1 /* 2 * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org) 3 * Copyright (C) 2001 - 2007 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/interrupt.h" 10 #include "linux/list.h" 11 #include "linux/mm.h" 12 #include "linux/module.h" 13 #include "linux/notifier.h" 14 #include "linux/reboot.h" 15 #include "linux/proc_fs.h" 16 #include "linux/slab.h" 17 #include "linux/syscalls.h" 18 #include "linux/utsname.h" 19 #include "linux/workqueue.h" 20 #include "asm/uaccess.h" 21 #include "init.h" 22 #include "irq_kern.h" 23 #include "irq_user.h" 24 #include "kern_util.h" 25 #include "mconsole.h" 26 #include "mconsole_kern.h" 27 #include "os.h" 28 29 static int do_unlink_socket(struct notifier_block *notifier, 30 unsigned long what, void *data) 31 { 32 return mconsole_unlink_socket(); 33 } 34 35 36 static struct notifier_block reboot_notifier = { 37 .notifier_call = do_unlink_socket, 38 .priority = 0, 39 }; 40 41 /* Safe without explicit locking for now. Tasklets provide their own 42 * locking, and the interrupt handler is safe because it can't interrupt 43 * itself and it can only happen on CPU 0. 44 */ 45 46 static LIST_HEAD(mc_requests); 47 48 static void mc_work_proc(struct work_struct *unused) 49 { 50 struct mconsole_entry *req; 51 unsigned long flags; 52 53 while (!list_empty(&mc_requests)) { 54 local_irq_save(flags); 55 req = list_entry(mc_requests.next, struct mconsole_entry, list); 56 list_del(&req->list); 57 local_irq_restore(flags); 58 req->request.cmd->handler(&req->request); 59 kfree(req); 60 } 61 } 62 63 static DECLARE_WORK(mconsole_work, mc_work_proc); 64 65 static irqreturn_t mconsole_interrupt(int irq, void *dev_id) 66 { 67 /* long to avoid size mismatch warnings from gcc */ 68 long fd; 69 struct mconsole_entry *new; 70 static struct mc_request req; /* that's OK */ 71 72 fd = (long) dev_id; 73 while (mconsole_get_request(fd, &req)) { 74 if (req.cmd->context == MCONSOLE_INTR) 75 (*req.cmd->handler)(&req); 76 else { 77 new = kmalloc(sizeof(*new), GFP_NOWAIT); 78 if (new == NULL) 79 mconsole_reply(&req, "Out of memory", 1, 0); 80 else { 81 new->request = req; 82 new->request.regs = get_irq_regs()->regs; 83 list_add(&new->list, &mc_requests); 84 } 85 } 86 } 87 if (!list_empty(&mc_requests)) 88 schedule_work(&mconsole_work); 89 reactivate_fd(fd, MCONSOLE_IRQ); 90 return IRQ_HANDLED; 91 } 92 93 void mconsole_version(struct mc_request *req) 94 { 95 char version[256]; 96 97 sprintf(version, "%s %s %s %s %s", utsname()->sysname, 98 utsname()->nodename, utsname()->release, utsname()->version, 99 utsname()->machine); 100 mconsole_reply(req, version, 0, 0); 101 } 102 103 void mconsole_log(struct mc_request *req) 104 { 105 int len; 106 char *ptr = req->request.data; 107 108 ptr += strlen("log "); 109 110 len = req->len - (ptr - req->request.data); 111 printk(KERN_WARNING "%.*s", len, ptr); 112 mconsole_reply(req, "", 0, 0); 113 } 114 115 /* This is a more convoluted version of mconsole_proc, which has some stability 116 * problems; however, we need it fixed, because it is expected that UML users 117 * mount HPPFS instead of procfs on /proc. And we want mconsole_proc to still 118 * show the real procfs content, not the ones from hppfs.