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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/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
29static 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
56static struct kmem_cache * proc_inode_cachep;
57
58static 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
79static 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
85static void proc_destroy_inode(struct inode *inode)
86{
87 call_rcu(&inode->i_rcu, proc_i_callback);
88}
89
90static 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
97void __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
106static 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
119static 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
129static 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
136void 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
143static 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
178static 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
200static 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
222static 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
244static 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
267static 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
290static 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
312static 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
363static 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
375static 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
417static 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
432static 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
444struct 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
486int 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}
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/printk.h>
17#include <linux/file.h>
18#include <linux/limits.h>
19#include <linux/init.h>
20#include <linux/module.h>
21#include <linux/sysctl.h>
22#include <linux/seq_file.h>
23#include <linux/slab.h>
24#include <linux/mount.h>
25#include <linux/magic.h>
26
27#include <linux/uaccess.h>
28
29#include "internal.h"
30
31static void proc_evict_inode(struct inode *inode)
32{
33 struct proc_dir_entry *de;
34 struct ctl_table_header *head;
35
36 truncate_inode_pages_final(&inode->i_data);
37 clear_inode(inode);
38
39 /* Stop tracking associated processes */
40 put_pid(PROC_I(inode)->pid);
41
42 /* Let go of any associated proc directory entry */
43 de = PDE(inode);
44 if (de)
45 pde_put(de);
46 head = PROC_I(inode)->sysctl;
47 if (head) {
48 RCU_INIT_POINTER(PROC_I(inode)->sysctl, NULL);
49 sysctl_head_put(head);
50 }
51}
52
53static struct kmem_cache * proc_inode_cachep;
54
55static struct inode *proc_alloc_inode(struct super_block *sb)
56{
57 struct proc_inode *ei;
58 struct inode *inode;
59
60 ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL);
61 if (!ei)
62 return NULL;
63 ei->pid = NULL;
64 ei->fd = 0;
65 ei->op.proc_get_link = NULL;
66 ei->pde = NULL;
67 ei->sysctl = NULL;
68 ei->sysctl_entry = NULL;
69 ei->ns_ops = NULL;
70 inode = &ei->vfs_inode;
71 return inode;
72}
73
74static void proc_i_callback(struct rcu_head *head)
75{
76 struct inode *inode = container_of(head, struct inode, i_rcu);
77 kmem_cache_free(proc_inode_cachep, PROC_I(inode));
78}
79
80static void proc_destroy_inode(struct inode *inode)
81{
82 call_rcu(&inode->i_rcu, proc_i_callback);
83}
84
85static void init_once(void *foo)
86{
87 struct proc_inode *ei = (struct proc_inode *) foo;
88
89 inode_init_once(&ei->vfs_inode);
90}
91
92void __init proc_init_inodecache(void)
93{
94 proc_inode_cachep = kmem_cache_create("proc_inode_cache",
95 sizeof(struct proc_inode),
96 0, (SLAB_RECLAIM_ACCOUNT|
97 SLAB_MEM_SPREAD|SLAB_ACCOUNT|
98 SLAB_PANIC),
99 init_once);
100}
101
102static int proc_show_options(struct seq_file *seq, struct dentry *root)
103{
104 struct super_block *sb = root->d_sb;
105 struct pid_namespace *pid = sb->s_fs_info;
106
107 if (!gid_eq(pid->pid_gid, GLOBAL_ROOT_GID))
108 seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, pid->pid_gid));
109 if (pid->hide_pid != 0)
110 seq_printf(seq, ",hidepid=%u", pid->hide_pid);
111
112 return 0;
113}
114
115static const struct super_operations proc_sops = {
116 .alloc_inode = proc_alloc_inode,
117 .destroy_inode = proc_destroy_inode,
118 .drop_inode = generic_delete_inode,
119 .evict_inode = proc_evict_inode,
120 .statfs = simple_statfs,
121 .remount_fs = proc_remount,
122 .show_options = proc_show_options,
123};
124
125enum {BIAS = -1U<<31};
126
127static inline int use_pde(struct proc_dir_entry *pde)
128{
129 return atomic_inc_unless_negative(&pde->in_use);
130}
131
132static void unuse_pde(struct proc_dir_entry *pde)
133{
134 if (atomic_dec_return(&pde->in_use) == BIAS)
135 complete(pde->pde_unload_completion);
136}
137
138/* pde is locked */
139static void close_pdeo(struct proc_dir_entry *pde, struct pde_opener *pdeo)
140{
141 /*
142 * close() (proc_reg_release()) can't delete an entry and proceed:
143 * ->release hook needs to be available at the right moment.
