Merge ../linus
[linux-2.6] / fs / nfs / idmap.c
1 /*
2  * fs/nfs/idmap.c
3  *
4  *  UID and GID to name mapping for clients.
5  *
6  *  Copyright (c) 2002 The Regents of the University of Michigan.
7  *  All rights reserved.
8  *
9  *  Marius Aamodt Eriksen <marius@umich.edu>
10  *
11  *  Redistribution and use in source and binary forms, with or without
12  *  modification, are permitted provided that the following conditions
13  *  are met:
14  *
15  *  1. Redistributions of source code must retain the above copyright
16  *     notice, this list of conditions and the following disclaimer.
17  *  2. Redistributions in binary form must reproduce the above copyright
18  *     notice, this list of conditions and the following disclaimer in the
19  *     documentation and/or other materials provided with the distribution.
20  *  3. Neither the name of the University nor the names of its
21  *     contributors may be used to endorse or promote products derived
22  *     from this software without specific prior written permission.
23  *
24  *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
25  *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
26  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
27  *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29  *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30  *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
31  *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
32  *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
33  *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
34  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35  */
36
37 #include <linux/module.h>
38 #include <linux/mutex.h>
39 #include <linux/init.h>
40 #include <linux/types.h>
41 #include <linux/slab.h>
42 #include <linux/socket.h>
43 #include <linux/in.h>
44 #include <linux/sched.h>
45
46 #include <linux/sunrpc/clnt.h>
47 #include <linux/workqueue.h>
48 #include <linux/sunrpc/rpc_pipe_fs.h>
49
50 #include <linux/nfs_fs.h>
51
52 #include <linux/nfs_idmap.h>
53 #include "nfs4_fs.h"
54
55 #define IDMAP_HASH_SZ          128
56
57 /* Default cache timeout is 10 minutes */
58 unsigned int nfs_idmap_cache_timeout = 600 * HZ;
59
60 struct idmap_hashent {
61         unsigned long ih_expires;
62         __u32 ih_id;
63         int ih_namelen;
64         char ih_name[IDMAP_NAMESZ];
65 };
66
67 struct idmap_hashtable {
68         __u8 h_type;
69         struct idmap_hashent h_entries[IDMAP_HASH_SZ];
70 };
71
72 struct idmap {
73         char                  idmap_path[48];
74         struct dentry        *idmap_dentry;
75         wait_queue_head_t     idmap_wq;
76         struct idmap_msg      idmap_im;
77         struct mutex          idmap_lock;    /* Serializes upcalls */
78         struct mutex          idmap_im_lock; /* Protects the hashtable */
79         struct idmap_hashtable idmap_user_hash;
80         struct idmap_hashtable idmap_group_hash;
81 };
82
83 static ssize_t   idmap_pipe_upcall(struct file *, struct rpc_pipe_msg *,
84                      char __user *, size_t);
85 static ssize_t   idmap_pipe_downcall(struct file *, const char __user *,
86                      size_t);
87 static void      idmap_pipe_destroy_msg(struct rpc_pipe_msg *);
88
89 static unsigned int fnvhash32(const void *, size_t);
90
91 static struct rpc_pipe_ops idmap_upcall_ops = {
92         .upcall         = idmap_pipe_upcall,
93         .downcall       = idmap_pipe_downcall,
94         .destroy_msg    = idmap_pipe_destroy_msg,
95 };
96
97 void
98 nfs_idmap_new(struct nfs4_client *clp)
99 {
100         struct idmap *idmap;
101
102         if (clp->cl_idmap != NULL)
103                 return;
104         if ((idmap = kzalloc(sizeof(*idmap), GFP_KERNEL)) == NULL)
105                 return;
106
107         snprintf(idmap->idmap_path, sizeof(idmap->idmap_path),
108             "%s/idmap", clp->cl_rpcclient->cl_pathname);
109
110         idmap->idmap_dentry = rpc_mkpipe(idmap->idmap_path,
111             idmap, &idmap_upcall_ops, 0);
112         if (IS_ERR(idmap->idmap_dentry)) {
113                 kfree(idmap);
114                 return;
115         }
116
117         mutex_init(&idmap->idmap_lock);
118         mutex_init(&idmap->idmap_im_lock);
119         init_waitqueue_head(&idmap->idmap_wq);
