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