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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>
17 #include <linux/ipc_namespace.h>
18 #include <linux/msg.h>
19 #include "util.h"
20
21 static void *get_ipc(struct 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 }
28
29 #ifdef CONFIG_PROC_SYSCTL
30 static int proc_ipc_dointvec(struct ctl_table *table, int write,
31 void __user *buffer, size_t *lenp, loff_t *ppos)
32 {
33 struct ctl_table ipc_table;
34
35 memcpy(&ipc_table, table, sizeof(ipc_table));
36 ipc_table.data = get_ipc(table);
37
38 return proc_dointvec(&ipc_table, write, buffer, lenp, ppos);
39 }
40
41 static int proc_ipc_dointvec_minmax(struct ctl_table *table, int write,
42 void __user *buffer, size_t *lenp, loff_t *ppos)
43 {
44 struct ctl_table ipc_table;
45
46 memcpy(&ipc_table, table, sizeof(ipc_table));
47 ipc_table.data = get_ipc(table);
48
49 return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
50 }
51
52 static int proc_ipc_dointvec_minmax_orphans(struct ctl_table *table, int write,
53 void __user *buffer, size_t *lenp, loff_t *ppos)
54 {
55 struct ipc_namespace *ns = current->nsproxy->ipc_ns;
56 int err = proc_ipc_dointvec_minmax(table, write, buffer, lenp, ppos);
57
58 if (err < 0)
59 return err;
60 if (ns->shm_rmid_forced)
61 shm_destroy_orphaned(ns);
62 return err;
63 }
64
65 static int proc_ipc_callback_dointvec_minmax(struct ctl_table *table, int write,
66 void __user *buffer, size_t *lenp, loff_t *ppos)
67 {
68 struct ctl_table ipc_table;
69 size_t lenp_bef = *lenp;
70 int rc;
71
72 memcpy(&ipc_table, table, sizeof(ipc_table));
73 ipc_table.data = get_ipc(table);
74
75 rc = proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
76
77 if (write && !rc && lenp_bef == *lenp)
78 /*
79 * Tunable has successfully been changed by hand. Disable its
80 * automatic adjustment. This simply requires unregistering
81 * the notifiers that trigger recalculation.
82 */
83 unregister_ipcns_notifier(current->nsproxy->ipc_ns);
84
85 return rc;
86 }
87
88 static int proc_ipc_doulongvec_minmax(struct ctl_table *table, int write,
89 void __user *buffer, size_t *lenp, loff_t *ppos)
90 {
91 struct ctl_table ipc_table;
92 memcpy(&ipc_table, table, sizeof(ipc_table));
93 ipc_table.data = get_ipc(table);
94
95 return proc_doulongvec_minmax(&ipc_table, write, buffer,
96 lenp, ppos);
97 }
98
99 /*
100 * Routine that is called when the file "auto_msgmni" has successfully been
101 * written.
102 * Two values are allowed:
103 * 0: unregister msgmni's callback routine from the ipc namespace notifier
104 * chain. This means that msgmni won't be recomputed anymore upon memory
105 * add/remove or ipc namespace creation/removal.
106 * 1: register back the callback routine.
107 */
108 static void ipc_auto_callback(int val)
109 {
110 if (!val)
111 unregister_ipcns_notifier(current->nsproxy->ipc_ns);
112 else {
113 /*
114 * Re-enable automatic recomputing only if not already
115 * enabled.
116 */
117 recompute_msgmni(current->nsproxy->ipc_ns);
118 cond_register_ipcns_notifier(current->nsproxy->ipc_ns);
119 }
120 }
121
122 static int proc_ipcauto_dointvec_minmax(struct ctl_table *table, int write,
123 void __user *buffer, size_t *lenp, loff_t *ppos)
124 {
125 struct ctl_table ipc_table;
126 size_t lenp_bef = *lenp;
127 int oldval;
128 int rc;
129
130 memcpy(&ipc_table, table, sizeof(ipc_table));
131 ipc_table.data = get_ipc(table);
132 oldval = *((int *)(ipc_table.data));
133
134 rc = proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
135
136 if (write && !rc && lenp_bef == *lenp) {
137 int newval = *((int *)(ipc_table.data));
138 /*
139 * The file "auto_msgmni" has correctly been set.
140 * React by (un)registering the corresponding tunable, if the
141 * value has changed.
