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hfs: get rid of hfs_sync_super
[linux/fpc-iii.git] / fs / proc / inode.c
blob7ac817b64a7193b71cf867f72fc0d94d68294c90
1 /*
2 * linux/fs/proc/inode.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7 #include <linux/time.h>
8 #include <linux/proc_fs.h>
9 #include <linux/kernel.h>
10 #include <linux/pid_namespace.h>
11 #include <linux/mm.h>
12 #include <linux/string.h>
13 #include <linux/stat.h>
14 #include <linux/completion.h>
15 #include <linux/poll.h>
16 #include <linux/file.h>
17 #include <linux/limits.h>
18 #include <linux/init.h>
19 #include <linux/module.h>
20 #include <linux/sysctl.h>
21 #include <linux/seq_file.h>
22 #include <linux/slab.h>
23 #include <linux/mount.h>
24
25 #include <asm/uaccess.h>
26
27 #include "internal.h"
28
29 static void proc_evict_inode(struct inode *inode)
30 {
31 struct proc_dir_entry *de;
32 struct ctl_table_header *head;
33 const struct proc_ns_operations *ns_ops;
34
35 truncate_inode_pages(&inode->i_data, 0);
36 clear_inode(inode);
37
38 /* Stop tracking associated processes */
39 put_pid(PROC_I(inode)->pid);
40
41 /* Let go of any associated proc directory entry */
42 de = PROC_I(inode)->pde;
43 if (de)
44 pde_put(de);
45 head = PROC_I(inode)->sysctl;
46 if (head) {
47 rcu_assign_pointer(PROC_I(inode)->sysctl, NULL);
48 sysctl_head_put(head);
49 }
50 /* Release any associated namespace */
51 ns_ops = PROC_I(inode)->ns_ops;
52 if (ns_ops && ns_ops->put)
53 ns_ops->put(PROC_I(inode)->ns);
54 }
55
56 static struct kmem_cache * proc_inode_cachep;
57
58 static struct inode *proc_alloc_inode(struct super_block *sb)
59 {
60 struct proc_inode *ei;
61 struct inode *inode;
62
63 ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL);
64 if (!ei)
65 return NULL;
66 ei->pid = NULL;
67 ei->fd = 0;
68 ei->op.proc_get_link = NULL;
69 ei->pde = NULL;
70 ei->sysctl = NULL;
71 ei->sysctl_entry = NULL;
72 ei->ns = NULL;
73 ei->ns_ops = NULL;
74 inode = &ei->vfs_inode;
75 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
76 return inode;
77 }
78
79 static void proc_i_callback(struct rcu_head *head)
80 {
81 struct inode *inode = container_of(head, struct inode, i_rcu);
82 kmem_cache_free(proc_inode_cachep, PROC_I(inode));
83 }
84
85 static void proc_destroy_inode(struct inode *inode)
86 {
87 call_rcu(&inode->i_rcu, proc_i_callback);
88 }
89
90 static void init_once(void *foo)
91 {
92 struct proc_inode *ei = (struct proc_inode *) foo;
93
94 inode_init_once(&ei->vfs_inode);
95 }
96
97 void __init proc_init_inodecache(void)
98 {
99 proc_inode_cachep = kmem_cache_create("proc_inode_cache",
100 sizeof(struct proc_inode),
101 0, (SLAB_RECLAIM_ACCOUNT|
102 SLAB_MEM_SPREAD|SLAB_PANIC),
103 init_once);
104 }
105
106 static int proc_show_options(struct seq_file *seq, struct dentry *root)
107 {
108 struct super_block *sb = root->d_sb;
109 struct pid_namespace *pid = sb->s_fs_info;
110
111 if (!gid_eq(pid->pid_gid, GLOBAL_ROOT_GID))
112 seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, pid->pid_gid));
113 if (pid->hide_pid != 0)
114 seq_printf(seq, ",hidepid=%u", pid->hide_pid);
115
116 return 0;
117 }
118
119 static const struct super_operations proc_sops = {
120 .alloc_inode = proc_alloc_inode,
121 .destroy_inode = proc_destroy_inode,
122 .drop_inode = generic_delete_inode,
123 .evict_inode = proc_evict_inode,
124 .statfs = simple_statfs,
125 .remount_fs = proc_remount,
126 .show_options = proc_show_options,
127 };
128
129 static void __pde_users_dec(struct proc_dir_entry *pde)
130 {
131 pde->pde_users--;
132 if (pde->pde_unload_completion && pde->pde_users == 0)
133 complete(pde->pde_unload_completion);
134 }
135
136 void pde_users_dec(struct proc_dir_entry *pde)
137 {
138 spin_lock(&pde->pde_unload_lock);
139 __pde_users_dec(pde);
140 spin_unlock(&pde->pde_unload_lock);
141 }
142
143 static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
144 {
145 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
146 loff_t rv = -EINVAL;
147 loff_t (*llseek)(struct file *, loff_t, int);
148
149 spin_lock(&pde->pde_unload_lock);
150 /*
151 * remove_proc_entry() is going to delete PDE (as part of module
152 * cleanup sequence). No new callers into module allowed.