144 *
145 * rmmod (remove_proc_entry() et al) can't delete an entry and proceed:
146 * "struct file" needs to be available at the right moment.
147 *
148 * Therefore, first process to enter this function does ->release() and
149 * signals its completion to the other process which does nothing.
150 */
151 if (pdeo->closing) {
152 /* somebody else is doing that, just wait */
153 DECLARE_COMPLETION_ONSTACK(c);
154 pdeo->c = &c;
155 spin_unlock(&pde->pde_unload_lock);
156 wait_for_completion(&c);
157 spin_lock(&pde->pde_unload_lock);
158 } else {
159 struct file *file;
160 pdeo->closing = true;
161 spin_unlock(&pde->pde_unload_lock);
162 file = pdeo->file;
163 pde->proc_fops->release(file_inode(file), file);
164 spin_lock(&pde->pde_unload_lock);
165 /* After ->release. */
166 list_del(&pdeo->lh);
167 if (pdeo->c)
168 complete(pdeo->c);
169 kfree(pdeo);
170 }
171}
172
173void proc_entry_rundown(struct proc_dir_entry *de)
174{
175 DECLARE_COMPLETION_ONSTACK(c);
176 /* Wait until all existing callers into module are done. */
177 de->pde_unload_completion = &c;
178 if (atomic_add_return(BIAS, &de->in_use) != BIAS)
179 wait_for_completion(&c);
180
181 /* ->pde_openers list can't grow from now on. */
182
183 spin_lock(&de->pde_unload_lock);
184 while (!list_empty(&de->pde_openers)) {
185 struct pde_opener *pdeo;
186 pdeo = list_first_entry(&de->pde_openers, struct pde_opener, lh);
187 close_pdeo(de, pdeo);
188 }
189 spin_unlock(&de->pde_unload_lock);
190}
191
192static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
193{
194 struct proc_dir_entry *pde = PDE(file_inode(file));
195 loff_t rv = -EINVAL;
196 if (use_pde(pde)) {
197 loff_t (*llseek)(struct file *, loff_t, int);
198 llseek = pde->proc_fops->llseek;
199 if (!llseek)
200 llseek = default_llseek;
201 rv = llseek(file, offset, whence);
202 unuse_pde(pde);
203 }
204 return rv;
205}
206
207static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
208{
209 ssize_t (*read)(struct file *, char __user *, size_t, loff_t *);
210 struct proc_dir_entry *pde = PDE(file_inode(file));
211 ssize_t rv = -EIO;
212 if (use_pde(pde)) {
213 read = pde->proc_fops->read;
214 if (read)
215 rv = read(file, buf, count, ppos);
216 unuse_pde(pde);
217 }
218 return rv;
219}
220
221static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
222{
223 ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *);
224 struct proc_dir_entry *pde = PDE(file_inode(file));
225 ssize_t rv = -EIO;
226 if (use_pde(pde)) {
227 write = pde->proc_fops->write;
228 if (write)
229 rv = write(file, buf, count, ppos);
230 unuse_pde(pde);
231 }
232 return rv;
233}
234
235static unsigned int proc_reg_poll(struct file *file, struct poll_table_struct *pts)
236{
237 struct proc_dir_entry *pde = PDE(file_inode(file));
238 unsigned int rv = DEFAULT_POLLMASK;
239 unsigned int (*poll)(struct file *, struct poll_table_struct *);
240 if (use_pde(pde)) {
241 poll = pde->proc_fops->poll;
242 if (poll)
243 rv = poll(file, pts);
244 unuse_pde(pde);
245 }
246 return rv;
247}
248
249static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
250{
251 struct proc_dir_entry *pde = PDE(file_inode(file));
252 long rv = -ENOTTY;
253 long (*ioctl)(struct file *, unsigned int, unsigned long);
254 if (use_pde(pde)) {
255 ioctl = pde->proc_fops->unlocked_ioctl;
256 if (ioctl)
257 rv = ioctl(file, cmd, arg);
