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 <linux/uuid.h> 27 #include <linux/ctype.h> 28 #include <net/sock.h> 29 #include <net/net_namespace.h> 30 31 32 u64 uevent_seqnum; 33 #ifdef CONFIG_UEVENT_HELPER 34 char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH; 35 #endif 36 #ifdef CONFIG_NET 37 struct uevent_sock { 38 struct list_head list; 39 struct sock *sk; 40 }; 41 static LIST_HEAD(uevent_sock_list); 42 #endif 43 44 /* This lock protects uevent_seqnum and uevent_sock_list */ 45 static DEFINE_MUTEX(uevent_sock_mutex); 46 47 /* the strings here must match the enum in include/linux/kobject.h */ 48 static const char *kobject_actions[] = { 49 [KOBJ_ADD] = "add", 50 [KOBJ_REMOVE] = "remove", 51 [KOBJ_CHANGE] = "change", 52 [KOBJ_MOVE] = "move", 53 [KOBJ_ONLINE] = "online", 54 [KOBJ_OFFLINE] = "offline", 55 [KOBJ_BIND] = "bind", 56 [KOBJ_UNBIND] = "unbind", 57 }; 58 59 static int kobject_action_type(const char *buf, size_t count, 60 enum kobject_action *type, 61 const char **args) 62 { 63 enum kobject_action action; 64 size_t count_first; 65 const char *args_start; 66 int ret = -EINVAL; 67 68 if (count && (buf[count-1] == '\n' || buf[count-1] == '\0')) 69 count--; 70 71 if (!count) 72 goto out; 73 74 args_start = strnchr(buf, count, ' '); 75 if (args_start) { 76 count_first = args_start - buf; 77 args_start = args_start + 1; 78 } else 79 count_first = count; 80 81 for (action = 0; action < ARRAY_SIZE(kobject_actions); action++) { 82 if (strncmp(kobject_actions[action], buf, count_first) != 0) 83 continue; 84 if (kobject_actions[action][count_first] != '\0') 85 continue; 86 if (args) 87 *args = args_start; 88 *type = action; 89 ret = 0; 90 break; 91 } 92 out: 93 return ret; 94 } 95 96 static const char *action_arg_word_end(const char *buf, const char *buf_end, 97 char delim) 98 { 99 const char *next = buf; 100 101 while (next <= buf_end && *next != delim) 102 if (!isalnum(*next++)) 103 return NULL; 104 105 if (next == buf) 106 return NULL; 107 108 return next; 109 } 110 111 static int kobject_action_args(const char *buf, size_t count, 112 struct kobj_uevent_env **ret_env) 113 { 114 struct kobj_uevent_env *env = NULL; 115 const char *next, *buf_end, *key; 116 int key_len; 117 int r = -EINVAL; 118 119 if (count && (buf[count - 1] == '\n' || buf[count - 1] == '\0')) 120 count--; 121 122 if (!count) 123 return -EINVAL; 124 125 env = kzalloc(sizeof(*env), GFP_KERNEL); 126 if (!env) 127 return -ENOMEM; 128 129 /* first arg is UUID */ 130 if (count < UUID_STRING_LEN || !uuid_is_valid(buf) || 131 add_uevent_var(env, "SYNTH_UUID=%.*s", UUID_STRING_LEN, buf)) 132 goto out; 133 134 /* 135 * the rest are custom environment variables in KEY=VALUE 136 * format with ' ' delimiter between each KEY=VALUE pair 137 */ 138 next = buf + UUID_STRING_LEN; 139 buf_end = buf + count - 1; 140 141 while (next <= buf_end) { 142 if (*next != ' ') 143 goto out; 144 145 /* skip the ' ', key must follow */ 146 key = ++next; 147 if (key > buf_end) 148 goto out; 149 150 buf = next; 151 next = action_arg_word_end(buf, buf_end, '='); 152 if (!next || next > buf_end || *next != '=') 153 goto out; 154 key_len = next - buf; 155 156 /* skip the '=', value must follow */ 157 if (++next > buf_end) 158 goto out; 159 160 buf = next; 161 next = action_arg_word_end(buf, buf_end, ' '); 162 if (!next) 163 goto out; 164 165 if (add_uevent_var(env, "SYNTH_ARG_%.*s=%.*s", 166 key_len, key, (int) (next - buf), buf)) 167 goto out; 168 } 169 170 r = 0; 171 out: 172 if (r) 173 kfree(env); 174 else 175 *ret_env = env; 176 return r; 177 } 178 179 /** 180 * kobject_synth_uevent - send synthetic uevent with arguments 181 * 182 * @kobj: struct kobject for which synthetic uevent is to be generated 183 * @buf: buffer containing action type and action args, newline is ignored 184 * @count: length of buffer 185 * 186 * Returns 0 if kobject_synthetic_uevent() is completed with success or the 187 * corresponding error when it fails. 