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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 int oldval;
127 int rc;
128
129 memcpy(&ipc_table, table, sizeof(ipc_table));
130 ipc_table.data = get_ipc(table);
131 oldval = *((int *)(ipc_table.data));
132
133 rc = proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
134
135 if (write && !rc) {
136 int newval = *((int *)(ipc_table.data));
137 /*
138 * The file "auto_msgmni" has correctly been set.
139 * React by (un)registering the corresponding tunable, if the
140 * value has changed.
141 */
142 if (newval != oldval)
143 ipc_auto_callback(newval);
144 }
145
146 return rc;
147 }
148
149 #else
150 #define proc_ipc_doulongvec_minmax NULL
151 #define proc_ipc_dointvec NULL
152 #define proc_ipc_dointvec_minmax NULL
153 #define proc_ipc_dointvec_minmax_orphans NULL
154 #define proc_ipc_callback_dointvec_minmax NULL
155 #define proc_ipcauto_dointvec_minmax NULL
156 #endif
157
158 static int zero;
159 static int one = 1;
160 static int int_max = INT_MAX;
161
162 static struct ctl_table ipc_kern_table[] = {
163 {
164 .procname = "shmmax",
165 .data = &init_ipc_ns.shm_ctlmax,
166 .maxlen = sizeof(init_ipc_ns.shm_ctlmax),
167 .mode = 0644,
168 .proc_handler = proc_ipc_doulongvec_minmax,
169 },
170 {
171 .procname = "shmall",
172 .data = &init_ipc_ns.shm_ctlall,
173 .maxlen = sizeof(init_ipc_ns.shm_ctlall),
174 .mode = 0644,
175 .proc_handler = proc_ipc_doulongvec_minmax,
176 },
177 {
178 .procname = "shmmni",
179 .data = &init_ipc_ns.shm_ctlmni,
180 .maxlen = sizeof(init_ipc_ns.shm_ctlmni),
181 .mode = 0644,
182 .proc_handler = proc_ipc_dointvec,
183 },
184 {
185 .procname = "shm_rmid_forced",
186 .data = &init_ipc_ns.shm_rmid_forced,
187 .maxlen = sizeof(init_ipc_ns.shm_rmid_forced),
188 .mode = 0644,
189 .proc_handler = proc_ipc_dointvec_minmax_orphans,
190 .extra1 = &zero,
191 .extra2 = &one,
192 },
193 {
194 .procname = "msgmax",
195 .data = &init_ipc_ns.msg_ctlmax,
196 .maxlen = sizeof(init_ipc_ns.msg_ctlmax),
197 .mode = 0644,
198 .proc_handler = proc_ipc_dointvec_minmax,
199 .extra1 = &zero,
200 .extra2 = &int_max,
201 },
202 {
203 .procname = "msgmni",
204 .data = &init_ipc_ns.msg_ctlmni,
205 .maxlen = sizeof(init_ipc_ns.msg_ctlmni),
206 .mode = 0644,
207 .proc_handler = proc_ipc_callback_dointvec_minmax,
208 .extra1 = &zero,
209 .extra2 = &int_max,
210 },
211 {
212 .procname = "msgmnb",
213 .data = &init_ipc_ns.msg_ctlmnb,
214 .maxlen = sizeof(init_ipc_ns.msg_ctlmnb),
215 .mode = 0644,
216 .proc_handler = proc_ipc_dointvec_minmax,
217 .extra1 = &zero,
218 .extra2 = &int_max,
219 },
220 {
221 .procname = "sem",
222 .data = &init_ipc_ns.sem_ctls,
223 .maxlen = 4*sizeof(int),
224 .mode = 0644,
225 .proc_handler = proc_ipc_dointvec,
226 },
227 {
228 .procname = "auto_msgmni",
229 .data = &init_ipc_ns.auto_msgmni,
230 .maxlen = sizeof(int),
231 .mode = 0644,
232 .proc_handler = proc_ipcauto_dointvec_minmax,
233 .extra1 = &zero,
234 .extra2 = &one,
235 },
236 #ifdef CONFIG_CHECKPOINT_RESTORE
237 {
238 .procname = "sem_next_id",
239 .data = &init_ipc_ns.ids[IPC_SEM_IDS].next_id,
240 .maxlen = sizeof(init_ipc_ns.ids[IPC_SEM_IDS].next_id),
241 .mode = 0644,
242 .proc_handler = proc_ipc_dointvec_minmax,
243 .extra1 = &zero,
244 .extra2 = &int_max,
245 },
246 {
247 .procname = "msg_next_id",
248 .data = &init_ipc_ns.ids[IPC_MSG_IDS].next_id,
249 .maxlen = sizeof(init_ipc_ns.ids[IPC_MSG_IDS].next_id),
250 .mode = 0644,
251 .proc_handler = proc_ipc_dointvec_minmax,
252 .extra1 = &zero,
253 .extra2 = &int_max,
254 },
255 {
256 .procname = "shm_next_id",
257 .data = &init_ipc_ns.ids[IPC_SHM_IDS].next_id,
258 .maxlen = sizeof(init_ipc_ns.ids[IPC_SHM_IDS].next_id),
259 .mode = 0644,
260 .proc_handler = proc_ipc_dointvec_minmax,
261 .extra1 = &zero,
262 .extra2 = &int_max,
263 },
264 #endif
265 {}
266 };
267
268 static struct ctl_table ipc_root_table[] = {
269 {
270 .procname = "kernel",
271 .mode = 0555,
272 .child = ipc_kern_table,
273 },
274 {}
275 };
276
277 static int __init ipc_sysctl_init(void)
278 {
279 register_sysctl_table(ipc_root_table);
280 return 0;
281 }
282
283 device_initcall(ipc_sysctl_init);