arch/um/drivers/mconsole_kern.c

   1 /*
   2  * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org)
   3  * Copyright (C) 2001 - 2003 Jeff Dike (jdike@addtoit.com)
   4  * Licensed under the GPL
   5  */
   6
   7 #include "linux/kernel.h"
   8 #include "linux/slab.h"
   9 #include "linux/init.h"
  10 #include "linux/notifier.h"
  11 #include "linux/reboot.h"
  12 #include "linux/utsname.h"
  13 #include "linux/ctype.h"
  14 #include "linux/interrupt.h"
  15 #include "linux/sysrq.h"
  16 #include "linux/workqueue.h"
  17 #include "linux/module.h"
  18 #include "linux/file.h"
  19 #include "linux/fs.h"
  20 #include "linux/namei.h"
  21 #include "linux/proc_fs.h"
  22 #include "linux/syscalls.h"
  23 #include "linux/list.h"
  24 #include "linux/mm.h"
  25 #include "linux/console.h"
  26 #include "asm/irq.h"
  27 #include "asm/uaccess.h"
  28 #include "user_util.h"
  29 #include "kern_util.h"
  30 #include "kern.h"
  31 #include "mconsole.h"
  32 #include "mconsole_kern.h"
  33 #include "irq_user.h"
  34 #include "init.h"
  35 #include "os.h"
  36 #include "irq_kern.h"
  37 #include "choose-mode.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,
  66                                  list);
  67                 list_del(&req->list);
  68                 local_irq_restore(flags);
  69                 req->request.cmd->handler(&req->request);
  70                 kfree(req);
  71         }
  72 }
  73
  74 static DECLARE_WORK(mconsole_work, mc_work_proc);
  75
  76 static irqreturn_t mconsole_interrupt(int irq, void *dev_id)
  77 {
  78         /* long to avoid size mismatch warnings from gcc */
  79         long fd;
  80         struct mconsole_entry *new;
  81         static struct mc_request req;   /* that's OK */
  82
  83         fd = (long) dev_id;
  84         while (mconsole_get_request(fd, &req)){
  85                 if(req.cmd->context == MCONSOLE_INTR)
  86                         (*req.cmd->handler)(&req);
  87                 else {
  88                         new = kmalloc(sizeof(*new), GFP_NOWAIT);
  89                         if(new == NULL)
  90                                 mconsole_reply(&req, "Out of memory", 1, 0);
  91                         else {
  92                                 new->request = req;
  93                                 new->request.regs = get_irq_regs()->regs;
  94                                 list_add(&new->list, &mc_requests);
  95                         }
  96                 }
  97         }
  98         if(!list_empty(&mc_requests))
  99                 schedule_work(&mconsole_work);
 100         reactivate_fd(fd, MCONSOLE_IRQ);
 101         return(IRQ_HANDLED);
 102 }
 103
 104 void mconsole_version(struct mc_request *req)
 105 {
 106         char version[256];
 107
 108         sprintf(version, "%s %s %s %s %s", utsname()->sysname,
 109                 utsname()->nodename, utsname()->release,
 110                 utsname()->version, utsname()->machine);
 111         mconsole_reply(req, version, 0, 0);
 112 }
 113
 114 void mconsole_log(struct mc_request *req)
 115 {
 116         int len;
 117         char *ptr = req->request.data;
 118
 119         ptr += strlen("log ");
 120
 121         len = req->len - (ptr - req->request.data);
 122         printk("%.*s", len, ptr);
 123         mconsole_reply(req, "", 0, 0);
 124 }
 125
 126 /* This is a more convoluted version of mconsole_proc, which has some stability
 127  * problems; however, we need it fixed, because it is expected that UML users
 128  * mount HPPFS instead of procfs on /proc. And we want mconsole_proc to still
 129  * show the real procfs content, not the ones from hppfs.*/
 130 #if 0
 131 void mconsole_proc(struct mc_request *req)
 132 {
 133         struct nameidata nd;
 134         struct file_system_type *proc;
 135         struct super_block *super;
 136         struct file *file;
 137         int n, err;
 138         char *ptr = req->request.data, *buf;
 139
 140         ptr += strlen("proc");
 141         while(isspace(*ptr)) ptr++;
 142
 143         proc = get_fs_type("proc");
 144         if(proc == NULL){
