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 < 0 || option > 2) {
62 pr_err("proc: hidepid value must be between 0 and 2.\n");
65 pid->hide_pid = option;
68 pr_err("proc: unrecognized mount option \"%s\" "
69 "or missing value\n", p);
77 int proc_remount(struct super_block *sb, int *flags, char *data)
79 struct pid_namespace *pid = sb->s_fs_info;
82 return !proc_parse_options(data, pid);
85 static struct dentry *proc_mount(struct file_system_type *fs_type,
86 int flags, const char *dev_name, void *data)
88 struct pid_namespace *ns;
90 if (flags & MS_KERNMOUNT) {
94 ns = task_active_pid_ns(current);
97 return mount_ns(fs_type, flags, data, ns, ns->user_ns, proc_fill_super);
100 static void proc_kill_sb(struct super_block *sb)
102 struct pid_namespace *ns;
104 ns = (struct pid_namespace *)sb->s_fs_info;
107 if (ns->proc_thread_self)
108 dput(ns->proc_thread_self);
113 static struct file_system_type proc_fs_type = {
116 .kill_sb = proc_kill_sb,
117 .fs_flags = FS_USERNS_MOUNT,
120 void __init proc_root_init(void)
124 proc_init_inodecache();
125 set_proc_pid_nlink();
126 err = register_filesystem(&proc_fs_type);
131 proc_thread_self_init();
132 proc_symlink("mounts", NULL, "self/mounts");
136 #ifdef CONFIG_SYSVIPC
137 proc_mkdir("sysvipc", NULL);
139 proc_mkdir("fs", NULL);
140 proc_mkdir("driver", NULL);
141 proc_create_mount_point("fs/nfsd"); /* somewhere for the nfsd filesystem to be mounted */
142 #if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
143 /* just give it a mountpoint */
144 proc_create_mount_point("openprom");
147 proc_mkdir("bus", NULL);
151 static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat
154 generic_fillattr(d_inode(dentry), stat);
155 stat->nlink = proc_root.nlink + nr_processes();
159 static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
161 if (!proc_pid_lookup(dir, dentry, flags))
164 return proc_lookup(dir, dentry, flags);
167 static int proc_root_readdir(struct file *file, struct dir_context *ctx)
169 if (ctx->pos < FIRST_PROCESS_ENTRY) {
170 int error = proc_readdir(file, ctx);
171 if (unlikely(error <= 0))
173 ctx->pos = FIRST_PROCESS_ENTRY;
176 return proc_pid_readdir(file, ctx);
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..
184 static const struct file_operations proc_root_operations = {
185 .read = generic_read_dir,
186 .iterate_shared = proc_root_readdir,
187 .llseek = generic_file_llseek,
191 * proc root can do almost nothing..
193 static const struct inode_operations proc_root_inode_operations = {
194 .lookup = proc_root_lookup,
195 .getattr = proc_root_getattr,
199 * This is the root "inode" in the /proc tree..
201 struct proc_dir_entry proc_root = {
202 .low_ino = PROC_ROOT_INO,
204 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
206 .count = ATOMIC_INIT(1),
207 .proc_iops = &proc_root_inode_operations,
208 .proc_fops = &proc_root_operations,
209 .parent = &proc_root,
214 int pid_ns_prepare_proc(struct pid_namespace *ns)
216 struct vfsmount *mnt;
218 mnt = kern_mount_data(&proc_fs_type, ns);
226 void pid_ns_release_proc(struct pid_namespace *ns)
228 kern_unmount(ns->proc_mnt);