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[net-next-2.6.git] / ipc / ipc_sysctl.c
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1/*
2 * Copyright (C) 2007
3 *
4 * Author: Eric Biederman <ebiederm@xmision.com>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as
8 * published by the Free Software Foundation, version 2 of the
9 * License.
10 */
11
12#include <linux/module.h>
13#include <linux/ipc.h>
14#include <linux/nsproxy.h>
15#include <linux/sysctl.h>
16#include <linux/uaccess.h>
ae5e1b22 17#include <linux/ipc_namespace.h>
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18#include <linux/msg.h>
19#include "util.h"
a5494dcd 20
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21static void *get_ipc(ctl_table *table)
22{
23 char *which = table->data;
24 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
25 which = (which - (char *)&init_ipc_ns) + (char *)ipc_ns;
26 return which;
27}
a5494dcd 28
11dea190 29#ifdef CONFIG_PROC_SYSCTL
8d65af78 30static int proc_ipc_dointvec(ctl_table *table, int write,
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31 void __user *buffer, size_t *lenp, loff_t *ppos)
32{
33 struct ctl_table ipc_table;
34 memcpy(&ipc_table, table, sizeof(ipc_table));
35 ipc_table.data = get_ipc(table);
36
8d65af78 37 return proc_dointvec(&ipc_table, write, buffer, lenp, ppos);
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38}
39
91cfb2b4 40static int proc_ipc_callback_dointvec(ctl_table *table, int write,
8d65af78 41 void __user *buffer, size_t *lenp, loff_t *ppos)
91cfb2b4 42{
6546bc42 43 struct ctl_table ipc_table;
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44 size_t lenp_bef = *lenp;
45 int rc;
46
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47 memcpy(&ipc_table, table, sizeof(ipc_table));
48 ipc_table.data = get_ipc(table);
49
8d65af78 50 rc = proc_dointvec(&ipc_table, write, buffer, lenp, ppos);
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51
52 if (write && !rc && lenp_bef == *lenp)
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53 /*
54 * Tunable has successfully been changed by hand. Disable its
55 * automatic adjustment. This simply requires unregistering
56 * the notifiers that trigger recalculation.
57 */
58 unregister_ipcns_notifier(current->nsproxy->ipc_ns);
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59
60 return rc;
61}
62
a5494dcd 63static int proc_ipc_doulongvec_minmax(ctl_table *table, int write,
8d65af78 64 void __user *buffer, size_t *lenp, loff_t *ppos)
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65{
66 struct ctl_table ipc_table;
67 memcpy(&ipc_table, table, sizeof(ipc_table));
68 ipc_table.data = get_ipc(table);
69
8d65af78 70 return proc_doulongvec_minmax(&ipc_table, write, buffer,
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71 lenp, ppos);
72}
73
4c2c3b4a 74/*
75 * Routine that is called when the file "auto_msgmni" has successfully been
76 * written.
77 * Two values are allowed:
78 * 0: unregister msgmni's callback routine from the ipc namespace notifier
79 * chain. This means that msgmni won't be recomputed anymore upon memory
80 * add/remove or ipc namespace creation/removal.
81 * 1: register back the callback routine.
82 */
83static void ipc_auto_callback(int val)
84{
85 if (!val)
86 unregister_ipcns_notifier(current->nsproxy->ipc_ns);
87 else {
88 /*
89 * Re-enable automatic recomputing only if not already
90 * enabled.
91 */
92 recompute_msgmni(current->nsproxy->ipc_ns);
93 cond_register_ipcns_notifier(current->nsproxy->ipc_ns);
94 }
95}
96
9eefe520 97static int proc_ipcauto_dointvec_minmax(ctl_table *table, int write,
8d65af78 98 void __user *buffer, size_t *lenp, loff_t *ppos)
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99{
100 struct ctl_table ipc_table;
101 size_t lenp_bef = *lenp;
102 int oldval;
103 int rc;
104
105 memcpy(&ipc_table, table, sizeof(ipc_table));
106 ipc_table.data = get_ipc(table);
107 oldval = *((int *)(ipc_table.data));
108
8d65af78 109 rc = proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
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110
111 if (write && !rc && lenp_bef == *lenp) {
112 int newval = *((int *)(ipc_table.data));
113 /*
114 * The file "auto_msgmni" has correctly been set.
115 * React by (un)registering the corresponding tunable, if the
116 * value has changed.
117 */
118 if (newval != oldval)
119 ipc_auto_callback(newval);
120 }
121
122 return rc;
123}
124
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125#else
126#define proc_ipc_doulongvec_minmax NULL
127#define proc_ipc_dointvec NULL
91cfb2b4 128#define proc_ipc_callback_dointvec NULL
9eefe520 129#define proc_ipcauto_dointvec_minmax NULL
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130#endif
131
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132static int zero;
133static int one = 1;
134
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135static struct ctl_table ipc_kern_table[] = {
136 {
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137 .procname = "shmmax",
138 .data = &init_ipc_ns.shm_ctlmax,
139 .maxlen = sizeof (init_ipc_ns.shm_ctlmax),
140 .mode = 0644,
141 .proc_handler = proc_ipc_doulongvec_minmax,
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142 },
143 {
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144 .procname = "shmall",
145 .data = &init_ipc_ns.shm_ctlall,
146 .maxlen = sizeof (init_ipc_ns.shm_ctlall),
147 .mode = 0644,
148 .proc_handler = proc_ipc_doulongvec_minmax,
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149 },
150 {
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151 .procname = "shmmni",
152 .data = &init_ipc_ns.shm_ctlmni,
153 .maxlen = sizeof (init_ipc_ns.shm_ctlmni),
154 .mode = 0644,
155 .proc_handler = proc_ipc_dointvec,
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156 },
157 {
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158 .procname = "msgmax",
159 .data = &init_ipc_ns.msg_ctlmax,
160 .maxlen = sizeof (init_ipc_ns.msg_ctlmax),
161 .mode = 0644,
162 .proc_handler = proc_ipc_dointvec,
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163 },
164 {
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165 .procname = "msgmni",
166 .data = &init_ipc_ns.msg_ctlmni,
167 .maxlen = sizeof (init_ipc_ns.msg_ctlmni),
168 .mode = 0644,
91cfb2b4 169 .proc_handler = proc_ipc_callback_dointvec,
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170 },
171 {
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172 .procname = "msgmnb",
173 .data = &init_ipc_ns.msg_ctlmnb,
174 .maxlen = sizeof (init_ipc_ns.msg_ctlmnb),
175 .mode = 0644,
176 .proc_handler = proc_ipc_dointvec,
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177 },
178 {
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179 .procname = "sem",
180 .data = &init_ipc_ns.sem_ctls,
181 .maxlen = 4*sizeof (int),
182 .mode = 0644,
183 .proc_handler = proc_ipc_dointvec,
a5494dcd 184 },
9eefe520 185 {
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186 .procname = "auto_msgmni",
187 .data = &init_ipc_ns.auto_msgmni,
188 .maxlen = sizeof(int),
189 .mode = 0644,
190 .proc_handler = proc_ipcauto_dointvec_minmax,
191 .extra1 = &zero,
192 .extra2 = &one,
193 },
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194 {}
195};
196
197static struct ctl_table ipc_root_table[] = {
198 {
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199 .procname = "kernel",
200 .mode = 0555,
201 .child = ipc_kern_table,
202 },
203 {}
204};
205
206static int __init ipc_sysctl_init(void)
207{
0b4d4147 208 register_sysctl_table(ipc_root_table);
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209 return 0;
210}
211
212__initcall(ipc_sysctl_init);