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_FS 30 static int proc_ipc_dointvec(ctl_table *table, int write, struct file *filp, 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, filp, buffer, lenp, ppos); 38 } 39 40 static int proc_ipc_callback_dointvec(ctl_table *table, int write, 41 struct file *filp, 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, filp, 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 struct file *filp, 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, filp, 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 struct file *filp, 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, filp, 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 #ifdef CONFIG_SYSCTL_SYSCALL 133 /* The generic sysctl ipc data routine. */ 134 static int sysctl_ipc_data(ctl_table *table, 135 void __user *oldval, size_t __user *oldlenp, 136 void __user *newval, size_t newlen) 137 { 138 size_t len; 139 void *data; 140 141 /* Get out of I don't have a variable */ 142 if (!table->data || !table->maxlen) 143 return -ENOTDIR; 144 145 data = get_ipc(table); 146 if (!data) 147 return -ENOTDIR; 148 149 if (oldval && oldlenp) { 150 if (get_user(len, oldlenp)) 151 return -EFAULT; 152 if (len) { 153 if (len > table->maxlen) 154 len = table->maxlen; 155 if (copy_to_user(oldval, data, len)) 156 return -EFAULT; 157 if (put_user(len, oldlenp)) 158 return -EFAULT; 159 } 160 } 161 162 if (newval && newlen) { 163 if (newlen > table->maxlen) 164 newlen = table->maxlen; 165 166 if (copy_from_user(data, newval, newlen)) 167 return -EFAULT; 168 } 169 return 1; 170 } 171 172 static int sysctl_ipc_registered_data(ctl_table *table, 173 void __user *oldval, size_t __user *oldlenp, 174 void __user *newval, size_t newlen) 175 { 176 int rc; 177 178 rc = sysctl_ipc_data(table, oldval, oldlenp, newval, newlen); 179 180 if (newval && newlen && rc > 0) 181 /* 182 * Tunable has successfully been changed from userland 183 */ 184 unregister_ipcns_notifier(current->nsproxy->ipc_ns); 185 186 return rc; 187 } 188 #else 189 #define sysctl_ipc_data NULL 190 #define sysctl_ipc_registered_data NULL 191 #endif 192 193 static int zero; 194 static int one = 1; 195 196 static struct ctl_table ipc_kern_table[] = { 197 { 198 .ctl_name = KERN_SHMMAX, 199 .procname = "shmmax", 200 .data = &init_ipc_ns.shm_ctlmax, 201 .maxlen = sizeof (init_ipc_ns.shm_ctlmax), 202 .mode = 0644, 203 .proc_handler = proc_ipc_doulongvec_minmax, 204 .strategy = sysctl_ipc_data, 205 }, 206 { 207 .ctl_name = KERN_SHMALL, 208 .procname = "shmall", 209 .data = &init_ipc_ns.shm_ctlall, 210 .maxlen = sizeof (init_ipc_ns.shm_ctlall), 211 .mode = 0644, 212 .proc_handler = proc_ipc_doulongvec_minmax, 213 .strategy = sysctl_ipc_data, 214 }, 215 { 216 .ctl_name = KERN_SHMMNI, 217 .procname = "shmmni", 218 .data = &init_ipc_ns.shm_ctlmni, 219 .maxlen = sizeof (init_ipc_ns.shm_ctlmni), 220 .mode = 0644, 221 .proc_handler = proc_ipc_dointvec, 222 .strategy = sysctl_ipc_data, 223 }, 224 { 225 .ctl_name = KERN_MSGMAX, 226 .procname = "msgmax", 227 .data = &init_ipc_ns.msg_ctlmax, 228 .maxlen = sizeof (init_ipc_ns.msg_ctlmax), 229 .mode = 0644, 230 .proc_handler = proc_ipc_dointvec, 231 .strategy = sysctl_ipc_data, 232 }, 233 { 234 .ctl_name = KERN_MSGMNI, 235 .procname = "msgmni", 236 .data = &init_ipc_ns.msg_ctlmni, 237 .maxlen = sizeof (init_ipc_ns.msg_ctlmni), 238 .mode = 0644, 239 .proc_handler = proc_ipc_callback_dointvec, 240 .strategy = sysctl_ipc_registered_data, 241 }, 242 { 243 .ctl_name = KERN_MSGMNB, 244 .procname = "msgmnb", 245 .data = &init_ipc_ns.msg_ctlmnb, 246 .maxlen = sizeof (init_ipc_ns.msg_ctlmnb), 247 .mode = 0644, 248 .proc_handler = proc_ipc_dointvec, 249 .strategy = sysctl_ipc_data, 250 }, 251 { 252 .ctl_name = KERN_SEM, 253 .procname = "sem", 254 .data = &init_ipc_ns.sem_ctls, 255 .maxlen = 4*sizeof (int), 256 .mode = 0644, 257 .proc_handler = proc_ipc_dointvec, 258 .strategy = sysctl_ipc_data, 259 }, 260 { 261 .ctl_name = CTL_UNNUMBERED, 262 .procname = "auto_msgmni", 263 .data = &init_ipc_ns.auto_msgmni, 264 .maxlen = sizeof(int), 265 .mode = 0644, 266 .proc_handler = proc_ipcauto_dointvec_minmax, 267 .extra1 = &zero, 268 .extra2 = &one, 269 }, 270 {} 271 }; 272 273 static struct ctl_table ipc_root_table[] = { 274 { 275 .ctl_name = CTL_KERN, 276 .procname = "kernel", 277 .mode = 0555, 278 .child = ipc_kern_table, 279 }, 280 {} 281 }; 282 283 static int __init ipc_sysctl_init(void) 284 { 285 register_sysctl_table(ipc_root_table); 286 return 0; 287 } 288 289 __initcall(ipc_sysctl_init); 290