2 * linux/fs/proc/inode.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
7 #include <linux/time.h>
8 #include <linux/proc_fs.h>
9 #include <linux/kernel.h>
10 #include <linux/pid_namespace.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>
27 #include <asm/uaccess.h>
31 static void proc_evict_inode(struct inode *inode)
33 struct proc_dir_entry *de;
34 struct ctl_table_header *head;
36 truncate_inode_pages_final(&inode->i_data);
39 /* Stop tracking associated processes */
40 put_pid(PROC_I(inode)->pid);
42 /* Let go of any associated proc directory entry */
46 head = PROC_I(inode)->sysctl;
48 RCU_INIT_POINTER(PROC_I(inode)->sysctl, NULL);
49 sysctl_head_put(head);
53 static struct kmem_cache * proc_inode_cachep;
55 static struct inode *proc_alloc_inode(struct super_block *sb)
57 struct proc_inode *ei;
60 ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL);
65 ei->op.proc_get_link = NULL;
68 ei->sysctl_entry = NULL;
70 inode = &ei->vfs_inode;
71 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
75 static void proc_i_callback(struct rcu_head *head)
77 struct inode *inode = container_of(head, struct inode, i_rcu);
78 kmem_cache_free(proc_inode_cachep, PROC_I(inode));
81 static void proc_destroy_inode(struct inode *inode)
83 call_rcu(&inode->i_rcu, proc_i_callback);
86 static void init_once(void *foo)
88 struct proc_inode *ei = (struct proc_inode *) foo;
90 inode_init_once(&ei->vfs_inode);
93 void __init proc_init_inodecache(void)
95 proc_inode_cachep = kmem_cache_create("proc_inode_cache",
96 sizeof(struct proc_inode),
97 0, (SLAB_RECLAIM_ACCOUNT|
98 SLAB_MEM_SPREAD|SLAB_PANIC),
102 static int proc_show_options(struct seq_file *seq, struct dentry *root)
104 struct super_block *sb = root->d_sb;
105 struct pid_namespace *pid = sb->s_fs_info;
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);
115 static 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,
125 enum {BIAS = -1U<<31};
127 static inline int use_pde(struct proc_dir_entry *pde)
129 return atomic_inc_unless_negative(&pde->in_use);
132 static void unuse_pde(struct proc_dir_entry *pde)
134 if (atomic_dec_return(&pde->in_use) == BIAS)
135 complete(pde->pde_unload_completion);
139 static void close_pdeo(struct proc_dir_entry *pde, struct pde_opener *pdeo)
142 /* somebody else is doing that, just wait */
143 DECLARE_COMPLETION_ONSTACK(c);
145 spin_unlock(&pde->pde_unload_lock);
146 wait_for_completion(&c);
147 spin_lock(&pde->pde_unload_lock);
151 spin_unlock(&pde->pde_unload_lock);
153 pde->proc_fops->release(file_inode(file), file);
154 spin_lock(&pde->pde_unload_lock);
155 list_del_init(&pdeo->lh);
162 void proc_entry_rundown(struct proc_dir_entry *de)
164 DECLARE_COMPLETION_ONSTACK(c);
165 /* Wait until all existing callers into module are done. */
166 de->pde_unload_completion = &c;
167 if (atomic_add_return(BIAS, &de->in_use) != BIAS)
168 wait_for_completion(&c);
170 spin_lock(&de->pde_unload_lock);
171 while (!list_empty(&de->pde_openers)) {
172 struct pde_opener *pdeo;
173 pdeo = list_first_entry(&de->pde_openers, struct pde_opener, lh);
174 close_pdeo(de, pdeo);
176 spin_unlock(&de->pde_unload_lock);
179 static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
181 struct proc_dir_entry *pde = PDE(file_inode(file));
184 loff_t (*llseek)(struct file *, loff_t, int);
185 llseek = pde->proc_fops->llseek;
187 llseek = default_llseek;
188 rv = llseek(file, offset, whence);
194 static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
196 ssize_t (*read)(struct file *, char __user *, size_t, loff_t *);
197 struct proc_dir_entry *pde = PDE(file_inode(file));
200 read = pde->proc_fops->read;
202 rv = read(file, buf, count, ppos);
208 static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
210 ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *);
211 struct proc_dir_entry *pde = PDE(file_inode(file));
214 write = pde->proc_fops->write;
216 rv = write(file, buf, count, ppos);
222 static unsigned int proc_reg_poll(struct file *file, struct poll_table_struct *pts)
224 struct proc_dir_entry *pde = PDE(file_inode(file));
225 unsigned int rv = DEFAULT_POLLMASK;
226 unsigned int (*poll)(struct file *, struct poll_table_struct *);
228 poll = pde->proc_fops->poll;
230 rv = poll(file, pts);
236 static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
238 struct proc_dir_entry *pde = PDE(file_inode(file));
240 long (*ioctl)(struct file *, unsigned int, unsigned long);
242 ioctl = pde->proc_fops->unlocked_ioctl;
244 rv = ioctl(file, cmd, arg);
251 static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
253 struct proc_dir_entry *pde = PDE(file_inode(file));
255 long (*compat_ioctl)(struct file *, unsigned int, unsigned long);
257 compat_ioctl = pde->proc_fops->compat_ioctl;
259 rv = compat_ioctl(file, cmd, arg);
266 static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma)
268 struct proc_dir_entry *pde = PDE(file_inode(file));
270 int (*mmap)(struct file *, struct vm_area_struct *);
272 mmap = pde->proc_fops->mmap;
274 rv = mmap(file, vma);
281 proc_reg_get_unmapped_area(struct file *file, unsigned long orig_addr,
282 unsigned long len, unsigned long pgoff,
285 struct proc_dir_entry *pde = PDE(file_inode(file));
286 unsigned long rv = -EIO;
289 typeof(proc_reg_get_unmapped_area) *get_area;
291 get_area = pde->proc_fops->get_unmapped_area;
294 get_area = current->mm->get_unmapped_area;
298 rv = get_area(file, orig_addr, len, pgoff, flags);
306 static int proc_reg_open(struct inode *inode, struct file *file)
308 struct proc_dir_entry *pde = PDE(inode);
310 int (*open)(struct inode *, struct file *);
311 int (*release)(struct inode *, struct file *);
312 struct pde_opener *pdeo;
315 * What for, you ask? Well, we can have open, rmmod, remove_proc_entry
316 * sequence. ->release won't be called because ->proc_fops will be
317 * cleared. Depending on complexity of ->release, consequences vary.