258 unuse_pde(pde);
259 }
260 return rv;
261}
262
263#ifdef CONFIG_COMPAT
264static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
265{
266 struct proc_dir_entry *pde = PDE(file_inode(file));
267 long rv = -ENOTTY;
268 long (*compat_ioctl)(struct file *, unsigned int, unsigned long);
269 if (use_pde(pde)) {
270 compat_ioctl = pde->proc_fops->compat_ioctl;
271 if (compat_ioctl)
272 rv = compat_ioctl(file, cmd, arg);
273 unuse_pde(pde);
274 }
275 return rv;
276}
277#endif
278
279static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma)
280{
281 struct proc_dir_entry *pde = PDE(file_inode(file));
282 int rv = -EIO;
283 int (*mmap)(struct file *, struct vm_area_struct *);
284 if (use_pde(pde)) {
285 mmap = pde->proc_fops->mmap;
286 if (mmap)
287 rv = mmap(file, vma);
288 unuse_pde(pde);
289 }
290 return rv;
291}
292
293static unsigned long
294proc_reg_get_unmapped_area(struct file *file, unsigned long orig_addr,
295 unsigned long len, unsigned long pgoff,
296 unsigned long flags)
297{
298 struct proc_dir_entry *pde = PDE(file_inode(file));
299 unsigned long rv = -EIO;
300
301 if (use_pde(pde)) {
302 typeof(proc_reg_get_unmapped_area) *get_area;
303
304 get_area = pde->proc_fops->get_unmapped_area;
305#ifdef CONFIG_MMU
306 if (!get_area)
307 get_area = current->mm->get_unmapped_area;
308#endif
309
310 if (get_area)
311 rv = get_area(file, orig_addr, len, pgoff, flags);
312 else
313 rv = orig_addr;
314 unuse_pde(pde);
315 }
316 return rv;
317}
318
319static int proc_reg_open(struct inode *inode, struct file *file)
320{
321 struct proc_dir_entry *pde = PDE(inode);
322 int rv = 0;
323 int (*open)(struct inode *, struct file *);
324 int (*release)(struct inode *, struct file *);
325 struct pde_opener *pdeo;
326
327 /*
328 * Ensure that
329 * 1) PDE's ->release hook will be called no matter what
330 * either normally by close()/->release, or forcefully by
331 * rmmod/remove_proc_entry.
332 *
333 * 2) rmmod isn't blocked by opening file in /proc and sitting on
334 * the descriptor (including "rmmod foo </proc/foo" scenario).
335 *
336 * Save every "struct file" with custom ->release hook.
337 */
338 pdeo = kmalloc(sizeof(struct pde_opener), GFP_KERNEL);
339 if (!pdeo)
340 return -ENOMEM;
341
342 if (!use_pde(pde)) {
343 kfree(pdeo);
344 return -ENOENT;
345 }
346 open = pde->proc_fops->open;
347 release = pde->proc_fops->release;
348
349 if (open)
350 rv = open(inode, file);
351
352 if (rv == 0 && release) {
353 /* To know what to release. */
354 pdeo->file = file;
355 pdeo->closing = false;
356 pdeo->c = NULL;
357 spin_lock(&pde->pde_unload_lock);
358 list_add(&pdeo->lh, &pde->pde_openers);
359 spin_unlock(&pde->pde_unload_lock);
360 } else
361 kfree(pdeo);
362
363 unuse_pde(pde);
364 return rv;
365}
366
367static int proc_reg_release(struct inode *inode, struct file *file)
368{
369 struct proc_dir_entry *pde = PDE(inode);
370 struct pde_opener *pdeo;
371 spin_lock(&pde->pde_unload_lock);
372 list_for_each_entry(pdeo, &pde->pde_openers, lh) {
373 if (pdeo->file == file) {
374 close_pdeo(pde, pdeo);
375 break;
376 }
377 }
378 spin_unlock(&pde->pde_unload_lock);
379 return 0;
380}
381
382static const struct file_operations proc_reg_file_ops = {
383 .llseek = proc_reg_llseek,
384 .read = proc_reg_read,
385 .write = proc_reg_write,
386 .poll = proc_reg_poll,
387 .unlocked_ioctl = proc_reg_unlocked_ioctl,
