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1 /* -*- c -*- --------------------------------------------------------------- *
2  *
3  * linux/fs/autofs/inode.c
4  *
5  *  Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
6  *  Copyright 2005-2006 Ian Kent <raven@themaw.net>
7  *
8  * This file is part of the Linux kernel and is made available under
9  * the terms of the GNU General Public License, version 2, or at your
10  * option, any later version, incorporated herein by reference.
11  *
12  * ------------------------------------------------------------------------- */
13
14 #include <linux/kernel.h>
15 #include <linux/slab.h>
16 #include <linux/file.h>
17 #include <linux/seq_file.h>
18 #include <linux/pagemap.h>
19 #include <linux/parser.h>
20 #include <linux/bitops.h>
21 #include <linux/magic.h>
22 #include "autofs_i.h"
23 #include <linux/module.h>
24
25 struct autofs_info *autofs4_new_ino(struct autofs_sb_info *sbi)
26 {
27         struct autofs_info *ino = kzalloc(sizeof(*ino), GFP_KERNEL);
28         if (ino) {
29                 INIT_LIST_HEAD(&ino->active);
30                 INIT_LIST_HEAD(&ino->expiring);
31                 ino->last_used = jiffies;
32                 ino->sbi = sbi;
33         }
34         return ino;
35 }
36
37 void autofs4_clean_ino(struct autofs_info *ino)
38 {
39         ino->uid = 0;
40         ino->gid = 0;
41         ino->last_used = jiffies;
42 }
43
44 void autofs4_free_ino(struct autofs_info *ino)
45 {
46         kfree(ino);
47 }
48
49 void autofs4_kill_sb(struct super_block *sb)
50 {
51         struct autofs_sb_info *sbi = autofs4_sbi(sb);
52
53         /*
54          * In the event of a failure in get_sb_nodev the superblock
55          * info is not present so nothing else has been setup, so
56          * just call kill_anon_super when we are called from
57          * deactivate_super.
58          */
59         if (!sbi)
60                 goto out_kill_sb;
61
62         /* Free wait queues, close pipe */
63         autofs4_catatonic_mode(sbi);
64
65         sb->s_fs_info = NULL;
66         kfree(sbi);
67
68 out_kill_sb:
69         DPRINTK("shutting down");
70         kill_litter_super(sb);
71 }
72
73 static int autofs4_show_options(struct seq_file *m, struct dentry *root)
74 {
75         struct autofs_sb_info *sbi = autofs4_sbi(root->d_sb);
76         struct inode *root_inode = root->d_sb->s_root->d_inode;
77
78         if (!sbi)
79                 return 0;
80
81         seq_printf(m, ",fd=%d", sbi->pipefd);
82         if (root_inode->i_uid != 0)
83                 seq_printf(m, ",uid=%u", root_inode->i_uid);
84         if (root_inode->i_gid != 0)
85                 seq_printf(m, ",gid=%u", root_inode->i_gid);
86         seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
87         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
88         seq_printf(m, ",minproto=%d", sbi->min_proto);
89         seq_printf(m, ",maxproto=%d", sbi->max_proto);
90
91         if (autofs_type_offset(sbi->type))
92                 seq_printf(m, ",offset");
93         else if (autofs_type_direct(sbi->type))
94                 seq_printf(m, ",direct");
95         else
96                 seq_printf(m, ",indirect");
97
98         return 0;
99 }
100
101 static void autofs4_evict_inode(struct inode *inode)
102 {
103         end_writeback(inode);
104         kfree(inode->i_private);
105 }
106
107 static const struct super_operations autofs4_sops = {
108         .statfs         = simple_statfs,
109         .show_options   = autofs4_show_options,
110         .evict_inode    = autofs4_evict_inode,
111 };
112
113 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
114         Opt_indirect, Opt_direct, Opt_offset};
115
116 static const match_table_t tokens = {
117         {Opt_fd, "fd=%u"},
118         {Opt_uid, "uid=%u"},
119         {Opt_gid, "gid=%u"},
120         {Opt_pgrp, "pgrp=%u"},
121         {Opt_minproto, "minproto=%u"},
122         {Opt_maxproto, "maxproto=%u"},
123         {Opt_indirect, "indirect"},
124         {Opt_direct, "direct"},
125         {Opt_offset, "offset"},
126         {Opt_err, NULL}
127 };
128
129 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
130                 pid_t *pgrp, unsigned int *type, int *minproto, int *maxproto)
131 {
132         char *p;
133         substring_t args[MAX_OPT_ARGS];
134         int option;
135
136         *uid = current_uid();
137         *gid = current_gid();
138         *pgrp = task_pgrp_nr(current);
139
140         *minproto = AUTOFS_MIN_PROTO_VERSION;
141         *maxproto = AUTOFS_MAX_PROTO_VERSION;
142
143         *pipefd = -1;
144
145         if (!options)
146                 return 1;
147
148         while ((p = strsep(&options, ",")) != NULL) {
149                 int token;
150                 if (!*p)
151                         continue;
152
153                 token = match_token(p, tokens, args);
154                 switch (token) {
155                 case Opt_fd:
156                         if (match_int(args, pipefd))
157                                 return 1;
158                         break;
159                 case Opt_uid:
160                         if (match_int(args, &option))
161                                 return 1;
162                         *uid = option;
163                         break;
164                 case Opt_gid:
165                         if (match_int(args, &option))
166                                 return 1;
167                         *gid = option;
168                         break;
169                 case Opt_pgrp:
170                         if (match_int(args, &option))
171                                 return 1;
172                         *pgrp = option;
173                         break;
174                 case Opt_minproto:
175                         if (match_int(args, &option))
176                                 return 1;
177                         *minproto = option;
178                         break;
179                 case Opt_maxproto:
180                         if (match_int(args, &option))
181                                 return 1;