*/ 119 #if 0 120 void mconsole_proc(struct mc_request *req) 121 { 122 struct nameidata nd; 123 struct file_system_type *proc; 124 struct super_block *super; 125 struct file *file; 126 int n, err; 127 char *ptr = req->request.data, *buf; 128 129 ptr += strlen("proc"); 130 while (isspace(*ptr)) ptr++; 131 132 proc = get_fs_type("proc"); 133 if (proc == NULL) { 134 mconsole_reply(req, "procfs not registered", 1, 0); 135 goto out; 136 } 137 138 super = (*proc->get_sb)(proc, 0, NULL, NULL); 139 put_filesystem(proc); 140 if (super == NULL) { 141 mconsole_reply(req, "Failed to get procfs superblock", 1, 0); 142 goto out; 143 } 144 up_write(&super->s_umount); 145 146 nd.dentry = super->s_root; 147 nd.mnt = NULL; 148 nd.flags = O_RDONLY + 1; 149 nd.last_type = LAST_ROOT; 150 151 /* START: it was experienced that the stability problems are closed 152 * if commenting out these two calls + the below read cycle. To 153 * make UML crash again, it was enough to readd either one.*/ 154 err = link_path_walk(ptr, &nd); 155 if (err) { 156 mconsole_reply(req, "Failed to look up file", 1, 0); 157 goto out_kill; 158 } 159 160 file = dentry_open(nd.dentry, nd.mnt, O_RDONLY); 161 if (IS_ERR(file)) { 162 mconsole_reply(req, "Failed to open file", 1, 0); 163 goto out_kill; 164 } 165 /*END*/ 166 167 buf = kmalloc(PAGE_SIZE, GFP_KERNEL); 168 if (buf == NULL) { 169 mconsole_reply(req, "Failed to allocate buffer", 1, 0); 170 goto out_fput; 171 } 172 173 if ((file->f_op != NULL) && (file->f_op->read != NULL)) { 174 do { 175 n = (*file->f_op->read)(file, buf, PAGE_SIZE - 1, 176 &file->f_pos); 177 if (n >= 0) { 178 buf[n] = '\0'; 179 mconsole_reply(req, buf, 0, (n > 0)); 180 } 181 else { 182 mconsole_reply(req, "Read of file failed", 183 1, 0); 184 goto out_free; 185 } 186 } while (n > 0); 187 } 188 else mconsole_reply(req, "", 0, 0); 189 190 out_free: 191 kfree(buf); 192 out_fput: 193 fput(file); 194 out_kill: 195 deactivate_super(super); 196 out: ; 197 } 198 #endif 199 200 void mconsole_proc(struct mc_request *req) 201 { 202 char path[64]; 203 char *buf; 204 int len; 205 int fd; 206 int first_chunk = 1; 207 char *ptr = req->request.data; 208 209 ptr += strlen("proc"); 210 while (isspace(*ptr)) 211 ptr++; 212 snprintf(path, sizeof(path), "/proc/%s", ptr); 213 214 fd = sys_open(path, 0, 0); 215 if (fd < 0) { 216 mconsole_reply(req, "Failed to open file", 1, 0); 217 printk(KERN_ERR "open %s: %d\n",path,fd); 218 goto out; 219 } 220 221 buf = kmalloc(PAGE_SIZE, GFP_KERNEL); 222 if (buf == NULL) { 223 mconsole_reply(req, "Failed to allocate buffer", 1, 0); 224 goto out_close; 225 } 226 227 for (;;) { 228 len = sys_read(fd, buf, PAGE_SIZE-1); 229 if (len < 0) { 230 mconsole_reply(req, "Read of file failed", 1, 0); 231 goto out_free; 232 } 233 /* Begin the file content on his own line. */ 234 if (first_chunk) { 235 mconsole_reply(req, "\n", 0, 1); 236 first_chunk = 0; 237 } 238 if (len == PAGE_SIZE-1) { 239 buf[len] = '\0'; 240 mconsole_reply(req, buf, 0, 1); 241 } else { 242 buf[len] = '\0'; 243 mconsole_reply(req, buf, 0, 0); 244 break; 245 } 246 } 247 248 out_free: 249 kfree(buf); 250 out_close: 251 sys_close(fd); 252 out: 253 /* nothing */; 254 } 255 256 #define UML_MCONSOLE_HELPTEXT \ 257 "Commands: \n\ 258 version - Get kernel version \n\ 259 help - Print this message \n\ 260 halt - Halt UML \n\ 261 reboot - Reboot UML \n\ 262 config <dev>=<config> - Add a new device to UML; \n\ 263 same syntax as command line \n\ 264 config <dev> - Query the configuration of a device \n\ 265 remove <dev> - Remove a device from UML \n\ 266 sysrq <letter> - Performs the SysRq action controlled by the letter \n\ 267 cad - invoke the Ctrl-Alt-Del handler \n\ 268 stop - pause the UML; it will do nothing until it receives a 'go' \n\ 269 go - continue the UML after a 'stop' \n\ 270 log <string> - make UML enter <string> into the kernel log\n\ 271 proc <file> - returns the contents of the UML's /proc/<file>\n\ 272 stack <pid> - returns the stack of the specified pid\n\ 273 " 274 275 void mconsole_help(struct mc_request *req) 276 { 277 mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0); 278 } 279 280 void mconsole_halt(struct mc_request *req) 281 { 282 mconsole_reply(req, "", 0, 0); 283 machine_halt(); 284 } 285 286 void mconsole_reboot(struct mc_request *req) 287 { 288 mconsole_reply(req, "", 0, 0); 289 machine_restart(NULL); 290 } 291 292 void mconsole_cad(struct mc_request *req) 293 { 294 mconsole_reply(req, "", 0, 0); 295 ctrl_alt_del(); 296 } 297 298 void mconsole_go(struct mc_request *req) 299 { 300 mconsole_reply(req, "Not stopped", 1, 0); 301 } 302 303 void mconsole_stop(struct mc_request *req) 304 { 305 deactivate_fd(req->originating_fd, MCONSOLE_IRQ); 306 os_set_fd_block(req->originating_fd, 1); 307 mconsole_reply(req, "stopped", 0, 0); 308 while (mconsole_get_request(req->originating_fd, req)) { 309 if (req->cmd->handler == mconsole_go) 310 break; 311 if (req->cmd->handler == mconsole_stop) { 312 mconsole_reply(req, "Already stopped", 1, 0); 313 continue; 314 } 315 if (req->cmd->handler == mconsole_sysrq) { 316 struct pt_regs *old_regs; 317 old_regs = set_irq_regs((struct pt_regs *)&req->regs); 318 mconsole_sysrq(req); 319 set_irq_regs(old_regs); 320 continue; 321 } 322 (*req->cmd->handler)(req); 323 } 324 os_set_fd_block(req->originating_fd, 0); 325 reactivate_fd(req->originating_fd, MCONSOLE_IRQ); 326 mconsole_reply(req, "", 0, 0); 327 } 328 329 static DEFINE_SPINLOCK(mc_devices_lock); 330 static LIST_HEAD(mconsole_devices); 331 332 void mconsole_register_dev(struct mc_device *new) 333 { 334 spin_lock(&mc_devices_lock); 335 BUG_ON(!list_empty(&new->list)); 336 list_add(&new->list, &mconsole_devices); 337 spin_unlock(&mc_devices_lock); 338 } 339 340 static struct mc_device *mconsole_find_dev(char *name) 341 { 342 struct list_head *ele; 343 struct mc_device *dev; 344 345 list_for_each(ele, &mconsole_devices) { 346 dev = list_entry(ele, struct mc_device, list); 347 if (!strncmp(name, dev->name, strlen(dev->name))) 348 return dev; 349 } 350 return NULL; 351 } 352 353 #define UNPLUGGED_PER_PAGE \ 354 ((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long)) 355 356 struct unplugged_pages { 357 struct list_head list; 358 void *pages[UNPLUGGED_PER_PAGE]; 359 }; 360 361 static DECLARE_MUTEX(plug_mem_mutex); 362 static unsigned long long unplugged_pages_count = 0; 363 static LIST_HEAD(unplugged_pages); 364 static int unplug_index = UNPLUGGED_PER_PAGE; 365 366 static int mem_config(char *str, char **error_out) 367 { 368 unsigned long long diff; 369 int err = -EINVAL, i, add; 370 char *ret; 371 372 if (str[0] != '=') { 373 *error_out = "Expected '=' after 'mem'"; 374 goto out; 375 } 376 377 str++; 378 if (str[0] == '-') 379 add = 0; 380 else if (str[0] == '+') { 381 add = 1; 382 } 383 else { 384 *error_out = "Expected increment to start with '-' or '+'"; 385 goto out; 386 } 387 388 str++; 389 diff = memparse(str, &ret); 390 if (*ret != '\0') { 391 *error_out = "Failed to parse memory increment"; 392 goto out; 393 } 394 395 diff /= PAGE_SIZE; 396 397 down(&plug_mem_mutex); 398 for (i = 0; i < diff; i++) { 399 struct unplugged_pages *unplugged; 400 void *addr; 401 402 if (add) { 403 if (list_empty(&unplugged_pages)) 404 break; 405 406 unplugged = list_entry(unplugged_pages.next, 407 struct unplugged_pages, list); 408 if (unplug_index > 0) 409 addr = unplugged->pages[--unplug_index]; 410 else { 411 list_del(&unplugged->list); 412 addr = unplugged; 413 unplug_index = UNPLUGGED_PER_PAGE; 414 } 415 416 free_page((unsigned long) addr); 417 unplugged_pages_count--; 418 } 419 else { 420 struct page *page; 421 422 page = alloc_page(GFP_ATOMIC); 423 if (page == NULL) 424 break; 425 426 unplugged = page_address(page); 427 if (unplug_index == UNPLUGGED_PER_PAGE) { 428 list_add(&unplugged->list, &unplugged_pages); 429 unplug_index = 0; 430 } 431 else { 432 struct list_head *entry = unplugged_pages.next; 433 addr = unplugged; 434 435 unplugged = list_entry(entry, 436 struct unplugged_pages, 437 list); 438 err = os_drop_memory(addr, PAGE_SIZE); 439 if (err) { 440 printk(KERN_ERR "Failed to release " 441 "memory - errno = %d\n", err); 442 *error_out = "Failed to release memory"; 443 goto out_unlock; 444 } 445 unplugged->pages[unplug_index++] = addr; 446 } 447 448 unplugged_pages_count++; 449 } 450 } 451 452 err = 0; 453 out_unlock: 454 up(&plug_mem_mutex); 455 out: 456 return err; 457 } 458 459 static int mem_get_config(char *name, char *str, int size, char **error_out) 460 { 461 char buf[sizeof("18446744073709551615")]; 462 int len = 0; 463 464 sprintf(buf, "%ld", uml_physmem); 465 CONFIG_CHUNK(str, size, len, buf, 1); 466 467 return len; 468 } 469 470 static int mem_id(char **str, int *start_out, int *end_out) 471 { 472 *start_out = 0; 473 *end_out = 0; 474 475 return 0; 476 } 477 478 static int mem_remove(int n, char **error_out) 479 { 480 *error_out = "Memory doesn't support the remove operation"; 481 return -EBUSY; 482 } 483 484 static struct mc_device mem_mc = { 485 .list = LIST_HEAD_INIT(mem_mc.list), 486 .name = "mem", 487 .config = mem_config, 488 .get_config = mem_get_config, 489 .id = mem_id, 490 .remove = mem_remove, 491 }; 492 493 static int __init mem_mc_init(void) 494 { 495 if (can_drop_memory()) 496 mconsole_register_dev(&mem_mc); 497 else printk(KERN_ERR "Can't release memory to the host - memory " 498 "hotplug won't be supported\n"); 499 return 0; 500 } 501 502 __initcall(mem_mc_init); 503 504 #define CONFIG_BUF_SIZE 64 505 506 static void mconsole_get_config(int (*get_config)(char *, char *, int, 507 char **), 508 struct mc_request *req, char *name) 509 { 510 char default_buf[CONFIG_BUF_SIZE], *error, *buf; 511 int n, size; 512 513 if (get_config == NULL) { 514 mconsole_reply(req, "No get_config routine defined", 1, 0); 515 return; 516 } 517 518 error = NULL; 519 size = ARRAY_SIZE(default_buf); 520 buf = default_buf; 521 522 while (1) { 523 n = (*get_config)(name, buf, size, &error); 524 if (error != NULL) { 525 mconsole_reply(req, error, 1, 0); 526 goto out; 527 } 528 529 if (n <= size) { 530 mconsole_reply(req, buf, 0, 0); 531 goto out; 532 } 533 534 if (buf != default_buf) 535 kfree(buf); 536 537 size = n; 538 buf = kmalloc(size, GFP_KERNEL); 539 if (buf == NULL) { 540 mconsole_reply(req, "Failed to allocate buffer", 1, 0); 541 return; 542 } 543 } 544 out: 545 if (buf != default_buf) 546 kfree(buf); 547 } 548 549 void mconsole_config(struct mc_request *req) 550 { 551 struct mc_device *dev; 552 char *ptr = req->request.data, *name, *error_string = ""; 553 int err; 554 555 ptr += strlen("config"); 556 while (isspace(*ptr)) 557 ptr++; 558 dev = mconsole_find_dev(ptr); 559 if (dev == NULL) { 560 mconsole_reply(req, "Bad configuration option", 1, 0); 561 return; 562 } 563 564 name = &ptr[strlen(dev->name)]; 565 ptr = name; 566 while ((*ptr != '=') && (*ptr != '\0')) 567 ptr++; 568 569 if (*ptr == '=') { 570 err = (*dev->config)(name, &error_string); 571 mconsole_reply(req, error_string, err, 0); 572 } 573 else mconsole_get_config(dev->get_config, req, name); 574 } 575 576 void mconsole_remove(struct mc_request *req) 577 { 578 struct mc_device *dev; 579 char *ptr = req->request.data, *err_msg = ""; 580 char error[256]; 581 int err, start, end, n; 582 583 ptr += strlen("remove"); 584 while (isspace(*ptr)) ptr++; 585 dev = mconsole_find_dev(ptr); 586 if (dev == NULL) { 587 mconsole_reply(req, "Bad remove option", 1, 0); 588 return; 589 } 590 591 ptr = &ptr[strlen(dev->name)]; 592 593 err = 1; 594 n = (*dev->id)(&ptr, &start, &end); 595 if (n < 0) { 596 err_msg = "Couldn't parse device number"; 597 goto out; 598 } 599 else if ((n < start) || (n > end)) { 600 sprintf(error, "Invalid device number - must be between " 601 "%d and %d", start, end); 602 err_msg = error; 603 goto out; 604 } 605 606 err_msg = NULL; 607 err = (*dev->remove)(n, &err_msg); 608 switch(err) { 609 case 0: 610 err_msg = ""; 611 break; 612 case -ENODEV: 613 if (err_msg == NULL) 614 err_msg = "Device doesn't exist"; 615 break; 616 case -EBUSY: 617 if (err_msg == NULL) 618 err_msg = "Device is currently open"; 619 break; 620 default: 621 break; 622 } 623 out: 624 mconsole_reply(req, err_msg, err, 0); 625 } 626 627 struct mconsole_output { 628 struct list_head list; 629 struct mc_request *req; 630 }; 631 632 static DEFINE_SPINLOCK(client_lock); 633 static LIST_HEAD(clients); 634 static char console_buf[MCONSOLE_MAX_DATA]; 635 636 static void console_write(struct console *console, const char *string, 637 unsigned int len) 638 { 639 struct list_head *ele; 640 int n; 641 642 if (list_empty(&clients)) 643 return; 644 645 while (len > 0) { 646 n = min((size_t) len, ARRAY_SIZE(console_buf)); 647 strncpy(console_buf, string, n); 648 string += n; 649 len -= n; 650 651 list_for_each(ele, &clients) { 652 struct mconsole_output *entry; 653 654 entry = list_entry(ele, struct mconsole_output, list); 655 mconsole_reply_len(entry->req, console_buf, n, 0, 1); 656 } 657 } 658 } 659 660 static struct console mc_console = { .name = "mc", 661 .write = console_write, 662 .flags = CON_ENABLED, 663 .index = -1 }; 664 665 