1 /* 2 * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org) 3 * Copyright (C) 2001 - 2008 Jeff Dike (jdike@{addtoit,linux.intel}.com) 4 * Licensed under the GPL 5 */ 6 7 #include <linux/console.h> 8 #include <linux/ctype.h> 9 #include <linux/string.h> 10 #include <linux/interrupt.h> 11 #include <linux/list.h> 12 #include <linux/mm.h> 13 #include <linux/module.h> 14 #include <linux/notifier.h> 15 #include <linux/reboot.h> 16 #include <linux/sched/debug.h> 17 #include <linux/proc_fs.h> 18 #include <linux/slab.h> 19 #include <linux/syscalls.h> 20 #include <linux/utsname.h> 21 #include <linux/socket.h> 22 #include <linux/un.h> 23 #include <linux/workqueue.h> 24 #include <linux/mutex.h> 25 #include <linux/fs.h> 26 #include <linux/mount.h> 27 #include <linux/file.h> 28 #include <linux/uaccess.h> 29 #include <asm/switch_to.h> 30 31 #include <init.h> 32 #include <irq_kern.h> 33 #include <irq_user.h> 34 #include <kern_util.h> 35 #include "mconsole.h" 36 #include "mconsole_kern.h" 37 #include <os.h> 38 39 static int do_unlink_socket(struct notifier_block *notifier, 40 unsigned long what, void *data) 41 { 42 return mconsole_unlink_socket(); 43 } 44 45 46 static struct notifier_block reboot_notifier = { 47 .notifier_call = do_unlink_socket, 48 .priority = 0, 49 }; 50 51 /* Safe without explicit locking for now. Tasklets provide their own 52 * locking, and the interrupt handler is safe because it can't interrupt 53 * itself and it can only happen on CPU 0. 54 */ 55 56 static LIST_HEAD(mc_requests); 57 58 static void mc_work_proc(struct work_struct *unused) 59 { 60 struct mconsole_entry *req; 61 unsigned long flags; 62 63 while (!list_empty(&mc_requests)) { 64 local_irq_save(flags); 65 req = list_entry(mc_requests.next, struct mconsole_entry, list); 66 list_del(&req->list); 67 local_irq_restore(flags); 68 req->request.cmd->handler(&req->request); 69 kfree(req); 70 } 71 } 72 73 static DECLARE_WORK(mconsole_work, mc_work_proc); 74 75 static irqreturn_t mconsole_interrupt(int irq, void *dev_id) 76 { 77 /* long to avoid size mismatch warnings from gcc */ 78 long fd; 79 struct mconsole_entry *new; 80 static struct mc_request req; /* that's OK */ 81 82 fd = (long) dev_id; 83 while (mconsole_get_request(fd, &req)) { 84 if (req.cmd->context == MCONSOLE_INTR) 85 (*req.cmd->handler)(&req); 86 else { 87 new = kmalloc(sizeof(*new), GFP_NOWAIT); 88 if (new == NULL) 89 mconsole_reply(&req, "Out of memory", 1, 0); 90 else { 91 new->request = req; 92 new->request.regs = get_irq_regs()->regs; 93 list_add(&new->list, &mc_requests); 94 } 95 } 96 } 97 if (!list_empty(&mc_requests)) 98 schedule_work(&mconsole_work); 99 reactivate_fd(fd, MCONSOLE_IRQ); 100 return IRQ_HANDLED; 101 } 102 103 void mconsole_version(struct mc_request *req) 104 { 105 char version[256]; 106 107 sprintf(version, "%s %s %s %s %s", utsname()->sysname, 108 utsname()->nodename, utsname()->release, utsname()->version, 109 utsname()->machine); 110 mconsole_reply(req, version, 0, 0); 111 } 112 113 void mconsole_log(struct mc_request *req) 114 { 115 int len; 116 char *ptr = req->request.data; 117 118 ptr += strlen("log "); 119 120 len = req->len - (ptr - req->request.data); 121 printk(KERN_WARNING "%.