[PATCH] VFS: Permit filesystem to override root dentry on mount
[linux-2.6.git] / fs / nfsd / nfsctl.c
1 /*
2  * linux/fs/nfsd/nfsctl.c
3  *
4  * Syscall interface to knfsd.
5  *
6  * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
7  */
8
9 #include <linux/config.h>
10 #include <linux/module.h>
11
12 #include <linux/linkage.h>
13 #include <linux/time.h>
14 #include <linux/errno.h>
15 #include <linux/fs.h>
16 #include <linux/fcntl.h>
17 #include <linux/net.h>
18 #include <linux/in.h>
19 #include <linux/syscalls.h>
20 #include <linux/unistd.h>
21 #include <linux/slab.h>
22 #include <linux/proc_fs.h>
23 #include <linux/seq_file.h>
24 #include <linux/pagemap.h>
25 #include <linux/init.h>
26 #include <linux/string.h>
27
28 #include <linux/nfs.h>
29 #include <linux/nfsd_idmap.h>
30 #include <linux/sunrpc/svc.h>
31 #include <linux/nfsd/nfsd.h>
32 #include <linux/nfsd/cache.h>
33 #include <linux/nfsd/xdr.h>
34 #include <linux/nfsd/syscall.h>
35 #include <linux/nfsd/interface.h>
36
37 #include <asm/uaccess.h>
38
39 unsigned int nfsd_versbits = ~0;
40
41 /*
42  *      We have a single directory with 9 nodes in it.
43  */
44 enum {
45         NFSD_Root = 1,
46         NFSD_Svc,
47         NFSD_Add,
48         NFSD_Del,
49         NFSD_Export,
50         NFSD_Unexport,
51         NFSD_Getfd,
52         NFSD_Getfs,
53         NFSD_List,
54         NFSD_Fh,
55         NFSD_Threads,
56         NFSD_Versions,
57         /*
58          * The below MUST come last.  Otherwise we leave a hole in nfsd_files[]
59          * with !CONFIG_NFSD_V4 and simple_fill_super() goes oops
60          */
61 #ifdef CONFIG_NFSD_V4
62         NFSD_Leasetime,
63         NFSD_RecoveryDir,
64 #endif
65 };
66
67 /*
68  * write() for these nodes.
69  */
70 static ssize_t write_svc(struct file *file, char *buf, size_t size);
71 static ssize_t write_add(struct file *file, char *buf, size_t size);
72 static ssize_t write_del(struct file *file, char *buf, size_t size);
73 static ssize_t write_export(struct file *file, char *buf, size_t size);
74 static ssize_t write_unexport(struct file *file, char *buf, size_t size);
75 static ssize_t write_getfd(struct file *file, char *buf, size_t size);
76 static ssize_t write_getfs(struct file *file, char *buf, size_t size);
77 static ssize_t write_filehandle(struct file *file, char *buf, size_t size);
78 static ssize_t write_threads(struct file *file, char *buf, size_t size);
79 static ssize_t write_versions(struct file *file, char *buf, size_t size);
80 #ifdef CONFIG_NFSD_V4
81 static ssize_t write_leasetime(struct file *file, char *buf, size_t size);
82 static ssize_t write_recoverydir(struct file *file, char *buf, size_t size);
83 #endif
84
85 static ssize_t (*write_op[])(struct file *, char *, size_t) = {
86         [NFSD_Svc] = write_svc,
87         [NFSD_Add] = write_add,
88         [NFSD_Del] = write_del,
89         [NFSD_Export] = write_export,
90         [NFSD_Unexport] = write_unexport,
91         [NFSD_Getfd] = write_getfd,
92         [NFSD_Getfs] = write_getfs,
93         [NFSD_Fh] = write_filehandle,
94         [NFSD_Threads] = write_threads,
95         [NFSD_Versions] = write_versions,
96 #ifdef CONFIG_NFSD_V4
97         [NFSD_Leasetime] = write_leasetime,
98         [NFSD_RecoveryDir] = write_recoverydir,
99 #endif
100 };
101
102 static ssize_t nfsctl_transaction_write(struct file *file, const char __user *buf, size_t size, loff_t *pos)
103 {
104         ino_t ino =  file->f_dentry->d_inode->i_ino;
105         char *data;
106         ssize_t rv;
107
108         if (ino >= ARRAY_SIZE(write_op) || !write_op[ino])
109                 return -EINVAL;
110
111         data = simple_transaction_get(file, buf, size);
112         if (IS_ERR(data))
113                 return PTR_ERR(data);
114
115         rv =  write_op[ino](file, data, size);
116         if (rv>0) {
117                 simple_transaction_set(file, rv);
118                 rv = size;
119         }
120         return rv;
121 }
122
123 static ssize_t nfsctl_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos)