153 */
154 if (!pde->proc_fops) {
155 spin_unlock(&pde->pde_unload_lock);
156 return rv;
157 }
158 /*
159 * Bump refcount so that remove_proc_entry will wail for ->llseek to
160 * complete.
161 */
162 pde->pde_users++;
163 /*
164 * Save function pointer under lock, to protect against ->proc_fops
165 * NULL'ifying right after ->pde_unload_lock is dropped.
166 */
167 llseek = pde->proc_fops->llseek;
168 spin_unlock(&pde->pde_unload_lock);
169
170 if (!llseek)
171 llseek = default_llseek;
172 rv = llseek(file, offset, whence);
173
174 pde_users_dec(pde);
175 return rv;
176 }
177
178 static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
179 {
180 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
181 ssize_t rv = -EIO;
182 ssize_t (*read)(struct file *, char __user *, size_t, loff_t *);
183
184 spin_lock(&pde->pde_unload_lock);
185 if (!pde->proc_fops) {
186 spin_unlock(&pde->pde_unload_lock);
187 return rv;
188 }
189 pde->pde_users++;
190 read = pde->proc_fops->read;
191 spin_unlock(&pde->pde_unload_lock);
192
193 if (read)
194 rv = read(file, buf, count, ppos);
195
196 pde_users_dec(pde);
197 return rv;
198 }
199
200 static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
201 {
202 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
203 ssize_t rv = -EIO;
204 ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *);
205
206 spin_lock(&pde->pde_unload_lock);
207 if (!pde->proc_fops) {
208 spin_unlock(&pde->pde_unload_lock);
209 return rv;
210 }
211 pde->pde_users++;
212 write = pde->proc_fops->write;
213 spin_unlock(&pde->pde_unload_lock);
214
215 if (write)
216 rv = write(file, buf, count, ppos);
217
218 pde_users_dec(pde);
219 return rv;
220 }
221
222 static unsigned int proc_reg_poll(struct file *file, struct poll_table_struct *pts)
223 {
224 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
225 unsigned int rv = DEFAULT_POLLMASK;
226 unsigned int (*poll)(struct file *, struct poll_table_struct *);
227
228 spin_lock(&pde->pde_unload_lock);
229 if (!pde->proc_fops) {
230 spin_unlock(&pde->pde_unload_lock);
231 return rv;
232 }
233 pde->pde_users++;
234 poll = pde->proc_fops->poll;
235 spin_unlock(&pde->pde_unload_lock);
236
237 if (poll)
238 rv = poll(file, pts);
239
240 pde_users_dec(pde);
241 return rv;
242 }
243
244 static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
245 {
246 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
247 long rv = -ENOTTY;
248 long (*ioctl)(struct file *, unsigned int, unsigned long);
249
250 spin_lock(&pde->pde_unload_lock);
251 if (!pde->proc_fops) {
252 spin_unlock(&pde->pde_unload_lock);
253 return rv;
254 }
255 pde->pde_users++;
256 ioctl = pde->proc_fops->unlocked_ioctl;
257 spin_unlock(&pde->pde_unload_lock);
258
259 if (ioctl)
260 rv = ioctl(file, cmd, arg);
261
262 pde_users_dec(pde);
263 return rv;
264 }
265
266 #ifdef CONFIG_COMPAT
267 static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
268 {
269 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
270 long rv = -ENOTTY;
271 long (*compat_ioctl)(struct file *, unsigned int, unsigned long);
272
273 spin_lock(&pde->pde_unload_lock);
274 if (!pde->proc_fops) {
275 spin_unlock(&pde->pde_unload_lock);
276 return rv;
277 }
278 pde->pde_users++;