388#ifdef CONFIG_COMPAT
389 .compat_ioctl = proc_reg_compat_ioctl,
390#endif
391 .mmap = proc_reg_mmap,
392 .get_unmapped_area = proc_reg_get_unmapped_area,
393 .open = proc_reg_open,
394 .release = proc_reg_release,
395};
396
397#ifdef CONFIG_COMPAT
398static const struct file_operations proc_reg_file_ops_no_compat = {
399 .llseek = proc_reg_llseek,
400 .read = proc_reg_read,
401 .write = proc_reg_write,
402 .poll = proc_reg_poll,
403 .unlocked_ioctl = proc_reg_unlocked_ioctl,
404 .mmap = proc_reg_mmap,
405 .get_unmapped_area = proc_reg_get_unmapped_area,
406 .open = proc_reg_open,
407 .release = proc_reg_release,
408};
409#endif
410
411static void proc_put_link(void *p)
412{
413 unuse_pde(p);
414}
415
416static const char *proc_get_link(struct dentry *dentry,
417 struct inode *inode,
418 struct delayed_call *done)
419{
420 struct proc_dir_entry *pde = PDE(inode);
421 if (unlikely(!use_pde(pde)))
422 return ERR_PTR(-EINVAL);
423 set_delayed_call(done, proc_put_link, pde);
424 return pde->data;
425}
426
427const struct inode_operations proc_link_inode_operations = {
428 .get_link = proc_get_link,
429};
430
431struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de)
432{
433 struct inode *inode = new_inode_pseudo(sb);
434
435 if (inode) {
436 inode->i_ino = de->low_ino;
437 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
438 PROC_I(inode)->pde = de;
439
440 if (is_empty_pde(de)) {
441 make_empty_dir_inode(inode);
442 return inode;
443 }
444 if (de->mode) {
445 inode->i_mode = de->mode;
446 inode->i_uid = de->uid;
447 inode->i_gid = de->gid;
448 }
449 if (de->size)
450 inode->i_size = de->size;
451 if (de->nlink)
452 set_nlink(inode, de->nlink);
453 WARN_ON(!de->proc_iops);
454 inode->i_op = de->proc_iops;
455 if (de->proc_fops) {
456 if (S_ISREG(inode->i_mode)) {
457#ifdef CONFIG_COMPAT
458 if (!de->proc_fops->compat_ioctl)
459 inode->i_fop =
460 &proc_reg_file_ops_no_compat;
461 else
462#endif
463 inode->i_fop = &proc_reg_file_ops;
464 } else {
465 inode->i_fop = de->proc_fops;
466 }
467 }
468 } else
469 pde_put(de);
470 return inode;
471}
472
473int proc_fill_super(struct super_block *s, void *data, int silent)
474{
475 struct pid_namespace *ns = get_pid_ns(s->s_fs_info);
476 struct inode *root_inode;
477 int ret;
478
479 if (!proc_parse_options(data, ns))
480 return -EINVAL;
481
482 /* User space would break if executables or devices appear on proc */
483 s->s_iflags |= SB_I_USERNS_VISIBLE | SB_I_NOEXEC | SB_I_NODEV;
484 s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC;
485 s->s_blocksize = 1024;
486 s->s_blocksize_bits = 10;
487 s->s_magic = PROC_SUPER_MAGIC;
488 s->s_op = &proc_sops;
489 s->s_time_gran = 1;
490
491 /*
492 * procfs isn't actually a stacking filesystem; however, there is
493 * too much magic going on inside it to permit stacking things on
494 * top of it
495 */
496 s->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;
497
498 pde_get(&proc_root);
499 root_inode = proc_get_inode(s, &proc_root);
500 if (!root_inode) {
501 pr_err("proc_fill_super: get root inode failed\n");
502 return -ENOMEM;
503 }
504
505 s->s_root = d_make_root(root_inode);
506 if (!s->s_root) {
507 pr_err("proc_fill_super: allocate dentry failed\n");
508 return -ENOMEM;
509 }
510
511 ret = proc_setup_self(s);
512 if (ret) {
513 return ret;
514 }
515 return proc_setup_thread_self(s);
516}