch (err) {
264         case 0:
265                 dput(nd->path.dentry);
266                 mntput(nd->path.mnt);
267                 nd->path.mnt = newmnt;
268                 nd->path.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->path.dentry) &&
273                        follow_down(&nd->path.mnt, &nd->path.dentry))
274                         ;
275                 err = 0;
276         default:
277                 mntput(newmnt);
278                 break;
279         }
280         return err;
281 }
282
283 static void dump_referral(const struct dfs_info3_param *ref)
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->path_consumed));
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", __func__));
306         BUG_ON(IS_ROOT(dentry));
307
308         xid = GetXid();
309
310         dput(nd->path.dentry);
311         nd->path.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                                         __func__, referrals[i].node_name));
340                                 rc = -EINVAL;
341                                 goto out_err;
342                         }
343                         mnt = cifs_dfs_do_refmount(nd->path.mnt,
344                                                 nd->path.dentry,
345                                                 referrals[i].node_name);
346                         cFYI(1, ("%s: cifs_dfs_do_refmount:%s , mnt:%p",
347                                          __func__,
348                                         referrals[i].node_name, mnt));
349
350                         /* complete mount procedure if we accured submount */
351                         if (!IS_ERR(mnt))
352                                 break;
353                 }
354         }
355
356         /* we need it cause for() above could exit without valid submount */
357         rc = PTR_ERR(mnt);
358         if (IS_ERR(mnt))
359                 goto out_err;
360
361         nd->path.mnt->mnt_flags |= MNT_SHRINKABLE;
362         rc = add_mount_helper(mnt, nd, &cifs_dfs_automount_list);
363
364 out:
365         FreeXid(xid);
366         free_dfs_info_array(referrals, num_referrals);
367         kfree(full_path);
368         cFYI(1, ("leaving %s" , __func__));
369         return ERR_PTR(rc);
370 out_err:
371         path_put(&nd->path);
372         goto out;
373 }
374
375 struct inode_operations cifs_dfs_referral_inode_operations = {
376         .follow_link = cifs_dfs_follow_mountpoint,
377 };
378