120         idmap->idmap_user_hash.h_type = IDMAP_TYPE_USER;
121         idmap->idmap_group_hash.h_type = IDMAP_TYPE_GROUP;
122
123         clp->cl_idmap = idmap;
124 }
125
126 void
127 nfs_idmap_delete(struct nfs4_client *clp)
128 {
129         struct idmap *idmap = clp->cl_idmap;
130
131         if (!idmap)
132                 return;
133         dput(idmap->idmap_dentry);
134         idmap->idmap_dentry = NULL;
135         rpc_unlink(idmap->idmap_path);
136         clp->cl_idmap = NULL;
137         kfree(idmap);
138 }
139
140 /*
141  * Helper routines for manipulating the hashtable
142  */
143 static inline struct idmap_hashent *
144 idmap_name_hash(struct idmap_hashtable* h, const char *name, size_t len)
145 {
146         return &h->h_entries[fnvhash32(name, len) % IDMAP_HASH_SZ];
147 }
148
149 static struct idmap_hashent *
150 idmap_lookup_name(struct idmap_hashtable *h, const char *name, size_t len)
151 {
152         struct idmap_hashent *he = idmap_name_hash(h, name, len);
153
154         if (he->ih_namelen != len || memcmp(he->ih_name, name, len) != 0)
155                 return NULL;
156         if (time_after(jiffies, he->ih_expires))
157                 return NULL;
158         return he;
159 }
160
161 static inline struct idmap_hashent *
162 idmap_id_hash(struct idmap_hashtable* h, __u32 id)
163 {
164         return &h->h_entries[fnvhash32(&id, sizeof(id)) % IDMAP_HASH_SZ];
165 }
166
167 static struct idmap_hashent *
168 idmap_lookup_id(struct idmap_hashtable *h, __u32 id)
169 {
170         struct idmap_hashent *he = idmap_id_hash(h, id);
171         if (he->ih_id != id || he->ih_namelen == 0)
172                 return NULL;
173         if (time_after(jiffies, he->ih_expires))
174                 return NULL;
175         return he;
176 }
177
178 /*
179  * Routines for allocating new entries in the hashtable.
180  * For now, we just have 1 entry per bucket, so it's all
181  * pretty trivial.
182  */
183 static inline struct idmap_hashent *
184 idmap_alloc_name(struct idmap_hashtable *h, char *name, unsigned len)
185 {
186         return idmap_name_hash(h, name, len);
187 }
188
189 static inline struct idmap_hashent *
190 idmap_alloc_id(struct idmap_hashtable *h, __u32 id)
191 {
192         return idmap_id_hash(h, id);
193 }
194
195 static void
196 idmap_update_entry(struct idmap_hashent *he, const char *name,
197                 size_t namelen, __u32 id)
198 {
199         he->ih_id = id;
200         memcpy(he->ih_name, name, namelen);
201         he->ih_name[namelen] = '\0';
202         he->ih_namelen = namelen;
203         he->ih_expires = jiffies + nfs_idmap_cache_timeout;
204 }
205
206 /*
207  * Name -> ID
208  */
209 static int
210 nfs_idmap_id(struct idmap *idmap, struct idmap_hashtable *h,
211                 const char *name, size_t namelen, __u32 *id)
212 {
213         struct rpc_pipe_msg msg;
214         struct idmap_msg *im;
215         struct idmap_hashent *he;
216         DECLARE_WAITQUEUE(wq, current);
217         int ret = -EIO;
218
219         im = &idmap->idmap_im;
220
221         /*
222          * String sanity checks
223          * Note that the userland daemon expects NUL terminated strings
224          */
225         for (;;) {
226                 if (namelen == 0)
227                         return -EINVAL;
228                 if (name[namelen-1] != '\0')
229                         break;
230                 namelen--;
231         }
232         if (namelen >= IDMAP_NAMESZ)
233                 return -EINVAL;
234
235         mutex_lock(&idmap->idmap_lock);
236         mutex_lock(&idmap->idmap_im_lock);
237
238         he = idmap_lookup_name(h, name, namelen);
239         if (he != NULL) {
240                 *id = he->ih_id;
241                 ret = 0;
242                 goto out;
243         }
244
245         memset(im, 0, sizeof(*im));
246         memcpy(im->im_name, name, namelen);
247
248         im->im_type = h->h_type;
249         im->im_conv = IDMAP_CONV_NAMETOID;
250
251         memset(&msg, 0, sizeof(msg));
252         msg.data = im;
253         msg.len = sizeof(*im);
254
255         add_wait_queue(&idmap->idmap_wq, &wq);
256         if (rpc_queue_upcall(idmap->idmap_dentry->d_inode, &msg) < 0) {
257                 remove_wait_queue(&idmap->idmap_wq, &wq);
