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                 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
 127 static 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
 142 static int proc_tgid_net_getattr(struct vfsmount *mnt, struct dentry *dentry,
 143                 struct kstat *stat)
 144 {
 145         struct inode *inode = dentry->d_inode;
 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
 160 const struct inode_operations proc_net_inode_operations = {
 161         .lookup         = proc_tgid_net_lookup,
 162         .getattr        = proc_tgid_net_getattr,
 163 };
 164
 165 static 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
 179 const struct file_operations proc_net_operations = {
 180         .llseek         = generic_file_llseek,
 181         .read           = generic_read_dir,
 182         .iterate        = proc_tgid_net_readdir,
 183 };
 184
 185 static __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->data = net;
 196         netd->nlink = 2;
 197         netd->namelen = 3;
 198         netd->parent = &proc_root;
 199         memcpy(netd->name, "net", 4);
 200
 201         err = -EEXIST;
 202         net_statd = proc_net_mkdir(net, "stat", netd);
 203         if (!net_statd)
 204                 goto free_net;
 205
 206         net->proc_net = netd;
 207         net->proc_net_stat = net_statd;
 208         return 0;
 209
 210 free_net:
 211         kfree(netd);
 212 out:
 213         return err;
 214 }
 215
 216 static __net_exit void proc_net_ns_exit(struct net *net)
 217 {
 218         remove_proc_entry("stat", net->proc_net);
 219         kfree(net->proc_net);
 220 }
 221
 222 static struct pernet_operations __net_initdata proc_net_ns_ops = {
 223         .init = proc_net_ns_init,
 224         .exit = proc_net_ns_exit,
 225 };
 226
 227 int __init proc_net_init(void)
 228 {
 229         proc_symlink("net", NULL, "self/net");
 230
 231         return register_pernet_subsys(&proc_net_ns_ops);
 232 }