142 */
143 if (newval != oldval)
144 ipc_auto_callback(newval);
145 }
146
147 return rc;
148 }
149
150 #else
151 #define proc_ipc_doulongvec_minmax NULL
152 #define proc_ipc_dointvec NULL
153 #define proc_ipc_dointvec_minmax NULL
154 #define proc_ipc_dointvec_minmax_orphans NULL
155 #define proc_ipc_callback_dointvec_minmax NULL
156 #define proc_ipcauto_dointvec_minmax NULL
157 #endif
158
159 static int zero;
160 static int one = 1;
161 static int int_max = INT_MAX;
162
163 static struct ctl_table ipc_kern_table[] = {
164 {
165 .procname = "shmmax",
166 .data = &init_ipc_ns.shm_ctlmax,
167 .maxlen = sizeof(init_ipc_ns.shm_ctlmax),
168 .mode = 0644,
169 .proc_handler = proc_ipc_doulongvec_minmax,
170 },
171 {
172 .procname = "shmall",
173 .data = &init_ipc_ns.shm_ctlall,
174 .maxlen = sizeof(init_ipc_ns.shm_ctlall),
175 .mode = 0644,
176 .proc_handler = proc_ipc_doulongvec_minmax,
177 },
178 {
179 .procname = "shmmni",
180 .data = &init_ipc_ns.shm_ctlmni,
181 .maxlen = sizeof(init_ipc_ns.shm_ctlmni),
182 .mode = 0644,
183 .proc_handler = proc_ipc_dointvec,
184 },
185 {
186 .procname = "shm_rmid_forced",
187 .data = &init_ipc_ns.shm_rmid_forced,
188 .maxlen = sizeof(init_ipc_ns.shm_rmid_forced),
189 .mode = 0644,
190 .proc_handler = proc_ipc_dointvec_minmax_orphans,
191 .extra1 = &zero,
192 .extra2 = &one,
193 },
194 {
195 .procname = "msgmax",
196 .data = &init_ipc_ns.msg_ctlmax,
197 .maxlen = sizeof(init_ipc_ns.msg_ctlmax),
198 .mode = 0644,
199 .proc_handler = proc_ipc_dointvec_minmax,
200 .extra1 = &zero,
201 .extra2 = &int_max,
202 },
203 {
204 .procname = "msgmni",
205 .data = &init_ipc_ns.msg_ctlmni,
206 .maxlen = sizeof(init_ipc_ns.msg_ctlmni),
207 .mode = 0644,
208 .proc_handler = proc_ipc_callback_dointvec_minmax,
209 .extra1 = &zero,
210 .extra2 = &int_max,
211 },
212 {
213 .procname = "msgmnb",
214 .data = &init_ipc_ns.msg_ctlmnb,
215 .maxlen = sizeof(init_ipc_ns.msg_ctlmnb),
216 .mode = 0644,
217 .proc_handler = proc_ipc_dointvec_minmax,
218 .extra1 = &zero,
219 .extra2 = &int_max,
220 },
221 {
222 .procname = "sem",
223 .data = &init_ipc_ns.sem_ctls,
224 .maxlen = 4*sizeof(int),
225 .mode = 0644,
226 .proc_handler = proc_ipc_dointvec,
227 },
228 {
229 .procname = "auto_msgmni",
230 .data = &init_ipc_ns.auto_msgmni,
231 .maxlen = sizeof(int),
232 .mode = 0644,
233 .proc_handler = proc_ipcauto_dointvec_minmax,
234 .extra1 = &zero,
235 .extra2 = &one,
236 },
237 #ifdef CONFIG_CHECKPOINT_RESTORE
238 {
239 .procname = "sem_next_id",
240 .data = &init_ipc_ns.ids[IPC_SEM_IDS].next_id,
241 .maxlen = sizeof(init_ipc_ns.ids[IPC_SEM_IDS].next_id),
242 .mode = 0644,
243 .proc_handler = proc_ipc_dointvec_minmax,
244 .extra1 = &zero,
245 .extra2 = &int_max,
246 },
247 {
248 .procname = "msg_next_id",
249 .data = &init_ipc_ns.ids[IPC_MSG_IDS].next_id,
250 .maxlen = sizeof(init_ipc_ns.ids[IPC_MSG_IDS].next_id),
251 .mode = 0644,
252 .proc_handler = proc_ipc_dointvec_minmax,
253 .extra1 = &zero,
254 .extra2 = &int_max,
255 },
256 {
257 .procname = "shm_next_id",
258 .data = &init_ipc_ns.ids[IPC_SHM_IDS].next_id,
259 .maxlen = sizeof(init_ipc_ns.ids[IPC_SHM_IDS].next_id),
260 .mode = 0644,
261 .proc_handler = proc_ipc_dointvec_minmax,
262 .extra1 = &zero,
263 .extra2 = &int_max,
264 },
265 #endif
266 {}
267 };
268
269 static struct ctl_table ipc_root_table[] = {
270 {
271 .procname = "kernel",
272 .mode = 0555,
273 .child = ipc_kern_table,
274 },
275 {}
276 };
277
278 static int __init ipc_sysctl_init(void)
279 {
280 register_sysctl_table(ipc_root_table);
281 return 0;
282 }
283
284 device_initcall(ipc_sysctl_init);