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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/proc/root.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 *
6 * proc root directory handling functions
7 */
8
9#include <asm/uaccess.h>
10
11#include <linux/errno.h>
12#include <linux/time.h>
13#include <linux/proc_fs.h>
14#include <linux/stat.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/init.h>
Al Viro914e2632006-10-18 13:55:46 -040016#include <linux/sched.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <linux/module.h>
18#include <linux/bitops.h>
Eric W. Biedermanf6c7a1f2006-10-02 02:17:07 -070019#include <linux/mount.h>
Pavel Emelyanov07543f52007-10-18 23:40:08 -070020#include <linux/pid_namespace.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070021
Adrian Bunkfee781e2006-01-08 01:04:16 -080022#include "internal.h"
23
Pavel Emelyanov07543f52007-10-18 23:40:08 -070024static int proc_test_super(struct super_block *sb, void *data)
25{
26 return sb->s_fs_info == data;
27}
28
29static int proc_set_super(struct super_block *sb, void *data)
30{
Al Viroff78fca2011-06-12 09:42:17 -040031 int err = set_anon_super(sb, NULL);
32 if (!err) {
33 struct pid_namespace *ns = (struct pid_namespace *)data;
34 sb->s_fs_info = get_pid_ns(ns);
35 }
36 return err;
Pavel Emelyanov07543f52007-10-18 23:40:08 -070037}
38
Al Viroaed1d842010-07-26 13:12:54 +040039static struct dentry *proc_mount(struct file_system_type *fs_type,
40 int flags, const char *dev_name, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -070041{
Pavel Emelyanov07543f52007-10-18 23:40:08 -070042 int err;
43 struct super_block *sb;
44 struct pid_namespace *ns;
45 struct proc_inode *ei;
46
Pavel Emelyanov07543f52007-10-18 23:40:08 -070047 if (flags & MS_KERNMOUNT)
48 ns = (struct pid_namespace *)data;
49 else
50 ns = current->nsproxy->pid_ns;
51
52 sb = sget(fs_type, proc_test_super, proc_set_super, ns);
53 if (IS_ERR(sb))
Al Viroaed1d842010-07-26 13:12:54 +040054 return ERR_CAST(sb);
Pavel Emelyanov07543f52007-10-18 23:40:08 -070055
56 if (!sb->s_root) {
57 sb->s_flags = flags;
58 err = proc_fill_super(sb);
59 if (err) {
Al Viro6f5bbff2009-05-06 01:34:22 -040060 deactivate_locked_super(sb);
Al Viroaed1d842010-07-26 13:12:54 +040061 return ERR_PTR(err);
Pavel Emelyanov07543f52007-10-18 23:40:08 -070062 }
63
Pavel Emelyanov07543f52007-10-18 23:40:08 -070064 sb->s_flags |= MS_ACTIVE;
Pavel Emelyanov07543f52007-10-18 23:40:08 -070065 }
66
Eric W. Biederman4308eeb2011-03-23 16:43:13 -070067 ei = PROC_I(sb->s_root->d_inode);
68 if (!ei->pid) {
69 rcu_read_lock();
70 ei->pid = get_pid(find_pid_ns(1, ns));
71 rcu_read_unlock();
72 }
73
Al Viroaed1d842010-07-26 13:12:54 +040074 return dget(sb->s_root);
Pavel Emelyanov07543f52007-10-18 23:40:08 -070075}
76
77static void proc_kill_sb(struct super_block *sb)
78{
79 struct pid_namespace *ns;
80
81 ns = (struct pid_namespace *)sb->s_fs_info;
82 kill_anon_super(sb);
83 put_pid_ns(ns);
Linus Torvalds1da177e2005-04-16 15:20:36 -070084}
85
Alexey Dobriyanc2319542007-11-28 16:21:23 -080086static struct file_system_type proc_fs_type = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070087 .name = "proc",
Al Viroaed1d842010-07-26 13:12:54 +040088 .mount = proc_mount,
Pavel Emelyanov07543f52007-10-18 23:40:08 -070089 .kill_sb = proc_kill_sb,
Linus Torvalds1da177e2005-04-16 15:20:36 -070090};
91
Linus Torvalds1da177e2005-04-16 15:20:36 -070092void __init proc_root_init(void)
93{
Oleg Nesterov52e9fc72011-03-23 16:43:14 -070094 struct vfsmount *mnt;
Alexey Dobriyan5bcd7ff2008-10-17 03:43:55 +040095 int err;
96
97 proc_init_inodecache();
Linus Torvalds1da177e2005-04-16 15:20:36 -070098 err = register_filesystem(&proc_fs_type);
99 if (err)
100 return;
Oleg Nesterov52e9fc72011-03-23 16:43:14 -0700101 mnt = kern_mount_data(&proc_fs_type, &init_pid_ns);
102 if (IS_ERR(mnt)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103 unregister_filesystem(&proc_fs_type);
104 return;
105 }
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700106