 145                 mconsole_reply(req, "procfs not registered", 1, 0);
 146                 goto out;
 147         }
 148
 149         super = (*proc->get_sb)(proc, 0, NULL, NULL);
 150         put_filesystem(proc);
 151         if(super == NULL){
 152                 mconsole_reply(req, "Failed to get procfs superblock", 1, 0);
 153                 goto out;
 154         }
 155         up_write(&super->s_umount);
 156
 157         nd.dentry = super->s_root;
 158         nd.mnt = NULL;
 159         nd.flags = O_RDONLY + 1;
 160         nd.last_type = LAST_ROOT;
 161
 162         /* START: it was experienced that the stability problems are closed
 163          * if commenting out these two calls + the below read cycle. To
 164          * make UML crash again, it was enough to readd either one.*/
 165         err = link_path_walk(ptr, &nd);
 166         if(err){
 167                 mconsole_reply(req, "Failed to look up file", 1, 0);
 168                 goto out_kill;
 169         }
 170
 171         file = dentry_open(nd.dentry, nd.mnt, O_RDONLY);
 172         if(IS_ERR(file)){
 173                 mconsole_reply(req, "Failed to open file", 1, 0);
 174                 goto out_kill;
 175         }
 176         /*END*/
 177
 178         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
 179         if(buf == NULL){
 180                 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
 181                 goto out_fput;
 182         }
 183
 184         if((file->f_op != NULL) && (file->f_op->read != NULL)){
 185                 do {
 186                         n = (*file->f_op->read)(file, buf, PAGE_SIZE - 1,
 187                                                 &file->f_pos);
 188                         if(n >= 0){
 189                                 buf[n] = '\0';
 190                                 mconsole_reply(req, buf, 0, (n > 0));
 191                         }
 192                         else {
 193                                 mconsole_reply(req, "Read of file failed",
 194                                                1, 0);
 195                                 goto out_free;
 196                         }
 197                 } while(n > 0);
 198         }
 199         else mconsole_reply(req, "", 0, 0);
 200
 201  out_free:
 202         kfree(buf);
 203  out_fput:
 204         fput(file);
 205  out_kill:
 206         deactivate_super(super);
 207  out: ;
 208 }
 209 #endif
 210
 211 void mconsole_proc(struct mc_request *req)
 212 {
 213         char path[64];
 214         char *buf;
 215         int len;
 216         int fd;
 217         int first_chunk = 1;
 218         char *ptr = req->request.data;
 219
 220         ptr += strlen("proc");
 221         while(isspace(*ptr)) ptr++;
 222         snprintf(path, sizeof(path), "/proc/%s", ptr);
 223
 224         fd = sys_open(path, 0, 0);
 225         if (fd < 0) {
 226                 mconsole_reply(req, "Failed to open file", 1, 0);
 227                 printk("open %s: %d\n",path,fd);
 228                 goto out;
 229         }
 230
 231         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
 232         if(buf == NULL){
 233                 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
 234                 goto out_close;
 235         }
 236
 237         for (;;) {
 238                 len = sys_read(fd, buf, PAGE_SIZE-1);
 239                 if (len < 0) {
 240                         mconsole_reply(req, "Read of file failed", 1, 0);
 241                         goto out_free;
 242                 }
 243                 /*Begin the file content on his own line.*/
 244                 if (first_chunk) {
 245                         mconsole_reply(req, "\n", 0, 1);
 246                         first_chunk = 0;
 247                 }
 248                 if (len == PAGE_SIZE-1) {
 249                         buf[len] = '\0';
 250                         mconsole_reply(req, buf, 0, 1);
 251                 } else {
 252                         buf[len] = '\0';
 253                         mconsole_reply(req, buf, 0, 0);
 254                         break;
 255                 }
