Root/fs/autofs/inode.c

1/* -*- linux-c -*- --------------------------------------------------------- *
2 *
3 * linux/fs/autofs/inode.c
4 *
5 * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
6 *
7 * This file is part of the Linux kernel and is made available under
8 * the terms of the GNU General Public License, version 2, or at your
9 * option, any later version, incorporated herein by reference.
10 *
11 * ------------------------------------------------------------------------- */
12
13#include <linux/kernel.h>
14#include <linux/mm.h>
15#include <linux/slab.h>
16#include <linux/file.h>
17#include <linux/parser.h>
18#include <linux/bitops.h>
19#include <linux/magic.h>
20#include "autofs_i.h"
21#include <linux/module.h>
22
23void autofs_kill_sb(struct super_block *sb)
24{
25    struct autofs_sb_info *sbi = autofs_sbi(sb);
26    unsigned int n;
27
28    /*
29     * In the event of a failure in get_sb_nodev the superblock
30     * info is not present so nothing else has been setup, so
31     * just call kill_anon_super when we are called from
32     * deactivate_super.
33     */
34    if (!sbi)
35        goto out_kill_sb;
36
37    if (!sbi->catatonic)
38        autofs_catatonic_mode(sbi); /* Free wait queues, close pipe */
39
40    put_pid(sbi->oz_pgrp);
41
42    autofs_hash_nuke(sbi);
43    for (n = 0; n < AUTOFS_MAX_SYMLINKS; n++) {
44        if (test_bit(n, sbi->symlink_bitmap))
45            kfree(sbi->symlink[n].data);
46    }
47
48    kfree(sb->s_fs_info);
49
50out_kill_sb:
51    DPRINTK(("autofs: shutting down\n"));
52    kill_anon_super(sb);
53}
54
55static const struct super_operations autofs_sops = {
56    .statfs = simple_statfs,
57    .show_options = generic_show_options,
58};
59
60enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto};
61
62static const match_table_t autofs_tokens = {
63    {Opt_fd, "fd=%u"},
64    {Opt_uid, "uid=%u"},
65    {Opt_gid, "gid=%u"},
66    {Opt_pgrp, "pgrp=%u"},
67    {Opt_minproto, "minproto=%u"},
68    {Opt_maxproto, "maxproto=%u"},
69    {Opt_err, NULL}
70};
71
72static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
73        pid_t *pgrp, int *minproto, int *maxproto)
74{
75    char *p;
76    substring_t args[MAX_OPT_ARGS];
77    int option;
78
79    *uid = current_uid();
80    *gid = current_gid();
81    *pgrp = task_pgrp_nr(current);
82
83    *minproto = *maxproto = AUTOFS_PROTO_VERSION;
84
85    *pipefd = -1;
86
87    if (!options)
88        return 1;
89
90    while ((p = strsep(&options, ",")) != NULL) {
91        int token;
92        if (!*p)
93            continue;
94
95        token = match_token(p, autofs_tokens, args);
96        switch (token) {
97        case Opt_fd:
98            if (match_int(&args[0], &option))
99                return 1;
100            *pipefd = option;
101            break;
102        case Opt_uid:
103            if (match_int(&args[0], &option))
104                return 1;
105            *uid = option;
106            break;
107        case Opt_gid:
108            if (match_int(&args[0], &option))
109                return 1;
110            *gid = option;
111            break;
112        case Opt_pgrp:
113            if (match_int(&args[0], &option))
114                return 1;
115            *pgrp = option;
116            break;
117        case Opt_minproto:
118            if (match_int(&args[0], &option))
119                return 1;
120            *minproto = option;
121            break;
122        case Opt_maxproto:
123            if (match_int(&args[0], &option))
124                return 1;
125            *maxproto = option;
126            break;
127        default:
128            return 1;
129        }
130    }
131    return (*pipefd < 0);
132}
133
134int autofs_fill_super(struct super_block *s, void *data, int silent)
135{
136    struct inode * root_inode;
137    struct dentry * root;
138    struct file * pipe;
139    int pipefd;
140    struct autofs_sb_info *sbi;
141    int minproto, maxproto;
142    pid_t pgid;
143
144    save_mount_options(s, data);
145
146    sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
147    if (!sbi)
148        goto fail_unlock;
149    DPRINTK(("autofs: starting up, sbi = %p\n",sbi));
150
151    s->s_fs_info = sbi;
152    sbi->magic = AUTOFS_SBI_MAGIC;
153    sbi->pipe = NULL;