124 {
125         if (! file->private_data) {
126                 /* An attempt to read a transaction file without writing
127                  * causes a 0-byte write so that the file can return
128                  * state information
129                  */
130                 ssize_t rv = nfsctl_transaction_write(file, buf, 0, pos);
131                 if (rv < 0)
132                         return rv;
133         }
134         return simple_transaction_read(file, buf, size, pos);
135 }
136
137 static const struct file_operations transaction_ops = {
138         .write          = nfsctl_transaction_write,
139         .read           = nfsctl_transaction_read,
140         .release        = simple_transaction_release,
141 };
142
143 extern struct seq_operations nfs_exports_op;
144 static int exports_open(struct inode *inode, struct file *file)
145 {
146         return seq_open(file, &nfs_exports_op);
147 }
148
149 static const struct file_operations exports_operations = {
150         .open           = exports_open,
151         .read           = seq_read,
152         .llseek         = seq_lseek,
153         .release        = seq_release,
154 };
155
156 /*----------------------------------------------------------------------------*/
157 /*
158  * payload - write methods
159  * If the method has a response, the response should be put in buf,
160  * and the length returned.  Otherwise return 0 or and -error.
161  */
162
163 static ssize_t write_svc(struct file *file, char *buf, size_t size)
164 {
165         struct nfsctl_svc *data;
166         if (size < sizeof(*data))
167                 return -EINVAL;
168         data = (struct nfsctl_svc*) buf;
169         return nfsd_svc(data->svc_port, data->svc_nthreads);
170 }
171
172 static ssize_t write_add(struct file *file, char *buf, size_t size)
173 {
174         struct nfsctl_client *data;
175         if (size < sizeof(*data))
176                 return -EINVAL;
177         data = (struct nfsctl_client *)buf;
178         return exp_addclient(data);
179 }
180
181 static ssize_t write_del(struct file *file, char *buf, size_t size)
182 {
183         struct nfsctl_client *data;
184         if (size < sizeof(*data))
185                 return -EINVAL;
186         data = (struct nfsctl_client *)buf;
187         return exp_delclient(data);
188 }
189
190 static ssize_t write_export(struct file *file, char *buf, size_t size)
191 {
192         struct nfsctl_export *data;
193         if (size < sizeof(*data))
194                 return -EINVAL;
195         data = (struct nfsctl_export*)buf;
196         return exp_export(data);
197 }
198
199 static ssize_t write_unexport(struct file *file, char *buf, size_t size)
200 {
201         struct nfsctl_export *data;
202
203         if (size < sizeof(*data))
204                 return -EINVAL;
205         data = (struct nfsctl_export*)buf;
206         return exp_unexport(data);
207 }
208
209 static ssize_t write_getfs(struct file *file, char *buf, size_t size)
210 {
211         struct nfsctl_fsparm *data;
212         struct sockaddr_in *sin;
213         struct auth_domain *clp;
214         int err = 0;
215         struct knfsd_fh *res;
216
217         if (size < sizeof(*data))
218                 return -EINVAL;
219         data = (struct nfsctl_fsparm*)buf;
220         err = -EPROTONOSUPPORT;
221         if (data->gd_addr.sa_family != AF_INET)
222                 goto out;
223         sin = (struct sockaddr_in *)&data->gd_addr;
224         if (data->gd_maxlen > NFS3_FHSIZE)
225                 data->gd_maxlen = NFS3_FHSIZE;
226
227         res = (struct knfsd_fh*)buf;
228
229         exp_readlock();
230         if (!(clp = auth_unix_lookup(sin->sin_addr)))
231                 err = -EPERM;
232         else {
233                 err = exp_rootfh(clp, data->gd_path, res, data->gd_maxlen);
234                 auth_domain_put(clp);
235         }
236         exp_readunlock();
237         if (err == 0)
238                 err = res->fh_size + (int)&((struct knfsd_fh*)0)->fh_base;
