fs/proc/proc_net.c

   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
  29 static inline struct net *PDE_NET(struct proc_dir_entry *pde)
  30 {
  31         return pde->parent->data;
  32 }
  33
  34 static struct net *get_proc_net(const struct inode *inode)
  35 {
  36         return maybe_get_net(PDE_NET(PDE(inode)));
  37 }
  38
  39 int 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 }
  61 EXPORT_SYMBOL_GPL(seq_open_net);
  62
  63 int 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
  80 err_open:
  81         put_net(net);
  82 err_net:
  83         return err;
  84 }
  85 EXPORT_SYMBOL_GPL(single_open_net);
  86
  87 int 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 }
  97 EXPORT_SYMBOL_GPL(seq_release_net);
  98
  99 int 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 }
 105 EXPORT_SYMBOL_GPL(single_release_net);
 106
 107 static 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                 ns = task_nsproxy(task);
 117                 if (ns != NULL)
 118                         net = get_net(ns->net_ns);
 119         }
 120         rcu_read_unlock();
 121
 122         return net;
 123 }
 124
 125 static struct dentry *proc_tgid_net_lookup(struct inode *dir,
 126                 struct dentry *dentry, unsigned int flags)
 127 {
 128         struct dentry *de;
 129         struct net *net;
 130
 131         de = ERR_PTR(-ENOENT);
 132         net = get_proc_task_net(dir);
 133         if (net != NULL) {
 134                 de = proc_lookup_de(net->proc_net, dir, dentry);
 135                 put_net(net);
 136         }
 137         return de;
 138 }
 139
 140 static int proc_tgid_net_getattr(struct vfsmount *mnt, struct dentry *dentry,
 141                 struct kstat *stat)
 142 {
 143         struct inode *inode = dentry->d_inode;
 144         struct net *net;
 145
 146         net = get_proc_task_net(inode);
 147
 148         generic_fillattr(inode, stat);
 149
 150         if (net != NULL) {
 151                 stat->nlink = net->proc_net->nlink;
 152                 put_net(net);
 153         }
 154
 155         return 0;
 156 }
 157
 158 const struct inode_operations proc_net_inode_operations = {
 159         .lookup         = proc_tgid_net_lookup,
 160         .getattr        = proc_tgid_net_getattr,
 161 };
 162
 163 static int proc_tgid_net_readdir(struct file *file, struct dir_context *ctx)
 164 {
 165         int ret;
 166         struct net *net;
 167
 168         ret = -EINVAL;
 169         net = get_proc_task_net(file_inode(file));
 170         if (net != NULL) {
 171                 ret = proc_readdir_de(net->proc_net, file, ctx);
 172                 put_net(net);
 173         }
 174         return ret;
 175 }
 176
 177 const struct file_operations proc_net_operations = {
 178         .llseek         = generic_file_llseek,
 179         .read           = generic_read_dir,
 180         .iterate        = proc_tgid_net_readdir,
 181 };
 182
 183 static __net_init int proc_net_ns_init(struct net *net)
 184 {
 185         struct proc_dir_entry *netd, *net_statd;
 186         int err;
 187
 188         err = -ENOMEM;
 189         netd = kzalloc(sizeof(*netd) + 4, GFP_KERNEL);
 190         if (!netd)
 191                 goto out;
 192
 193         netd->data = net;
 194         netd->nlink = 2;
 195         netd->namelen = 3;
 196         netd->parent = &proc_root;
 197         memcpy(netd->name, "net", 4);
 198
 199         err = -EEXIST;
 200         net_statd = proc_net_mkdir(net, "stat", netd);
 201         if (!net_statd)
 202                 goto free_net;
 203
 204         net->proc_net = netd;
 205         net->proc_net_stat = net_statd;
 206         return 0;
 207
 208 free_net:
 209         kfree(netd);
 210 out:
 211         return err;
 212 }
 213
 214 static __net_exit void proc_net_ns_exit(struct net *net)
 215 {
 216         remove_proc_entry("stat", net->proc_net);
 217         kfree(net->proc_net);
 218 }
 219
 220 static struct pernet_operations __net_initdata proc_net_ns_ops = {
 221         .init = proc_net_ns_init,
 222         .exit = proc_net_ns_exit,
 223 };
 224
 225 int __init proc_net_init(void)
 226 {
 227         proc_symlink("net", NULL, "self/net");
 228
 229         return register_pernet_subsys(&proc_net_ns_ops);
 230 }