#include <linux/proc_fs.h>#include <linux/nsproxy.h>#include <linux/sched.h>#include <linux/ptrace.h>#include <linux/fs_struct.h>#include <linux/mount.h>#include <linux/path.h>#include <linux/namei.h>#include <linux/file.h>#include <linux/utsname.h>#include <net/net_namespace.h>#include <linux/ipc_namespace.h>#include <linux/pid_namespace.h>#include "internal.h"  static const struct proc_ns_operations *ns_entries[] = {#ifdef CONFIG_NET_NS	&netns_operations,#endif#ifdef CONFIG_UTS_NS	&utsns_operations,#endif#ifdef CONFIG_IPC_NS	&ipcns_operations,#endif}; static const struct file_operations ns_file_operations = {	.llseek		= no_llseek,}; static struct dentry *proc_ns_instantiate(struct inode *dir,	struct dentry *dentry, struct task_struct *task, const void *ptr){	const struct proc_ns_operations *ns_ops = ptr;	struct inode *inode;	struct proc_inode *ei;	struct dentry *error = ERR_PTR(-ENOENT);	void *ns; 	inode = proc_pid_make_inode(dir->i_sb, task);	if (!inode)		goto out; 	ns = ns_ops->get(task);	if (!ns)		goto out_iput; 	ei = PROC_I(inode);	inode->i_mode = S_IFREG|S_IRUSR;	inode->i_fop  = &ns_file_operations;	ei->ns_ops    = ns_ops;	ei->ns	      = ns; 	d_set_d_op(dentry, &pid_dentry_operations);	d_add(dentry, inode);	/* Close the race of the process dying before we return the dentry */	if (pid_revalidate(dentry, NULL))		error = NULL;out:	return error;out_iput:	iput(inode);	goto out;} static int proc_ns_fill_cache(struct file *filp, void *dirent,	filldir_t filldir, struct task_struct *task,	const struct proc_ns_operations *ops){	return proc_fill_cache(filp, dirent, filldir,				ops->name, strlen(ops->name),				proc_ns_instantiate, task, ops);} static int proc_ns_dir_readdir(struct file *filp, void *dirent,				filldir_t filldir){	int i;	struct dentry *dentry = filp->f_path.dentry;	struct inode *inode = dentry->d_inode;	struct task_struct *task = get_proc_task(inode);	const struct proc_ns_operations **entry, **last;	ino_t ino;	int ret; 	ret = -ENOENT;	if (!task)		goto out_no_task; 	ret = -EPERM;	if (!ptrace_may_access(task, PTRACE_MODE_READ))		goto out; 	ret = 0;	i = filp->f_pos;	switch (i) {	case 0:		ino = inode->i_ino;		if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)			goto out;		i++;		filp->f_pos++;		/* fall through */	case 1:		ino = parent_ino(dentry);		if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)			goto out;		i++;		filp->f_pos++;		/* fall through */	default:		i -= 2;		if (i >= ARRAY_SIZE(ns_entries)) {			ret = 1;			goto out;		}		entry = ns_entries + i;		last = &ns_entries[ARRAY_SIZE(ns_entries) - 1];		while (entry <= last) {			if (proc_ns_fill_cache(filp, dirent, filldir,						task, *entry) < 0)				goto out;			filp->f_pos++;			entry++;		}	} 	ret = 1;out:	put_task_struct(task);out_no_task:	return ret;} const struct file_operations proc_ns_dir_operations = {	.read		= generic_read_dir,	.readdir	= proc_ns_dir_readdir,}; static struct dentry *proc_ns_dir_lookup(struct inode *dir,				struct dentry *dentry, struct nameidata *nd){	struct dentry *error;	struct task_struct *task = get_proc_task(dir);	const struct proc_ns_operations **entry, **last;	unsigned int len = dentry->d_name.len; 	error = ERR_PTR(-ENOENT); 	if (!task)		goto out_no_task; 	error = ERR_PTR(-EPERM);	if (!ptrace_may_access(task, PTRACE_MODE_READ))		goto out; 	last = &ns_entries[ARRAY_SIZE(ns_entries)];	for (entry = ns_entries; entry < last; entry++) {		if (strlen((*entry)->name) != len)			continue;		if (!memcmp(dentry->d_name.name, (*entry)->name, len))			break;	}	error = ERR_PTR(-ENOENT);	if (entry == last)		goto out; 	error = proc_ns_instantiate(dir, dentry, task, *entry);out:	put_task_struct(task);out_no_task:	return error;} const struct inode_operations proc_ns_dir_inode_operations = {	.lookup		= proc_ns_dir_lookup,	.getattr	= pid_getattr,	.setattr	= proc_setattr,}; struct file *proc_ns_fget(int fd){	struct file *file; 	file = fget(fd);	if (!file)		return ERR_PTR(-EBADF); 	if (file->f_op != &ns_file_operations)		goto out_invalid; 	return file; out_invalid:	fput(file);	return ERR_PTR(-EINVAL);}