*s", len, ptr); 122 mconsole_reply(req, "", 0, 0); 123 } 124 125 void mconsole_proc(struct mc_request *req) 126 { 127 struct vfsmount *mnt = task_active_pid_ns(current)->proc_mnt; 128 char *buf; 129 int len; 130 struct file *file; 131 int first_chunk = 1; 132 char *ptr = req->request.data; 133 loff_t pos = 0; 134 135 ptr += strlen("proc"); 136 ptr = skip_spaces(ptr); 137 138 file = file_open_root(mnt->mnt_root, mnt, ptr, O_RDONLY, 0); 139 if (IS_ERR(file)) { 140 mconsole_reply(req, "Failed to open file", 1, 0); 141 printk(KERN_ERR "open /proc/%s: %ld\n", ptr, PTR_ERR(file)); 142 goto out; 143 } 144 145 buf = kmalloc(PAGE_SIZE, GFP_KERNEL); 146 if (buf == NULL) { 147 mconsole_reply(req, "Failed to allocate buffer", 1, 0); 148 goto out_fput; 149 } 150 151 do { 152 len = kernel_read(file, buf, PAGE_SIZE - 1, &pos); 153 if (len < 0) { 154 mconsole_reply(req, "Read of file failed", 1, 0); 155 goto out_free; 156 } 157 /* Begin the file content on his own line. */ 158 if (first_chunk) { 159 mconsole_reply(req, "\n", 0, 1); 160 first_chunk = 0; 161 } 162 buf[len] = '\0'; 163 mconsole_reply(req, buf, 0, (len > 0)); 164 } while (len > 0); 165 out_free: 166 kfree(buf); 167 out_fput: 168 fput(file); 169 out: ; 170 } 171 172 #define UML_MCONSOLE_HELPTEXT \ 173 "Commands: \n\ 174 version - Get kernel version \n\ 175 help - Print this message \n\ 176 halt - Halt UML \n\ 177 reboot - Reboot UML \n\ 178 config <dev>=<config> - Add a new device to UML; \n\ 179 same syntax as command line \n\ 180 config <dev> - Query the configuration of a device \n\ 181 remove <dev> - Remove a device from UML \n\ 182 sysrq <letter> - Performs the SysRq action controlled by the letter \n\ 183 cad - invoke the Ctrl-Alt-Del handler \n\ 184 stop - pause the UML; it will do nothing until it receives a 'go' \n\ 185 go - continue the UML after a 'stop' \n\ 186 log <string> - make UML enter <string> into the kernel log\n\ 187 proc <file> - returns the contents of the UML's /proc/<file>\n\ 188 stack <pid> - returns the stack of the specified pid\n\ 189 " 190 191 void mconsole_help(struct mc_request *req) 192 { 193 mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0); 194 } 195 196 void mconsole_halt(struct mc_request *req) 197 { 198 mconsole_reply(req, "", 0, 0); 199 machine_halt(); 200 } 201 202 void mconsole_reboot(struct mc_request *req) 203 { 204 mconsole_reply(req, "", 0, 0); 205 machine_restart(NULL); 206 } 207 208 void mconsole_cad(struct mc_request *req) 209 { 210 mconsole_reply(req, "", 0, 0); 211 ctrl_alt_del(); 212 } 213 214 void mconsole_go(struct mc_request *req) 215 { 216 mconsole_reply(req, "Not stopped", 1, 0); 217 } 218 219 void mconsole_stop(struct mc_request *req) 220 { 221 deactivate_fd(req->originating_fd, MCONSOLE_IRQ); 222 os_set_fd_block(req->originating_fd, 1); 223 mconsole_reply(req, "stopped", 0, 0); 224 for (;;) { 225 if (!mconsole_get_request(req->originating_fd, req)) 226 continue; 227 if (req->cmd->handler == mconsole_go) 228 break; 229 if (req->cmd->handler == mconsole_stop) { 230 mconsole_reply(req, "Already stopped", 1, 0); 231 continue; 232 } 233 if (req->cmd->handler == mconsole_sysrq) { 234 struct pt_regs *old_regs; 235 old_regs = set_irq_regs((struct pt_regs *)&req->regs); 236 mconsole_sysrq(req); 237 set_irq_regs(old_regs); 238 continue; 239 } 240 (*req->cmd->handler)(req); 241 } 242 os_set_fd_block(req->originating_fd, 0); 243 reactivate_fd(req->originating_fd, MCONSOLE_IRQ); 244 mconsole_reply(req, "", 0, 0); 245 } 246 247 static DEFINE_SPINLOCK(mc_devices_lock); 248 static LIST_HEAD(mconsole_devices); 249 250 void mconsole_register_dev(struct mc_device *new) 251 { 252 spin_lock(&mc_devices_lock); 253 BUG_ON(!list_empty(&new->list)); 254 