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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
Linus Torvalds7c0f6ba2016-12-24 11:46:01 -08009#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070010
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
Vasiliy Kulikov97412952012-01-10 15:11:27 -080026enum {
Vasiliy Kulikov04996802012-01-10 15:11:31 -080027 Opt_gid, Opt_hidepid, Opt_err,
Vasiliy Kulikov97412952012-01-10 15:11:27 -080028};
29
30static const match_table_t tokens = {
Vasiliy Kulikov04996802012-01-10 15:11:31 -080031 {Opt_hidepid, "hidepid=%u"},
32 {Opt_gid, "gid=%u"},
Vasiliy Kulikov97412952012-01-10 15:11:27 -080033 {Opt_err, NULL},
34};
35
Eric W. Biedermane94591d2016-06-09 15:32:10 -050036int proc_parse_options(char *options, struct pid_namespace *pid)
Vasiliy Kulikov97412952012-01-10 15:11:27 -080037{
38 char *p;
39 substring_t args[MAX_OPT_ARGS];
Vasiliy Kulikov04996802012-01-10 15:11:31 -080040 int option;
Vasiliy Kulikov97412952012-01-10 15:11:27 -080041
42 if (!options)
43 return 1;
44
45 while ((p = strsep(&options, ",")) != NULL) {
46 int token;
47 if (!*p)
48 continue;
49
Sachin Kamat9fb88442012-10-04 17:15:46 -070050 args[0].to = args[0].from = NULL;
Vasiliy Kulikov97412952012-01-10 15:11:27 -080051 token = match_token(p, tokens, args);
52 switch (token) {
Vasiliy Kulikov04996802012-01-10 15:11:31 -080053 case Opt_gid:
54 if (match_int(&args[0], &option))
55 return 0;
Eric W. Biedermandcb0f222012-02-09 08:48:21 -080056 pid->pid_gid = make_kgid(current_user_ns(), option);
Vasiliy Kulikov04996802012-01-10 15:11:31 -080057 break;
58 case Opt_hidepid:
59 if (match_int(&args[0], &option))
60 return 0;
61 if (option < 0 || option > 2) {
62 pr_err("proc: hidepid value must be between 0 and 2.\n");
63 return 0;
64 }
65 pid->hide_pid = option;
66 break;
Vasiliy Kulikov97412952012-01-10 15:11:27 -080067 default:
68 pr_err("proc: unrecognized mount option \"%s\" "
69 "or missing value\n", p);
70 return 0;
71 }
72 }
73
74 return 1;
75}
76
77int proc_remount(struct super_block *sb, int *flags, char *data)
78{
79 struct pid_namespace *pid = sb->s_fs_info;
Theodore Ts'o02b99842014-03-13 10:14:33 -040080
81 sync_filesystem(sb);
Vasiliy Kulikov97412952012-01-10 15:11:27 -080082 return !proc_parse_options(data, pid);
83}
84
Al Viroaed1d842010-07-26 13:12:54 +040085static struct dentry *proc_mount(struct file_system_type *fs_type,
86 int flags, const char *dev_name, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -070087{
Pavel Emelyanov07543f52007-10-18 23:40:08 -070088 struct pid_namespace *ns;
Pavel Emelyanov07543f52007-10-18 23:40:08 -070089
Vasiliy Kulikov97412952012-01-10 15:11:27 -080090 if (flags & MS_KERNMOUNT) {
Eric W. Biedermane94591d2016-06-09 15:32:10 -050091 ns = data;
92 data = NULL;
Vasiliy Kulikov97412952012-01-10 15:11:27 -080093 } else {
Eric W. Biederman17cf22c2010-03-02 14:51:53 -080094 ns = task_active_pid_ns(current);
Vasiliy Kulikov97412952012-01-10 15:11:27 -080095 }
Pavel Emelyanov07543f52007-10-18 23:40:08 -070096
Eric W. Biedermane94591d2016-06-09 15:32:10 -050097 return mount_ns(fs_type, flags, data, ns, ns->user_ns, proc_fill_super);
Pavel Emelyanov07543f52007-10-18 23:40:08 -070098}
99
100static void proc_kill_sb(struct super_block *sb)
101{
102 struct pid_namespace *ns;
103
104 ns = (struct pid_namespace *)sb->s_fs_info;
Al Viro021ada72013-03-29 19:27:05 -0400105 if (ns->proc_self)
106 dput(ns->proc_self);
Eric W. Biederman00978752014-07-31 03:10:50 -0700107 if (ns->proc_thread_self)
108 dput(ns->proc_thread_self);
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700109 kill_anon_super(sb);
110 put_pid_ns(ns);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111}
112
Alexey Dobriyanc2319542007-11-28 16:21:23 -0800113static struct file_system_type proc_fs_type = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 .name = "proc",
Al Viroaed1d842010-07-26 13:12:54 +0400115 .mount = proc_mount,
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700116 .kill_sb = proc_kill_sb,
Eric W. Biederman8654df42016-06-09 16:06:06 -0500117 .fs_flags = FS_USERNS_MOUNT,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118};
119
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120void __init proc_root_init(void)
121{
Alexey Dobriyan5bcd7ff2008-10-17 03:43:55 +0400122 int err;
123
124 proc_init_inodecache();
Alexey Dobriyan1270dd82016-12-12 16:45:32 -0800125 set_proc_pid_nlink();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 err = register_filesystem(&proc_fs_type);
127 if (err)
128 return;
Pavel Emelyanov07543f52007-10-18 23:40:08 -0700129
Eric W. Biedermane656d8a2010-07-10 14:52:49 -0700130 proc_self_init();
