Home Home > GIT Browse
summaryrefslogtreecommitdiff
blob: 63da38c2d820920b270cc2f469b965e445fecc05 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
/*
 *  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>

static void *get_uts(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(ctl_table *table, int write, void *which)
{
	if (!write)
		up_read(&uts_sem);
	else
		up_write(&uts_sem);
}

#ifdef CONFIG_PROC_SYSCTL
/*
 *	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(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;
}

__initcall(utsname_sysctl_init);