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 single_open_net(struct inode *inode, struct file *file,
  55                 int (*show)(struct seq_file *, void *))
  56 {
  57         int err;
  58         struct net *net;
  59
  60         err = -ENXIO;
  61         net = get_proc_net(inode);
  62         if (net == NULL)
  63                 goto err_net;
  64
  65         err = single_open(file, show, net);
  66         if (err < 0)
  67                 goto err_open;
  68
  69         return 0;
  70
  71 err_open:
  72         put_net(net);
  73 err_net:
  74         return err;
  75 }
  76 EXPORT_SYMBOL_GPL(single_open_net);
  77
  78 int seq_release_net(struct inode *ino, struct file *f)
  79 {
  80         struct seq_file *seq;
  81
  82         seq = f->private_data;
  83
  84         put_net(seq_file_net(seq));
  85         seq_release_private(ino, f);
  86         return 0;
  87 }
  88 EXPORT_SYMBOL_GPL(seq_release_net);
  89
  90 int single_release_net(struct inode *ino, struct file *f)
  91 {
  92         struct seq_file *seq = f->private_data;
  93         put_net(seq->private);
  94         return single_release(ino, f);
  95 }
  96 EXPORT_SYMBOL_GPL(single_release_net);
  97
  98 static struct net *get_proc_task_net(struct inode *dir)
  99 {
 100         struct task_struct *task;
 101         struct nsproxy *ns;
 102         struct net *net = NULL;
 103
 104         rcu_read_lock();
 105         task = pid_task(proc_pid(dir), PIDTYPE_PID);
 106         if (task != NULL) {
 107                 ns = task_nsproxy(task);
 108                 if (ns != NULL)
 109                         net = get_net(ns->net_ns);
 110         }
 111         rcu_read_unlock();
 112
 113         return net;
 114 }
 115
 116 static struct dentry *proc_tgid_net_lookup(struct inode *dir,
 117                 struct dentry *dentry, struct nameidata *nd)
 118 {
 119         struct dentry *de;
 120         struct net *net;
 121
 122         de = ERR_PTR(-ENOENT);
 123         net = get_proc_task_net(dir);
 124         if (net != NULL) {
 125                 de = proc_lookup_de(net->proc_net, dir, dentry);
 126                 put_net(net);
 127         }
 128         return de;
 129 }
 130
 131 static int proc_tgid_net_getattr(struct vfsmount *mnt, struct dentry *dentry,
 132                 struct kstat *stat)
 133 {
 134         struct inode *inode = dentry->d_inode;
 135         struct net *net;
 136
 137         net = get_proc_task_net(inode);
 138
 139         generic_fillattr(inode, stat);
 140
 141         if (net != NULL) {
 142                 stat->nlink = net->proc_net->nlink;
 143                 put_net(net);
 144         }
 145
 146         return 0;
 147 }
 148
 149 const struct inode_operations proc_net_inode_operations = {
 150         .lookup         = proc_tgid_net_lookup,
 151         .getattr        = proc_tgid_net_getattr,
 152 };
 153
 154 static int proc_tgid_net_readdir(struct file *filp, void *dirent,
 155                 filldir_t filldir)
 156 {
 157         int ret;
 158         struct net *net;
 159
 160         ret = -EINVAL;
 161         net = get_proc_task_net(filp->f_path.dentry->d_inode);
 162         if (net != NULL) {
 163                 ret = proc_readdir_de(net->proc_net, filp, dirent, filldir);
 164                 put_net(net);
 165         }
 166         return ret;
 167 }
 168
 169 const struct file_operations proc_net_operations = {
 170         .read           = generic_read_dir,
 171         .readdir        = proc_tgid_net_readdir,
 172 };
 173
 174
 175 struct proc_dir_entry *proc_net_fops_create(struct net *net,
 176         const char *name, mode_t mode, const struct file_operations *fops)
 177 {
 178         return proc_create(name, mode, net->proc_net, fops);
 179 }
 180 EXPORT_SYMBOL_GPL(proc_net_fops_create);
 181
 182 void proc_net_remove(struct net *net, const char *name)
 183 {
 184         remove_proc_entry(name, net->proc_net);
 185 }
 186 EXPORT_SYMBOL_GPL(proc_net_remove);
 187
 188 struct net *get_proc_net(const struct inode *inode)
 189 {
 190         return maybe_get_net(PDE_NET(PDE(inode)));
 191 }
 192 EXPORT_SYMBOL_GPL(get_proc_net);
 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), GFP_KERNEL);
 201         if (!netd)
 202                 goto out;
 203
 204         netd->data = net;
 205         netd->nlink = 2;
 206         netd->name = "net";
 207         netd->namelen = 3;
 208         netd->parent = &proc_root;
 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 }