static int mc_add_console(void) 666 { 667 register_console(&mc_console); 668 return 0; 669 } 670 671 late_initcall(mc_add_console); 672 673 static void with_console(struct mc_request *req, void (*proc)(void *), 674 void *arg) 675 { 676 struct mconsole_output entry; 677 unsigned long flags; 678 679 entry.req = req; 680 spin_lock_irqsave(&client_lock, flags); 681 list_add(&entry.list, &clients); 682 spin_unlock_irqrestore(&client_lock, flags); 683 684 (*proc)(arg); 685 686 mconsole_reply_len(req, "", 0, 0, 0); 687 688 spin_lock_irqsave(&client_lock, flags); 689 list_del(&entry.list); 690 spin_unlock_irqrestore(&client_lock, flags); 691 } 692 693 #ifdef CONFIG_MAGIC_SYSRQ 694 695 #include <linux/sysrq.h> 696 697 static void sysrq_proc(void *arg) 698 { 699 char *op = arg; 700 handle_sysrq(*op, NULL); 701 } 702 703 void mconsole_sysrq(struct mc_request *req) 704 { 705 char *ptr = req->request.data; 706 707 ptr += strlen("sysrq"); 708 while (isspace(*ptr)) ptr++; 709 710 /* 711 * With 'b', the system will shut down without a chance to reply, 712 * so in this case, we reply first. 713 */ 714 if (*ptr == 'b') 715 mconsole_reply(req, "", 0, 0); 716 717 with_console(req, sysrq_proc, ptr); 718 } 719 #else 720 void mconsole_sysrq(struct mc_request *req) 721 { 722 mconsole_reply(req, "Sysrq not compiled in", 1, 0); 723 } 724 #endif 725 726 static void stack_proc(void *arg) 727 { 728 struct task_struct *from = current, *to = arg; 729 730 to->thread.saved_task = from; 731 switch_to(from, to, from); 732 } 733 734 /* 735 * Mconsole stack trace 736 * Added by Allan Graves, Jeff Dike 737 * Dumps a stacks registers to the linux console. 738 * Usage stack <pid>. 739 */ 740 void mconsole_stack(struct mc_request *req) 741 { 742 char *ptr = req->request.data; 743 int pid_requested= -1; 744 struct task_struct *from = NULL; 745 struct task_struct *to = NULL; 746 747 /* 748 * Would be nice: 749 * 1) Send showregs output to mconsole. 750 * 2) Add a way to stack dump all pids. 751 */ 752 753 ptr += strlen("stack"); 754 while (isspace(*ptr)) 755 ptr++; 756 757 /* 758 * Should really check for multiple pids or reject bad args here 759 */ 760 /* What do the arguments in mconsole_reply mean? */ 761 if (sscanf(ptr, "%d", &pid_requested) == 0) { 762 mconsole_reply(req, "Please specify a pid", 1, 0); 763 return; 764 } 765 766 from = current; 767 768 to = find_task_by_pid(pid_requested); 769 if ((to == NULL) || (pid_requested == 0)) { 770 mconsole_reply(req, "Couldn't find that pid", 1, 0); 771 return; 772 } 773 with_console(req, stack_proc, to); 774 } 775 776 /* 777 * Changed by mconsole_setup, which is __setup, and called before SMP is 778 * active. 779 */ 780 static char *notify_socket = NULL; 781 782 static int __init mconsole_init(void) 783 { 784 /* long to avoid size mismatch warnings from gcc */ 785 long sock; 786 int err; 787 char file[256]; 788 789 if (umid_file_name("mconsole", file, sizeof(file))) 790 return -1; 791 snprintf(mconsole_socket_name, sizeof(file), "%s", file); 792 793 sock = os_create_unix_socket(file, sizeof(file), 1); 794 if (sock < 0) { 795 printk(KERN_ERR "Failed to initialize management console\n"); 796 return 1; 797 } 798 799 register_reboot_notifier(&reboot_notifier); 800 801 