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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>
Vasiliy Kulikov97412952012-01-10 15:11:27 -080021#include <linux/parser.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022
Adrian Bunkfee781e2006-01-08 01:04:16 -080023#include "internal.h"
24
Pavel Emelyanov07543f52007-10-18 23:40:08 -070025static int proc_test_super(struct super_block *sb, void *data)
26{
27 return sb->s_fs_info == data;
28}
29
30static int proc_set_super(struct super_block *sb, void *data)
31{
Al Viroff78fca2011-06-12 09:42:17 -040032 int err = set_anon_super(sb, NULL);
33 if (!err) {
34 struct pid_namespace *ns = (struct pid_namespace *)data;
35 sb->s_fs_info = get_pid_ns(ns);
36 }
37 return err;
Pavel Emelyanov07543f52007-10-18 23:40:08 -070038}
39
Vasiliy Kulikov97412952012-01-10 15:11:27 -080040enum {
Vasiliy Kulikov04996802012-01-10 15:11:31 -080041 Opt_gid, Opt_hidepid, Opt_err,
Vasiliy Kulikov97412952012-01-10 15:11:27 -080042};
43
44static const match_table_t tokens = {
Vasiliy Kulikov04996802012-01-10 15:11:31 -080045 {Opt_hidepid, "hidepid=%u"},
46 {Opt_gid, "gid=%u"},
Vasiliy Kulikov97412952012-01-10 15:11:27 -080047 {Opt_err, NULL},
48};
49
50static int proc_parse_options(char *options, struct pid_namespace *pid)
51{
52 char *p;
53 substring_t args[MAX_OPT_ARGS];
Vasiliy Kulikov04996802012-01-10 15:11:31 -080054 int option;
Vasiliy Kulikov97412952012-01-10 15:11:27 -080055
56 if (!options)
57 return 1;
58
59 while ((p = strsep(&options, ",")) != NULL) {
60 int token;
61 if (!*p)
62 continue;
63
64 args[0].to = args[0].from = 0;
65 token = match_token(p, tokens, args);
66 switch (token) {
Vasiliy Kulikov04996802012-01-10 15:11:31 -080067 case Opt_gid:
68 if (match_int(&args[0], &option))
69 return 0;
Eric W. Biedermandcb0f222012-02-09 08:48:21 -080070 pid->pid_gid = make_kgid(current_user_ns(), option);
Vasiliy Kulikov04996802012-01-10 15:11:31 -080071 break;
72 case Opt_hidepid:
73 if (match_int(&args[0], &option))
74 return 0;
75 if (option < 0 || option > 2) {
76 pr_err("proc: hidepid value must be between 0 and 2.\n");
77 return 0;
78 }
79 pid->hide_pid = option;
80 break;
Vasiliy Kulikov97412952012-01-10 15:11:27 -080081 default:
82 pr_err("proc: unrecognized mount option \"%s\" "
83 "or missing value\n", p);
84 return 0;
85 }
86 }
87
88 return 1;
89}
90
91int proc_remount(struct super_block *sb, int *flags, char *data)
92{
93 struct pid_namespace *pid = sb->s_fs_info;
94 return !proc_parse_options(data, pid);
95}
96
Al Viroaed1d842010-07-26 13:12:54 +040097static struct dentry *proc_mount(struct file_system_type *fs_type,
98 int flags, const char *dev_name, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -070099{
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700100 int err;
101 struct super_block *sb;
102 struct pid_namespace *ns;
103 struct proc_inode *ei;
Vasiliy Kulikov97412952012-01-10 15:11:27 -0800104 char *options;
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700105
Vasiliy Kulikov97412952012-01-10 15:11:27 -0800106 if (flags & MS_KERNMOUNT) {
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700107 ns = (struct pid_namespace *)data;
Vasiliy Kulikov97412952012-01-10 15:11:27 -0800108 options = NULL;
109 } else {
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700110 ns = current->nsproxy->pid_ns;
Vasiliy Kulikov97412952012-01-10 15:11:27 -0800111 options = data;
112 }
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700113
David Howells9249e172012-06-25 12:55:37 +0100114 sb = sget(fs_type, proc_test_super, proc_set_super, flags, ns);
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700115 if (IS_ERR(sb))
Al Viroaed1d842010-07-26 13:12:54 +0400116 return ERR_CAST(sb);
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700117
Vasiliy Kulikov99663be2012-04-05 14:25:04 -0700118 if (!proc_parse_options(options, ns)) {
119 deactivate_locked_super(sb);
120 return ERR_PTR(-EINVAL);
121 }
122
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700123 if (!sb->s_root) {
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700124 err = proc_fill_super(sb);
125 if (err) {
Al Viro6f5bbff2009-05-06 01:34:22 -0400126 deactivate_locked_super(sb);
Al Viroaed1d842010-07-26 13:12:54 +0400127 return ERR_PTR(err);
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700128 }
129
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700130 sb->s_flags |= MS_ACTIVE;
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700131 }
132
Eric W. Biederman4308eeb2011-03-23 16:43:13 -0700133 ei = PROC_I(sb->s_root->d_inode);
134 if (!ei->pid) {
135 rcu_read_lock();
136 ei->pid = get_pid(find_pid_ns(1, ns));
137 rcu_read_unlock();
138 }
139
Al Viroaed1d842010-07-26 13:12:54 +0400140 return dget(sb->s_root);
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700141}
142
143static void proc_kill_sb(struct super_block *sb)
144{
145 struct pid_namespace *ns;
146
147 ns = (struct pid_namespace *)sb->s_fs_info;
148 kill_anon_super(sb);
149 put_pid_ns(ns);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150}
151