188 */ 189 int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count) 190 { 191 char *no_uuid_envp[] = { "SYNTH_UUID=0", NULL }; 192 enum kobject_action action; 193 const char *action_args; 194 struct kobj_uevent_env *env; 195 const char *msg = NULL, *devpath; 196 int r; 197 198 r = kobject_action_type(buf, count, &action, &action_args); 199 if (r) { 200 msg = "unknown uevent action string\n"; 201 goto out; 202 } 203 204 if (!action_args) { 205 r = kobject_uevent_env(kobj, action, no_uuid_envp); 206 goto out; 207 } 208 209 r = kobject_action_args(action_args, 210 count - (action_args - buf), &env); 211 if (r == -EINVAL) { 212 msg = "incorrect uevent action arguments\n"; 213 goto out; 214 } 215 216 if (r) 217 goto out; 218 219 r = kobject_uevent_env(kobj, action, env->envp); 220 kfree(env); 221 out: 222 if (r) { 223 devpath = kobject_get_path(kobj, GFP_KERNEL); 224 printk(KERN_WARNING "synth uevent: %s: %s", 225 devpath ?: "unknown device", 226 msg ?: "failed to send uevent"); 227 kfree(devpath); 228 } 229 return r; 230 } 231 232 #ifdef CONFIG_NET 233 static int kobj_bcast_filter(struct sock *dsk, struct sk_buff *skb, void *data) 234 { 235 struct kobject *kobj = data, *ksobj; 236 const struct kobj_ns_type_operations *ops; 237 238 ops = kobj_ns_ops(kobj); 239 if (!ops && kobj->kset) { 240 ksobj = &kobj->kset->kobj; 241 if (ksobj->parent != NULL) 242 ops = kobj_ns_ops(ksobj->parent); 243 } 244 245 if (ops && ops->netlink_ns && kobj->ktype->namespace) { 246 const void *sock_ns, *ns; 247 ns = kobj->ktype->namespace(kobj); 248 sock_ns = ops->netlink_ns(dsk); 249 return sock_ns != ns; 250 } 251 252 return 0; 253 } 254 #endif 255 256 #ifdef CONFIG_UEVENT_HELPER 257 static int kobj_usermode_filter(struct kobject *kobj) 258 { 259 const struct kobj_ns_type_operations *ops; 260 261 ops = kobj_ns_ops(kobj); 262 if (ops) { 263 const void *init_ns, *ns; 264 ns = kobj->ktype->namespace(kobj); 265 init_ns = ops->initial_ns(); 266 return ns != init_ns; 267 } 268 269 return 0; 270 } 271 272 static int init_uevent_argv(struct kobj_uevent_env *env, const char *subsystem) 273 { 274 int len; 275 276 len = strlcpy(&env->buf[env->buflen], subsystem, 277 sizeof(env->buf) - env->buflen); 278 if (len >= (sizeof(env->buf) - env->buflen)) { 279 WARN(1, KERN_ERR "init_uevent_argv: buffer size too small\n"); 280 return -ENOMEM; 281 } 282 283 env->argv[0] = uevent_helper; 284 env->argv[1] = &env->buf[env->buflen]; 285 env->argv[2] = NULL; 286 287 env->buflen += len + 1; 288 return 0; 289 } 290 291 static void cleanup_uevent_env(struct subprocess_info *info) 292 { 293 kfree(info->data); 294 } 295 #endif 296 297 static int kobject_uevent_net_broadcast(struct kobject *kobj, 298 struct kobj_uevent_env *env, 299 const char *action_string, 300 const char *devpath) 301 { 302 int retval = 0; 303 #if defined(CONFIG_NET) 304 struct sk_buff *skb = NULL; 305 struct uevent_sock *ue_sk; 306 307 /* send netlink message */ 308 list_for_each_entry(ue_sk, &uevent_sock_list, list) { 309 struct sock *uevent_sock = ue_sk->sk; 310 311 if (!netlink_has_listeners(uevent_sock, 1)) 312 continue; 313 314 if (!skb) { 315 /* allocate message with the maximum possible size */ 316 size_t len = strlen(action_string) + strlen(devpath) + 2; 317 char *scratch; 318 319 retval = -ENOMEM; 320 skb = alloc_skb(len + env->buflen, GFP_KERNEL); 321 if (!skb) 322 continue; 323 324 /* add header */ 325 scratch = skb_put(skb, len); 326 sprintf(scratch, "%s@%s", action_string, devpath); 327 328 skb_put_data(skb, env->buf, env->buflen); 329 330 NETLINK_CB(skb).dst_group = 1; 331 } 332 333 retval = netlink_broadcast_filtered(uevent_sock, skb_get(skb), 334 0, 1, GFP_KERNEL, 335 kobj_bcast_filter, 336 kobj); 337 /* ENOBUFS should be handled in userspace */ 338 if (retval == -ENOBUFS || retval == -ESRCH) 339 retval = 0; 340 } 341 consume_skb(skb); 342 #endif 343 return retval; 344 } 345 346 /** 347 * kobject_uevent_env - send an uevent with environmental data 348 * 349 * @kobj: struct kobject that the action is happening to 350 * @action: action that is happening 351 * @envp_ext: pointer to environmental data 352 * 353 * Returns 0 if kobject_uevent_env() is completed with success or the 354 * corresponding error when it fails. 