4 * Copyright (C) 1991, 1992 Linus Torvalds
6 * proc root directory handling functions
9 #include <linux/uaccess.h>
11 #include <linux/errno.h>
12 #include <linux/time.h>
13 #include <linux/proc_fs.h>
14 #include <linux/stat.h>
15 #include <linux/init.h>
16 #include <linux/sched.h>
17 #include <linux/module.h>
18 #include <linux/bitops.h>
19 #include <linux/user_namespace.h>
20 #include <linux/mount.h>
21 #include <linux/pid_namespace.h>
22 #include <linux/parser.h>
23 #include <linux/cred.h>
28 Opt_gid
, Opt_hidepid
, Opt_err
,
31 static const match_table_t tokens
= {
32 {Opt_hidepid
, "hidepid=%u"},
37 int proc_parse_options(char *options
, struct pid_namespace
*pid
)
40 substring_t args
[MAX_OPT_ARGS
];
46 while ((p
= strsep(&options
, ",")) != NULL
) {
51 args
[0].to
= args
[0].from
= NULL
;
52 token
= match_token(p
, tokens
, args
);
55 if (match_int(&args
[0], &option
))
57 pid
->pid_gid
= make_kgid(current_user_ns(), option
);
60 if (match_int(&args
[0], &option
))
62 if (option
< HIDEPID_OFF
||
63 option
> HIDEPID_INVISIBLE
) {
64 pr_err("proc: hidepid value must be between 0 and 2.\n");
67 pid
->hide_pid
= option
;
70 pr_err("proc: unrecognized mount option \"%s\" "
71 "or missing value\n", p
);
79 int proc_remount(struct super_block
*sb
, int *flags
, char *data
)
81 struct pid_namespace
*pid
= sb
->s_fs_info
;
84 return !proc_parse_options(data
, pid
);
87 static struct dentry
*proc_mount(struct file_system_type
*fs_type
,
88 int flags
, const char *dev_name
, void *data
)
90 struct pid_namespace
*ns
;
92 if (flags
& MS_KERNMOUNT
) {
96 ns
= task_active_pid_ns(current
);
99 return mount_ns(fs_type
, flags
, data
, ns
, ns
->user_ns
, proc_fill_super
);
102 static void proc_kill_sb(struct super_block
*sb
)
104 struct pid_namespace
*ns
;
106 ns
= (struct pid_namespace
*)sb
->s_fs_info
;
109 if (ns
->proc_thread_self
)
110 dput(ns
->proc_thread_self
);
115 static struct file_system_type proc_fs_type
= {
118 .kill_sb
= proc_kill_sb
,
119 .fs_flags
= FS_USERNS_MOUNT
,
122 void __init
proc_root_init(void)
126 proc_init_inodecache();
127 set_proc_pid_nlink();
128 err
= register_filesystem(&proc_fs_type
);
133 proc_thread_self_init();
134 proc_symlink("mounts", NULL
, "self/mounts");
138 #ifdef CONFIG_SYSVIPC
139 proc_mkdir("sysvipc", NULL
);
141 proc_mkdir("fs", NULL
);
142 proc_mkdir("driver", NULL
);
143 proc_create_mount_point("fs/nfsd"); /* somewhere for the nfsd filesystem to be mounted */
144 #if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
145 /* just give it a mountpoint */
146 proc_create_mount_point("openprom");
149 proc_mkdir("bus", NULL
);
153 static int proc_root_getattr(struct vfsmount
*mnt
, struct dentry
*dentry
, struct kstat
*stat
156 generic_fillattr(d_inode(dentry
), stat
);
157 stat
->nlink
= proc_root
.nlink
+ nr_processes();
161 static struct dentry
*proc_root_lookup(struct inode
* dir
, struct dentry
* dentry
, unsigned int flags
)
163 if (!proc_pid_lookup(dir
, dentry
, flags
))
166 return proc_lookup(dir
, dentry
, flags
);
169 static int proc_root_readdir(struct file
*file
, struct dir_context
*ctx
)
171 if (ctx
->pos
< FIRST_PROCESS_ENTRY
) {
172 int error
= proc_readdir(file
, ctx
);
173 if (unlikely(error
<= 0))
175 ctx
->pos
= FIRST_PROCESS_ENTRY
;
178 return proc_pid_readdir(file
, ctx
);
182 * The root /proc directory is special, as it has the
183 * <pid> directories. Thus we don't use the generic
184 * directory handling functions for that..
186 static const struct file_operations proc_root_operations
= {
187 .read
= generic_read_dir
,
188 .iterate_shared
= proc_root_readdir
,
189 .llseek
= generic_file_llseek
,
193 * proc root can do almost nothing..
195 static const struct inode_operations proc_root_inode_operations
= {
196 .lookup
= proc_root_lookup
,
197 .getattr
= proc_root_getattr
,
201 * This is the root "inode" in the /proc tree..
203 struct proc_dir_entry proc_root
= {
204 .low_ino
= PROC_ROOT_INO
,
206 .mode
= S_IFDIR
| S_IRUGO
| S_IXUGO
,
208 .count
= ATOMIC_INIT(1),
209 .proc_iops
= &proc_root_inode_operations
,
210 .proc_fops
= &proc_root_operations
,
211 .parent
= &proc_root
,
216 int pid_ns_prepare_proc(struct pid_namespace
*ns
)
218 struct vfsmount
*mnt
;
220 mnt
= kern_mount_data(&proc_fs_type
, ns
);
228 void pid_ns_release_proc(struct pid_namespace
*ns
)
230 kern_unmount(ns
->proc_mnt
);