Alexey Dobriyanc2319542007-11-28 16:21:23 -0800152static struct file_system_type proc_fs_type = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153 .name = "proc",
Al Viroaed1d842010-07-26 13:12:54 +0400154 .mount = proc_mount,
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700155 .kill_sb = proc_kill_sb,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156};
157
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158void __init proc_root_init(void)
159{
Alexey Dobriyan5bcd7ff2008-10-17 03:43:55 +0400160 int err;
161
162 proc_init_inodecache();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163 err = register_filesystem(&proc_fs_type);
164 if (err)
165 return;
Al Viro905ad262011-12-08 23:20:45 -0500166 err = pid_ns_prepare_proc(&init_pid_ns);
167 if (err) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168 unregister_filesystem(&proc_fs_type);
169 return;
170 }
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700171
Alexey Dobriyan59c75722008-10-06 14:49:39 +0400172 proc_symlink("mounts", NULL, "self/mounts");
Eric W. Biederman457c4cb2007-09-12 12:01:34 +0200173
174 proc_net_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175
176#ifdef CONFIG_SYSVIPC
177 proc_mkdir("sysvipc", NULL);
178#endif
Alexey Dobriyan36a5aeb2008-04-29 01:01:42 -0700179 proc_mkdir("fs", NULL);
Alexey Dobriyan928b4d82008-04-29 01:01:44 -0700180 proc_mkdir("driver", NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181 proc_mkdir("fs/nfsd", NULL); /* somewhere for the nfsd filesystem to be mounted */
182#if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
183 /* just give it a mountpoint */
184 proc_mkdir("openprom", NULL);
185#endif
186 proc_tty_init();
187#ifdef CONFIG_PROC_DEVICETREE
188 proc_device_tree_init();
189#endif
Alexey Dobriyan9c370662008-04-29 01:01:41 -0700190 proc_mkdir("bus", NULL);
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800191 proc_sys_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192}
193
Al Viro76b61592006-02-08 14:37:40 -0500194static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat
195)
196{
197 generic_fillattr(dentry->d_inode, stat);
198 stat->nlink = proc_root.nlink + nr_processes();
199 return 0;
200}
201
Al Viro00cd8dd2012-06-10 17:13:09 -0400202static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203{
Al Viro00cd8dd2012-06-10 17:13:09 -0400204 if (!proc_lookup(dir, dentry, flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206
Al Viro00cd8dd2012-06-10 17:13:09 -0400207 return proc_pid_lookup(dir, dentry, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208}
209
210static int proc_root_readdir(struct file * filp,
211 void * dirent, filldir_t filldir)
212{
213 unsigned int nr = filp->f_pos;
214 int ret;
215
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 if (nr < FIRST_PROCESS_ENTRY) {
217 int error = proc_readdir(filp, dirent, filldir);
Alexey Dobriyanb4df2b92008-10-27 22:48:36 +0300218 if (error <= 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 filp->f_pos = FIRST_PROCESS_ENTRY;
221 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222
223 ret = proc_pid_readdir(filp, dirent, filldir);
224 return ret;
225}
226
227/*
228 * The root /proc directory is special, as it has the
229 * <pid> directories. Thus we don't use the generic
230 * directory handling functions for that..
231 */
Arjan van de Ven00977a52007-02-12 00:55:34 -0800232static const struct file_operations proc_root_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233 .read = generic_read_dir,
234 .readdir = proc_root_readdir,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200235 .llseek = default_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236};
237
238/*
239 * proc root can do almost nothing..
240 */
Arjan van de Venc5ef1c42007-02-12 00:55:40 -0800241static const struct inode_operations proc_root_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242 .lookup = proc_root_lookup,
Al Viro76b61592006-02-08 14:37:40 -0500243 .getattr = proc_root_getattr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244};
245
246/*
247 * This is the root "inode" in the /proc tree..
248 */
249struct proc_dir_entry proc_root = {
250 .low_ino = PROC_ROOT_INO,
251 .namelen = 5,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
253 .nlink = 2,
Alexey Dobriyan5a622f22007-12-04 23:45:28 -0800254 .count = ATOMIC_INIT(1),
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255 .proc_iops = &proc_root_inode_operations,
256 .proc_fops = &proc_root_operations,
257 .parent = &proc_root,
David Howells09570f92011-07-27 21:47:03 +0300258 .name = "/proc",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259};
260
Pavel Emelyanov6f4e6432007-10-18 23:40:11 -0700261int pid_ns_prepare_proc(struct pid_namespace *ns)
262{
263 struct vfsmount *mnt;
264
265 mnt = kern_mount_data(&proc_fs_type, ns);
266 if (IS_ERR(mnt))
267 return PTR_ERR(mnt);
268
Al Viro579441a2010-07-26 13:09:36 +0400269 ns->proc_mnt = mnt;
Pavel Emelyanov6f4e6432007-10-18 23:40:11 -0700270 return 0;
271}
272
273void pid_ns_release_proc(struct pid_namespace *ns)
274{
Al Viro905ad262011-12-08 23:20:45 -0500275 kern_unmount(ns->proc_mnt);
Pavel Emelyanov6f4e6432007-10-18 23:40:11 -0700276}