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
25struct 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
37void autofs4_clean_ino(struct autofs_info *ino)
38{
39	ino->uid = GLOBAL_ROOT_UID;
40	ino->gid = GLOBAL_ROOT_GID;
41	ino->last_used = jiffies;
42}
43
44void autofs4_free_ino(struct autofs_info *ino)
45{
46	kfree(ino);
47}
48
49void 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		/* Free wait queues, close pipe */
61		autofs4_catatonic_mode(sbi);
62		put_pid(sbi->oz_pgrp);
63	}
64
65	DPRINTK("shutting down");
66	kill_litter_super(sb);
67	if (sbi)
68		kfree_rcu(sbi, rcu);
69}
70
71static int autofs4_show_options(struct seq_file *m, struct dentry *root)
72{
73	struct autofs_sb_info *sbi = autofs4_sbi(root->d_sb);
74	struct inode *root_inode = d_inode(root->d_sb->s_root);
75
76	if (!sbi)
77		return 0;
78
79	seq_printf(m, ",fd=%d", sbi->pipefd);
80	if (!uid_eq(root_inode->i_uid, GLOBAL_ROOT_UID))
81		seq_printf(m, ",uid=%u",
82			from_kuid_munged(&init_user_ns, root_inode->i_uid));
83	if (!gid_eq(root_inode->i_gid, GLOBAL_ROOT_GID))
84		seq_printf(m, ",gid=%u",
85			from_kgid_munged(&init_user_ns, root_inode->i_gid));
86	seq_printf(m, ",pgrp=%d", pid_vnr(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
101static void autofs4_evict_inode(struct inode *inode)
102{
103	clear_inode(inode);
104	kfree(inode->i_private);
105}
106
107static const struct super_operations autofs4_sops = {
108	.statfs		= simple_statfs,
109	.show_options	= autofs4_show_options,
110	.evict_inode	= autofs4_evict_inode,
111};
112
113enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
114	Opt_indirect, Opt_direct, Opt_offset};
115
116static 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
129static int parse_options(char *options, int *pipefd, kuid_t *uid, kgid_t *gid,
130			 int *pgrp, bool *pgrp_set, unsigned int *type,
131			 int *minproto, int *maxproto)
132{
133	char *p;
134	substring_t args[MAX_OPT_ARGS];
135	int option;
136
137	*uid = current_uid();
138	*gid = current_gid();
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 = make_kuid(current_user_ns(), option);
163			if (!uid_valid(*uid))
164				return 1;
165			break;
166		case Opt_gid:
167			if (match_int(args, &option))
168				return 1;
169			*gid = make_kgid(current_user_ns(), option);
170			if (!gid_valid(*gid))
171				return 1;
172			break;
173		case Opt_pgrp:
174			if (match_int(args, &option))
175				return 1;
176			*pgrp = option;
177			*pgrp_set = true;
178			break;
179		case Opt_minproto:
180			if (match_int(args, &option))
181				return 1;
182			*minproto = option;
183			break;
184		case Opt_maxproto:
185			if (match_int(args, &option))
186				return 1;
187			*maxproto = option;
188			break;
189		case Opt_indirect:
190			set_autofs_type_indirect(type);
191			break;
192		case Opt_direct:
193			set_autofs_type_direct(type);
194			break;
195		case Opt_offset:
196			set_autofs_type_offset(type);
197			break;
198		default:
199			return 1;
200		}
201	}
202	return (*pipefd < 0);
203}
204
205int autofs4_fill_super(struct super_block *s, void *data, int silent)
206{
207	struct inode * root_inode;
208	struct dentry * root;
209	struct file * pipe;
210	int pipefd;
211	struct autofs_sb_info *sbi;
212	struct autofs_info *ino;
213	int pgrp = 0;
214	bool pgrp_set = false;
215	int ret = -EINVAL;
216
217	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
218	if (!sbi)
219		return -ENOMEM;
220	DPRINTK("starting up, sbi = %p",sbi);
221
222	s->s_fs_info = sbi;
223	sbi->magic = AUTOFS_SBI_MAGIC;
224	sbi->pipefd = -1;
225	sbi->pipe = NULL;
226	sbi->catatonic = 1;
227	sbi->exp_timeout = 0;
228	sbi->oz_pgrp = NULL;
229	sbi->sb = s;
230	sbi->version = 0;
231	sbi->sub_version = 0;
232	set_autofs_type_indirect(&sbi->type);
233	sbi->min_proto = 0;
234	sbi->max_proto = 0;
235	mutex_init(&sbi->wq_mutex);
236	mutex_init(&sbi->pipe_mutex);
237	spin_lock_init(&sbi->fs_lock);
238	sbi->queues = NULL;
239	spin_lock_init(&sbi->lookup_lock);
240	INIT_LIST_HEAD(&sbi->active_list);
241	INIT_LIST_HEAD(&sbi->expiring_list);
242	s->s_blocksize = 1024;
243	s->s_blocksize_bits = 10;
244	s->s_magic = AUTOFS_SUPER_MAGIC;
245	s->s_op = &autofs4_sops;
246	s->s_d_op = &autofs4_dentry_operations;
247	s->s_time_gran = 1;
248
249	/*
250	 * Get the root inode and dentry, but defer checking for errors.