279 compat_ioctl = pde->proc_fops->compat_ioctl;
280 spin_unlock(&pde->pde_unload_lock);
281
282 if (compat_ioctl)
283 rv = compat_ioctl(file, cmd, arg);
284
285 pde_users_dec(pde);
286 return rv;
287 }
288 #endif
289
290 static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma)
291 {
292 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
293 int rv = -EIO;
294 int (*mmap)(struct file *, struct vm_area_struct *);
295
296 spin_lock(&pde->pde_unload_lock);
297 if (!pde->proc_fops) {
298 spin_unlock(&pde->pde_unload_lock);
299 return rv;
300 }
301 pde->pde_users++;
302 mmap = pde->proc_fops->mmap;
303 spin_unlock(&pde->pde_unload_lock);
304
305 if (mmap)
306 rv = mmap(file, vma);
307
308 pde_users_dec(pde);
309 return rv;
310 }
311
312 static int proc_reg_open(struct inode *inode, struct file *file)
313 {
314 struct proc_dir_entry *pde = PDE(inode);
315 int rv = 0;
316 int (*open)(struct inode *, struct file *);
317 int (*release)(struct inode *, struct file *);
318 struct pde_opener *pdeo;
319
320 /*
321 * What for, you ask? Well, we can have open, rmmod, remove_proc_entry
322 * sequence. ->release won't be called because ->proc_fops will be
323 * cleared. Depending on complexity of ->release, consequences vary.
324 *
325 * We can't wait for mercy when close will be done for real, it's
326 * deadlockable: rmmod foo </proc/foo . So, we're going to do ->release
327 * by hand in remove_proc_entry(). For this, save opener's credentials
328 * for later.
329 */
330 pdeo = kmalloc(sizeof(struct pde_opener), GFP_KERNEL);
331 if (!pdeo)
332 return -ENOMEM;
333
334 spin_lock(&pde->pde_unload_lock);
335 if (!pde->proc_fops) {
336 spin_unlock(&pde->pde_unload_lock);
337 kfree(pdeo);
338 return -ENOENT;
339 }
340 pde->pde_users++;
341 open = pde->proc_fops->open;
342 release = pde->proc_fops->release;
343 spin_unlock(&pde->pde_unload_lock);
344
345 if (open)
346 rv = open(inode, file);
347
348 spin_lock(&pde->pde_unload_lock);
349 if (rv == 0 && release) {
350 /* To know what to release. */
351 pdeo->inode = inode;
352 pdeo->file = file;
353 /* Strictly for "too late" ->release in proc_reg_release(). */
354 pdeo->release = release;
355 list_add(&pdeo->lh, &pde->pde_openers);
356 } else
357 kfree(pdeo);
358 __pde_users_dec(pde);
359 spin_unlock(&pde->pde_unload_lock);
360 return rv;
361 }
362
363 static struct pde_opener *find_pde_opener(struct proc_dir_entry *pde,
364 struct inode *inode, struct file *file)
365 {
366 struct pde_opener *pdeo;
367
368 list_for_each_entry(pdeo, &pde->pde_openers, lh) {
369 if (pdeo->inode == inode && pdeo->file == file)
370 return pdeo;
371 }
372 return NULL;
373 }
374
375 static int proc_reg_release(struct inode *inode, struct file *file)
376 {
377 struct proc_dir_entry *pde = PDE(inode);
378 int rv = 0;
379 int (*release)(struct inode *, struct file *);
380 struct pde_opener *pdeo;
381
382 spin_lock(&pde->pde_unload_lock);
383 pdeo = find_pde_opener(pde, inode, file);
384 if (!pde->proc_fops) {
385 /*
386 * Can't simply exit, __fput() will think that everything is OK,
387 * and move on to freeing struct file. remove_proc_entry() will
388 * find slacker in opener's list and will try to do non-trivial
389 * things with struct file. Therefore, remove opener from list.