list_add(&new->list, &mconsole_devices); 255 spin_unlock(&mc_devices_lock); 256 } 257 258 static struct mc_device *mconsole_find_dev(char *name) 259 { 260 struct list_head *ele; 261 struct mc_device *dev; 262 263 list_for_each(ele, &mconsole_devices) { 264 dev = list_entry(ele, struct mc_device, list); 265 if (!strncmp(name, dev->name, strlen(dev->name))) 266 return dev; 267 } 268 return NULL; 269 } 270 271 #define UNPLUGGED_PER_PAGE \ 272 ((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long)) 273 274 struct unplugged_pages { 275 struct list_head list; 276 void *pages[UNPLUGGED_PER_PAGE]; 277 }; 278 279 static DEFINE_MUTEX(plug_mem_mutex); 280 static unsigned long long unplugged_pages_count = 0; 281 static LIST_HEAD(unplugged_pages); 282 static int unplug_index = UNPLUGGED_PER_PAGE; 283 284 static int mem_config(char *str, char **error_out) 285 { 286 unsigned long long diff; 287 int err = -EINVAL, i, add; 288 char *ret; 289 290 if (str[0] != '=') { 291 *error_out = "Expected '=' after 'mem'"; 292 goto out; 293 } 294 295 str++; 296 if (str[0] == '-') 297 add = 0; 298 else if (str[0] == '+') { 299 add = 1; 300 } 301 else { 302 *error_out = "Expected increment to start with '-' or '+'"; 303 goto out; 304 } 305 306 str++; 307 diff = memparse(str, &ret); 308 if (*ret != '\0') { 309 *error_out = "Failed to parse memory increment"; 310 goto out; 311 } 312 313 diff /= PAGE_SIZE; 314 315 mutex_lock(&plug_mem_mutex); 316 for (i = 0; i < diff; i++) { 317 struct unplugged_pages *unplugged; 318 void *addr; 319 320 if (add) { 321 if (list_empty(&unplugged_pages)) 322 break; 323 324 unplugged = list_entry(unplugged_pages.next, 325 struct unplugged_pages, list); 326 if (unplug_index > 0) 327 addr = unplugged->pages[--unplug_index]; 328 else { 329 list_del(&unplugged->list); 330 addr = unplugged; 331 unplug_index = UNPLUGGED_PER_PAGE; 332 } 333 334 free_page((unsigned long) addr); 335 unplugged_pages_count--; 336 } 337 else { 338 struct page *page; 339 340 page = alloc_page(GFP_ATOMIC); 341 if (page == NULL) 342 break; 343 344 unplugged = page_address(page); 345 if (unplug_index == UNPLUGGED_PER_PAGE) { 346 list_add(&unplugged->list, &unplugged_pages); 347 unplug_index = 0; 348 } 349 else { 350 struct list_head *entry = unplugged_pages.next; 351 addr = unplugged; 352 353 unplugged = list_entry(entry, 354 struct unplugged_pages, 355 list); 356 err = os_drop_memory(addr, PAGE_SIZE); 357 if (err) { 358 printk(KERN_ERR "Failed to release " 359 "memory - errno = %d\n", err); 360 *error_out = "Failed to release memory"; 361 goto out_unlock; 362 } 363 unplugged->pages[unplug_index++] = addr; 364 } 365 366 unplugged_pages_count++; 367 } 368 } 369 370 err = 0; 371 out_unlock: 372 mutex_unlock(&plug_mem_mutex); 373 out: 374 return err; 375 } 376 377 static int mem_get_config(char *name, char *str, int size, char **error_out) 378 { 379 char buf[sizeof("18446744073709551615")]; 380 int len = 0; 381 382 sprintf(buf, "%ld", uml_physmem); 383 CONFIG_CHUNK(str, size, len, buf, 1); 384 385 return len; 386 } 387 388 static int mem_id(char **str, int *start_out, int *end_out) 389 { 390 *start_out = 0; 391 *end_out = 0; 392 393 return 0; 394 } 395 396 static int mem_remove(int n, char **error_out) 397 { 398 *error_out = "Memory doesn't support the remove operation"; 399 return -EBUSY; 400 } 401 402 static struct mc_device mem_mc = { 403 .list = LIST_HEAD_INIT(mem_mc.list), 404 .name = "mem", 405 .config = mem_config, 406 .get_config = mem_get_config, 407 .id = mem_id, 408 .remove = mem_remove, 409 }; 410 411 static int __init mem_mc_init(void) 412 { 413 if (can_drop_memory()) 414 mconsole_register_dev(&mem_mc); 415 else printk(KERN_ERR "Can't release memory to the host - memory " 416 "hotplug won't be supported\n"); 417 return 0; 418 } 419 420 __initcall(mem_mc_init); 421 422 #define CONFIG_BUF_SIZE 64 423 424 static void mconsole_get_config(int (*get_config)(char *, char *, int, 425 char **), 426 struct mc_request *req, char *name) 427 { 428 char default_buf[CONFIG_BUF_SIZE], *error, *buf; 429 int n, size; 430 431 if (get_config == NULL) { 432 mconsole_reply(req, "No get_config routine defined", 1, 0); 433 return; 434 } 435 436 error = NULL; 437 size = ARRAY_SIZE(default_buf); 438 buf = default_buf; 439 440 while (1) { 441 n = (*get_config)(name, buf, size, &error); 442 if (error != NULL) { 443 mconsole_reply(req, error, 1, 0); 444 goto out; 445 } 446 447 if (n <= size) { 448 mconsole_reply(req, buf, 0, 0); 449 goto out; 450 } 451 452 if (buf != default_buf) 453 kfree(buf); 454 455 size = n; 456 buf = kmalloc(size, GFP_KERNEL); 457 if (buf == NULL) { 458 mconsole_reply(req, "Failed to allocate buffer", 1, 0); 459 return; 460 } 461 } 462 out: 463 if (buf != default_buf) 464 kfree(buf); 465 } 466 467 void mconsole_config(struct mc_request *req) 468 { 469 struct mc_device *dev; 470 char *ptr = req->request.data, *name, *error_string = ""; 471 int err; 472 473 ptr += strlen("config"); 474 ptr = skip_spaces(ptr); 475 dev = mconsole_find_dev(ptr); 476 if (dev == NULL) { 477 mconsole_reply(req, "Bad configuration option", 1, 0); 478 return; 479 } 480 481 name = &ptr[strlen(dev->name)]; 482 ptr = name; 483 while ((*ptr != '=') && (*ptr != '\0')) 484 ptr++; 485 486 if (*ptr == '=') { 487 err = (*dev->config)(name, &error_string); 488 mconsole_reply(req, error_string, err, 0); 489 } 490 else mconsole_get_config(dev->get_config, req, name); 491 } 492 493 void mconsole_remove(struct mc_request *req) 494 { 495 struct mc_device *dev; 496 char *ptr = req->request.data, *err_msg = ""; 497 char error[256]; 498 int err, start, end, n; 499 500 ptr += strlen("remove"); 501 ptr = skip_spaces(ptr); 502 dev = mconsole_find_dev(ptr); 503 if (dev == NULL) { 504 mconsole_reply(req, "Bad remove option", 1, 0); 505 return; 506 } 507 508 ptr = &ptr[strlen(dev->name)]; 509 510 err = 1; 511 n = (*dev->id)(&ptr, &start, &end); 512 if (n < 0) { 513 err_msg = "Couldn't parse device number"; 514 goto out; 515 } 516 else if ((n < start) || (n > end)) { 517 sprintf(error, "Invalid device number - must be between " 518 "%d and %d", start, end); 519 err_msg = error; 520 goto out; 521 } 522 523 err_msg = NULL; 524 err = (*dev->remove)(n, &err_msg); 525 switch(err) { 526 case 0: 527 err_msg = ""; 528 break; 529 case -ENODEV: 530 if (err_msg == NULL) 531 err_msg = "Device doesn't exist"; 532 break; 533 case -EBUSY: 534 if (err_msg == NULL) 535 err_msg = "Device is currently open"; 536 break; 537 default: 538 break; 539 } 540 out: 541 mconsole_reply(req, err_msg, err, 0); 542 } 543 544 struct mconsole_output { 545 struct list_head list; 546 struct mc_request *req; 547 }; 548 549 static DEFINE_SPINLOCK(client_lock); 550 static LIST_HEAD(clients); 551 static char console_buf[MCONSOLE_MAX_DATA]; 552 553 static void console_write(struct console *console, const char *string, 554 unsigned int len) 555 { 556 struct list_head *ele; 557 int n; 558 559 if (list_empty(&clients)) 560 