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
  30 static struct net *get_proc_net(const struct inode *inode)
  31 {
  32         return maybe_get_net(PDE_NET(PDE(inode)));
  33 }
  34
  35 int seq_open_net(struct inode *ino, struct file *f,
  36                  const struct seq_operations *ops, int size)
  37 {
  38         struct net *net;
  39         struct seq_net_private *p;
  40
  41         BUG_ON(size < sizeof(*p));
  42
  43         net = get_proc_net(ino);
  44         if (net == NULL)
  45                 return -ENXIO;
  46
  47         p = __seq_open_private(f, ops, size);
  48         if (p == NULL) {
  49                 put_net(net);
  50                 return -ENOMEM;
  51         }
  52 #ifdef CONFIG_NET_NS
  53         p->net = net;
  54 #endif
  55         return 0;
  56 }
  57 EXPORT_SYMBOL_GPL(seq_open_net);
  58
  59 int single_open_net(struct inode *inode, struct file *file,
  60                 int (*show)(struct seq_file *, void *))
  61 {
  62         int err;
  63         struct net *net;
  64
  65         err = -ENXIO;
  66         net = get_proc_net(inode);
  67         if (net == NULL)
  68                 goto err_net;
  69
  70         err = single_open(file, show, net);
  71         if (err < 0)
  72                 goto err_open;
  73
  74         return 0;
  75
  76 err_open:
  77         put_net(net);
  78 err_net:
  79         return err;
  80 }
  81 EXPORT_SYMBOL_GPL(single_open_net);
  82
  83 int seq_release_net(struct inode *ino, struct file *f)
  84 {
  85         struct seq_file *seq;
  86
  87         seq = f->private_data;
  88
  89         put_net(seq_file_net(seq));
  90         seq_release_private(ino, f);
  91         return 0;
  92 }
  93 EXPORT_SYMBOL_GPL(seq_release_net);
  94
  95 int single_release_net(struct inode *ino, struct file *f)
  96 {
  97         struct seq_file *seq = f->private_data;
  98         put_net(seq->private);
  99         return single_release(ino, f);
 100 }
 101 EXPORT_SYMBOL_GPL(single_release_net);
 102
 103 static struct net *get_proc_task_net(struct inode *dir)
 104 {
 105         struct task_struct *task;
 106         struct nsproxy *ns;
 107         struct net *net = NULL;
 108
 109         rcu_read_lock();
 110         task = pid_task(proc_pid(dir), PIDTYPE_PID);
 111         if (task != NULL) {
 112                 ns = task_nsproxy(task);
 113                 if (ns != NULL)
 114                         net = get_net(ns->net_ns);
 115         }
 116         rcu_read_unlock();
 117
 118         return net;
 119 }
 120
 121 static struct dentry *proc_tgid_net_lookup(struct inode *dir,
 122                 struct dentry *dentry, struct nameidata *nd)
 123 {
 124         struct dentry *de;
 125         struct net *net;
 126
 127         de = ERR_PTR(-ENOENT);
 128         net = get_proc_task_net(dir);
 129         if (net != NULL) {
 130                 de = proc_lookup_de(net->proc_net, dir, dentry);
 131                 put_net(net);
 132         }
 133         return de;
 134 }
 135
 136 static int proc_tgid_net_getattr(struct vfsmount *mnt, struct dentry *dentry,
 137                 struct kstat *stat)
 138 {
 139         struct inode *inode = dentry->d_inode;
 140         struct net *net;
 141
 142         net = get_proc_task_net(inode);
 143
 144         generic_fillattr(inode, stat);
 145
 146         if (net != NULL) {
 147                 stat->nlink = net->proc_net->nlink;
 148                 put_net(net);
 149         }
 150
 151         return 0;
 152 }
 153
 154 const struct inode_operations proc_net_inode_operations = {
 155         .lookup         = proc_tgid_net_lookup,
 156         .getattr        = proc_tgid_net_getattr,
 157 };
 158
 159 static int proc_tgid_net_readdir(struct file *filp, void *dirent,
 160                 filldir_t filldir)
 161 {
 162         int ret;
 163         struct net *net;
 164
 165         ret = -EINVAL;
 166         net = get_proc_task_net(filp->f_path.dentry->d_inode);
 167         if (net != NULL) {
 168                 ret = proc_readdir_de(net->proc_net, filp, dirent, filldir);
 169                 put_net(net);
 170         }
 171         return ret;
 172 }
 173
 174 const struct file_operations proc_net_operations = {
 175         .llseek         = generic_file_llseek,
 176         .read           = generic_read_dir,
 177         .readdir        = proc_tgid_net_readdir,
 178 };
 179
 180
 181 struct proc_dir_entry *proc_net_fops_create(struct net *net,
 182         const char *name, mode_t mode, const struct file_operations *fops)
 183 {
 184         return proc_create(name, mode, net->proc_net, fops);
 185 }
 186 EXPORT_SYMBOL_GPL(proc_net_fops_create);
 187
 188 void proc_net_remove(struct net *net, const char *name)
 189 {
 190         remove_proc_entry(name, net->proc_net);
 191 }
 192 EXPORT_SYMBOL_GPL(proc_net_remove);
 193
 194 static __net_init int proc_net_ns_init(struct net *net)
 195 {
 196         struct proc_dir_entry *netd, *net_statd;
 197         int err;
 198
 199         err = -ENOMEM;
 200         netd = kzalloc(sizeof(*netd) + 4, GFP_KERNEL);
 201         if (!netd)
 202                 goto out;
 203
 204         netd->data = net;
 205         netd->nlink = 2;
 206         netd->namelen = 3;
 207         netd->parent = &proc_root;
 208         memcpy(netd->name, "net", 4);
 209
 210         err = -EEXIST;
 211         net_statd = proc_net_mkdir(net, "stat", netd);
 212         if (!net_statd)
 213                 goto free_net;
 214
 215         net->proc_net = netd;
 216         net->proc_net_stat = net_statd;
 217         return 0;
 218
 219 free_net:
 220         kfree(netd);
 221 out:
 222         return err;
 223 }
 224
 225 static __net_exit void proc_net_ns_exit(struct net *net)
 226 {
 227         remove_proc_entry("stat", net->proc_net);
 228         kfree(net->proc_net);
 229 }
 230
 231 static struct pernet_operations __net_initdata proc_net_ns_ops = {
 232         .init = proc_net_ns_init,
 233         .exit = proc_net_ns_exit,
 234 };
 235
 236 int __init proc_net_init(void)
 237 {
 238         proc_symlink("net", NULL, "self/net");
 239
 240         return register_pernet_subsys(&proc_net_ns_ops);
 241 }