390 *
391 * But if opener is removed from list, who will ->release it?
392 */
393 if (pdeo) {
394 list_del(&pdeo->lh);
395 spin_unlock(&pde->pde_unload_lock);
396 rv = pdeo->release(inode, file);
397 kfree(pdeo);
398 } else
399 spin_unlock(&pde->pde_unload_lock);
400 return rv;
401 }
402 pde->pde_users++;
403 release = pde->proc_fops->release;
404 if (pdeo) {
405 list_del(&pdeo->lh);
406 kfree(pdeo);
407 }
408 spin_unlock(&pde->pde_unload_lock);
409
410 if (release)
411 rv = release(inode, file);
412
413 pde_users_dec(pde);
414 return rv;
415 }
416
417 static const struct file_operations proc_reg_file_ops = {
418 .llseek = proc_reg_llseek,
419 .read = proc_reg_read,
420 .write = proc_reg_write,
421 .poll = proc_reg_poll,
422 .unlocked_ioctl = proc_reg_unlocked_ioctl,
423 #ifdef CONFIG_COMPAT
424 .compat_ioctl = proc_reg_compat_ioctl,
425 #endif
426 .mmap = proc_reg_mmap,
427 .open = proc_reg_open,
428 .release = proc_reg_release,
429 };
430
431 #ifdef CONFIG_COMPAT
432 static const struct file_operations proc_reg_file_ops_no_compat = {
433 .llseek = proc_reg_llseek,
434 .read = proc_reg_read,
435 .write = proc_reg_write,
436 .poll = proc_reg_poll,
437 .unlocked_ioctl = proc_reg_unlocked_ioctl,
438 .mmap = proc_reg_mmap,
439 .open = proc_reg_open,
440 .release = proc_reg_release,
441 };
442 #endif
443
444 struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de)
445 {
446 struct inode * inode;
447
448 inode = iget_locked(sb, de->low_ino);
449 if (!inode)
450 return NULL;
451 if (inode->i_state & I_NEW) {
452 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
453 PROC_I(inode)->fd = 0;
454 PROC_I(inode)->pde = de;
455
456 if (de->mode) {
457 inode->i_mode = de->mode;
458 inode->i_uid = de->uid;
459 inode->i_gid = de->gid;
460 }
461 if (de->size)
462 inode->i_size = de->size;
463 if (de->nlink)
464 set_nlink(inode, de->nlink);
465 if (de->proc_iops)
466 inode->i_op = de->proc_iops;
467 if (de->proc_fops) {
468 if (S_ISREG(inode->i_mode)) {
469 #ifdef CONFIG_COMPAT
470 if (!de->proc_fops->compat_ioctl)
471 inode->i_fop =
472 &proc_reg_file_ops_no_compat;
473 else
474 #endif
475 inode->i_fop = &proc_reg_file_ops;
476 } else {
477 inode->i_fop = de->proc_fops;
478 }
479 }
480 unlock_new_inode(inode);
481 } else
482 pde_put(de);
483 return inode;
484 }
485
486 int proc_fill_super(struct super_block *s)
487 {
488 s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC;
489 s->s_blocksize = 1024;
490 s->s_blocksize_bits = 10;
491 s->s_magic = PROC_SUPER_MAGIC;
492 s->s_op = &proc_sops;
493 s->s_time_gran = 1;
494
495 pde_get(&proc_root);
496 s->s_root = d_make_root(proc_get_inode(s, &proc_root));
497 if (s->s_root)
498 return 0;
499
500 printk("proc_read_super: get root inode failed\n");
501 pde_put(&proc_root);
502 return -ENOMEM;
503 }
Linux with added FPC-III support