linux-stable/kernel/utsname_sysctl.c
Ingo Molnar cd9c513be3 sched/headers: Remove <linux/rwsem.h> from <linux/sched.h>
This is a stray header that is not needed by anything in sched.h,
so remove it.

Update files that relied on the stray inclusion.

This reduces the size of the header dependency graph.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-03 01:45:36 +01:00

139 lines
3 KiB
C

/*
* 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);