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 <linux/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 <linux/uidgid.h>
  25 #include <net/net_namespace.h>
  26 #include <linux/seq_file.h>
  27
  28 #include "internal.h"
  29
  30 static inline struct net *PDE_NET(struct proc_dir_entry *pde)
  31 {
  32         return pde->parent->data;
  33 }
  34
  35 static struct net *get_proc_net(const struct inode *inode)
  36 {
  37         return maybe_get_net(PDE_NET(PDE(inode)));
  38 }
  39
  40 int seq_open_net(struct inode *ino, struct file *f,
  41                  const struct seq_operations *ops, int size)
  42 {
  43         struct net *net;
  44         struct seq_net_private *p;
  45
  46         BUG_ON(size < sizeof(*p));
  47
  48         net = get_proc_net(ino);
  49         if (net == NULL)
  50                 return -ENXIO;
  51
  52         p = __seq_open_private(f, ops, size);
  53         if (p == NULL) {
  54                 put_net(net);
  55                 return -ENOMEM;
  56         }
  57 #ifdef CONFIG_NET_NS
  58         p->net = net;
  59 #endif
  60         return 0;
  61 }
  62 EXPORT_SYMBOL_GPL(seq_open_net);
  63
  64 int single_open_net(struct inode *inode, struct file *file,
  65                 int (*show)(struct seq_file *, void *))
  66 {
  67         int err;
  68         struct net *net;
  69
  70         err = -ENXIO;
  71         net = get_proc_net(inode);
  72         if (net == NULL)
  73                 goto err_net;
  74
  75         err = single_open(file, show, net);
  76         if (err < 0)
  77                 goto err_open;
  78
  79         return 0;
  80
  81 err_open:
  82         put_net(net);
  83 err_net:
  84         return err;
  85 }
  86 EXPORT_SYMBOL_GPL(single_open_net);
  87
  88 int seq_release_net(struct inode *ino, struct file *f)
  89 {
  90         struct seq_file *seq;
  91
  92         seq = f->private_data;
  93
  94         put_net(seq_file_net(seq));
  95         seq_release_private(ino, f);
  96         return 0;
  97 }
  98 EXPORT_SYMBOL_GPL(seq_release_net);
  99
 100 int single_release_net(struct inode *ino, struct file *f)
 101 {
 102         struct seq_file *seq = f->private_data;
 103         put_net(seq->private);
 104         return single_release(ino, f);
 105 }
 106 EXPORT_SYMBOL_GPL(single_release_net);
 107
 108 static struct net *get_proc_task_net(struct inode *dir)
 109 {
 110         struct task_struct *task;
 111         struct nsproxy *ns;
 112         struct net *net = NULL;
 113
 114         rcu_read_lock();
 115         task = pid_task(proc_pid(dir), PIDTYPE_PID);
 116         if (task != NULL) {
 117                 task_lock(task);
 118                 ns = task->nsproxy;
 119                 if (ns != NULL)
 120                         net = get_net(ns->net_ns);
 121                 task_unlock(task);
 122         }
 123         rcu_read_unlock();
 124
 125         return net;
 126 }
 127
 128 static struct dentry *proc_tgid_net_lookup(struct inode *dir,
 129                 struct dentry *dentry, unsigned int flags)
 130 {
 131         struct dentry *de;
 132         struct net *net;
 133
 134         de = ERR_PTR(-ENOENT);
 135         net = get_proc_task_net(dir);
 136         if (net != NULL) {
 137                 de = proc_lookup_de(net->proc_net, dir, dentry);
 138                 put_net(net);
 139         }
 140         return de;
 141 }
 142
 143 static int proc_tgid_net_getattr(struct vfsmount *mnt, struct dentry *dentry,
 144                 struct kstat *stat)
 145 {
 146         struct inode *inode = d_inode(dentry);
 147         struct net *net;
 148
 149         net = get_proc_task_net(inode);
 150
 151         generic_fillattr(inode, stat);
 152
 153         if (net != NULL) {
 154                 stat->nlink = net->proc_net->nlink;
 155                 put_net(net);
 156         }
 157
 158         return 0;
 159 }
 160
 161 const struct inode_operations proc_net_inode_operations = {
 162         .lookup         = proc_tgid_net_lookup,
 163         .getattr        = proc_tgid_net_getattr,
 164 };
 165
 166 static int proc_tgid_net_readdir(struct file *file, struct dir_context *ctx)
 167 {
 168         int ret;
 169         struct net *net;
 170
 171         ret = -EINVAL;
 172         net = get_proc_task_net(file_inode(file));
 173         if (net != NULL) {
 174                 ret = proc_readdir_de(net->proc_net, file, ctx);
 175                 put_net(net);
 176         }
 177         return ret;
 178 }
 179
 180 const struct file_operations proc_net_operations = {
 181         .llseek         = generic_file_llseek,
 182         .read           = generic_read_dir,
 183         .iterate_shared = proc_tgid_net_readdir,
 184 };
 185
 186 static __net_init int proc_net_ns_init(struct net *net)
 187 {
 188         struct proc_dir_entry *netd, *net_statd;
 189         kuid_t uid;
 190         kgid_t gid;
 191         int err;
 192
 193         err = -ENOMEM;
 194         netd = kzalloc(sizeof(*netd) + 4, GFP_KERNEL);
 195         if (!netd)
 196                 goto out;
 197
 198         netd->subdir = RB_ROOT;
 199         netd->data = net;
 200         netd->nlink = 2;
 201         netd->namelen = 3;
 202         netd->parent = &proc_root;
 203         memcpy(netd->name, "net", 4);
 204
 205         uid = make_kuid(net->user_ns, 0);
 206         if (!uid_valid(uid))
 207                 uid = netd->uid;
 208
 209         gid = make_kgid(net->user_ns, 0);
 210         if (!gid_valid(gid))
 211                 gid = netd->gid;
 212
 213         proc_set_user(netd, uid, gid);
 214
 215         err = -EEXIST;
 216         net_statd = proc_net_mkdir(net, "stat", netd);
 217         if (!net_statd)
 218                 goto free_net;
 219
 220         net->proc_net = netd;
 221         net->proc_net_stat = net_statd;
 222         return 0;
 223
 224 free_net:
 225         kfree(netd);
 226 out:
 227         return err;
 228 }
 229
 230 static __net_exit void proc_net_ns_exit(struct net *net)
 231 {
 232         remove_proc_entry("stat", net->proc_net);
 233         kfree(net->proc_net);
 234 }
 235
 236 static struct pernet_operations __net_initdata proc_net_ns_ops = {
 237         .init = proc_net_ns_init,
 238         .exit = proc_net_ns_exit,
 239 };
 240
 241 int __init proc_net_init(void)
 242 {
 243         proc_symlink("net", NULL, "self/net");
 244
 245         return register_pernet_subsys(&proc_net_ns_ops);
 246 }