239  out:
240         return err;
241 }
242
243 static ssize_t write_getfd(struct file *file, char *buf, size_t size)
244 {
245         struct nfsctl_fdparm *data;
246         struct sockaddr_in *sin;
247         struct auth_domain *clp;
248         int err = 0;
249         struct knfsd_fh fh;
250         char *res;
251
252         if (size < sizeof(*data))
253                 return -EINVAL;
254         data = (struct nfsctl_fdparm*)buf;
255         err = -EPROTONOSUPPORT;
256         if (data->gd_addr.sa_family != AF_INET)
257                 goto out;
258         err = -EINVAL;
259         if (data->gd_version < 2 || data->gd_version > NFSSVC_MAXVERS)
260                 goto out;
261
262         res = buf;
263         sin = (struct sockaddr_in *)&data->gd_addr;
264         exp_readlock();
265         if (!(clp = auth_unix_lookup(sin->sin_addr)))
266                 err = -EPERM;
267         else {
268                 err = exp_rootfh(clp, data->gd_path, &fh, NFS_FHSIZE);
269                 auth_domain_put(clp);
270         }
271         exp_readunlock();
272
273         if (err == 0) {
274                 memset(res,0, NFS_FHSIZE);
275                 memcpy(res, &fh.fh_base, fh.fh_size);
276                 err = NFS_FHSIZE;
277         }
278  out:
279         return err;
280 }
281
282 static ssize_t write_filehandle(struct file *file, char *buf, size_t size)
283 {
284         /* request is:
285          *   domain path maxsize
286          * response is
287          *   filehandle
288          *
289          * qword quoting is used, so filehandle will be \x....
290          */
291         char *dname, *path;
292         int maxsize;
293         char *mesg = buf;
294         int len;
295         struct auth_domain *dom;
296         struct knfsd_fh fh;
297
298         if (buf[size-1] != '\n')
299                 return -EINVAL;
300         buf[size-1] = 0;
301
302         dname = mesg;
303         len = qword_get(&mesg, dname, size);
304         if (len <= 0) return -EINVAL;
305         
306         path = dname+len+1;
307         len = qword_get(&mesg, path, size);
308         if (len <= 0) return -EINVAL;
309
310         len = get_int(&mesg, &maxsize);
311         if (len)
312                 return len;
313
314         if (maxsize < NFS_FHSIZE)
315                 return -EINVAL;
316         if (maxsize > NFS3_FHSIZE)
317                 maxsize = NFS3_FHSIZE;
318
319         if (qword_get(&mesg, mesg, size)>0)
320                 return -EINVAL;
321
322         /* we have all the words, they are in buf.. */
323         dom = unix_domain_find(dname);
324         if (!dom)
325                 return -ENOMEM;
326
327         len = exp_rootfh(dom, path, &fh,  maxsize);
328         auth_domain_put(dom);
329         if (len)
330                 return len;
331         
332         mesg = buf; len = SIMPLE_TRANSACTION_LIMIT;
333         qword_addhex(&mesg, &len, (char*)&fh.fh_base, fh.fh_size);
334         mesg[-1] = '\n';
335         return mesg - buf;      
336 }
337
338 extern int nfsd_nrthreads(void);
339
340 static ssize_t write_threads(struct file *file, char *buf, size_t size)
341 {
342         /* if size > 0, look for a number of threads and call nfsd_svc
343          * then write out number of threads as reply
344          */
345         char *mesg = buf;
346         int rv;
347         if (size > 0) {
348                 int newthreads;
349                 rv = get_int(&mesg, &newthreads);
350                 if (rv)
351                         return rv;
352                 if (newthreads <0)
353                         return -EINVAL;
354                 rv = nfsd_svc(2049, newthreads);
355                 if (rv)
356                         return rv;
357         }
358         sprintf(buf, "%d\n", nfsd_nrthreads());
359         return strlen(buf);
360 }
361
362 static ssize_t write_versions(struct file *file, char *buf, size_t size)
363 {
364         /*
365          * Format:
366          *   [-/+]vers [-/+]vers ...
