4 * Copyright (C) 1991, 1992 Linus Torvalds
6 * proc root directory handling functions
9 #include <asm/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/mount.h>
20 #include <linux/pid_namespace.h>
21 #include <linux/parser.h>
25 static int proc_test_super(struct super_block *sb, void *data)
27 return sb->s_fs_info == data;
30 static int proc_set_super(struct super_block *sb, void *data)
32 int err = set_anon_super(sb, NULL);
34 struct pid_namespace *ns = (struct pid_namespace *)data;
35 sb->s_fs_info = get_pid_ns(ns);
41 Opt_gid, Opt_hidepid, Opt_err,
44 static const match_table_t tokens = {
45 {Opt_hidepid, "hidepid=%u"},
50 static int proc_parse_options(char *options, struct pid_namespace *pid)
53 substring_t args[MAX_OPT_ARGS];
59 while ((p = strsep(&options, ",")) != NULL) {
64 args[0].to = args[0].from = NULL;
65 token = match_token(p, tokens, args);
68 if (match_int(&args[0], &option))
70 pid->pid_gid = make_kgid(current_user_ns(), option);
73 if (match_int(&args[0], &option))
75 if (option < 0 || option > 2) {
76 pr_err("proc: hidepid value must be between 0 and 2.\n");
79 pid->hide_pid = option;
82 pr_err("proc: unrecognized mount option \"%s\" "
83 "or missing value\n", p);
91 int proc_remount(struct super_block *sb, int *flags, char *data)
93 struct pid_namespace *pid = sb->s_fs_info;
94 return !proc_parse_options(data, pid);
97 static struct dentry *proc_mount(struct file_system_type *fs_type,
98 int flags, const char *dev_name, void *data)
101 struct super_block *sb;
102 struct pid_namespace *ns;
105 if (flags & MS_KERNMOUNT) {
106 ns = (struct pid_namespace *)data;
109 ns = task_active_pid_ns(current);
113 sb = sget(fs_type, proc_test_super, proc_set_super, flags, ns);
117 if (!proc_parse_options(options, ns)) {
118 deactivate_locked_super(sb);
119 return ERR_PTR(-EINVAL);
123 err = proc_fill_super(sb);
125 deactivate_locked_super(sb);
129 sb->s_flags |= MS_ACTIVE;
132 return dget(sb->s_root);
135 static void proc_kill_sb(struct super_block *sb)
137 struct pid_namespace *ns;
139 ns = (struct pid_namespace *)sb->s_fs_info;
144 static struct file_system_type proc_fs_type = {
147 .kill_sb = proc_kill_sb,
148 .fs_flags = FS_USERNS_MOUNT,
151 void __init proc_root_init(void)
155 proc_init_inodecache();
156 err = register_filesystem(&proc_fs_type);
161 proc_symlink("mounts", NULL, "self/mounts");
165 #ifdef CONFIG_SYSVIPC
166 proc_mkdir("sysvipc", NULL);
168 proc_mkdir("fs", NULL);
169 proc_mkdir("driver", NULL);
170 proc_mkdir("fs/nfsd", NULL); /* somewhere for the nfsd filesystem to be mounted */
171 #if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
172 /* just give it a mountpoint */
173 proc_mkdir("openprom", NULL);
176 #ifdef CONFIG_PROC_DEVICETREE
177 proc_device_tree_init();
179 proc_mkdir("bus", NULL);
183 static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat
186 generic_fillattr(dentry->d_inode, stat);
187 stat->nlink = proc_root.nlink + nr_processes();
191 static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
193 if (!proc_lookup(dir, dentry, flags))
196 return proc_pid_lookup(dir, dentry, flags);
199 static int proc_root_readdir(struct file * filp,
200 void * dirent, filldir_t filldir)
202 unsigned int nr = filp->f_pos;
205 if (nr < FIRST_PROCESS_ENTRY) {
206 int error = proc_readdir(filp, dirent, filldir);
209 filp->f_pos = FIRST_PROCESS_ENTRY;
212 ret = proc_pid_readdir(filp, dirent, filldir);
217 * The root /proc directory is special, as it has the
218 * <pid> directories. Thus we don't use the generic
219 * directory handling functions for that..
221 static const struct file_operations proc_root_operations = {
222 .read = generic_read_dir,
223 .readdir = proc_root_readdir,
224 .llseek = default_llseek,
228 * proc root can do almost nothing..
230 static const struct inode_operations proc_root_inode_operations = {
231 .lookup = proc_root_lookup,
232 .getattr = proc_root_getattr,
236 * This is the root "inode" in the /proc tree..
238 struct proc_dir_entry proc_root = {
239 .low_ino = PROC_ROOT_INO,
241 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
243 .count = ATOMIC_INIT(1),
244 .proc_iops = &proc_root_inode_operations,
245 .proc_fops = &proc_root_operations,
246 .parent = &proc_root,
250 int pid_ns_prepare_proc(struct pid_namespace *ns)
252 struct vfsmount *mnt;
254 mnt = kern_mount_data(&proc_fs_type, ns);
262 void pid_ns_release_proc(struct pid_namespace *ns)
264 kern_unmount(ns->proc_mnt);