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>
27 Opt_gid, Opt_hidepid, Opt_err,
30 static const match_table_t tokens = {
31 {Opt_hidepid, "hidepid=%u"},
36 int proc_parse_options(char *options, struct pid_namespace *pid)
39 substring_t args[MAX_OPT_ARGS];
45 while ((p = strsep(&options, ",")) != NULL) {
50 args[0].to = args[0].from = NULL;
51 token = match_token(p, tokens, args);
54 if (match_int(&args[0], &option))
56 pid->pid_gid = make_kgid(current_user_ns(), option);
59 if (match_int(&args[0], &option))
61 if (option < HIDEPID_OFF ||
62 option > HIDEPID_INVISIBLE) {
63 pr_err("proc: hidepid value must be between 0 and 2.\n");
66 pid->hide_pid = option;
69 pr_err("proc: unrecognized mount option \"%s\" "
70 "or missing value\n", p);
78 int proc_remount(struct super_block *sb, int *flags, char *data)
80 struct pid_namespace *pid = sb->s_fs_info;
83 return !proc_parse_options(data, pid);
86 static struct dentry *proc_mount(struct file_system_type *fs_type,
87 int flags, const char *dev_name, void *data)
89 struct pid_namespace *ns;
91 if (flags & MS_KERNMOUNT) {
95 ns = task_active_pid_ns(current);
98 return mount_ns(fs_type, flags, data, ns, ns->user_ns, proc_fill_super);
101 static void proc_kill_sb(struct super_block *sb)
103 struct pid_namespace *ns;
105 ns = (struct pid_namespace *)sb->s_fs_info;
108 if (ns->proc_thread_self)
109 dput(ns->proc_thread_self);
114 static struct file_system_type proc_fs_type = {
117 .kill_sb = proc_kill_sb,
118 .fs_flags = FS_USERNS_MOUNT,
121 void __init proc_root_init(void)
125 proc_init_inodecache();
126 set_proc_pid_nlink();
127 err = register_filesystem(&proc_fs_type);
132 proc_thread_self_init();
133 proc_symlink("mounts", NULL, "self/mounts");
137 #ifdef CONFIG_SYSVIPC
138 proc_mkdir("sysvipc", NULL);
140 proc_mkdir("fs", NULL);
141 proc_mkdir("driver", NULL);
142 proc_create_mount_point("fs/nfsd"); /* somewhere for the nfsd filesystem to be mounted */
143 #if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
144 /* just give it a mountpoint */
145 proc_create_mount_point("openprom");
148 proc_mkdir("bus", NULL);
152 static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat
155 generic_fillattr(d_inode(dentry), stat);
156 stat->nlink = proc_root.nlink + nr_processes();
160 static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
162 if (!proc_pid_lookup(dir, dentry, flags))
165 return proc_lookup(dir, dentry, flags);
168 static int proc_root_readdir(struct file *file, struct dir_context *ctx)
170 if (ctx->pos < FIRST_PROCESS_ENTRY) {
171 int error = proc_readdir(file, ctx);
172 if (unlikely(error <= 0))
174 ctx->pos = FIRST_PROCESS_ENTRY;
177 return proc_pid_readdir(file, ctx);
181 * The root /proc directory is special, as it has the
182 * <pid> directories. Thus we don't use the generic
183 * directory handling functions for that..
185 static const struct file_operations proc_root_operations = {
186 .read = generic_read_dir,
187 .iterate_shared = proc_root_readdir,
188 .llseek = generic_file_llseek,
192 * proc root can do almost nothing..
194 static const struct inode_operations proc_root_inode_operations = {
195 .lookup = proc_root_lookup,
196 .getattr = proc_root_getattr,
200 * This is the root "inode" in the /proc tree..
202 struct proc_dir_entry proc_root = {
203 .low_ino = PROC_ROOT_INO,
205 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
207 .count = ATOMIC_INIT(1),
208 .proc_iops = &proc_root_inode_operations,
209 .proc_fops = &proc_root_operations,
210 .parent = &proc_root,
215 int pid_ns_prepare_proc(struct pid_namespace *ns)
217 struct vfsmount *mnt;
219 mnt = kern_mount_data(&proc_fs_type, ns);
227 void pid_ns_release_proc(struct pid_namespace *ns)
229 kern_unmount(ns->proc_mnt);