1 /* 2 * kernel userspace event delivery 3 * 4 * Copyright (C) 2004 Red Hat, Inc. All rights reserved. 5 * Copyright (C) 2004 Novell, Inc. All rights reserved. 6 * Copyright (C) 2004 IBM, Inc. All rights reserved. 7 * 8 * Licensed under the GNU GPL v2. 9 * 10 * Authors: 11 * Robert Love <rml@novell.com> 12 * Kay Sievers <kay.sievers@vrfy.org> 13 * Arjan van de Ven <arjanv@redhat.com> 14 * Greg Kroah-Hartman <greg@kroah.com> 15 */ 16 17 #include <linux/spinlock.h> 18 #include <linux/string.h> 19 #include <linux/kobject.h> 20 #include <linux/export.h> 21 #include <linux/kmod.h> 22 #include <linux/slab.h> 23 #include <linux/socket.h> 24 #include <linux/skbuff.h> 25 #include <linux/netlink.h> 26 #include <net/sock.h> 27 #include <net/net_namespace.h> 28 29 30 u64 uevent_seqnum; 31 #ifdef CONFIG_UEVENT_HELPER 32 char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH; 33 #endif 34 #ifdef CONFIG_NET 35 struct uevent_sock { 36 struct list_head list; 37 struct sock *sk; 38 }; 39 static LIST_HEAD(uevent_sock_list); 40 #endif 41 42 /* This lock protects uevent_seqnum and uevent_sock_list */ 43 static DEFINE_MUTEX(uevent_sock_mutex); 44 45 /* the strings here must match the enum in include/linux/kobject.h */ 46 static const char *kobject_actions[] = { 47 [KOBJ_ADD] = "add", 48 [KOBJ_REMOVE] = "remove", 49 [KOBJ_CHANGE] = "change", 50 [KOBJ_MOVE] = "move", 51 [KOBJ_ONLINE] = "online", 52 [KOBJ_OFFLINE] = "offline", 53 }; 54 55 /** 56 * kobject_action_type - translate action string to numeric type 57 * 58 * @buf: buffer containing the action string, newline is ignored 59 * @len: length of buffer 60 * @type: pointer to the location to store the action type 61 * 62 * Returns 0 if the action string was recognized. 63 */ 64 int kobject_action_type(const char *buf, size_t count, 65 enum kobject_action *type) 66 { 67 enum kobject_action action; 68 int ret = -EINVAL; 69 70 if (count && (buf[count-1] == '\n' || buf[count-1] == '\0')) 71 count--; 72 73 if (!count) 74 goto out; 75 76 for (action = 0; action < ARRAY_SIZE(kobject_actions); action++) { 77 if (strncmp(kobject_actions[action], buf, count) != 0) 78 continue; 79 if (kobject_actions[action][count] != '\0') 80 continue; 81 *type = action; 82 ret = 0; 83 break; 84 } 85 out: 86 return ret; 87 } 88 89 #ifdef CONFIG_NET 90 static int kobj_bcast_filter(struct sock *dsk, struct sk_buff *skb, void *data) 91 { 92 struct kobject *kobj = data, *ksobj; 93 const struct kobj_ns_type_operations *ops; 94 95 ops = kobj_ns_ops(kobj); 96 if (!ops && kobj->kset) { 97 ksobj = &kobj->kset->kobj; 98 if (ksobj->parent != NULL) 99 ops = kobj_ns_ops(ksobj->parent); 100 } 101 102 if (ops && ops->netlink_ns && kobj->ktype->namespace) { 103 const void *sock_ns, *ns; 104 ns = kobj->ktype->namespace(kobj); 105 sock_ns = ops->netlink_ns(dsk); 106 return sock_ns != ns; 107 } 108 109 return 0; 110 } 111 #endif 112 113 #ifdef CONFIG_UEVENT_HELPER 114 static int kobj_usermode_filter(struct kobject *kobj) 115 { 116 const struct kobj_ns_type_operations *ops; 117 118 ops = kobj_ns_ops(kobj); 119 if (ops) { 120 const void *init_ns, *ns; 121 ns = kobj->ktype->namespace(kobj); 122 init_ns = ops->initial_ns(); 123 