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