251	 */
252	ino = autofs4_new_ino(sbi);
253	if (!ino) {
254		ret = -ENOMEM;
255		goto fail_free;
256	}
257	root_inode = autofs4_get_inode(s, S_IFDIR | 0755);
258	root = d_make_root(root_inode);
259	if (!root)
260		goto fail_ino;
261	pipe = NULL;
262
263	root->d_fsdata = ino;
264
265	/* Can this call block? */
266	if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
267			  &pgrp, &pgrp_set, &sbi->type, &sbi->min_proto,
268			  &sbi->max_proto)) {
269		printk("autofs: called with bogus options\n");
270		goto fail_dput;
271	}
272
273	if (pgrp_set) {
274		sbi->oz_pgrp = find_get_pid(pgrp);
275		if (!sbi->oz_pgrp) {
276			pr_warn("autofs: could not find process group %d\n",
277				pgrp);
278			goto fail_dput;
279		}
280	} else {
281		sbi->oz_pgrp = get_task_pid(current, PIDTYPE_PGID);
282	}
283
284	if (autofs_type_trigger(sbi->type))
285		__managed_dentry_set_managed(root);
286
287	root_inode->i_fop = &autofs4_root_operations;
288	root_inode->i_op = &autofs4_dir_inode_operations;
289
290	/* Couldn't this be tested earlier? */
291	if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
292	    sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
293		printk("autofs: kernel does not match daemon version "
294		       "daemon (%d, %d) kernel (%d, %d)\n",
295			sbi->min_proto, sbi->max_proto,
296			AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
297		goto fail_dput;
298	}
299
300	/* Establish highest kernel protocol version */
301	if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
302		sbi->version = AUTOFS_MAX_PROTO_VERSION;
303	else
304		sbi->version = sbi->max_proto;
305	sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
306
307	DPRINTK("pipe fd = %d, pgrp = %u", pipefd, pid_nr(sbi->oz_pgrp));
308	pipe = fget(pipefd);
309
310	if (!pipe) {
311		printk("autofs: could not open pipe file descriptor\n");
312		goto fail_dput;
313	}
314	ret = autofs_prepare_pipe(pipe);
315	if (ret < 0)
316		goto fail_fput;
317	sbi->pipe = pipe;
318	sbi->pipefd = pipefd;
319	sbi->catatonic = 0;
320
321	/*
322	 * Success! Install the root dentry now to indicate completion.
323	 */
324	s->s_root = root;
325	return 0;
326
327	/*
328	 * Failure ... clean up.
329	 */
330fail_fput:
331	printk("autofs: pipe file descriptor does not contain proper ops\n");
332	fput(pipe);
333	/* fall through */
334fail_dput:
335	dput(root);
336	goto fail_free;
337fail_ino:
338	kfree(ino);
339fail_free:
340	put_pid(sbi->oz_pgrp);
341	kfree(sbi);
342	s->s_fs_info = NULL;
343	return ret;
344}
345
346struct inode *autofs4_get_inode(struct super_block *sb, umode_t mode)
347{
348	struct inode *inode = new_inode(sb);
349
350	if (inode == NULL)
351		return NULL;
352
353	inode->i_mode = mode;
354	if (sb->s_root) {
355		inode->i_uid = d_inode(sb->s_root)->i_uid;
356		inode->i_gid = d_inode(sb->s_root)->i_gid;
357	}
358	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
359	inode->i_ino = get_next_ino();
360
361	if (S_ISDIR(mode)) {
362		set_nlink(inode, 2);
363		inode->i_op = &autofs4_dir_inode_operations;
364		inode->i_fop = &autofs4_dir_operations;
365	} else if (S_ISLNK(mode)) {
366		inode->i_op = &autofs4_symlink_inode_operations;
367	}
368
369	return inode;
370}
371