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);