 256         }
 257
 258  out_free:
 259         kfree(buf);
 260  out_close:
 261         sys_close(fd);
 262  out:
 263         /* nothing */;
 264 }
 265
 266 #define UML_MCONSOLE_HELPTEXT \
 267 "Commands: \n\
 268     version - Get kernel version \n\
 269     help - Print this message \n\
 270     halt - Halt UML \n\
 271     reboot - Reboot UML \n\
 272     config <dev>=<config> - Add a new device to UML;  \n\
 273         same syntax as command line \n\
 274     config <dev> - Query the configuration of a device \n\
 275     remove <dev> - Remove a device from UML \n\
 276     sysrq <letter> - Performs the SysRq action controlled by the letter \n\
 277     cad - invoke the Ctrl-Alt-Del handler \n\
 278     stop - pause the UML; it will do nothing until it receives a 'go' \n\
 279     go - continue the UML after a 'stop' \n\
 280     log <string> - make UML enter <string> into the kernel log\n\
 281     proc <file> - returns the contents of the UML's /proc/<file>\n\
 282     stack <pid> - returns the stack of the specified pid\n\
 283 "
 284
 285 void mconsole_help(struct mc_request *req)
 286 {
 287         mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0);
 288 }
 289
 290 void mconsole_halt(struct mc_request *req)
 291 {
 292         mconsole_reply(req, "", 0, 0);
 293         machine_halt();
 294 }
 295
 296 void mconsole_reboot(struct mc_request *req)
 297 {
 298         mconsole_reply(req, "", 0, 0);
 299         machine_restart(NULL);
 300 }
 301
 302 void mconsole_cad(struct mc_request *req)
 303 {
 304         mconsole_reply(req, "", 0, 0);
 305         ctrl_alt_del();
 306 }
 307
 308 void mconsole_go(struct mc_request *req)
 309 {
 310         mconsole_reply(req, "Not stopped", 1, 0);
 311 }
 312
 313 void mconsole_stop(struct mc_request *req)
 314 {
 315         deactivate_fd(req->originating_fd, MCONSOLE_IRQ);
 316         os_set_fd_block(req->originating_fd, 1);
 317         mconsole_reply(req, "stopped", 0, 0);
 318         while (mconsole_get_request(req->originating_fd, req)) {
 319                 if (req->cmd->handler == mconsole_go)
 320                         break;
 321                 if (req->cmd->handler == mconsole_stop) {
 322                         mconsole_reply(req, "Already stopped", 1, 0);
 323                         continue;
 324                 }
 325                 if (req->cmd->handler == mconsole_sysrq) {
 326                         struct pt_regs *old_regs;
 327                         old_regs = set_irq_regs((struct pt_regs *)&req->regs);
 328                         mconsole_sysrq(req);
 329                         set_irq_regs(old_regs);
 330                         continue;
 331                 }
 332                 (*req->cmd->handler)(req);
 333         }
 334         os_set_fd_block(req->originating_fd, 0);
 335         reactivate_fd(req->originating_fd, MCONSOLE_IRQ);
 336         mconsole_reply(req, "", 0, 0);
 337 }
 338
 339 static DEFINE_SPINLOCK(mc_devices_lock);
 340 static LIST_HEAD(mconsole_devices);
 341
 342 void mconsole_register_dev(struct mc_device *new)
 343 {
 344         spin_lock(&mc_devices_lock);
 345         BUG_ON(!list_empty(&new->list));
 346         list_add(&new->list, &mconsole_devices);
 347         spin_unlock(&mc_devices_lock);
 348 }
 349
 350 static struct mc_device *mconsole_find_dev(char *name)
 351 {
 352         struct list_head *ele;
 353         struct mc_device *dev;
 354
 355         list_for_each(ele, &mconsole_devices){
 356                 dev = list_entry(ele, struct mc_device, list);
 357                 if(!strncmp(name, dev->name, strlen(dev->name)))
 358                         return(dev);
 359         }
 360         return(NULL);
 361 }
 362
 363 #define UNPLUGGED_PER_PAGE \
 364         ((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long))
 365
 366 struct unplugged_pages {
 367         struct list_head list;
 368         void *pages[UNPLUGGED_PER_PAGE];
 369 };
 370
 371 static DECLARE_MUTEX(plug_mem_mutex);
 372 static unsigned long long unplugged_pages_count = 0;
 373 static LIST_HEAD(unplugged_pages);