182                         *maxproto = option;
183                         break;
184                 case Opt_indirect:
185                         set_autofs_type_indirect(type);
186                         break;
187                 case Opt_direct:
188                         set_autofs_type_direct(type);
189                         break;
190                 case Opt_offset:
191                         set_autofs_type_offset(type);
192                         break;
193                 default:
194                         return 1;
195                 }
196         }
197         return (*pipefd < 0);
198 }
199
200 int autofs4_fill_super(struct super_block *s, void *data, int silent)
201 {
202         struct inode * root_inode;
203         struct dentry * root;
204         struct file * pipe;
205         int pipefd;
206         struct autofs_sb_info *sbi;
207         struct autofs_info *ino;
208
209         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
210         if (!sbi)
211                 goto fail_unlock;
212         DPRINTK("starting up, sbi = %p",sbi);
213
214         s->s_fs_info = sbi;
215         sbi->magic = AUTOFS_SBI_MAGIC;
216         sbi->pipefd = -1;
217         sbi->pipe = NULL;
218         sbi->catatonic = 1;
219         sbi->exp_timeout = 0;
220         sbi->oz_pgrp = task_pgrp_nr(current);
221         sbi->sb = s;
222         sbi->version = 0;
223         sbi->sub_version = 0;
224         set_autofs_type_indirect(&sbi->type);
225         sbi->min_proto = 0;
226         sbi->max_proto = 0;
227         mutex_init(&sbi->wq_mutex);
228         mutex_init(&sbi->pipe_mutex);
229         spin_lock_init(&sbi->fs_lock);
230         sbi->queues = NULL;
231         spin_lock_init(&sbi->lookup_lock);
232         INIT_LIST_HEAD(&sbi->active_list);
233         INIT_LIST_HEAD(&sbi->expiring_list);
234         s->s_blocksize = 1024;
235         s->s_blocksize_bits = 10;
236         s->s_magic = AUTOFS_SUPER_MAGIC;
237         s->s_op = &autofs4_sops;
238         s->s_d_op = &autofs4_dentry_operations;
239         s->s_time_gran = 1;
240
241         /*
242          * Get the root inode and dentry, but defer checking for errors.
243          */
244         ino = autofs4_new_ino(sbi);
245         if (!ino)
246                 goto fail_free;
247         root_inode = autofs4_get_inode(s, S_IFDIR | 0755);
248         if (!root_inode)
249                 goto fail_ino;
250
251         root = d_alloc_root(root_inode);
252         if (!root)
253                 goto fail_iput;
254         pipe = NULL;
255
256         root->d_fsdata = ino;
257
258         /* Can this call block? */
259         if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
260                                 &sbi->oz_pgrp, &sbi->type, &sbi->min_proto,
261                                 &sbi->max_proto)) {
262                 printk("autofs: called with bogus options\n");
263                 goto fail_dput;
264         }
265
266         if (autofs_type_trigger(sbi->type))
267                 __managed_dentry_set_managed(root);
268
269         root_inode->i_fop = &autofs4_root_operations;
270         root_inode->i_op = &autofs4_dir_inode_operations;
271
272         /* Couldn't this be tested earlier? */
273         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
274             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
275                 printk("autofs: kernel does not match daemon version "
276                        "daemon (%d, %d) kernel (%d, %d)\n",
277                         sbi->min_proto, sbi->max_proto,
278                         AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
279                 goto fail_dput;
280         }
281
282         /* Establish highest kernel protocol version */
283         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
284                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
285         else
286                 sbi->version = sbi->max_proto;
287         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
288
289         DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
290         pipe = fget(pipefd);
291         
292         if (!pipe) {
293                 printk("autofs: could not open pipe file descriptor\n");
294                 goto fail_dput;
295         }
296         if (!pipe->f_op || !pipe->f_op->write)
297                 goto fail_fput;
298         sbi->pipe = pipe;
299         sbi->pipefd = pipefd;
300         sbi->catatonic = 0;
301
302         /*
303          * Success! Install the root dentry now to indicate completion.
304          */
305         s->s_root = root;
306         return 0;
307         
308         /*
309          * Failure ... clean up.
310          */
311 fail_fput:
312         printk("autofs: pipe file descriptor does not contain proper ops\n");
313         fput(pipe);
314         /* fall through */
315 fail_dput:
316         dput(root);
317         goto fail_free;
318 fail_iput:
319         printk("autofs: get root dentry failed\n");
320         iput(root_inode);
321 fail_ino:
322         kfree(ino);
323 fail_free:
324         kfree(sbi);
325         s->s_fs_info = NULL;
326 fail_unlock:
327         return -EINVAL;
328 }
329
330 struct inode *autofs4_get_inode(struct super_block *sb, umode_t mode)
331 {
332         struct inode *inode = new_inode(sb);
333
334         if (inode == NULL)
335                 return NULL;
336
337         inode->i_mode = mode;
338         if (sb->s_root) {
339                 inode->i_uid = sb->s_root->d_inode->i_uid;
340                 inode->i_gid = sb->s_root->d_inode->i_gid;
341         }
342         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
343         inode->i_ino = get_next_ino();
344
345         if (S_ISDIR(mode)) {
346                 set_nlink(inode, 2);
347                 inode->i_op = &autofs4_dir_inode_operations;
348                 inode->i_fop = &autofs4_dir_operations;
349         } else if (S_ISLNK(mode)) {
350                 inode->i_op = &autofs4_symlink_inode_operations;
351         }
352
353         return inode;
354 }