Eric W. Biederman00978752014-07-31 03:10:50 -0700131 proc_thread_self_init();
Linus Torvalds155134f2014-08-10 21:24:59 -0700132 proc_symlink("mounts", NULL, "self/mounts");
Eric W. Biederman457c4cb2007-09-12 12:01:34 +0200133
134 proc_net_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135
136#ifdef CONFIG_SYSVIPC
137 proc_mkdir("sysvipc", NULL);
138#endif
Alexey Dobriyan36a5aeb2008-04-29 01:01:42 -0700139 proc_mkdir("fs", NULL);
Alexey Dobriyan928b4d82008-04-29 01:01:44 -0700140 proc_mkdir("driver", NULL);
Eric W. Biedermaneb6d38d2015-05-11 16:44:25 -0500141 proc_create_mount_point("fs/nfsd"); /* somewhere for the nfsd filesystem to be mounted */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142#if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
143 /* just give it a mountpoint */
Eric W. Biedermaneb6d38d2015-05-11 16:44:25 -0500144 proc_create_mount_point("openprom");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145#endif
146 proc_tty_init();
Alexey Dobriyan9c370662008-04-29 01:01:41 -0700147 proc_mkdir("bus", NULL);
Eric W. Biederman77b14db2007-02-14 00:34:12 -0800148 proc_sys_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149}
150
Al Viro76b61592006-02-08 14:37:40 -0500151static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat
152)
153{
David Howells2b0143b2015-03-17 22:25:59 +0000154 generic_fillattr(d_inode(dentry), stat);
Al Viro76b61592006-02-08 14:37:40 -0500155 stat->nlink = proc_root.nlink + nr_processes();
156 return 0;
157}
158
Al Viro00cd8dd2012-06-10 17:13:09 -0400159static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160{
Alexey Dobriyan335eb532014-08-08 14:21:27 -0700161 if (!proc_pid_lookup(dir, dentry, flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163
Alexey Dobriyan335eb532014-08-08 14:21:27 -0700164 return proc_lookup(dir, dentry, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165}
166
Al Virof0c3b502013-05-16 12:07:31 -0400167static int proc_root_readdir(struct file *file, struct dir_context *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168{
Al Virof0c3b502013-05-16 12:07:31 -0400169 if (ctx->pos < FIRST_PROCESS_ENTRY) {
Richard Genoud94fc5d92013-08-19 18:30:31 +0200170 int error = proc_readdir(file, ctx);
171 if (unlikely(error <= 0))
172 return error;
Al Virof0c3b502013-05-16 12:07:31 -0400173 ctx->pos = FIRST_PROCESS_ENTRY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175
Al Virof0c3b502013-05-16 12:07:31 -0400176 return proc_pid_readdir(file, ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177}
178
179/*
180 * The root /proc directory is special, as it has the
181 * <pid> directories. Thus we don't use the generic
182 * directory handling functions for that..
183 */
Arjan van de Ven00977a52007-02-12 00:55:34 -0800184static const struct file_operations proc_root_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 .read = generic_read_dir,
Al Virof50752e2016-04-20 17:13:54 -0400186 .iterate_shared = proc_root_readdir,
187 .llseek = generic_file_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188};
189
190/*
191 * proc root can do almost nothing..
192 */
Arjan van de Venc5ef1c42007-02-12 00:55:40 -0800193static const struct inode_operations proc_root_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 .lookup = proc_root_lookup,
Al Viro76b61592006-02-08 14:37:40 -0500195 .getattr = proc_root_getattr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196};
197
198/*
199 * This is the root "inode" in the /proc tree..
200 */
201struct proc_dir_entry proc_root = {
202 .low_ino = PROC_ROOT_INO,
203 .namelen = 5,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
205 .nlink = 2,
Alexey Dobriyan5a622f22007-12-04 23:45:28 -0800206 .count = ATOMIC_INIT(1),
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 .proc_iops = &proc_root_inode_operations,
208 .proc_fops = &proc_root_operations,
209 .parent = &proc_root,
Nicolas Dichtel710585d2014-12-10 15:45:01 -0800210 .subdir = RB_ROOT,
David Howells09570f92011-07-27 21:47:03 +0300211 .name = "/proc",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212};
213
Pavel Emelyanov6f4e6432007-10-18 23:40:11 -0700214int pid_ns_prepare_proc(struct pid_namespace *ns)
215{
216 struct vfsmount *mnt;
217
218 mnt = kern_mount_data(&proc_fs_type, ns);
219 if (IS_ERR(mnt))
220 return PTR_ERR(mnt);
221
Al Viro579441a2010-07-26 13:09:36 +0400222 ns->proc_mnt = mnt;
Pavel Emelyanov6f4e6432007-10-18 23:40:11 -0700223 return 0;
224}
225
226void pid_ns_release_proc(struct pid_namespace *ns)
227{
Al Viro905ad262011-12-08 23:20:45 -0500228 kern_unmount(ns->proc_mnt);
Pavel Emelyanov6f4e6432007-10-18 23:40:11 -0700229}