projects/linux·blob v3.7 · refs

248 lines · 6.0 KiB

1/*
2 * Copyright (C) 2007
3 *
4 * Author: Eric Biederman <[email protected]>
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
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}
28
29#ifdef CONFIG_PROC_SYSCTL
30static int proc_ipc_dointvec(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
41static int proc_ipc_dointvec_minmax(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
52static int proc_ipc_dointvec_minmax_orphans(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
65static int proc_ipc_callback_dointvec(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(&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
88static int proc_ipc_doulongvec_minmax(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 */
108static 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
122static int proc_ipcauto_dointvec_minmax(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 NULL
156#define proc_ipcauto_dointvec_minmax NULL
157#endif
158
159static int zero;
160static int one = 1;
161
162static 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,
199 },
200 {
201 .procname = "msgmni",
202 .data = &init_ipc_ns.msg_ctlmni,
203 .maxlen = sizeof (init_ipc_ns.msg_ctlmni),
204 .mode = 0644,
205 .proc_handler = proc_ipc_callback_dointvec,
206 },
207 {
208 .procname = "msgmnb",
209 .data = &init_ipc_ns.msg_ctlmnb,
210 .maxlen = sizeof (init_ipc_ns.msg_ctlmnb),
211 .mode = 0644,
212 .proc_handler = proc_ipc_dointvec,
213 },
214 {
215 .procname = "sem",
216 .data = &init_ipc_ns.sem_ctls,
217 .maxlen = 4*sizeof (int),
218 .mode = 0644,
219 .proc_handler = proc_ipc_dointvec,
220 },
221 {
222 .procname = "auto_msgmni",
223 .data = &init_ipc_ns.auto_msgmni,
224 .maxlen = sizeof(int),
225 .mode = 0644,
226 .proc_handler = proc_ipcauto_dointvec_minmax,
227 .extra1 = &zero,
228 .extra2 = &one,
229 },
230 {}
231};
232
233static struct ctl_table ipc_root_table[] = {
234 {
235 .procname = "kernel",
236 .mode = 0555,
237 .child = ipc_kern_table,
238 },
239 {}
240};
241
242static int __init ipc_sysctl_init(void)
243{
244 register_sysctl_table(ipc_root_table);
245 return 0;
246}
247
248__initcall(ipc_sysctl_init);