return ns != init_ns; 124 } 125 126 return 0; 127 } 128 129 static int init_uevent_argv(struct kobj_uevent_env *env, const char *subsystem) 130 { 131 int len; 132 133 len = strlcpy(&env->buf[env->buflen], subsystem, 134 sizeof(env->buf) - env->buflen); 135 if (len >= (sizeof(env->buf) - env->buflen)) { 136 WARN(1, KERN_ERR "init_uevent_argv: buffer size too small\n"); 137 return -ENOMEM; 138 } 139 140 env->argv[0] = uevent_helper; 141 env->argv[1] = &env->buf[env->buflen]; 142 env->argv[2] = NULL; 143 144 env->buflen += len + 1; 145 return 0; 146 } 147 148 static void cleanup_uevent_env(struct subprocess_info *info) 149 { 150 kfree(info->data); 151 } 152 #endif 153 154 /** 155 * kobject_uevent_env - send an uevent with environmental data 156 * 157 * @action: action that is happening 158 * @kobj: struct kobject that the action is happening to 159 * @envp_ext: pointer to environmental data 160 * 161 * Returns 0 if kobject_uevent_env() is completed with success or the 162 * corresponding error when it fails. 163 */ 164 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action, 165 char *envp_ext[]) 166 { 167 struct kobj_uevent_env *env; 168 const char *action_string = kobject_actions[action]; 169 const char *devpath = NULL; 170 const char *subsystem; 171 struct kobject *top_kobj; 172 struct kset *kset; 173 const struct kset_uevent_ops *uevent_ops; 174 int i = 0; 175 int retval = 0; 176 #ifdef CONFIG_NET 177 struct uevent_sock *ue_sk; 178 #endif 179 180 pr_debug("kobject: '%s' (%p): %s\n", 181 kobject_name(kobj), kobj, __func__); 182 183 /* search the kset we belong to */ 184 top_kobj = kobj; 185 while (!top_kobj->kset && top_kobj->parent) 186 top_kobj = top_kobj->parent; 187 188 if (!top_kobj->kset) { 189 pr_debug("kobject: '%s' (%p): %s: attempted to send uevent " 190 "without kset!\n", kobject_name(kobj), kobj, 191 __func__); 192 return -EINVAL; 193 } 194 195 kset = top_kobj->kset; 196 uevent_ops = kset->uevent_ops; 197 198 /* skip the event, if uevent_suppress is set*/ 199 if (kobj->uevent_suppress) { 200 pr_debug("kobject: '%s' (%p): %s: uevent_suppress " 201 "caused the event to drop!\n", 202 kobject_name(kobj), kobj, __func__); 203 return 0; 204 } 205 /* skip the event, if the filter returns zero. */ 206 if (uevent_ops && uevent_ops->filter) 207 if (!uevent_ops->filter(kset, kobj)) { 208 pr_debug("kobject: '%s' (%p): %s: filter function " 209 "caused the event to drop!\n", 210 kobject_name(kobj), kobj, __func__); 211 return 0; 212 } 213 214 /* originating subsystem */ 215 if (uevent_ops && uevent_ops->name) 216 subsystem = uevent_ops->name(kset, kobj); 217 else 218 subsystem = kobject_name(&kset->kobj); 219 if (!subsystem) { 220 pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the " 221 "event to drop!