154    sbi->catatonic = 1;
155    sbi->exp_timeout = 0;
156    autofs_initialize_hash(&sbi->dirhash);
157    sbi->queues = NULL;
158    memset(sbi->symlink_bitmap, 0, sizeof(long)*AUTOFS_SYMLINK_BITMAP_LEN);
159    sbi->next_dir_ino = AUTOFS_FIRST_DIR_INO;
160    s->s_blocksize = 1024;
161    s->s_blocksize_bits = 10;
162    s->s_magic = AUTOFS_SUPER_MAGIC;
163    s->s_op = &autofs_sops;
164    s->s_time_gran = 1;
165    sbi->sb = s;
166
167    root_inode = autofs_iget(s, AUTOFS_ROOT_INO);
168    if (IS_ERR(root_inode))
169        goto fail_free;
170    root = d_alloc_root(root_inode);
171    pipe = NULL;
172
173    if (!root)
174        goto fail_iput;
175
176    /* Can this call block? - WTF cares? s is locked. */
177    if (parse_options(data, &pipefd, &root_inode->i_uid,
178                &root_inode->i_gid, &pgid, &minproto,
179                &maxproto)) {
180        printk("autofs: called with bogus options\n");
181        goto fail_dput;
182    }
183
184    /* Couldn't this be tested earlier? */
185    if (minproto > AUTOFS_PROTO_VERSION ||
186         maxproto < AUTOFS_PROTO_VERSION) {
187        printk("autofs: kernel does not match daemon version\n");
188        goto fail_dput;
189    }
190
191    DPRINTK(("autofs: pipe fd = %d, pgrp = %u\n", pipefd, pgid));
192    sbi->oz_pgrp = find_get_pid(pgid);
193
194    if (!sbi->oz_pgrp) {
195        printk("autofs: could not find process group %d\n", pgid);
196        goto fail_dput;
197    }
198
199    pipe = fget(pipefd);
200    
201    if (!pipe) {
202        printk("autofs: could not open pipe file descriptor\n");
203        goto fail_put_pid;
204    }
205
206    if (!pipe->f_op || !pipe->f_op->write)
207        goto fail_fput;
208    sbi->pipe = pipe;
209    sbi->catatonic = 0;
210
211    /*
212     * Success! Install the root dentry now to indicate completion.
213     */
214    s->s_root = root;
215    return 0;
216
217fail_fput:
218    printk("autofs: pipe file descriptor does not contain proper ops\n");
219    fput(pipe);
220fail_put_pid:
221    put_pid(sbi->oz_pgrp);
222fail_dput:
223    dput(root);
224    goto fail_free;
225fail_iput:
226    printk("autofs: get root dentry failed\n");
227    iput(root_inode);
228fail_free:
229    kfree(sbi);
230    s->s_fs_info = NULL;
231fail_unlock:
232    return -EINVAL;
233}
234
235struct inode *autofs_iget(struct super_block *sb, unsigned long ino)
236{
237    unsigned int n;
238    struct autofs_sb_info *sbi = autofs_sbi(sb);
239    struct inode *inode;
240
241    inode = iget_locked(sb, ino);
242    if (!inode)
243        return ERR_PTR(-ENOMEM);
244    if (!(inode->i_state & I_NEW))
245        return inode;
246
247    /* Initialize to the default case (stub directory) */
248
249    inode->i_op = &simple_dir_inode_operations;
250    inode->i_fop = &simple_dir_operations;
251    inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
252    inode->i_nlink = 2;
253    inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
254
255    if (ino == AUTOFS_ROOT_INO) {
256        inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR;
257        inode->i_op = &autofs_root_inode_operations;
258        inode->i_fop = &autofs_root_operations;
259        goto done;
260    }
261    
262    inode->i_uid = inode->i_sb->s_root->d_inode->i_uid;
263    inode->i_gid = inode->i_sb->s_root->d_inode->i_gid;
264    
265    if (ino >= AUTOFS_FIRST_SYMLINK && ino < AUTOFS_FIRST_DIR_INO) {
266        /* Symlink inode - should be in symlink list */
267        struct autofs_symlink *sl;
268
269        n = ino - AUTOFS_FIRST_SYMLINK;
270        if (n >= AUTOFS_MAX_SYMLINKS || !test_bit(n,sbi->symlink_bitmap)) {
271            printk("autofs: Looking for bad symlink inode %u\n", (unsigned int) ino);
272            goto done;
273        }
274        
275        inode->i_op = &autofs_symlink_inode_operations;
276        sl = &sbi->symlink[n];
277        inode->i_private = sl;
278        inode->i_mode = S_IFLNK | S_IRWXUGO;
279        inode->i_mtime.tv_sec = inode->i_ctime.tv_sec = sl->mtime;
280        inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
281        inode->i_size = sl->len;
282        inode->i_nlink = 1;
283    }
284
285done:
286    unlock_new_inode(inode);
287    return inode;
288}
289

Archive Download this file



interactive