return; 561 562 while (len > 0) { 563 n = min((size_t) len, ARRAY_SIZE(console_buf)); 564 strncpy(console_buf, string, n); 565 string += n; 566 len -= n; 567 568 list_for_each(ele, &clients) { 569 struct mconsole_output *entry; 570 571 entry = list_entry(ele, struct mconsole_output, list); 572 mconsole_reply_len(entry->req, console_buf, n, 0, 1); 573 } 574 } 575 } 576 577 static struct console mc_console = { .name = "mc", 578 .write = console_write, 579 .flags = CON_ENABLED, 580 .index = -1 }; 581 582 static int mc_add_console(void) 583 { 584 register_console(&mc_console); 585 return 0; 586 } 587 588 late_initcall(mc_add_console); 589 590 static void with_console(struct mc_request *req, void (*proc)(void *), 591 void *arg) 592 { 593 struct mconsole_output entry; 594 unsigned long flags; 595 596 entry.req = req; 597 spin_lock_irqsave(&client_lock, flags); 598 list_add(&entry.list, &clients); 599 spin_unlock_irqrestore(&client_lock, flags); 600 601 (*proc)(arg); 602 603 mconsole_reply_len(req, "", 0, 0, 0); 604 605 spin_lock_irqsave(&client_lock, flags); 606 list_del(&entry.list); 607 spin_unlock_irqrestore(&client_lock, flags); 608 } 609 610 #ifdef CONFIG_MAGIC_SYSRQ 611 612 #include <linux/sysrq.h> 613 614 static void sysrq_proc(void *arg) 615 { 616 char *op = arg; 617 handle_sysrq(*op); 618 } 619 620 void mconsole_sysrq(struct mc_request *req) 621 { 622 char *ptr = req->request.data; 623 624 ptr += strlen("sysrq"); 625 ptr = skip_spaces(ptr); 626 627 /* 628 * With 'b', the system will shut down without a chance to reply, 629 * so in this case, we reply first. 630 */ 631 if (*ptr == 'b') 632 mconsole_reply(req, "", 0, 0); 633 634 with_console(req, sysrq_proc, ptr); 635 } 636 #else 637 void mconsole_sysrq(struct mc_request *req) 638 { 639 mconsole_reply(req, "Sysrq not compiled in", 1, 0); 640 } 641 #endif 642 643 static void stack_proc(void *arg) 644 { 645 struct task_struct *task = arg; 646 647 show_stack(task, NULL); 648 } 649 650 /* 651 * Mconsole stack trace 652 * Added by Allan Graves, Jeff Dike 653 * Dumps a stacks registers to the linux console. 654 * Usage stack <pid>. 655 */ 656 void mconsole_stack(struct mc_request *req) 657 { 658 char *ptr = req->request.data; 659 int pid_requested= -1; 660 struct task_struct *to = NULL; 661 662 /* 663 * Would be nice: 664 * 1) Send showregs output to mconsole. 665 * 2) Add a way to stack dump all pids. 666 */ 667 668 ptr += strlen("stack"); 669 ptr = skip_spaces(ptr); 670 671 /* 672 * Should really check for multiple pids or reject bad args here 673 */ 674 /* What do the arguments in mconsole_reply mean? */ 675 if (sscanf(ptr, "%d", &pid_requested) == 0) { 676 mconsole_reply(req, "Please specify a pid", 1, 0); 677 return; 678 } 679 680 to = find_task_by_pid_ns(pid_requested, &init_pid_ns); 681 if ((to == NULL) || (pid_requested == 0)) { 682 mconsole_reply(req, "Couldn't find that pid", 1, 0); 683 return; 684 } 685 with_console(req, stack_proc, to); 686 } 687 688 /* 689 * Changed by mconsole_setup, which is __setup, and called before SMP is 690 * active. 