\n", kobject_name(kobj), kobj, 222 __func__); 223 return 0; 224 } 225 226 /* environment buffer */ 227 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL); 228 if (!env) 229 return -ENOMEM; 230 231 /* complete object path */ 232 devpath = kobject_get_path(kobj, GFP_KERNEL); 233 if (!devpath) { 234 retval = -ENOENT; 235 goto exit; 236 } 237 238 /* default keys */ 239 retval = add_uevent_var(env, "ACTION=%s", action_string); 240 if (retval) 241 goto exit; 242 retval = add_uevent_var(env, "DEVPATH=%s", devpath); 243 if (retval) 244 goto exit; 245 retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem); 246 if (retval) 247 goto exit; 248 249 /* keys passed in from the caller */ 250 if (envp_ext) { 251 for (i = 0; envp_ext[i]; i++) { 252 retval = add_uevent_var(env, "%s", envp_ext[i]); 253 if (retval) 254 goto exit; 255 } 256 } 257 258 /* let the kset specific function add its stuff */ 259 if (uevent_ops && uevent_ops->uevent) { 260 retval = uevent_ops->uevent(kset, kobj, env); 261 if (retval) { 262 pr_debug("kobject: '%s' (%p): %s: uevent() returned " 263 "%d\n", kobject_name(kobj), kobj, 264 __func__, retval); 265 goto exit; 266 } 267 } 268 269 /* 270 * Mark "add" and "remove" events in the object to ensure proper 271 * events to userspace during automatic cleanup. If the object did 272 * send an "add" event, "remove" will automatically generated by 273 * the core, if not already done by the caller. 274 */ 275 if (action == KOBJ_ADD) 276 kobj->state_add_uevent_sent = 1; 277 else if (action == KOBJ_REMOVE) 278 kobj->state_remove_uevent_sent = 1; 279 280 mutex_lock(&uevent_sock_mutex); 281 /* we will send an event, so request a new sequence number */ 282 retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)++uevent_seqnum); 283 if (retval) { 284 mutex_unlock(&uevent_sock_mutex); 285 goto exit; 286 } 287 288 #if defined(CONFIG_NET) 289 /* send netlink message */ 290 list_for_each_entry(ue_sk, &uevent_sock_list, list) { 291 struct sock *uevent_sock = ue_sk->sk; 292 struct sk_buff *skb; 293 size_t len; 294 295 if (!netlink_has_listeners(uevent_sock, 1)) 296 continue; 297 298 /* allocate message with the maximum possible size */ 299 len = strlen(action_string) + strlen(devpath) + 2; 300 skb = alloc_skb(len + env->buflen, GFP_KERNEL); 301 if (skb) { 302 char *scratch; 303 304 /* add header */ 305 scratch = skb_put(skb, len); 306 sprintf(scratch, "%s@%s", action_string, devpath); 307 308 /* copy keys to our continuous event payload buffer */ 309 for (i = 0; i < env->envp_idx; i++) { 310 len = strlen(env->envp[i]) + 1; 311 scratch = skb_put(skb, len); 312 strcpy(scratch, env->envp[i]); 313 } 314 315 NETLINK_CB(skb).dst_group = 1; 316 retval = netlink_broadcast_filtered(uevent_sock, skb, 317 0, 1, GFP_KERNEL, 318 kobj_bcast_filter, 319 kobj); 320 /* ENOBUFS should be handled in userspace */ 321 if (retval == -ENOBUFS || retval == -ESRCH) 322 retval = 0; 323 } else 324 retval = -ENOMEM; 325 } 326 #endif 327 mutex_unlock(&uevent_sock_mutex); 328 329 #ifdef CONFIG_UEVENT_HELPER 330 /* call uevent_helper, usually only enabled during early boot */ 331 if (uevent_helper[0] && !kobj_usermode_filter(kobj)) { 332 struct subprocess_info *info; 333 334 retval = add_uevent_var(env, "HOME=/"); 335 if (retval) 336 goto exit; 337 retval = add_uevent_var(env, 338 "PATH=/sbin:/bin:/usr/sbin:/usr/bin"); 339 if (retval) 340 goto exit; 341 retval = init_uevent_argv(env, subsystem); 342 if (retval) 343 goto exit; 344 345 retval = -ENOMEM; 346 info = call_usermodehelper_setup(env->argv[0], env->argv, 347 env->envp, GFP_KERNEL, 348 