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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(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(ctl_table *table, int write, | |
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 | ||
37 | return proc_dointvec(&ipc_table, write, buffer, lenp, ppos); | |
38 | } | |
39 | ||
40 | static int proc_ipc_callback_dointvec(ctl_table *table, int write, | |
41 | void __user *buffer, size_t *lenp, loff_t *ppos) | |
42 | { | |
43 | struct ctl_table ipc_table; | |
44 | size_t lenp_bef = *lenp; | |
45 | int rc; | |
46 | ||
47 | memcpy(&ipc_table, table, sizeof(ipc_table)); | |
48 | ipc_table.data = get_ipc(table); | |
49 | ||
50 | rc = proc_dointvec(&ipc_table, write, buffer, lenp, ppos); | |
51 | ||
52 | if (write && !rc && lenp_bef == *lenp) | |
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); | |
59 | ||
60 | return rc; | |
61 | } | |
62 | ||
63 | static int proc_ipc_doulongvec_minmax(ctl_table *table, int write, | |
64 | void __user *buffer, size_t *lenp, loff_t *ppos) | |
65 | { | |
66 | struct ctl_table ipc_table; | |
67 | memcpy(&ipc_table, table, sizeof(ipc_table)); | |
68 | ipc_table.data = get_ipc(table); | |
69 | ||
70 | return proc_doulongvec_minmax(&ipc_table, write, buffer, | |
71 | lenp, ppos); | |
72 | } | |
73 | ||
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 | */ | |
83 | static 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 | ||
97 | static int proc_ipcauto_dointvec_minmax(ctl_table *table, int write, | |
98 | void __user *buffer, size_t *lenp, loff_t *ppos) | |
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 | ||
109 | rc = proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos); | |
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 | ||
125 | #else | |
126 | #define proc_ipc_doulongvec_minmax NULL | |
127 | #define proc_ipc_dointvec NULL | |
128 | #define proc_ipc_callback_dointvec NULL | |
129 | #define proc_ipcauto_dointvec_minmax NULL | |
130 | #endif | |
131 | ||
132 | static int zero; | |
133 | static int one = 1; | |
134 | ||
135 | static struct ctl_table ipc_kern_table[] = { | |
136 | { | |
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, | |
142 | }, | |
143 | { | |
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, | |
149 | }, | |
150 | { | |
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, | |
156 | }, | |
157 | { | |
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, | |
163 | }, | |
164 | { | |
165 | .procname = "msgmni", | |
166 | .data = &init_ipc_ns.msg_ctlmni, | |
167 | .maxlen = sizeof (init_ipc_ns.msg_ctlmni), | |
168 | .mode = 0644, | |
169 | .proc_handler = proc_ipc_callback_dointvec, | |
170 | }, | |
171 | { | |
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, | |
177 | }, | |
178 | { | |
179 | .procname = "sem", | |
180 | .data = &init_ipc_ns.sem_ctls, | |
181 | .maxlen = 4*sizeof (int), | |
182 | .mode = 0644, | |
183 | .proc_handler = proc_ipc_dointvec, | |
184 | }, | |
185 | { | |
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 | }, | |
194 | {} | |
195 | }; | |
196 | ||
197 | static struct ctl_table ipc_root_table[] = { | |
198 | { | |
199 | .procname = "kernel", | |
200 | .mode = 0555, | |
201 | .child = ipc_kern_table, | |
202 | }, | |
203 | {} | |
204 | }; | |
205 | ||
206 | static int __init ipc_sysctl_init(void) | |
207 | { | |
208 | register_sysctl_table(ipc_root_table); | |
209 | return 0; | |
210 | } | |
211 | ||
212 | __initcall(ipc_sysctl_init); |