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1 /*
2  * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
3  * Copyright 2005-2006 Ian Kent <raven@themaw.net>
4  *
5  * This file is part of the Linux kernel and is made available under
6  * the terms of the GNU General Public License, version 2, or at your
7  * option, any later version, incorporated herein by reference.
8  */
9 
10 #include <linux/kernel.h>
11 #include <linux/slab.h>
12 #include <linux/file.h>
13 #include <linux/seq_file.h>
14 #include <linux/pagemap.h>
15 #include <linux/parser.h>
16 #include <linux/bitops.h>
17 #include <linux/magic.h>
18 #include "autofs_i.h"
19 #include <linux/module.h>
20 
autofs4_new_ino(struct autofs_sb_info * sbi)21 struct autofs_info *autofs4_new_ino(struct autofs_sb_info *sbi)
22 {
23 	struct autofs_info *ino;
24 
25 	ino = kzalloc(sizeof(*ino), GFP_KERNEL);
26 	if (ino) {
27 		INIT_LIST_HEAD(&ino->active);
28 		INIT_LIST_HEAD(&ino->expiring);
29 		ino->last_used = jiffies;
30 		ino->sbi = sbi;
31 	}
32 	return ino;
33 }
34 
autofs4_clean_ino(struct autofs_info * ino)35 void autofs4_clean_ino(struct autofs_info *ino)
36 {
37 	ino->uid = GLOBAL_ROOT_UID;
38 	ino->gid = GLOBAL_ROOT_GID;
39 	ino->last_used = jiffies;
40 }
41 
autofs4_free_ino(struct autofs_info * ino)42 void autofs4_free_ino(struct autofs_info *ino)
43 {
44 	kfree(ino);
45 }
46 
autofs4_kill_sb(struct super_block * sb)47 void autofs4_kill_sb(struct super_block *sb)
48 {
49 	struct autofs_sb_info *sbi = autofs4_sbi(sb);
50 
51 	/*
52 	 * In the event of a failure in get_sb_nodev the superblock
53 	 * info is not present so nothing else has been setup, so
54 	 * just call kill_anon_super when we are called from
55 	 * deactivate_super.
56 	 */
57 	if (sbi) {
58 		/* Free wait queues, close pipe */
59 		autofs4_catatonic_mode(sbi);
60 		put_pid(sbi->oz_pgrp);
61 	}
62 
63 	pr_debug("shutting down\n");
64 	kill_litter_super(sb);
65 	if (sbi)
66 		kfree_rcu(sbi, rcu);
67 }
68 
autofs4_show_options(struct seq_file * m,struct dentry * root)69 static int autofs4_show_options(struct seq_file *m, struct dentry *root)
70 {
71 	struct autofs_sb_info *sbi = autofs4_sbi(root->d_sb);
72 	struct inode *root_inode = d_inode(root->d_sb->s_root);
73 
74 	if (!sbi)
75 		return 0;
76 
77 	seq_printf(m, ",fd=%d", sbi->pipefd);
78 	if (!uid_eq(root_inode->i_uid, GLOBAL_ROOT_UID))
79 		seq_printf(m, ",uid=%u",
80 			from_kuid_munged(&init_user_ns, root_inode->i_uid));
81 	if (!gid_eq(root_inode->i_gid, GLOBAL_ROOT_GID))
82 		seq_printf(m, ",gid=%u",
83 			from_kgid_munged(&init_user_ns, root_inode->i_gid));
84 	seq_printf(m, ",pgrp=%d", pid_vnr(sbi->oz_pgrp));
85 	seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
86 	seq_printf(m, ",minproto=%d", sbi->min_proto);
87 	seq_printf(m, ",maxproto=%d", sbi->max_proto);
88 
89 	if (autofs_type_offset(sbi->type))
90 		seq_printf(m, ",offset");
91 	else if (autofs_type_direct(sbi->type))
92 		seq_printf(m, ",direct");
93 	else
94 		seq_printf(m, ",indirect");
95 #ifdef CONFIG_CHECKPOINT_RESTORE
96 	if (sbi->pipe)
97 		seq_printf(m, ",pipe_ino=%ld", sbi->pipe->f_inode->i_ino);
98 	else
99 		seq_printf(m, ",pipe_ino=-1");
100 #endif
101 	return 0;
102 }
103 
autofs4_evict_inode(struct inode * inode)104 static void autofs4_evict_inode(struct inode *inode)
105 {
106 	clear_inode(inode);
107 	kfree(inode->i_private);
108 }
109 
110 static const struct super_operations autofs4_sops = {
111 	.statfs		= simple_statfs,
112 	.show_options	= autofs4_show_options,
113 	.evict_inode	= autofs4_evict_inode,
114 };
115 
116 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
117 	Opt_indirect, Opt_direct, Opt_offset};
118 