367          */
368         char *mesg = buf;
369         char *vers, sign;
370         int len, num;
371         ssize_t tlen = 0;
372         char *sep;
373
374         if (size>0) {
375                 if (nfsd_serv)
376                         return -EBUSY;
377                 if (buf[size-1] != '\n')
378                         return -EINVAL;
379                 buf[size-1] = 0;
380
381                 vers = mesg;
382                 len = qword_get(&mesg, vers, size);
383                 if (len <= 0) return -EINVAL;
384                 do {
385                         sign = *vers;
386                         if (sign == '+' || sign == '-')
387                                 num = simple_strtol((vers+1), NULL, 0);
388                         else
389                                 num = simple_strtol(vers, NULL, 0);
390                         switch(num) {
391                         case 2:
392                         case 3:
393                         case 4:
394                                 if (sign != '-')
395                                         NFSCTL_VERSET(nfsd_versbits, num);
396                                 else
397                                         NFSCTL_VERUNSET(nfsd_versbits, num);
398                                 break;
399                         default:
400                                 return -EINVAL;
401                         }
402                         vers += len + 1;
403                         tlen += len;
404                 } while ((len = qword_get(&mesg, vers, size)) > 0);
405                 /* If all get turned off, turn them back on, as
406                  * having no versions is BAD
407                  */
408                 if ((nfsd_versbits & NFSCTL_VERALL)==0)
409                         nfsd_versbits = NFSCTL_VERALL;
410         }
411         /* Now write current state into reply buffer */
412         len = 0;
413         sep = "";
414         for (num=2 ; num <= 4 ; num++)
415                 if (NFSCTL_VERISSET(NFSCTL_VERALL, num)) {
416                         len += sprintf(buf+len, "%s%c%d", sep,
417                                        NFSCTL_VERISSET(nfsd_versbits, num)?'+':'-',
418                                        num);
419                         sep = " ";
420                 }
421         len += sprintf(buf+len, "\n");
422         return len;
423 }
424
425 #ifdef CONFIG_NFSD_V4
426 extern time_t nfs4_leasetime(void);
427
428 static ssize_t write_leasetime(struct file *file, char *buf, size_t size)
429 {
430         /* if size > 10 seconds, call
431          * nfs4_reset_lease() then write out the new lease (seconds) as reply
432          */
433         char *mesg = buf;
434         int rv;
435
436         if (size > 0) {
437                 int lease;
438                 rv = get_int(&mesg, &lease);
439                 if (rv)
440                         return rv;
441                 if (lease < 10 || lease > 3600)
442                         return -EINVAL;
443                 nfs4_reset_lease(lease);
444         }
445         sprintf(buf, "%ld\n", nfs4_lease_time());
446         return strlen(buf);
447 }
448
449 static ssize_t write_recoverydir(struct file *file, char *buf, size_t size)
450 {
451         char *mesg = buf;
452         char *recdir;
453         int len, status;
454
455         if (size > PATH_MAX || buf[size-1] != '\n')
456                 return -EINVAL;
457         buf[size-1] = 0;
458
459         recdir = mesg;
460         len = qword_get(&mesg, recdir, size);
461         if (len <= 0)
462                 return -EINVAL;
463
464         status = nfs4_reset_recoverydir(recdir);
465         return strlen(buf);
466 }
467 #endif
468
469 /*----------------------------------------------------------------------------*/
470 /*
471  *      populating the filesystem.
