Linux kernel mirror (for testing)
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linux
1/*
2 * linux/fs/proc/root.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 *
6 * proc root directory handling functions
7 */
8
9#include <asm/uaccess.h>
10
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
22#include "internal.h"
23
24static int proc_test_super(struct super_block *sb, void *data)
25{
26 return sb->s_fs_info == data;
27}
28
29static int proc_set_super(struct super_block *sb, void *data)
30{
31 struct pid_namespace *ns;
32
33 ns = (struct pid_namespace *)data;
34 sb->s_fs_info = get_pid_ns(ns);
35 return set_anon_super(sb, NULL);
36}
37
38static int proc_get_sb(struct file_system_type *fs_type,
39 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
40{
41 int err;
42 struct super_block *sb;
43 struct pid_namespace *ns;
44 struct proc_inode *ei;
45
46 if (proc_mnt) {
47 /* Seed the root directory with a pid so it doesn't need
48 * to be special in base.c. I would do this earlier but
49 * the only task alive when /proc is mounted the first time
50 * is the init_task and it doesn't have any pids.
51 */
52 ei = PROC_I(proc_mnt->mnt_sb->s_root->d_inode);
53 if (!ei->pid)
54 ei->pid = find_get_pid(1);
55 }
56
57 if (flags & MS_KERNMOUNT)
58 ns = (struct pid_namespace *)data;
59 else
60 ns = current->nsproxy->pid_ns;
61
62 sb = sget(fs_type, proc_test_super, proc_set_super, ns);
63 if (IS_ERR(sb))
64 return PTR_ERR(sb);
65
66 if (!sb->s_root) {
67 sb->s_flags = flags;
68 err = proc_fill_super(sb);
69 if (err) {
70 up_write(&sb->s_umount);
71 deactivate_super(sb);
72 return err;
73 }
74
75 ei = PROC_I(sb->s_root->d_inode);
76 if (!ei->pid) {
77 rcu_read_lock();
78 ei->pid = get_pid(find_pid_ns(1, ns));
79 rcu_read_unlock();
80 }
81
82 sb->s_flags |= MS_ACTIVE;
83 ns->proc_mnt = mnt;
84 }
85
86 simple_set_mnt(mnt, sb);
87 return 0;
88}
89
90static void proc_kill_sb(struct super_block *sb)
91{
92 struct pid_namespace *ns;
93
94 ns = (struct pid_namespace *)sb->s_fs_info;
95 kill_anon_super(sb);
96 put_pid_ns(ns);
97}
98
99static struct file_system_type proc_fs_type = {
100 .name = "proc",
101 .get_sb = proc_get_sb,
102 .kill_sb = proc_kill_sb,
103};
104
105void __init proc_root_init(void)
106{
107 int err;
108
109 proc_init_inodecache();
110 err = register_filesystem(&proc_fs_type);
111 if (err)
112 return;
113 proc_mnt = kern_mount_data(&proc_fs_type, &init_pid_ns);
114 err = PTR_ERR(proc_mnt);
115 if (IS_ERR(proc_mnt)) {
116 unregister_filesystem(&proc_fs_type);
117 return;
118 }
119
120 proc_symlink("mounts", NULL, "self/mounts");
121
122 proc_net_init();
123
124#ifdef CONFIG_SYSVIPC
125 proc_mkdir("sysvipc", NULL);
126#endif
127 proc_mkdir("fs", NULL);
128 proc_mkdir("driver", NULL);
129 proc_mkdir("fs/nfsd", NULL); /* somewhere for the nfsd filesystem to be mounted */
130#if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
131 /* just give it a mountpoint */
132 proc_mkdir("openprom", NULL);
133#endif
134 proc_tty_init();
135#ifdef CONFIG_PROC_DEVICETREE
136 proc_device_tree_init();
137#endif
138 proc_mkdir("bus", NULL);
139 proc_sys_init();
140}
141
142static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat
143)
144{
145 generic_fillattr(dentry->d_inode, stat);
146 stat->nlink = proc_root.nlink + nr_processes();
147 return 0;
148}
149
150static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
151{
152 if (!proc_lookup(dir, dentry, nd)) {
153 return NULL;
154 }
155
156 return proc_pid_lookup(dir, dentry, nd);
157}
158
159static int proc_root_readdir(struct file * filp,
160 void * dirent, filldir_t filldir)
161{
162 unsigned int nr = filp->f_pos;
163 int ret;
164
165 if (nr < FIRST_PROCESS_ENTRY) {
166 int error = proc_readdir(filp, dirent, filldir);
167 if (error <= 0)
168 return error;
169 filp->f_pos = FIRST_PROCESS_ENTRY;
170 }
171
172 ret = proc_pid_readdir(filp, dirent, filldir);
173 return ret;
174}
175
176/*
177 * The root /proc directory is special, as it has the
178 * <pid> directories. Thus we don't use the generic
179 * directory handling functions for that..
180 */
181static const struct file_operations proc_root_operations = {
182 .read = generic_read_dir,
183 .readdir = proc_root_readdir,
184};
185
186/*
187 * proc root can do almost nothing..
188 */
189static const struct inode_operations proc_root_inode_operations = {
190 .lookup = proc_root_lookup,
191 .getattr = proc_root_getattr,
192};
193
194/*
195 * This is the root "inode" in the /proc tree..
196 */
197struct proc_dir_entry proc_root = {
198 .low_ino = PROC_ROOT_INO,
199 .namelen = 5,
200 .name = "/proc",
201 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
202 .nlink = 2,
203 .count = ATOMIC_INIT(1),
204 .proc_iops = &proc_root_inode_operations,
205 .proc_fops = &proc_root_operations,
206 .parent = &proc_root,
207};
208
209int pid_ns_prepare_proc(struct pid_namespace *ns)
210{
211 struct vfsmount *mnt;
212
213 mnt = kern_mount_data(&proc_fs_type, ns);
214 if (IS_ERR(mnt))
215 return PTR_ERR(mnt);
216
217 return 0;
218}
219
220void pid_ns_release_proc(struct pid_namespace *ns)
221{
222 mntput(ns->proc_mnt);
223}
224
225EXPORT_SYMBOL(proc_symlink);
226EXPORT_SYMBOL(proc_mkdir);
227EXPORT_SYMBOL(create_proc_entry);
228EXPORT_SYMBOL(proc_create_data);
229EXPORT_SYMBOL(remove_proc_entry);