119 static const match_table_t tokens = {
120 	{Opt_fd, "fd=%u"},
121 	{Opt_uid, "uid=%u"},
122 	{Opt_gid, "gid=%u"},
123 	{Opt_pgrp, "pgrp=%u"},
124 	{Opt_minproto, "minproto=%u"},
125 	{Opt_maxproto, "maxproto=%u"},
126 	{Opt_indirect, "indirect"},
127 	{Opt_direct, "direct"},
128 	{Opt_offset, "offset"},
129 	{Opt_err, NULL}
130 };
131 
parse_options(char * options,int * pipefd,kuid_t * uid,kgid_t * gid,int * pgrp,bool * pgrp_set,unsigned int * type,int * minproto,int * maxproto)132 static int parse_options(char *options, int *pipefd, kuid_t *uid, kgid_t *gid,
133 			 int *pgrp, bool *pgrp_set, unsigned int *type,
134 			 int *minproto, int *maxproto)
135 {
136 	char *p;
137 	substring_t args[MAX_OPT_ARGS];
138 	int option;
139 
140 	*uid = current_uid();
141 	*gid = current_gid();
142 
143 	*minproto = AUTOFS_MIN_PROTO_VERSION;
144 	*maxproto = AUTOFS_MAX_PROTO_VERSION;
145 
146 	*pipefd = -1;
147 
148 	if (!options)
149 		return 1;
150 
151 	while ((p = strsep(&options, ",")) != NULL) {
152 		int token;
153 
154 		if (!*p)
155 			continue;
156 
157 		token = match_token(p, tokens, args);
158 		switch (token) {
159 		case Opt_fd:
160 			if (match_int(args, pipefd))
161 				return 1;
162 			break;
163 		case Opt_uid:
164 			if (match_int(args, &option))
165 				return 1;
166 			*uid = make_kuid(current_user_ns(), option);
167 			if (!uid_valid(*uid))
168 				return 1;
169 			break;
170 		case Opt_gid:
171 			if (match_int(args, &option))
172 				return 1;
173 			*gid = make_kgid(current_user_ns(), option);
174 			if (!gid_valid(*gid))
175 				return 1;
176 			break;
177 		case Opt_pgrp:
178 			if (match_int(args, &option))
179 				return 1;
180 			*pgrp = option;
181 			*pgrp_set = true;
182 			break;
183 		case Opt_minproto:
184 			if (match_int(args, &option))
185 				return 1;
186 			*minproto = option;
187 			break;
188 		case Opt_maxproto:
189 			if (match_int(args, &option))
190 				return 1;
191 			*maxproto = option;
192 			break;
193 		case Opt_indirect:
194 			set_autofs_type_indirect(type);
195 			break;
196 		case Opt_direct:
197 			set_autofs_type_direct(type);
198 			break;
199 		case Opt_offset:
200 			set_autofs_type_offset(type);
201 			break;
202 		default:
203 			return 1;
204 		}
205 	}
206 	return (*pipefd < 0);
207 }
208 
autofs4_fill_super(struct super_block * s,void * data,int silent)209 int autofs4_fill_super(struct super_block *s, void *data, int silent)
210 {
211 	struct inode *root_inode;
212 	struct dentry *root;
213 	struct file *pipe;
214 	int pipefd;
215 	struct autofs_sb_info *sbi;
216 	struct autofs_info *ino;
217 	int pgrp = 0;
218 	bool pgrp_set = false;
219 	int ret = -EINVAL;
220 
221 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
222 	if (!sbi)
223 		return -ENOMEM;
224 	pr_debug("starting up, sbi = %p\n", sbi);
225 
226 	s->s_fs_info = sbi;
227 	sbi->magic = AUTOFS_SBI_MAGIC;
228 	sbi->pipefd = -1;
229 	sbi->pipe = NULL;
230 	sbi->catatonic = 1;
231 	sbi->exp_timeout = 0;
232 	sbi->oz_pgrp = NULL;
233 	sbi->sb = s;
234 	sbi->version = 0;
235 	sbi->sub_version = 0;
236 	set_autofs_type_indirect(&sbi->type);
237 	sbi->min_proto = 0;
238 	sbi->max_proto = 0;
239 	mutex_init(&sbi->wq_mutex);
240 	mutex_init(&sbi->pipe_mutex);
241 	spin_lock_init(&sbi->fs_lock);
242 	sbi->queues = NULL;
243 	spin_lock_init(&sbi->lookup_lock);
244 	INIT_LIST_HEAD(&sbi->active_list);
245 	INIT_LIST_HEAD(&sbi->expiring_list);
246 	s->s_blocksize = 1024;
247 	s->s_blocksize_bits = 10;
248 	s->s_magic = AUTOFS_SUPER_MAGIC;
249 	s->s_op = &autofs4_sops;
250 	s->s_d_op = &autofs4_dentry_operations;
251 	s->s_time_gran = 1;
252 
253 	/*
254 	 * Get the root inode and dentry, but defer checking for errors.