NULL, cleanup_uevent_env, env); 349 if (info) { 350 retval = call_usermodehelper_exec(info, UMH_NO_WAIT); 351 env = NULL; /* freed by cleanup_uevent_env */ 352 } 353 } 354 #endif 355 356 exit: 357 kfree(devpath); 358 kfree(env); 359 return retval; 360 } 361 EXPORT_SYMBOL_GPL(kobject_uevent_env); 362 363 /** 364 * kobject_uevent - notify userspace by sending an uevent 365 * 366 * @action: action that is happening 367 * @kobj: struct kobject that the action is happening to 368 * 369 * Returns 0 if kobject_uevent() is completed with success or the 370 * corresponding error when it fails. 371 */ 372 int kobject_uevent(struct kobject *kobj, enum kobject_action action) 373 { 374 return kobject_uevent_env(kobj, action, NULL); 375 } 376 EXPORT_SYMBOL_GPL(kobject_uevent); 377 378 /** 379 * add_uevent_var - add key value string to the environment buffer 380 * @env: environment buffer structure 381 * @format: printf format for the key=value pair 382 * 383 * Returns 0 if environment variable was added successfully or -ENOMEM 384 * if no space was available. 385 */ 386 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...) 387 { 388 va_list args; 389 int len; 390 391 if (env->envp_idx >= ARRAY_SIZE(env->envp)) { 392 WARN(1, KERN_ERR "add_uevent_var: too many keys\n"); 393 return -ENOMEM; 394 } 395 396 va_start(args, format); 397 len = vsnprintf(&env->buf[env->buflen], 398 sizeof(env->buf) - env->buflen, 399 format, args); 400 va_end(args); 401 402 if (len >= (sizeof(env->buf) - env->buflen)) { 403 WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n"); 404 return -ENOMEM; 405 } 406 407 env->envp[env->envp_idx++] = &env->buf[env->buflen]; 408 env->buflen += len + 1; 409 return 0; 410 } 411 EXPORT_SYMBOL_GPL(add_uevent_var); 412 413 #if defined(CONFIG_NET) 414 static int uevent_net_init(struct net *net) 415 { 416 struct uevent_sock *ue_sk; 417 struct netlink_kernel_cfg cfg = { 418 .groups = 1, 419 .flags = NL_CFG_F_NONROOT_RECV, 420 }; 421 422 ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL); 423 if (!ue_sk) 424 return -ENOMEM; 425 426 ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT, &cfg); 427 if (!ue_sk->sk) { 428 printk(KERN_ERR 429 "kobject_uevent: unable to create netlink socket!\n"); 430 kfree(ue_sk); 431 return -ENODEV; 432 } 433 mutex_lock(&uevent_sock_mutex); 434 list_add_tail(&ue_sk->list, &uevent_sock_list); 435 mutex_unlock(&uevent_sock_mutex); 436 return 0; 437 } 438 439 static void uevent_net_exit(struct net *net) 440 { 441 struct uevent_sock *ue_sk; 442 443 mutex_lock(&uevent_sock_mutex); 444 list_for_each_entry(ue_sk, &uevent_sock_list, list) { 445 if (sock_net(ue_sk->sk) == net) 446 goto found; 447 } 448 mutex_unlock(&uevent_sock_mutex); 449 return; 450 451 found: 452 list_del(&ue_sk->list); 453 mutex_unlock(&uevent_sock_mutex); 454 455 netlink_kernel_release(ue_sk->sk); 456 kfree(ue_sk); 457 } 458 459 static struct pernet_operations uevent_net_ops = { 460 .init = uevent_net_init, 461 .exit = uevent_net_exit, 462 }; 463 464 static int __init kobject_uevent_init(void) 465 { 466 return register_pernet_subsys(&uevent_net_ops); 467 } 468 469 470 postcore_initcall(kobject_uevent_init); 471 #endif 472