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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. Biederman87a8ebd2013-03-24 14:28:27 -070019#include <linux/user_namespace.h>
Eric W. Biedermanf6c7a1f2006-10-02 02:17:07 -070020#include <linux/mount.h>
Pavel Emelyanov07543f52007-10-18 23:40:08 -070021#include <linux/pid_namespace.h>
Vasiliy Kulikov97412952012-01-10 15:11:27 -080022#include <linux/parser.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023
Adrian Bunkfee781e2006-01-08 01:04:16 -080024#include "internal.h"
25
Pavel Emelyanov07543f52007-10-18 23:40:08 -070026static int proc_test_super(struct super_block *sb, void *data)
27{
28 return sb->s_fs_info == data;
29}
30
31static int proc_set_super(struct super_block *sb, void *data)
32{
Al Viroff78fca2011-06-12 09:42:17 -040033 int err = set_anon_super(sb, NULL);
34 if (!err) {
35 struct pid_namespace *ns = (struct pid_namespace *)data;
36 sb->s_fs_info = get_pid_ns(ns);
37 }
38 return err;
Pavel Emelyanov07543f52007-10-18 23:40:08 -070039}
40
Vasiliy Kulikov97412952012-01-10 15:11:27 -080041enum {
Vasiliy Kulikov04996802012-01-10 15:11:31 -080042 Opt_gid, Opt_hidepid, Opt_err,
Vasiliy Kulikov97412952012-01-10 15:11:27 -080043};
44
45static const match_table_t tokens = {
Vasiliy Kulikov04996802012-01-10 15:11:31 -080046 {Opt_hidepid, "hidepid=%u"},
47 {Opt_gid, "gid=%u"},
Vasiliy Kulikov97412952012-01-10 15:11:27 -080048 {Opt_err, NULL},
49};
50
51static int proc_parse_options(char *options, struct pid_namespace *pid)
52{
53 char *p;
54 substring_t args[MAX_OPT_ARGS];
Vasiliy Kulikov04996802012-01-10 15:11:31 -080055 int option;
Vasiliy Kulikov97412952012-01-10 15:11:27 -080056
57 if (!options)
58 return 1;
59
60 while ((p = strsep(&options, ",")) != NULL) {
61 int token;
62 if (!*p)
63 continue;
64
Sachin Kamat9fb88442012-10-04 17:15:46 -070065 args[0].to = args[0].from = NULL;
Vasiliy Kulikov97412952012-01-10 15:11:27 -080066 token = match_token(p, tokens, args);
67 switch (token) {
Vasiliy Kulikov04996802012-01-10 15:11:31 -080068 case Opt_gid:
69 if (match_int(&args[0], &option))
70 return 0;
Eric W. Biedermandcb0f222012-02-09 08:48:21 -080071 pid->pid_gid = make_kgid(current_user_ns(), option);
Vasiliy Kulikov04996802012-01-10 15:11:31 -080072 break;
73 case Opt_hidepid:
74 if (match_int(&args[0], &option))
75 return 0;
76 if (option < 0 || option > 2) {
77 pr_err("proc: hidepid value must be between 0 and 2.\n");
78 return 0;
79 }
80 pid->hide_pid = option;
81 break;
Vasiliy Kulikov97412952012-01-10 15:11:27 -080082 default:
83 pr_err("proc: unrecognized mount option \"%s\" "
84 "or missing value\n", p);
85 return 0;
86 }
87 }
88
89 return 1;
90}
91
92int proc_remount(struct super_block *sb, int *flags, char *data)
93{
94 struct pid_namespace *pid = sb->s_fs_info;
95 return !proc_parse_options(data, pid);
96}
97
Al Viroaed1d842010-07-26 13:12:54 +040098static struct dentry *proc_mount(struct file_system_type *fs_type,
99 int flags, const char *dev_name, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100{
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700101 int err;
102 struct super_block *sb;
103 struct pid_namespace *ns;
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 {
Eric W. Biederman17cf22c2010-03-02 14:51:53 -0800110 ns = task_active_pid_ns(current);
Vasiliy Kulikov97412952012-01-10 15:11:27 -0800111 options = data;
Eric W. Biederman87a8ebd2013-03-24 14:28:27 -0700112
113 if (!current_user_ns()->may_mount_proc)
114 return ERR_PTR(-EPERM);
Vasiliy Kulikov97412952012-01-10 15:11:27 -0800115 }
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700116
David Howells9249e172012-06-25 12:55:37 +0100117 sb = sget(fs_type, proc_test_super, proc_set_super, flags, ns);
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700118 if (IS_ERR(sb))
Al Viroaed1d842010-07-26 13:12:54 +0400119 return ERR_CAST(sb);
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700120
Vasiliy Kulikov99663be2012-04-05 14:25:04 -0700121 if (!proc_parse_options(options, ns)) {
122 deactivate_locked_super(sb);
123 return ERR_PTR(-EINVAL);
124 }
125
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700126 if (!sb->s_root) {
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700127 err = proc_fill_super(sb);
128 if (err) {
Al Viro6f5bbff2009-05-06 01:34:22 -0400129 deactivate_locked_super(sb);
Al Viroaed1d842010-07-26 13:12:54 +0400130 return ERR_PTR(err);
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700131 }
132
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700133 sb->s_flags |= MS_ACTIVE;
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700134 }
135
Al Viroaed1d842010-07-26 13:12:54 +0400136 return dget(sb->s_root);
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700137}
138
139static void proc_kill_sb(struct super_block *sb)
140{
141 struct pid_namespace *ns;
142
143 ns = (struct pid_namespace *)sb->s_fs_info;
Al Viro021ada72013-03-29 19:27:05 -0400144 if (ns->proc_self)
145 dput(ns->proc_self);
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700146 kill_anon_super(sb);
147 put_pid_ns(ns);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148}
149
