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/init.h>
  18 #include <linux/sched.h>
  19 #include <linux/module.h>
  20 #include <linux/bitops.h>
  21 #include <linux/mount.h>
  22 #include <linux/nsproxy.h>
  23 #include <net/net_namespace.h>
  24 #include <linux/seq_file.h>
  25
  26 #include "internal.h"
  27
  28
  29 static struct net *get_proc_net(const struct inode *inode)
  30 {
  31         return maybe_get_net(PDE_NET(PDE(inode)));
  32 }
  33
  34 int seq_open_net(struct inode *ino, struct file *f,
  35                  const struct seq_operations *ops, int size)
  36 {
  37         struct net *net;
  38         struct seq_net_private *p;
  39
  40         BUG_ON(size < sizeof(*p));
  41
  42         net = get_proc_net(ino);
  43         if (net == NULL)
  44                 return -ENXIO;
  45
  46         p = __seq_open_private(f, ops, size);
  47         if (p == NULL) {
  48                 put_net(net);
  49                 return -ENOMEM;
  50         }
  51 #ifdef CONFIG_NET_NS
  52         p->net = net;
  53 #endif
  54         return 0;
  55 }
  56 EXPORT_SYMBOL_GPL(seq_open_net);
  57
  58 int single_open_net(struct inode *inode, struct file *file,
  59                 int (*show)(struct seq_file *, void *))
  60 {
  61         int err;
  62         struct net *net;
  63
  64         err = -ENXIO;
  65         net = get_proc_net(inode);
  66         if (net == NULL)
  67                 goto err_net;
  68
  69         err = single_open(file, show, net);
  70         if (err < 0)
  71                 goto err_open;
  72
  73         return 0;
  74
  75 err_open:
  76         put_net(net);
  77 err_net:
  78         return err;
  79 }
  80 EXPORT_SYMBOL_GPL(single_open_net);
  81
  82 int seq_release_net(struct inode *ino, struct file *f)
  83 {
  84         struct seq_file *seq;
  85
  86         seq = f->private_data;
  87
  88         put_net(seq_file_net(seq));
  89         seq_release_private(ino, f);
  90         return 0;
  91 }
  92 EXPORT_SYMBOL_GPL(seq_release_net);
  93
  94 int single_release_net(struct inode *ino, struct file *f)
  95 {
  96         struct seq_file *seq = f->private_data;
  97         put_net(seq->private);
  98         return single_release(ino, f);
  99 }
 100 EXPORT_SYMBOL_GPL(single_release_net);
 101
 102 static struct net *get_proc_task_net(struct inode *dir)
 103 {
 104         struct task_struct *task;
 105         struct nsproxy *ns;
 106         struct net *net = NULL;
 107
 108         rcu_read_lock();
 109         task = pid_task(proc_pid(dir), PIDTYPE_PID);
 110         if (task != NULL) {
 111                 ns = task_nsproxy(task);
 112                 if (ns != NULL)
 113                         net = get_net(ns->net_ns);
 114         }
 115         rcu_read_unlock();
 116
 117         return net;
 118 }
 119
 120 static struct dentry *proc_tgid_net_lookup(struct inode *dir,
 121                 struct dentry *dentry, struct nameidata *nd)
 122 {
 123         struct dentry *de;
 124         struct net *net;
 125
 126         de = ERR_PTR(-ENOENT);
 127         net = get_proc_task_net(dir);
 128         if (net != NULL) {
 129                 de = proc_lookup_de(net->proc_net, dir, dentry);
 130                 put_net(net);
 131         }
 132         return de;
 133 }
 134
 135 static int proc_tgid_net_getattr(struct vfsmount *mnt, struct dentry *dentry,
 136                 struct kstat *stat)
 137 {
 138         struct inode *inode = dentry->d_inode;
 139         struct net *net;
 140
 141         net = get_proc_task_net(inode);
 142
 143         generic_fillattr(inode, stat);
 144
 145         if (net != NULL) {
 146                 stat->nlink = net->proc_net->nlink;
 147                 put_net(net);
 148         }
 149
 150         return 0;
 151 }
 152
 153 const struct inode_operations proc_net_inode_operations = {
 154         .lookup         = proc_tgid_net_lookup,
 155         .getattr        = proc_tgid_net_getattr,
 156 };
 157
 158 static int proc_tgid_net_readdir(struct file *filp, void *dirent,
 159                 filldir_t filldir)
 160 {
 161         int ret;
 162         struct net *net;
 163
 164         ret = -EINVAL;
 165         net = get_proc_task_net(filp->f_path.dentry->d_inode);
 166         if (net != NULL) {
 167                 ret = proc_readdir_de(net->proc_net, filp, dirent, filldir);
 168                 put_net(net);
 169         }
 170         return ret;
 171 }
 172
 173 const struct file_operations proc_net_operations = {
 174         .llseek         = generic_file_llseek,
 175         .read           = generic_read_dir,
 176         .readdir        = proc_tgid_net_readdir,
 177 };
 178
 179
 180 struct proc_dir_entry *proc_net_fops_create(struct net *net,
 181         const char *name, mode_t mode, const struct file_operations *fops)
 182 {
 183         return proc_create(name, mode, net->proc_net, fops);
 184 }
 185 EXPORT_SYMBOL_GPL(proc_net_fops_create);
 186
 187 void proc_net_remove(struct net *net, const char *name)
 188 {
 189         remove_proc_entry(name, net->proc_net);
 190 }
 191 EXPORT_SYMBOL_GPL(proc_net_remove);
 192
 193 static __net_init int proc_net_ns_init(struct net *net)
 194 {
 195         struct proc_dir_entry *netd, *net_statd;
 196         int err;
 197
 198         err = -ENOMEM;
 199         netd = kzalloc(sizeof(*netd), GFP_KERNEL);
 200         if (!netd)
 201                 goto out;
 202
 203         netd->data = net;
 204         netd->nlink = 2;
 205         netd->name = "net";
 206         netd->namelen = 3;
 207         netd->parent = &proc_root;
 208
 209         err = -EEXIST;
 210         net_statd = proc_net_mkdir(net, "stat", netd);
 211         if (!net_statd)
 212                 goto free_net;
 213
 214         net->proc_net = netd;
 215         net->proc_net_stat = net_statd;
 216         return 0;
 217
 218 free_net:
 219         kfree(netd);
 220 out:
 221         return err;
 222 }
 223
 224 static __net_exit void proc_net_ns_exit(struct net *net)
 225 {
 226         remove_proc_entry("stat", net->proc_net);
 227         kfree(net->proc_net);
 228 }
 229
 230 static struct pernet_operations __net_initdata proc_net_ns_ops = {
 231         .init = proc_net_ns_init,
 232         .exit = proc_net_ns_exit,
 233 };
 234
 235 int __init proc_net_init(void)
 236 {
 237         proc_symlink("net", NULL, "self/net");
 238
 239         return register_pernet_subsys(&proc_net_ns_ops);
 240 }