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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{
31 struct pid_namespace *ns;
32
33 ns = (struct pid_namespace *)data;
34 sb->s_fs_info = get_pid_ns(ns);
35 return set_anon_super(sb, NULL);
36}
37
David Howells454e2392006-06-23 02:02:57 -070038static int proc_get_sb(struct file_system_type *fs_type,
39 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
Linus Torvalds1da177e2005-04-16 15:20:36 -070040{
Pavel Emelyanov07543f52007-10-18 23:40:08 -070041 int err;
42 struct super_block *sb;
43 struct pid_namespace *ns;
44 struct proc_inode *ei;
45
Eric W. Biedermanf6c7a1f2006-10-02 02:17:07 -070046 if (proc_mnt) {
47 /* Seed the root directory with a pid so it doesn't need
48 * to be special in base.c. I would do this earlier but
49 * the only task alive when /proc is mounted the first time
50 * is the init_task and it doesn't have any pids.
51 */
Eric W. Biedermanf6c7a1f2006-10-02 02:17:07 -070052 ei = PROC_I(proc_mnt->mnt_sb->s_root->d_inode);
53 if (!ei->pid)
54 ei->pid = find_get_pid(1);
55 }
Pavel Emelyanov07543f52007-10-18 23:40:08 -070056
57 if (flags & MS_KERNMOUNT)
58 ns = (struct pid_namespace *)data;
59 else
60 ns = current->nsproxy->pid_ns;
61
62 sb = sget(fs_type, proc_test_super, proc_set_super, ns);
63 if (IS_ERR(sb))
64 return PTR_ERR(sb);
65
66 if (!sb->s_root) {
67 sb->s_flags = flags;
68 err = proc_fill_super(sb);
69 if (err) {
Al Viro6f5bbff2009-05-06 01:34:22 -040070 deactivate_locked_super(sb);
Pavel Emelyanov07543f52007-10-18 23:40:08 -070071 return err;
72 }
73
74 ei = PROC_I(sb->s_root->d_inode);
75 if (!ei->pid) {
76 rcu_read_lock();
77 ei->pid = get_pid(find_pid_ns(1, ns));
78 rcu_read_unlock();
79 }
80
81 sb->s_flags |= MS_ACTIVE;
82 ns->proc_mnt = mnt;
83 }
84
Sukadev Bhattiprolua3ec9472009-03-04 12:06:34 -080085 simple_set_mnt(mnt, sb);
86 return 0;
Pavel Emelyanov07543f52007-10-18 23:40:08 -070087}
88
89static void proc_kill_sb(struct super_block *sb)
90{
91 struct pid_namespace *ns;
92
93 ns = (struct pid_namespace *)sb->s_fs_info;
94 kill_anon_super(sb);
95 put_pid_ns(ns);
Linus Torvalds1da177e2005-04-16 15:20:36 -070096}
97
Alexey Dobriyanc2319542007-11-28 16:21:23 -080098static struct file_system_type proc_fs_type = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070099 .name = "proc",
100 .get_sb = proc_get_sb,
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700101 .kill_sb = proc_kill_sb,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102};
103
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104void __init proc_root_init(void)
105{
Alexey Dobriyan5bcd7ff2008-10-17 03:43:55 +0400106 int err;
107
108 proc_init_inodecache();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109 err = register_filesystem(&proc_fs_type);
110 if (err)
111 return;
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700112 proc_mnt = kern_mount_data(&proc_fs_type, &init_pid_ns);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 if (IS_ERR(proc_mnt)) {
114 unregister_filesystem(&proc_fs_type);
115 return;
116 }
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700117
Alexey Dobriyan59c75722008-10-06 14:49:39 +0400118 proc_symlink("mounts", NULL, "self/mounts");
Eric W. Biederman457c4cb2007-09-12 12:01:34 +0200119
120 proc_net_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121
122#ifdef CONFIG_SYSVIPC
123 proc_mkdir("sysvipc", NULL);
124#endif
Alexey Dobriyan36a5aeb2008-04-29 01:01:42 -0700125 proc_mkdir("fs", NULL);
Alexey Dobriyan928b4d82008-04-29 01:01:44 -0700126 proc_mkdir("driver", NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127 proc_mkdir("fs/nfsd", NULL); /* somewhere for the nfsd filesystem to be mounted */
128#if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
129 /* just give it a mountpoint */
130 proc_mkdir("openprom", NULL);
131#endif
132 proc_tty_init();
133#ifdef CONFIG_PROC_DEVICETREE
134 proc_device_tree_init();
135#endif
Alexey Dobriyan9c370662008-04-29 01:01:41 -0700136 proc_mkdir("bus", NULL);
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800137 proc_sys_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138}
139
Al Viro76b61592006-02-08 14:37:40 -0500140static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat
141)
142{
143 generic_fillattr(dentry->d_inode, stat);
144 stat->nlink = proc_root.nlink + nr_processes();
145 return 0;
146}
147
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
149{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 if (!proc_lookup(dir, dentry, nd)) {
151 return NULL;
152 }
153
154 return proc_pid_lookup(dir, dentry, nd);
155}
156
157static int proc_root_readdir(struct file * filp,
158 void * dirent, filldir_t filldir)
159{
160 unsigned int nr = filp->f_pos;
161 int ret;
162
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163 if (nr < FIRST_PROCESS_ENTRY) {
164 int error = proc_readdir(filp, dirent, filldir);
Alexey Dobriyanb4df2b92008-10-27 22:48:36 +0300165 if (error <= 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167 filp->f_pos = FIRST_PROCESS_ENTRY;
168 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169
170 ret = proc_pid_readdir(filp, dirent, filldir);
171 return ret;
172}
173
174/*
175 * The root /proc directory is special, as it has the
176 * <pid> directories. Thus we don't use the generic
177 * directory handling functions for that..
178 */
Arjan van de Ven00977a52007-02-12 00:55:34 -0800179static const struct file_operations proc_root_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 .read = generic_read_dir,
181 .readdir = proc_root_readdir,
182};
183
184/*
185 * proc root can do almost nothing..
186 */
Arjan van de Venc5ef1c42007-02-12 00:55:40 -0800187static const struct inode_operations proc_root_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188 .lookup = proc_root_lookup,
Al Viro76b61592006-02-08 14:37:40 -0500189 .getattr = proc_root_getattr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190};
191
192/*
193 * This is the root "inode" in the /proc tree..
194 */
195struct proc_dir_entry proc_root = {
196 .low_ino = PROC_ROOT_INO,
197 .namelen = 5,
198 .name = "/proc",
199 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
200 .nlink = 2,
Alexey Dobriyan5a622f22007-12-04 23:45:28 -0800201 .count = ATOMIC_INIT(1),
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202 .proc_iops = &proc_root_inode_operations,
203 .proc_fops = &proc_root_operations,
204 .parent = &proc_root,
205};
206
Pavel Emelyanov6f4e6432007-10-18 23:40:11 -0700207int pid_ns_prepare_proc(struct pid_namespace *ns)
208{
209 struct vfsmount *mnt;
210
211 mnt = kern_mount_data(&proc_fs_type, ns);
212 if (IS_ERR(mnt))
213 return PTR_ERR(mnt);
214
215 return 0;
216}
217
218void pid_ns_release_proc(struct pid_namespace *ns)
219{
220 mntput(ns->proc_mnt);
221}