355 */ 356 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action, 357 char *envp_ext[]) 358 { 359 struct kobj_uevent_env *env; 360 const char *action_string = kobject_actions[action]; 361 const char *devpath = NULL; 362 const char *subsystem; 363 struct kobject *top_kobj; 364 struct kset *kset; 365 const struct kset_uevent_ops *uevent_ops; 366 int i = 0; 367 int retval = 0; 368 369 pr_debug("kobject: '%s' (%p): %s\n", 370 kobject_name(kobj), kobj, __func__); 371 372 /* search the kset we belong to */ 373 top_kobj = kobj; 374 while (!top_kobj->kset && top_kobj->parent) 375 top_kobj = top_kobj->parent; 376 377 if (!top_kobj->kset) { 378 pr_debug("kobject: '%s' (%p): %s: attempted to send uevent " 379 "without kset!\n", kobject_name(kobj), kobj, 380 __func__); 381 return -EINVAL; 382 } 383 384 kset = top_kobj->kset; 385 uevent_ops = kset->uevent_ops; 386 387 /* skip the event, if uevent_suppress is set*/ 388 if (kobj->uevent_suppress) { 389 pr_debug("kobject: '%s' (%p): %s: uevent_suppress " 390 "caused the event to drop!\n", 391 kobject_name(kobj), kobj, __func__); 392 return 0; 393 } 394 /* skip the event, if the filter returns zero. */ 395 if (uevent_ops && uevent_ops->filter) 396 if (!uevent_ops->filter(kset, kobj)) { 397 pr_debug("kobject: '%s' (%p): %s: filter function " 398 "caused the event to drop!\n", 399 kobject_name(kobj), kobj, __func__); 400 return 0; 401 } 402 403 /* originating subsystem */ 404 if (uevent_ops && uevent_ops->name) 405 subsystem = uevent_ops->name(kset, kobj); 406 else 407 subsystem = kobject_name(&kset->kobj); 408 if (!subsystem) { 409 pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the " 410 "event to drop!\n", kobject_name(kobj), kobj, 411 __func__); 412 return 0; 413 } 414 415 /* environment buffer */ 416 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL); 417 if (!env) 418 return -ENOMEM; 419 420 /* complete object path */ 421 devpath = kobject_get_path(kobj, GFP_KERNEL); 422 if (!devpath) { 423 retval = -ENOENT; 424 goto exit; 425 } 426 427 /* default keys */ 428 retval = add_uevent_var(env, "ACTION=%s", action_string); 429 if (retval) 430 goto exit; 431 retval = add_uevent_var(env, "DEVPATH=%s", devpath); 432 if (retval) 433 goto exit; 434 retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem); 435 if (retval) 436 goto exit; 437 438 /* keys passed in from the caller */ 439 if (envp_ext) { 440 for (i = 0; envp_ext[i]; i++) { 441 retval = add_uevent_var(env, "%s", envp_ext[i]); 442 if (retval) 443 goto exit; 444 } 445 } 446 447 /* let the kset specific function add its stuff */ 448 if (uevent_ops && uevent_ops->uevent) { 449 retval = uevent_ops->uevent(kset, kobj, env); 450 if (retval) { 451 pr_debug("kobject: '%s' (%p): %s: uevent() returned " 452 "%d\n", kobject_name(kobj), kobj, 453 __func__, retval); 454 goto exit; 455 } 456 } 457 458 /* 459 * Mark "add" and "remove" events in the object to ensure proper 460 * events to userspace during automatic cleanup. If the object did 461 * send an "add" event, "remove" will automatically generated by 462 * the core, if not already done by the caller. 