err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt, 802 IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM, 803 "mconsole", (void *)sock); 804 if (err) { 805 printk(KERN_ERR "Failed to get IRQ for management console\n"); 806 return 1; 807 } 808 809 if (notify_socket != NULL) { 810 notify_socket = kstrdup(notify_socket, GFP_KERNEL); 811 if (notify_socket != NULL) 812 mconsole_notify(notify_socket, MCONSOLE_SOCKET, 813 mconsole_socket_name, 814 strlen(mconsole_socket_name) + 1); 815 else printk(KERN_ERR "mconsole_setup failed to strdup " 816 "string\n"); 817 } 818 819 printk(KERN_INFO "mconsole (version %d) initialized on %s\n", 820 MCONSOLE_VERSION, mconsole_socket_name); 821 return 0; 822 } 823 824 __initcall(mconsole_init); 825 826 static int write_proc_mconsole(struct file *file, const char __user *buffer, 827 unsigned long count, void *data) 828 { 829 char *buf; 830 831 buf = kmalloc(count + 1, GFP_KERNEL); 832 if (buf == NULL) 833 return -ENOMEM; 834 835 if (copy_from_user(buf, buffer, count)) { 836 count = -EFAULT; 837 goto out; 838 } 839 840 buf[count] = '\0'; 841 842 mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count); 843 out: 844 kfree(buf); 845 return count; 846 } 847 848 static int create_proc_mconsole(void) 849 { 850 struct proc_dir_entry *ent; 851 852 if (notify_socket == NULL) 853 return 0; 854 855 ent = create_proc_entry("mconsole", S_IFREG | 0200, NULL); 856 if (ent == NULL) { 857 printk(KERN_INFO "create_proc_mconsole : create_proc_entry " 858 "failed\n"); 859 return 0; 860 } 861 862 ent->read_proc = NULL; 863 ent->write_proc = write_proc_mconsole; 864 return 0; 865 } 866 867 static DEFINE_SPINLOCK(notify_spinlock); 868 869 void lock_notify(void) 870 { 871 spin_lock(¬ify_spinlock); 872 } 873 874 void unlock_notify(void) 875 { 876 spin_unlock(¬ify_spinlock); 877 } 878 879 __initcall(create_proc_mconsole); 880 881 #define NOTIFY "notify:" 882 883 static int mconsole_setup(char *str) 884 { 885 if (!strncmp(str, NOTIFY, strlen(NOTIFY))) { 886 str += strlen(NOTIFY); 887 notify_socket = str; 888 } 889 else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str); 890 return 1; 891 } 892 893 __setup("mconsole=", mconsole_setup); 894 895 __uml_help(mconsole_setup, 896 "mconsole=notify:<socket>\n" 897 " Requests that the mconsole driver send a message to the named Unix\n" 898 " socket containing the name of the mconsole socket. This also serves\n" 899 " to notify outside processes when UML has booted far enough to respond\n" 900 " to mconsole requests.\n\n" 901 ); 902 903 static int notify_panic(struct notifier_block *self, unsigned long unused1, 904 void *ptr) 905 { 906 char *message = ptr; 907 908 if (notify_socket == NULL) 909 return 0; 910 911 mconsole_notify(notify_socket, MCONSOLE_PANIC, message, 912 strlen(message) + 1); 913 return 0; 914 } 915 916 static struct notifier_block panic_exit_notifier = { 917 .notifier_call = notify_panic, 918 .next = NULL, 919 .priority = 1 920 }; 921 922 static int add_notifier(void) 923 { 924 atomic_notifier_chain_register(&panic_notifier_list, 925 &panic_exit_notifier); 926 return 0; 927 } 928 929 __initcall(add_notifier); 930 931 char *mconsole_notify_socket(void) 932 { 933 return notify_socket; 934 } 935 936 EXPORT_SYMBOL(mconsole_notify_socket); 937