258                 goto out;
259         }
260
261         set_current_state(TASK_UNINTERRUPTIBLE);
262         mutex_unlock(&idmap->idmap_im_lock);
263         schedule();
264         current->state = TASK_RUNNING;
265         remove_wait_queue(&idmap->idmap_wq, &wq);
266         mutex_lock(&idmap->idmap_im_lock);
267
268         if (im->im_status & IDMAP_STATUS_SUCCESS) {
269                 *id = im->im_id;
270                 ret = 0;
271         }
272
273  out:
274         memset(im, 0, sizeof(*im));
275         mutex_unlock(&idmap->idmap_im_lock);
276         mutex_unlock(&idmap->idmap_lock);
277         return (ret);
278 }
279
280 /*
281  * ID -> Name
282  */
283 static int
284 nfs_idmap_name(struct idmap *idmap, struct idmap_hashtable *h,
285                 __u32 id, char *name)
286 {
287         struct rpc_pipe_msg msg;
288         struct idmap_msg *im;
289         struct idmap_hashent *he;
290         DECLARE_WAITQUEUE(wq, current);
291         int ret = -EIO;
292         unsigned int len;
293
294         im = &idmap->idmap_im;
295
296         mutex_lock(&idmap->idmap_lock);
297         mutex_lock(&idmap->idmap_im_lock);
298
299         he = idmap_lookup_id(h, id);
300         if (he != 0) {
301                 memcpy(name, he->ih_name, he->ih_namelen);
302                 ret = he->ih_namelen;
303                 goto out;
304         }
305
306         memset(im, 0, sizeof(*im));
307         im->im_type = h->h_type;
308         im->im_conv = IDMAP_CONV_IDTONAME;
309         im->im_id = id;
310
311         memset(&msg, 0, sizeof(msg));
312         msg.data = im;
313         msg.len = sizeof(*im);
314
315         add_wait_queue(&idmap->idmap_wq, &wq);
316
317         if (rpc_queue_upcall(idmap->idmap_dentry->d_inode, &msg) < 0) {
318                 remove_wait_queue(&idmap->idmap_wq, &wq);
319                 goto out;
320         }
321
322         set_current_state(TASK_UNINTERRUPTIBLE);
323         mutex_unlock(&idmap->idmap_im_lock);
324         schedule();
325         current->state = TASK_RUNNING;
326         remove_wait_queue(&idmap->idmap_wq, &wq);
327         mutex_lock(&idmap->idmap_im_lock);
328
329         if (im->im_status & IDMAP_STATUS_SUCCESS) {
330                 if ((len = strnlen(im->im_name, IDMAP_NAMESZ)) == 0)
331                         goto out;
332                 memcpy(name, im->im_name, len);
333                 ret = len;
334         }
335
336  out:
337         memset(im, 0, sizeof(*im));
338         mutex_unlock(&idmap->idmap_im_lock);
339         mutex_unlock(&idmap->idmap_lock);
340         return ret;
341 }
342
343 /* RPC pipefs upcall/downcall routines */
344 static ssize_t
345 idmap_pipe_upcall(struct file *filp, struct rpc_pipe_msg *msg,
346     char __user *dst, size_t buflen)
347 {
348         char *data = (char *)msg->data + msg->copied;
349         ssize_t mlen = msg->len - msg->copied;
350         ssize_t left;
351
352         if (mlen > buflen)
353                 mlen = buflen;
354
355         left = copy_to_user(dst, data, mlen);
356         if (left < 0) {
357                 msg->errno = left;
358                 return left;
359         }
360         mlen -= left;
361         msg->copied += mlen;
362         msg->errno = 0;
363         return mlen;
364 }
365
366 static ssize_t
367 idmap_pipe_downcall(struct file *filp, const char __user *src, size_t mlen)
368 {
369         struct rpc_inode *rpci = RPC_I(filp->f_dentry->d_inode);
370         struct idmap *idmap = (struct idmap *)rpci->private;
371         struct idmap_msg im_in, *im = &idmap->idmap_im;
372         struct idmap_hashtable *h;
373         struct idmap_hashent *he = NULL;
374         int namelen_in;
375         int ret;
376
377         if (mlen != sizeof(im_in))
378                 return (-ENOSPC);
379
380         if (copy_from_user(&im_in, src, mlen) != 0)
381                 return (-EFAULT);
382
383         mutex_lock(&idmap->idmap_im_lock);
384
385         ret = mlen;
386         im->im_status = im_in.im_status;
387         /* If we got an error, terminate now, and wake up pending upcalls */
388         if (!(im_in.im_status & IDMAP_STATUS_SUCCESS)) {
389                 wake_up(&idmap->idmap_wq);
390                 goto out;
391         }
392
393         /* Sanity checking of strings */
394         ret = -EINVAL;