472  */
473
474 static int nfsd_fill_super(struct super_block * sb, void * data, int silent)
475 {
476         static struct tree_descr nfsd_files[] = {
477                 [NFSD_Svc] = {".svc", &transaction_ops, S_IWUSR},
478                 [NFSD_Add] = {".add", &transaction_ops, S_IWUSR},
479                 [NFSD_Del] = {".del", &transaction_ops, S_IWUSR},
480                 [NFSD_Export] = {".export", &transaction_ops, S_IWUSR},
481                 [NFSD_Unexport] = {".unexport", &transaction_ops, S_IWUSR},
482                 [NFSD_Getfd] = {".getfd", &transaction_ops, S_IWUSR|S_IRUSR},
483                 [NFSD_Getfs] = {".getfs", &transaction_ops, S_IWUSR|S_IRUSR},
484                 [NFSD_List] = {"exports", &exports_operations, S_IRUGO},
485                 [NFSD_Fh] = {"filehandle", &transaction_ops, S_IWUSR|S_IRUSR},
486                 [NFSD_Threads] = {"threads", &transaction_ops, S_IWUSR|S_IRUSR},
487                 [NFSD_Versions] = {"versions", &transaction_ops, S_IWUSR|S_IRUSR},
488 #ifdef CONFIG_NFSD_V4
489                 [NFSD_Leasetime] = {"nfsv4leasetime", &transaction_ops, S_IWUSR|S_IRUSR},
490                 [NFSD_RecoveryDir] = {"nfsv4recoverydir", &transaction_ops, S_IWUSR|S_IRUSR},
491 #endif
492                 /* last one */ {""}
493         };
494         return simple_fill_super(sb, 0x6e667364, nfsd_files);
495 }
496
497 static int nfsd_get_sb(struct file_system_type *fs_type,
498         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
499 {
500         return get_sb_single(fs_type, flags, data, nfsd_fill_super, mnt);
501 }
502
503 static struct file_system_type nfsd_fs_type = {
504         .owner          = THIS_MODULE,
505         .name           = "nfsd",
506         .get_sb         = nfsd_get_sb,
507         .kill_sb        = kill_litter_super,
508 };
509
510 static int __init init_nfsd(void)
511 {
512         int retval;
513         printk(KERN_INFO "Installing knfsd (copyright (C) 1996 okir@monad.swb.de).\n");
514
515         nfsd_stat_init();       /* Statistics */
516         nfsd_cache_init();      /* RPC reply cache */
517         nfsd_export_init();     /* Exports table */
518         nfsd_lockd_init();      /* lockd->nfsd callbacks */
519         nfs4_state_init();      /* NFSv4 locking state */
520         nfsd_idmap_init();      /* Name to ID mapping */
521         if (proc_mkdir("fs/nfs", NULL)) {
522                 struct proc_dir_entry *entry;
523                 entry = create_proc_entry("fs/nfs/exports", 0, NULL);
524                 if (entry)
525                         entry->proc_fops =  &exports_operations;
526         }
527         retval = register_filesystem(&nfsd_fs_type);
528         if (retval) {
529                 nfsd_export_shutdown();
530                 nfsd_cache_shutdown();
531                 remove_proc_entry("fs/nfs/exports", NULL);
532                 remove_proc_entry("fs/nfs", NULL);
533                 nfsd_stat_shutdown();
534                 nfsd_lockd_shutdown();
535         }
536         return retval;
537 }
538
539 static void __exit exit_nfsd(void)
540 {
541         nfsd_export_shutdown();
542         nfsd_cache_shutdown();
543         remove_proc_entry("fs/nfs/exports", NULL);
544         remove_proc_entry("fs/nfs", NULL);
545         nfsd_stat_shutdown();
546         nfsd_lockd_shutdown();
547         nfsd_idmap_shutdown();
548         unregister_filesystem(&nfsd_fs_type);
549 }
550
551 MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>");
552 MODULE_LICENSE("GPL");
553 module_init(init_nfsd)
554 module_exit(exit_nfsd)