1/*
2 *  linux/fs/proc/net.c
3 *
4 *  Copyright (C) 2007
5 *
6 *  Author: Eric Biederman <ebiederm@xmission.com>
7 *
8 *  proc net directory handling functions
9 */
10
11#include <asm/uaccess.h>
12
13#include <linux/errno.h>
14#include <linux/time.h>
15#include <linux/proc_fs.h>
16#include <linux/stat.h>
17#include <linux/slab.h>
18#include <linux/init.h>
19#include <linux/sched.h>
20#include <linux/module.h>
21#include <linux/bitops.h>
22#include <linux/mount.h>
23#include <linux/nsproxy.h>
24#include <net/net_namespace.h>
25#include <linux/seq_file.h>
26
27#include "internal.h"
28
29static inline struct net *PDE_NET(struct proc_dir_entry *pde)
30{
31	return pde->parent->data;
32}
33
34static struct net *get_proc_net(const struct inode *inode)
35{
36	return maybe_get_net(PDE_NET(PDE(inode)));
37}
38
39int seq_open_net(struct inode *ino, struct file *f,
40		 const struct seq_operations *ops, int size)
41{
42	struct net *net;
43	struct seq_net_private *p;
44
45	BUG_ON(size < sizeof(*p));
46
47	net = get_proc_net(ino);
48	if (net == NULL)
49		return -ENXIO;
50
51	p = __seq_open_private(f, ops, size);
52	if (p == NULL) {
53		put_net(net);
54		return -ENOMEM;
55	}
56#ifdef CONFIG_NET_NS
57	p->net = net;
58#endif
59	return 0;
60}
61EXPORT_SYMBOL_GPL(seq_open_net);
62
63int single_open_net(struct inode *inode, struct file *file,
64		int (*show)(struct seq_file *, void *))
65{
66	int err;
67	struct net *net;
68
69	err = -ENXIO;
70	net = get_proc_net(inode);
71	if (net == NULL)
72		goto err_net;
73
74	err = single_open(file, show, net);
75	if (err < 0)
76		goto err_open;
77
78	return 0;
79
80err_open:
81	put_net(net);
82err_net:
83	return err;
84}
85EXPORT_SYMBOL_GPL(single_open_net);
86
87int seq_release_net(struct inode *ino, struct file *f)
88{
89	struct seq_file *seq;
90
91	seq = f->private_data;
92
93	put_net(seq_file_net(seq));
94	seq_release_private(ino, f);
95	return 0;
96}
97EXPORT_SYMBOL_GPL(seq_release_net);
98
99int single_release_net(struct inode *ino, struct file *f)
100{
101	struct seq_file *seq = f->private_data;
102	put_net(seq->private);
103	return single_release(ino, f);
104}
105EXPORT_SYMBOL_GPL(single_release_net);
106
107static struct net *get_proc_task_net(struct inode *dir)
108{
109	struct task_struct *task;
110	struct nsproxy *ns;
111	struct net *net = NULL;
112
113	rcu_read_lock();
114	task = pid_task(proc_pid(dir), PIDTYPE_PID);
115	if (task != NULL) {
116		task_lock(task);
117		ns = task->nsproxy;
118		if (ns != NULL)
119			net = get_net(ns->net_ns);
120		task_unlock(task);
121	}
122	rcu_read_unlock();
123
124	return net;
125}
126
127static struct dentry *proc_tgid_net_lookup(struct inode *dir,
128		struct dentry *dentry, unsigned int flags)
129{
130	struct dentry *de;
131	struct net *net;
132
133	de = ERR_PTR(-ENOENT);
134	net = get_proc_task_net(dir);
135	if (net != NULL) {
136		de = proc_lookup_de(net->proc_net, dir, dentry);
137		put_net(net);
138	}
139	return de;
140}
141
142static int proc_tgid_net_getattr(struct vfsmount *mnt, struct dentry *dentry,
143		struct kstat *stat)
144{
145	struct inode *inode = d_inode(dentry);
146	struct net *net;
147
148	net = get_proc_task_net(inode);
149
150	generic_fillattr(inode, stat);
151
152	if (net != NULL) {
153		stat->nlink = net->proc_net->nlink;
154		put_net(net);
155	}
156
157	return 0;
158}
159
160const struct inode_operations proc_net_inode_operations = {
161	.lookup		= proc_tgid_net_lookup,
162	.getattr	= proc_tgid_net_getattr,
163};
164
165static int proc_tgid_net_readdir(struct file *file, struct dir_context *ctx)
166{
167	int ret;
168	struct net *net;
169
170	ret = -EINVAL;
171	net = get_proc_task_net(file_inode(file));
172	if (net != NULL) {
173		ret = proc_readdir_de(net->proc_net, file, ctx);
174		put_net(net);
175	}
176	return ret;
177}
178
179const struct file_operations proc_net_operations = {
180	.llseek		= generic_file_llseek,
181	.read		= generic_read_dir,
182	.iterate	= proc_tgid_net_readdir,
183};
184
185static __net_init int proc_net_ns_init(struct net *net)
186{
187	struct proc_dir_entry *netd, *net_statd;
188	int err;
189
190	err = -ENOMEM;
191	netd = kzalloc(sizeof(*netd) + 4, GFP_KERNEL);
192	if (!netd)
193		goto out;
194
195	netd->subdir = RB_ROOT;
196	netd->data = net;
197	netd->nlink = 2;
198	netd->namelen = 3;
199	netd->parent = &proc_root;
200	memcpy(netd->name, "net", 4);
201
202	err = -EEXIST;
203	net_statd = proc_net_mkdir(net, "stat", netd);
204	if (!net_statd)
205		goto free_net;
206
207	net->proc_net = netd;
208	net->proc_net_stat = net_statd;
209	return 0;
210
211free_net:
212	kfree(netd);
213out:
214	return err;
215}
216
217static __net_exit void proc_net_ns_exit(struct net *net)
218{
219	remove_proc_entry("stat", net->proc_net);
220	kfree(net->proc_net);
221}
222
223static struct pernet_operations __net_initdata proc_net_ns_ops = {
224	.init = proc_net_ns_init,
225	.exit = proc_net_ns_exit,
226};
227
228int __init proc_net_init(void)
229{
230	proc_symlink("net", NULL, "self/net");
231
232	return register_pernet_subsys(&proc_net_ns_ops);
233}
234