Alexey Dobriyanc2319542007-11-28 16:21:23 -0800150static struct file_system_type proc_fs_type = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151 .name = "proc",
Al Viroaed1d842010-07-26 13:12:54 +0400152 .mount = proc_mount,
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700153 .kill_sb = proc_kill_sb,
Eric W. Biederman4f326c02012-07-27 05:56:48 -0700154 .fs_flags = FS_USERNS_MOUNT,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155};
156
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157void __init proc_root_init(void)
158{
Alexey Dobriyan5bcd7ff2008-10-17 03:43:55 +0400159 int err;
160
161 proc_init_inodecache();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162 err = register_filesystem(&proc_fs_type);
163 if (err)
164 return;
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700165
Eric W. Biedermane656d8a2010-07-10 14:52:49 -0700166 proc_self_init();
Alexey Dobriyan59c75722008-10-06 14:49:39 +0400167 proc_symlink("mounts", NULL, "self/mounts");
Eric W. Biederman457c4cb2007-09-12 12:01:34 +0200168
169 proc_net_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170
171#ifdef CONFIG_SYSVIPC
172 proc_mkdir("sysvipc", NULL);
173#endif
Alexey Dobriyan36a5aeb2008-04-29 01:01:42 -0700174 proc_mkdir("fs", NULL);
Alexey Dobriyan928b4d82008-04-29 01:01:44 -0700175 proc_mkdir("driver", NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176 proc_mkdir("fs/nfsd", NULL); /* somewhere for the nfsd filesystem to be mounted */
177#if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
178 /* just give it a mountpoint */
179 proc_mkdir("openprom", NULL);
180#endif
181 proc_tty_init();
182#ifdef CONFIG_PROC_DEVICETREE
183 proc_device_tree_init();
184#endif
Alexey Dobriyan9c370662008-04-29 01:01:41 -0700185 proc_mkdir("bus", NULL);
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800186 proc_sys_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187}
188
Al Viro76b61592006-02-08 14:37:40 -0500189static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat
190)
191{
192 generic_fillattr(dentry->d_inode, stat);
193 stat->nlink = proc_root.nlink + nr_processes();
194 return 0;
195}
196
Al Viro00cd8dd2012-06-10 17:13:09 -0400197static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198{
Al Viro00cd8dd2012-06-10 17:13:09 -0400199 if (!proc_lookup(dir, dentry, flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201
Al Viro00cd8dd2012-06-10 17:13:09 -0400202 return proc_pid_lookup(dir, dentry, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203}
204
Al Virof0c3b502013-05-16 12:07:31 -0400205static int proc_root_readdir(struct file *file, struct dir_context *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206{
Al Virof0c3b502013-05-16 12:07:31 -0400207 if (ctx->pos < FIRST_PROCESS_ENTRY) {
Richard Genoud94fc5d92013-08-19 18:30:31 +0200208 int error = proc_readdir(file, ctx);
209 if (unlikely(error <= 0))
210 return error;
Al Virof0c3b502013-05-16 12:07:31 -0400211 ctx->pos = FIRST_PROCESS_ENTRY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213
Al Virof0c3b502013-05-16 12:07:31 -0400214 return proc_pid_readdir(file, ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215}
216
217/*
218 * The root /proc directory is special, as it has the
219 * <pid> directories. Thus we don't use the generic
220 * directory handling functions for that..
221 */
Arjan van de Ven00977a52007-02-12 00:55:34 -0800222static const struct file_operations proc_root_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 .read = generic_read_dir,
Al Virof0c3b502013-05-16 12:07:31 -0400224 .iterate = proc_root_readdir,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200225 .llseek = default_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226};
227
228/*
229 * proc root can do almost nothing..
230 */
Arjan van de Venc5ef1c42007-02-12 00:55:40 -0800231static const struct inode_operations proc_root_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232 .lookup = proc_root_lookup,
Al Viro76b61592006-02-08 14:37:40 -0500233 .getattr = proc_root_getattr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234};
235
236/*
237 * This is the root "inode" in the /proc tree..
238 */
239struct proc_dir_entry proc_root = {
240 .low_ino = PROC_ROOT_INO,
241 .namelen = 5,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
243 .nlink = 2,
Alexey Dobriyan5a622f22007-12-04 23:45:28 -0800244 .count = ATOMIC_INIT(1),
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 .proc_iops = &proc_root_inode_operations,
246 .proc_fops = &proc_root_operations,
247 .parent = &proc_root,
David Howells09570f92011-07-27 21:47:03 +0300248 .name = "/proc",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249};
250
Pavel Emelyanov6f4e6432007-10-18 23:40:11 -0700251int pid_ns_prepare_proc(struct pid_namespace *ns)
252{
253 struct vfsmount *mnt;
254
255 mnt = kern_mount_data(&proc_fs_type, ns);
256 if (IS_ERR(mnt))
257 return PTR_ERR(mnt);
258
Al Viro579441a2010-07-26 13:09:36 +0400259 ns->proc_mnt = mnt;
Pavel Emelyanov6f4e6432007-10-18 23:40:11 -0700260 return 0;
261}
262
263void pid_ns_release_proc(struct pid_namespace *ns)
264{
Al Viro905ad262011-12-08 23:20:45 -0500265 kern_unmount(ns->proc_mnt);
Pavel Emelyanov6f4e6432007-10-18 23:40:11 -0700266}