463 */ 464 if (action == KOBJ_ADD) 465 kobj->state_add_uevent_sent = 1; 466 else if (action == KOBJ_REMOVE) 467 kobj->state_remove_uevent_sent = 1; 468 469 mutex_lock(&uevent_sock_mutex); 470 /* we will send an event, so request a new sequence number */ 471 retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)++uevent_seqnum); 472 if (retval) { 473 mutex_unlock(&uevent_sock_mutex); 474 goto exit; 475 } 476 retval = kobject_uevent_net_broadcast(kobj, env, action_string, 477 devpath); 478 mutex_unlock(&uevent_sock_mutex); 479 480 #ifdef CONFIG_UEVENT_HELPER 481 /* call uevent_helper, usually only enabled during early boot */ 482 if (uevent_helper[0] && !kobj_usermode_filter(kobj)) { 483 struct subprocess_info *info; 484 485 retval = add_uevent_var(env, "HOME=/"); 486 if (retval) 487 goto exit; 488 retval = add_uevent_var(env, 489 "PATH=/sbin:/bin:/usr/sbin:/usr/bin"); 490 if (retval) 491 goto exit; 492 retval = init_uevent_argv(env, subsystem); 493 if (retval) 494 goto exit; 495 496 retval = -ENOMEM; 497 info = call_usermodehelper_setup(env->argv[0], env->argv, 498 env->envp, GFP_KERNEL, 499 NULL, cleanup_uevent_env, env); 500 if (info) { 501 retval = call_usermodehelper_exec(info, UMH_NO_WAIT); 502 env = NULL; /* freed by cleanup_uevent_env */ 503 } 504 } 505 #endif 506 507 exit: 508 kfree(devpath); 509 kfree(env); 510 return retval; 511 } 512 EXPORT_SYMBOL_GPL(kobject_uevent_env); 513 514 /** 515 * kobject_uevent - notify userspace by sending an uevent 516 * 517 * @kobj: struct kobject that the action is happening to 518 * @action: action that is happening 519 * 520 * Returns 0 if kobject_uevent() is completed with success or the 521 * corresponding error when it fails. 522 */ 523 int kobject_uevent(struct kobject *kobj, enum kobject_action action) 524 { 525 return kobject_uevent_env(kobj, action, NULL); 526 } 527 EXPORT_SYMBOL_GPL(kobject_uevent); 528 529 /** 530 * add_uevent_var - add key value string to the environment buffer 531 * @env: environment buffer structure 532 * @format: printf format for the key=value pair 533 * 534 * Returns 0 if environment variable was added successfully or -ENOMEM 535 * if no space was available. 536 */ 537 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...) 538 { 539 va_list args; 540 int len; 541 542 if (env->envp_idx >= ARRAY_SIZE(env->envp)) { 543 WARN(1, KERN_ERR "add_uevent_var: too many keys\n"); 544 return -ENOMEM; 545 } 546 547 va_start(args, format); 548 len = vsnprintf(&env->buf[env->buflen], 549 sizeof(env->buf) - env->buflen, 550 format, args); 551 va_end(args); 552 553 if (len >= (sizeof(env->buf) - env->buflen)) { 554 WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n"); 555 return -ENOMEM; 556 } 557 558 env->envp[env->envp_idx++] = &env->buf[env->buflen]; 559 env->buflen += len + 1; 560 return 0; 561 } 562 EXPORT_SYMBOL_GPL(add_uevent_var); 563 564 #if defined(CONFIG_NET) 565 static int uevent_net_init(struct net *net) 566 { 567 struct uevent_sock *ue_sk; 568 struct netlink_kernel_cfg cfg = { 569 .groups = 1, 570 .flags = NL_CFG_F_NONROOT_RECV, 571 }; 572 573 ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL); 574 if (!ue_sk) 575 return -ENOMEM; 576 577 ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT, &cfg); 578 if (!ue_sk->sk) { 579 printk(KERN_ERR 580 "kobject_uevent: unable to create netlink socket!\n"); 581 kfree(ue_sk); 582 return -ENODEV; 583 } 584 mutex_lock(&uevent_sock_mutex); 585 list_add_tail(&ue_sk->list, &uevent_sock_list); 586 mutex_unlock(&uevent_sock_mutex); 587 return 0; 588 } 589 590 static void uevent_net_exit(struct net *net) 591 { 592 struct uevent_sock *ue_sk; 593 594 mutex_lock(&uevent_sock_mutex); 595 list_for_each_entry(ue_sk, &uevent_sock_list, list) { 596 if (sock_net(ue_sk->sk) == net) 597 goto found; 598 } 599 mutex_unlock(&uevent_sock_mutex); 600 return; 601 602 found: 603 list_del(&ue_sk->list); 604 mutex_unlock(&uevent_sock_mutex); 605 606 netlink_kernel_release(ue_sk->sk); 607 kfree(ue_sk); 608 } 609 610 static struct pernet_operations uevent_net_ops = { 611 .init = uevent_net_init, 612 .exit = uevent_net_exit, 613 }; 614 615 static int __init kobject_uevent_init(void) 616 { 617 return register_pernet_subsys(&uevent_net_ops); 618 } 619 620 621 postcore_initcall(kobject_uevent_init); 622 #endif 623