Oleg Nesterov52e9fc72011-03-23 16:43:14 -0700107 init_pid_ns.proc_mnt = mnt;
Alexey Dobriyan59c75722008-10-06 14:49:39 +0400108 proc_symlink("mounts", NULL, "self/mounts");
Eric W. Biederman457c4cb2007-09-12 12:01:34 +0200109
110 proc_net_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111
112#ifdef CONFIG_SYSVIPC
113 proc_mkdir("sysvipc", NULL);
114#endif
Alexey Dobriyan36a5aeb2008-04-29 01:01:42 -0700115 proc_mkdir("fs", NULL);
Alexey Dobriyan928b4d82008-04-29 01:01:44 -0700116 proc_mkdir("driver", NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117 proc_mkdir("fs/nfsd", NULL); /* somewhere for the nfsd filesystem to be mounted */
118#if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
119 /* just give it a mountpoint */
120 proc_mkdir("openprom", NULL);
121#endif
122 proc_tty_init();
123#ifdef CONFIG_PROC_DEVICETREE
124 proc_device_tree_init();
125#endif
Alexey Dobriyan9c370662008-04-29 01:01:41 -0700126 proc_mkdir("bus", NULL);
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800127 proc_sys_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128}
129
Al Viro76b61592006-02-08 14:37:40 -0500130static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat
131)
132{
133 generic_fillattr(dentry->d_inode, stat);
134 stat->nlink = proc_root.nlink + nr_processes();
135 return 0;
136}
137
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
139{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140 if (!proc_lookup(dir, dentry, nd)) {
141 return NULL;
142 }
143
144 return proc_pid_lookup(dir, dentry, nd);
145}
146
147static int proc_root_readdir(struct file * filp,
148 void * dirent, filldir_t filldir)
149{
150 unsigned int nr = filp->f_pos;
151 int ret;
152
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153 if (nr < FIRST_PROCESS_ENTRY) {
154 int error = proc_readdir(filp, dirent, filldir);
Alexey Dobriyanb4df2b92008-10-27 22:48:36 +0300155 if (error <= 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157 filp->f_pos = FIRST_PROCESS_ENTRY;
158 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159
160 ret = proc_pid_readdir(filp, dirent, filldir);
161 return ret;
162}
163
164/*
165 * The root /proc directory is special, as it has the
166 * <pid> directories. Thus we don't use the generic
167 * directory handling functions for that..
168 */
Arjan van de Ven00977a52007-02-12 00:55:34 -0800169static const struct file_operations proc_root_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 .read = generic_read_dir,
171 .readdir = proc_root_readdir,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200172 .llseek = default_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173};
174
175/*
176 * proc root can do almost nothing..
177 */
Arjan van de Venc5ef1c42007-02-12 00:55:40 -0800178static const struct inode_operations proc_root_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179 .lookup = proc_root_lookup,
Al Viro76b61592006-02-08 14:37:40 -0500180 .getattr = proc_root_getattr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181};
182
183/*
184 * This is the root "inode" in the /proc tree..
185 */
186struct proc_dir_entry proc_root = {
187 .low_ino = PROC_ROOT_INO,
188 .namelen = 5,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
190 .nlink = 2,
Alexey Dobriyan5a622f22007-12-04 23:45:28 -0800191 .count = ATOMIC_INIT(1),
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192 .proc_iops = &proc_root_inode_operations,
193 .proc_fops = &proc_root_operations,
194 .parent = &proc_root,
David Howells09570f92011-07-27 21:47:03 +0300195 .name = "/proc",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196};
197
Pavel Emelyanov6f4e6432007-10-18 23:40:11 -0700198int pid_ns_prepare_proc(struct pid_namespace *ns)
199{
200 struct vfsmount *mnt;
201
202 mnt = kern_mount_data(&proc_fs_type, ns);
203 if (IS_ERR(mnt))
204 return PTR_ERR(mnt);
205
Al Viro579441a2010-07-26 13:09:36 +0400206 ns->proc_mnt = mnt;
Pavel Emelyanov6f4e6432007-10-18 23:40:11 -0700207 return 0;
208}
209
210void pid_ns_release_proc(struct pid_namespace *ns)
211{
212 mntput(ns->proc_mnt);
213}