319 * We can't wait for mercy when close will be done for real, it's
320 * deadlockable: rmmod foo </proc/foo . So, we're going to do ->release
321 * by hand in remove_proc_entry(). For this, save opener's credentials
324 pdeo = kzalloc(sizeof(struct pde_opener), GFP_KERNEL);
332 open = pde->proc_fops->open;
333 release = pde->proc_fops->release;
336 rv = open(inode, file);
338 if (rv == 0 && release) {
339 /* To know what to release. */
341 /* Strictly for "too late" ->release in proc_reg_release(). */
342 spin_lock(&pde->pde_unload_lock);
343 list_add(&pdeo->lh, &pde->pde_openers);
344 spin_unlock(&pde->pde_unload_lock);
352 static int proc_reg_release(struct inode *inode, struct file *file)
354 struct proc_dir_entry *pde = PDE(inode);
355 struct pde_opener *pdeo;
356 spin_lock(&pde->pde_unload_lock);
357 list_for_each_entry(pdeo, &pde->pde_openers, lh) {
358 if (pdeo->file == file) {
359 close_pdeo(pde, pdeo);
363 spin_unlock(&pde->pde_unload_lock);
367 static const struct file_operations proc_reg_file_ops = {
368 .llseek = proc_reg_llseek,
369 .read = proc_reg_read,
370 .write = proc_reg_write,
371 .poll = proc_reg_poll,
372 .unlocked_ioctl = proc_reg_unlocked_ioctl,
374 .compat_ioctl = proc_reg_compat_ioctl,
376 .mmap = proc_reg_mmap,
377 .get_unmapped_area = proc_reg_get_unmapped_area,
378 .open = proc_reg_open,
379 .release = proc_reg_release,
383 static const struct file_operations proc_reg_file_ops_no_compat = {
384 .llseek = proc_reg_llseek,
385 .read = proc_reg_read,
386 .write = proc_reg_write,
387 .poll = proc_reg_poll,
388 .unlocked_ioctl = proc_reg_unlocked_ioctl,
389 .mmap = proc_reg_mmap,
390 .get_unmapped_area = proc_reg_get_unmapped_area,
391 .open = proc_reg_open,
392 .release = proc_reg_release,
396 struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de)
398 struct inode *inode = new_inode_pseudo(sb);
401 inode->i_ino = de->low_ino;
402 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
403 PROC_I(inode)->pde = de;
406 inode->i_mode = de->mode;
407 inode->i_uid = de->uid;
408 inode->i_gid = de->gid;
411 inode->i_size = de->size;
413 set_nlink(inode, de->nlink);
414 WARN_ON(!de->proc_iops);
415 inode->i_op = de->proc_iops;
417 if (S_ISREG(inode->i_mode)) {
419 if (!de->proc_fops->compat_ioctl)
421 &proc_reg_file_ops_no_compat;
424 inode->i_fop = &proc_reg_file_ops;
426 inode->i_fop = de->proc_fops;
434 int proc_fill_super(struct super_block *s)
436 struct inode *root_inode;
439 s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC;
440 s->s_blocksize = 1024;
441 s->s_blocksize_bits = 10;
442 s->s_magic = PROC_SUPER_MAGIC;
443 s->s_op = &proc_sops;
447 root_inode = proc_get_inode(s, &proc_root);
449 pr_err("proc_fill_super: get root inode failed\n");
453 s->s_root = d_make_root(root_inode);
455 pr_err("proc_fill_super: allocate dentry failed\n");
459 ret = proc_setup_self(s);
463 return proc_setup_thread_self(s);