File-copy from v4.4.100
This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Please refer to that tree for all history prior to this point.
Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/fs/proc/proc_net.c b/fs/proc/proc_net.c
new file mode 100644
index 0000000..350984a
--- /dev/null
+++ b/fs/proc/proc_net.c
@@ -0,0 +1,233 @@
+/*
+ * linux/fs/proc/net.c
+ *
+ * Copyright (C) 2007
+ *
+ * Author: Eric Biederman <ebiederm@xmission.com>
+ *
+ * proc net directory handling functions
+ */
+
+#include <asm/uaccess.h>
+
+#include <linux/errno.h>
+#include <linux/time.h>
+#include <linux/proc_fs.h>
+#include <linux/stat.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/module.h>
+#include <linux/bitops.h>
+#include <linux/mount.h>
+#include <linux/nsproxy.h>
+#include <net/net_namespace.h>
+#include <linux/seq_file.h>
+
+#include "internal.h"
+
+static inline struct net *PDE_NET(struct proc_dir_entry *pde)
+{
+ return pde->parent->data;
+}
+
+static struct net *get_proc_net(const struct inode *inode)
+{
+ return maybe_get_net(PDE_NET(PDE(inode)));
+}
+
+int seq_open_net(struct inode *ino, struct file *f,
+ const struct seq_operations *ops, int size)
+{
+ struct net *net;
+ struct seq_net_private *p;
+
+ BUG_ON(size < sizeof(*p));
+
+ net = get_proc_net(ino);
+ if (net == NULL)
+ return -ENXIO;
+
+ p = __seq_open_private(f, ops, size);
+ if (p == NULL) {
+ put_net(net);
+ return -ENOMEM;
+ }
+#ifdef CONFIG_NET_NS
+ p->net = net;
+#endif
+ return 0;
+}
+EXPORT_SYMBOL_GPL(seq_open_net);
+
+int single_open_net(struct inode *inode, struct file *file,
+ int (*show)(struct seq_file *, void *))
+{
+ int err;
+ struct net *net;
+
+ err = -ENXIO;
+ net = get_proc_net(inode);
+ if (net == NULL)
+ goto err_net;
+
+ err = single_open(file, show, net);
+ if (err < 0)
+ goto err_open;
+
+ return 0;
+
+err_open:
+ put_net(net);
+err_net:
+ return err;
+}
+EXPORT_SYMBOL_GPL(single_open_net);
+
+int seq_release_net(struct inode *ino, struct file *f)
+{
+ struct seq_file *seq;
+
+ seq = f->private_data;
+
+ put_net(seq_file_net(seq));
+ seq_release_private(ino, f);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(seq_release_net);
+
+int single_release_net(struct inode *ino, struct file *f)
+{
+ struct seq_file *seq = f->private_data;
+ put_net(seq->private);
+ return single_release(ino, f);
+}
+EXPORT_SYMBOL_GPL(single_release_net);
+
+static struct net *get_proc_task_net(struct inode *dir)
+{
+ struct task_struct *task;
+ struct nsproxy *ns;
+ struct net *net = NULL;
+
+ rcu_read_lock();
+ task = pid_task(proc_pid(dir), PIDTYPE_PID);
+ if (task != NULL) {
+ task_lock(task);
+ ns = task->nsproxy;
+ if (ns != NULL)
+ net = get_net(ns->net_ns);
+ task_unlock(task);
+ }
+ rcu_read_unlock();
+
+ return net;
+}
+
+static struct dentry *proc_tgid_net_lookup(struct inode *dir,
+ struct dentry *dentry, unsigned int flags)
+{
+ struct dentry *de;
+ struct net *net;
+
+ de = ERR_PTR(-ENOENT);
+ net = get_proc_task_net(dir);
+ if (net != NULL) {
+ de = proc_lookup_de(net->proc_net, dir, dentry);
+ put_net(net);
+ }
+ return de;
+}
+
+static int proc_tgid_net_getattr(struct vfsmount *mnt, struct dentry *dentry,
+ struct kstat *stat)
+{
+ struct inode *inode = d_inode(dentry);
+ struct net *net;
+
+ net = get_proc_task_net(inode);
+
+ generic_fillattr(inode, stat);
+
+ if (net != NULL) {
+ stat->nlink = net->proc_net->nlink;
+ put_net(net);
+ }
+
+ return 0;
+}
+
+const struct inode_operations proc_net_inode_operations = {
+ .lookup = proc_tgid_net_lookup,
+ .getattr = proc_tgid_net_getattr,
+};
+
+static int proc_tgid_net_readdir(struct file *file, struct dir_context *ctx)
+{
+ int ret;
+ struct net *net;
+
+ ret = -EINVAL;
+ net = get_proc_task_net(file_inode(file));
+ if (net != NULL) {
+ ret = proc_readdir_de(net->proc_net, file, ctx);
+ put_net(net);
+ }
+ return ret;
+}
+
+const struct file_operations proc_net_operations = {
+ .llseek = generic_file_llseek,
+ .read = generic_read_dir,
+ .iterate = proc_tgid_net_readdir,
+};
+
+static __net_init int proc_net_ns_init(struct net *net)
+{
+ struct proc_dir_entry *netd, *net_statd;
+ int err;
+
+ err = -ENOMEM;
+ netd = kzalloc(sizeof(*netd) + 4, GFP_KERNEL);
+ if (!netd)
+ goto out;
+
+ netd->subdir = RB_ROOT;
+ netd->data = net;
+ netd->nlink = 2;
+ netd->namelen = 3;
+ netd->parent = &proc_root;
+ memcpy(netd->name, "net", 4);
+
+ err = -EEXIST;
+ net_statd = proc_net_mkdir(net, "stat", netd);
+ if (!net_statd)
+ goto free_net;
+
+ net->proc_net = netd;
+ net->proc_net_stat = net_statd;
+ return 0;
+
+free_net:
+ kfree(netd);
+out:
+ return err;
+}
+
+static __net_exit void proc_net_ns_exit(struct net *net)
+{
+ remove_proc_entry("stat", net->proc_net);
+ kfree(net->proc_net);
+}
+
+static struct pernet_operations __net_initdata proc_net_ns_ops = {
+ .init = proc_net_ns_init,
+ .exit = proc_net_ns_exit,
+};
+
+int __init proc_net_init(void)
+{
+ proc_symlink("net", NULL, "self/net");
+
+ return register_pernet_subsys(&proc_net_ns_ops);
+}