255 	 */
256 	ino = autofs4_new_ino(sbi);
257 	if (!ino) {
258 		ret = -ENOMEM;
259 		goto fail_free;
260 	}
261 	root_inode = autofs4_get_inode(s, S_IFDIR | 0755);
262 	root = d_make_root(root_inode);
263 	if (!root)
264 		goto fail_ino;
265 	pipe = NULL;
266 
267 	root->d_fsdata = ino;
268 
269 	/* Can this call block? */
270 	if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
271 			  &pgrp, &pgrp_set, &sbi->type, &sbi->min_proto,
272 			  &sbi->max_proto)) {
273 		pr_err("called with bogus options\n");
274 		goto fail_dput;
275 	}
276 
277 	/* Test versions first */
278 	if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
279 	    sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
280 		pr_err("kernel does not match daemon version "
281 		       "daemon (%d, %d) kernel (%d, %d)\n",
282 		       sbi->min_proto, sbi->max_proto,
283 		       AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
284 		goto fail_dput;
285 	}
286 
287 	/* Establish highest kernel protocol version */
288 	if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
289 		sbi->version = AUTOFS_MAX_PROTO_VERSION;
290 	else
291 		sbi->version = sbi->max_proto;
292 	sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
293 
294 	if (pgrp_set) {
295 		sbi->oz_pgrp = find_get_pid(pgrp);
296 		if (!sbi->oz_pgrp) {
297 			pr_err("could not find process group %d\n",
298 				pgrp);
299 			goto fail_dput;
300 		}
301 	} else {
302 		sbi->oz_pgrp = get_task_pid(current, PIDTYPE_PGID);
303 	}
304 
305 	if (autofs_type_trigger(sbi->type))
306 		__managed_dentry_set_managed(root);
307 
308 	root_inode->i_fop = &autofs4_root_operations;
309 	root_inode->i_op = &autofs4_dir_inode_operations;
310 
311 	pr_debug("pipe fd = %d, pgrp = %u\n", pipefd, pid_nr(sbi->oz_pgrp));
312 	pipe = fget(pipefd);
313 
314 	if (!pipe) {
315 		pr_err("could not open pipe file descriptor\n");
316 		goto fail_put_pid;
317 	}
318 	ret = autofs_prepare_pipe(pipe);
319 	if (ret < 0)
320 		goto fail_fput;
321 	sbi->pipe = pipe;
322 	sbi->pipefd = pipefd;
323 	sbi->catatonic = 0;
324 
325 	/*
326 	 * Success! Install the root dentry now to indicate completion.
327 	 */
328 	s->s_root = root;
329 	return 0;
330 
331 	/*
332 	 * Failure ... clean up.
333 	 */
334 fail_fput:
335 	pr_err("pipe file descriptor does not contain proper ops\n");
336 	fput(pipe);
337 fail_put_pid:
338 	put_pid(sbi->oz_pgrp);
339 fail_dput:
340 	dput(root);
341 	goto fail_free;
342 fail_ino:
343 	autofs4_free_ino(ino);
344 fail_free:
345 	kfree(sbi);
346 	s->s_fs_info = NULL;
347 	return ret;
348 }
349 
autofs4_get_inode(struct super_block * sb,umode_t mode)350 struct inode *autofs4_get_inode(struct super_block *sb, umode_t mode)
351 {
352 	struct inode *inode = new_inode(sb);
353 
354 	if (inode == NULL)
355 		return NULL;
356 
357 	inode->i_mode = mode;
358 	if (sb->s_root) {
359 		inode->i_uid = d_inode(sb->s_root)->i_uid;
360 		inode->i_gid = d_inode(sb->s_root)->i_gid;
361 	}
362 	inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
363 	inode->i_ino = get_next_ino();
364 
365 	if (S_ISDIR(mode)) {
366 		set_nlink(inode, 2);
367 		inode->i_op = &autofs4_dir_inode_operations;
368 		inode->i_fop = &autofs4_dir_operations;
369 	} else if (S_ISLNK(mode)) {
370 		inode->i_op = &autofs4_symlink_inode_operations;
371 	} else
372 		WARN_ON(1);
373 
374 	return inode;
375 }
376