691 */ 692 static char *notify_socket = NULL; 693 694 static int __init mconsole_init(void) 695 { 696 /* long to avoid size mismatch warnings from gcc */ 697 long sock; 698 int err; 699 char file[UNIX_PATH_MAX]; 700 701 if (umid_file_name("mconsole", file, sizeof(file))) 702 return -1; 703 snprintf(mconsole_socket_name, sizeof(file), "%s", file); 704 705 sock = os_create_unix_socket(file, sizeof(file), 1); 706 if (sock < 0) { 707 printk(KERN_ERR "Failed to initialize management console\n"); 708 return 1; 709 } 710 if (os_set_fd_block(sock, 0)) 711 goto out; 712 713 register_reboot_notifier(&reboot_notifier); 714 715 err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt, 716 IRQF_SHARED, "mconsole", (void *)sock); 717 if (err) { 718 printk(KERN_ERR "Failed to get IRQ for management console\n"); 719 goto out; 720 } 721 722 if (notify_socket != NULL) { 723 notify_socket = kstrdup(notify_socket, GFP_KERNEL); 724 if (notify_socket != NULL) 725 mconsole_notify(notify_socket, MCONSOLE_SOCKET, 726 mconsole_socket_name, 727 strlen(mconsole_socket_name) + 1); 728 else printk(KERN_ERR "mconsole_setup failed to strdup " 729 "string\n"); 730 } 731 732 printk(KERN_INFO "mconsole (version %d) initialized on %s\n", 733 MCONSOLE_VERSION, mconsole_socket_name); 734 return 0; 735 736 out: 737 os_close_file(sock); 738 return 1; 739 } 740 741 __initcall(mconsole_init); 742 743 static ssize_t mconsole_proc_write(struct file *file, 744 const char __user *buffer, size_t count, loff_t *pos) 745 { 746 char *buf; 747 748 buf = memdup_user_nul(buffer, count); 749 if (IS_ERR(buf)) 750 return PTR_ERR(buf); 751 752 mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count); 753 kfree(buf); 754 return count; 755 } 756 757 static const struct file_operations mconsole_proc_fops = { 758 .owner = THIS_MODULE, 759 .write = mconsole_proc_write, 760 .llseek = noop_llseek, 761 }; 762 763 static int create_proc_mconsole(void) 764 { 765 struct proc_dir_entry *ent; 766 767 if (notify_socket == NULL) 768 return 0; 769 770 ent = proc_create("mconsole", 0200, NULL, &mconsole_proc_fops); 771 if (ent == NULL) { 772 printk(KERN_INFO "create_proc_mconsole : proc_create failed\n"); 773 return 0; 774 } 775 return 0; 776 } 777 778 static DEFINE_SPINLOCK(notify_spinlock); 779 780 void lock_notify(void) 781 { 782 spin_lock(¬ify_spinlock); 783 } 784 785 void unlock_notify(void) 786 { 787 spin_unlock(¬ify_spinlock); 788 } 789 790 __initcall(create_proc_mconsole); 791 792 #define NOTIFY "notify:" 793 794 static int mconsole_setup(char *str) 795 { 796 if (!strncmp(str, NOTIFY, strlen(NOTIFY))) { 797 str += strlen(NOTIFY); 798 notify_socket = str; 799 } 800 else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str); 801 return 1; 802 } 803 804 __setup("mconsole=", mconsole_setup); 805 806 __uml_help(mconsole_setup, 807 "mconsole=notify:<socket>\n" 808 " Requests that the mconsole driver send a message to the named Unix\n" 809 " socket containing the name of the mconsole socket. This also serves\n" 810 " to notify outside processes when UML has booted far enough to respond\n" 811 " to mconsole requests.\n\n" 812 ); 813 814 static int notify_panic(struct notifier_block *self, unsigned long unused1, 815 void *ptr) 816 { 817 char *message = ptr; 818 819 if (notify_socket == NULL) 820 return 0; 821 822 mconsole_notify(notify_socket, MCONSOLE_PANIC, message, 823 strlen(message) + 1); 824 return 0; 825 } 826 827 static struct notifier_block panic_exit_notifier = { 828 .notifier_call = notify_panic, 829 .next = NULL, 830 .priority = 1 831 }; 832 833 static int add_notifier(void) 834 { 835 atomic_notifier_chain_register(&panic_notifier_list, 836 &panic_exit_notifier); 837 return 0; 838 } 839 840 __initcall(add_notifier); 841 842 char *mconsole_notify_socket(void) 843 { 844 return notify_socket; 845 } 846 847 EXPORT_SYMBOL(mconsole_notify_socket); 848