/* *  Copyright (C) 2007 * *  Author: Eric Biederman <ebiederm@xmision.com> * *  This program is free software; you can redistribute it and/or *  modify it under the terms of the GNU General Public License as *  published by the Free Software Foundation, version 2 of the *  License. */ #include <linux/export.h>#include <linux/uts.h>#include <linux/utsname.h>#include <linux/sysctl.h>#include <linux/wait.h>#include <linux/rwsem.h> #ifdef CONFIG_PROC_SYSCTL static void *get_uts(struct ctl_table *table, int write){	char *which = table->data;	struct uts_namespace *uts_ns; 	uts_ns = current->nsproxy->uts_ns;	which = (which - (char *)&init_uts_ns) + (char *)uts_ns; 	if (!write)		down_read(&uts_sem);	else		down_write(&uts_sem);	return which;} static void put_uts(struct ctl_table *table, int write, void *which){	if (!write)		up_read(&uts_sem);	else		up_write(&uts_sem);} /* *	Special case of dostring for the UTS structure. This has locks *	to observe. Should this be in kernel/sys.c ???? */static int proc_do_uts_string(struct ctl_table *table, int write,		  void __user *buffer, size_t *lenp, loff_t *ppos){	struct ctl_table uts_table;	int r;	memcpy(&uts_table, table, sizeof(uts_table));	uts_table.data = get_uts(table, write);	r = proc_dostring(&uts_table, write, buffer, lenp, ppos);	put_uts(table, write, uts_table.data); 	if (write)		proc_sys_poll_notify(table->poll); 	return r;}#else#define proc_do_uts_string NULL#endif static DEFINE_CTL_TABLE_POLL(hostname_poll);static DEFINE_CTL_TABLE_POLL(domainname_poll); static struct ctl_table uts_kern_table[] = {	{		.procname	= "ostype",		.data		= init_uts_ns.name.sysname,		.maxlen		= sizeof(init_uts_ns.name.sysname),		.mode		= 0444,		.proc_handler	= proc_do_uts_string,	},	{		.procname	= "osrelease",		.data		= init_uts_ns.name.release,		.maxlen		= sizeof(init_uts_ns.name.release),		.mode		= 0444,		.proc_handler	= proc_do_uts_string,	},	{		.procname	= "version",		.data		= init_uts_ns.name.version,		.maxlen		= sizeof(init_uts_ns.name.version),		.mode		= 0444,		.proc_handler	= proc_do_uts_string,	},	{		.procname	= "hostname",		.data		= init_uts_ns.name.nodename,		.maxlen		= sizeof(init_uts_ns.name.nodename),		.mode		= 0644,		.proc_handler	= proc_do_uts_string,		.poll		= &hostname_poll,	},	{		.procname	= "domainname",		.data		= init_uts_ns.name.domainname,		.maxlen		= sizeof(init_uts_ns.name.domainname),		.mode		= 0644,		.proc_handler	= proc_do_uts_string,		.poll		= &domainname_poll,	},	{}}; static struct ctl_table uts_root_table[] = {	{		.procname	= "kernel",		.mode		= 0555,		.child		= uts_kern_table,	},	{}}; #ifdef CONFIG_PROC_SYSCTL/* * Notify userspace about a change in a certain entry of uts_kern_table, * identified by the parameter proc. */void uts_proc_notify(enum uts_proc proc){	struct ctl_table *table = &uts_kern_table[proc]; 	proc_sys_poll_notify(table->poll);}#endif static int __init utsname_sysctl_init(void){	register_sysctl_table(uts_root_table);	return 0;} device_initcall(utsname_sysctl_init);