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 deactivate_locked_super(sb);
71 return err;
72 }
73
74 ei = PROC_I(sb->s_root->d_inode);
75 if (!ei->pid) {
76 rcu_read_lock();
77 ei->pid = get_pid(find_pid_ns(1, ns));
78 rcu_read_unlock();
79 }
80
81 sb->s_flags |= MS_ACTIVE;
82 ns->proc_mnt = mnt;
83 }
84
85 simple_set_mnt(mnt, sb);
86 return 0;
87}
88
89static void proc_kill_sb(struct super_block *sb)
90{
91 struct pid_namespace *ns;
92
93 ns = (struct pid_namespace *)sb->s_fs_info;
94 kill_anon_super(sb);
95 put_pid_ns(ns);
96}
97
98static struct file_system_type proc_fs_type = {
99 .name = "proc",
100 .get_sb = proc_get_sb,
101 .kill_sb = proc_kill_sb,
102};
103
104void __init proc_root_init(void)
105{
106 int err;
107
108 proc_init_inodecache();
109 err = register_filesystem(&proc_fs_type);
110 if (err)
111 return;
112 proc_mnt = kern_mount_data(&proc_fs_type, &init_pid_ns);
113 err = PTR_ERR(proc_mnt);
114 if (IS_ERR(proc_mnt)) {
115 unregister_filesystem(&proc_fs_type);
116 return;
117 }
118
119 proc_symlink("mounts", NULL, "self/mounts");
120
121 proc_net_init();
122
123#ifdef CONFIG_SYSVIPC
124 proc_mkdir("sysvipc", NULL);
125#endif
126 proc_mkdir("fs", NULL);
127 proc_mkdir("driver", NULL);
128 proc_mkdir("fs/nfsd", NULL); /* somewhere for the nfsd filesystem to be mounted */
129#if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
130 /* just give it a mountpoint */
131 proc_mkdir("openprom", NULL);
132#endif
133 proc_tty_init();
134#ifdef CONFIG_PROC_DEVICETREE
135 proc_device_tree_init();
136#endif
137 proc_mkdir("bus", NULL);
138 proc_sys_init();
139}
140
141static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat
142)
143{
144 generic_fillattr(dentry->d_inode, stat);
145 stat->nlink = proc_root.nlink + nr_processes();
146 return 0;
147}
148
149static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
150{
151 if (!proc_lookup(dir, dentry, nd)) {
152 return NULL;
153 }
154
155 return proc_pid_lookup(dir, dentry, nd);
156}
157
158static int proc_root_readdir(struct file * filp,
159 void * dirent, filldir_t filldir)
160{
161 unsigned int nr = filp->f_pos;
162 int ret;
163
164 if (nr < FIRST_PROCESS_ENTRY) {
165 int error = proc_readdir(filp, dirent, filldir);
166 if (error <= 0)
167 return error;
168 filp->f_pos = FIRST_PROCESS_ENTRY;
169 }
170
171 ret = proc_pid_readdir(filp, dirent, filldir);
172 return ret;
173}
174
175/*
176 * The root /proc directory is special, as it has the
177 * <pid> directories. Thus we don't use the generic
178 * directory handling functions for that..
179 */
180static const struct file_operations proc_root_operations = {
181 .read = generic_read_dir,
182 .readdir = proc_root_readdir,
183};
184
185/*
186 * proc root can do almost nothing..
187 */
188static const struct inode_operations proc_root_inode_operations = {
189 .lookup = proc_root_lookup,
190 .getattr = proc_root_getattr,
191};
192
193/*
194 * This is the root "inode" in the /proc tree..
195 */
196struct proc_dir_entry proc_root = {
197 .low_ino = PROC_ROOT_INO,
198 .namelen = 5,
199 .name = "/proc",
200 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
201 .nlink = 2,
202 .count = ATOMIC_INIT(1),
203 .proc_iops = &proc_root_inode_operations,
204 .proc_fops = &proc_root_operations,
205 .parent = &proc_root,
206};
207
208int pid_ns_prepare_proc(struct pid_namespace *ns)
209{
210 struct vfsmount *mnt;
211
212 mnt = kern_mount_data(&proc_fs_type, ns);
213 if (IS_ERR(mnt))
214 return PTR_ERR(mnt);
215
216 return 0;
217}
218
219void pid_ns_release_proc(struct pid_namespace *ns)
220{
221 mntput(ns->proc_mnt);
222}
223
224EXPORT_SYMBOL(proc_symlink);
225EXPORT_SYMBOL(proc_mkdir);
226EXPORT_SYMBOL(create_proc_entry);
227EXPORT_SYMBOL(proc_create_data);
228EXPORT_SYMBOL(remove_proc_entry);