395         namelen_in = strnlen(im_in.im_name, IDMAP_NAMESZ);
396         if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ)
397                 goto out;
398
399         switch (im_in.im_type) {
400                 case IDMAP_TYPE_USER:
401                         h = &idmap->idmap_user_hash;
402                         break;
403                 case IDMAP_TYPE_GROUP:
404                         h = &idmap->idmap_group_hash;
405                         break;
406                 default:
407                         goto out;
408         }
409
410         switch (im_in.im_conv) {
411         case IDMAP_CONV_IDTONAME:
412                 /* Did we match the current upcall? */
413                 if (im->im_conv == IDMAP_CONV_IDTONAME
414                                 && im->im_type == im_in.im_type
415                                 && im->im_id == im_in.im_id) {
416                         /* Yes: copy string, including the terminating '\0'  */
417                         memcpy(im->im_name, im_in.im_name, namelen_in);
418                         im->im_name[namelen_in] = '\0';
419                         wake_up(&idmap->idmap_wq);
420                 }
421                 he = idmap_alloc_id(h, im_in.im_id);
422                 break;
423         case IDMAP_CONV_NAMETOID:
424                 /* Did we match the current upcall? */
425                 if (im->im_conv == IDMAP_CONV_NAMETOID
426                                 && im->im_type == im_in.im_type
427                                 && strnlen(im->im_name, IDMAP_NAMESZ) == namelen_in
428                                 && memcmp(im->im_name, im_in.im_name, namelen_in) == 0) {
429                         im->im_id = im_in.im_id;
430                         wake_up(&idmap->idmap_wq);
431                 }
432                 he = idmap_alloc_name(h, im_in.im_name, namelen_in);
433                 break;
434         default:
435                 goto out;
436         }
437
438         /* If the entry is valid, also copy it to the cache */
439         if (he != NULL)
440                 idmap_update_entry(he, im_in.im_name, namelen_in, im_in.im_id);
441         ret = mlen;
442 out:
443         mutex_unlock(&idmap->idmap_im_lock);
444         return ret;
445 }
446
447 static void
448 idmap_pipe_destroy_msg(struct rpc_pipe_msg *msg)
449 {
450         struct idmap_msg *im = msg->data;
451         struct idmap *idmap = container_of(im, struct idmap, idmap_im); 
452
453         if (msg->errno >= 0)
454                 return;
455         mutex_lock(&idmap->idmap_im_lock);
456         im->im_status = IDMAP_STATUS_LOOKUPFAIL;
457         wake_up(&idmap->idmap_wq);
458         mutex_unlock(&idmap->idmap_im_lock);
459 }
460
461 /* 
462  * Fowler/Noll/Vo hash
463  *    http://www.isthe.com/chongo/tech/comp/fnv/
464  */
465
466 #define FNV_P_32 ((unsigned int)0x01000193) /* 16777619 */
467 #define FNV_1_32 ((unsigned int)0x811c9dc5) /* 2166136261 */
468
469 static unsigned int fnvhash32(const void *buf, size_t buflen)
470 {
471         const unsigned char *p, *end = (const unsigned char *)buf + buflen;
472         unsigned int hash = FNV_1_32;
473
474         for (p = buf; p < end; p++) {
475                 hash *= FNV_P_32;
476                 hash ^= (unsigned int)*p;
477         }
478
479         return (hash);
480 }
481
482 int nfs_map_name_to_uid(struct nfs4_client *clp, const char *name, size_t namelen, __u32 *uid)
483 {
484         struct idmap *idmap = clp->cl_idmap;
485
486         return nfs_idmap_id(idmap, &idmap->idmap_user_hash, name, namelen, uid);
487 }
488
489 int nfs_map_group_to_gid(struct nfs4_client *clp, const char *name, size_t namelen, __u32 *uid)
490 {
491         struct idmap *idmap = clp->cl_idmap;
492
493         return nfs_idmap_id(idmap, &idmap->idmap_group_hash, name, namelen, uid);
494 }
495
496 int nfs_map_uid_to_name(struct nfs4_client *clp, __u32 uid, char *buf)
497 {
498         struct idmap *idmap = clp->cl_idmap;
499
500         return nfs_idmap_name(idmap, &idmap->idmap_user_hash, uid, buf);
501 }
502 int nfs_map_gid_to_group(struct nfs4_client *clp, __u32 uid, char *buf)
503 {
504         struct idmap *idmap = clp->cl_idmap;
505
506         return nfs_idmap_name(idmap, &idmap->idmap_group_hash, uid, buf);
507 }
508