 374 static int unplug_index = UNPLUGGED_PER_PAGE;
 375
 376 static int mem_config(char *str, char **error_out)
 377 {
 378         unsigned long long diff;
 379         int err = -EINVAL, i, add;
 380         char *ret;
 381
 382         if(str[0] != '='){
 383                 *error_out = "Expected '=' after 'mem'";
 384                 goto out;
 385         }
 386
 387         str++;
 388         if(str[0] == '-')
 389                 add = 0;
 390         else if(str[0] == '+'){
 391                 add = 1;
 392         }
 393         else {
 394                 *error_out = "Expected increment to start with '-' or '+'";
 395                 goto out;
 396         }
 397
 398         str++;
 399         diff = memparse(str, &ret);
 400         if(*ret != '\0'){
 401                 *error_out = "Failed to parse memory increment";
 402                 goto out;
 403         }
 404
 405         diff /= PAGE_SIZE;
 406
 407         down(&plug_mem_mutex);
 408         for(i = 0; i < diff; i++){
 409                 struct unplugged_pages *unplugged;
 410                 void *addr;
 411
 412                 if(add){
 413                         if(list_empty(&unplugged_pages))
 414                                 break;
 415
 416                         unplugged = list_entry(unplugged_pages.next,
 417                                                struct unplugged_pages, list);
 418                         if(unplug_index > 0)
 419                                 addr = unplugged->pages[--unplug_index];
 420                         else {
 421                                 list_del(&unplugged->list);
 422                                 addr = unplugged;
 423                                 unplug_index = UNPLUGGED_PER_PAGE;
 424                         }
 425
 426                         free_page((unsigned long) addr);
 427                         unplugged_pages_count--;
 428                 }
 429                 else {
 430                         struct page *page;
 431
 432                         page = alloc_page(GFP_ATOMIC);
 433                         if(page == NULL)
 434                                 break;
 435
 436                         unplugged = page_address(page);
 437                         if(unplug_index == UNPLUGGED_PER_PAGE){
 438                                 list_add(&unplugged->list, &unplugged_pages);
 439                                 unplug_index = 0;
 440                         }
 441                         else {
 442                                 struct list_head *entry = unplugged_pages.next;
 443                                 addr = unplugged;
 444
 445                                 unplugged = list_entry(entry,
 446                                                        struct unplugged_pages,
 447                                                        list);
 448                                 err = os_drop_memory(addr, PAGE_SIZE);
 449                                 if(err){
 450                                         printk("Failed to release memory - "
 451                                                "errno = %d\n", err);
 452                                         *error_out = "Failed to release memory";
 453                                         goto out_unlock;
 454                                 }
 455                                 unplugged->pages[unplug_index++] = addr;
 456                         }
 457
 458                         unplugged_pages_count++;
 459                 }
 460         }
 461
 462         err = 0;
 463 out_unlock:
 464         up(&plug_mem_mutex);
 465 out:
 466         return err;
 467 }
 468
 469 static int mem_get_config(char *name, char *str, int size, char **error_out)
 470 {
 471         char buf[sizeof("18446744073709551615")];
 472         int len = 0;
 473
 474         sprintf(buf, "%ld", uml_physmem);
 475         CONFIG_CHUNK(str, size, len, buf, 1);
 476
 477         return len;
 478 }
 479
 480 static int mem_id(char **str, int *start_out, int *end_out)
 481 {
 482         *start_out = 0;
 483         *end_out = 0;
 484
 485         return 0;
 486 }
 487
 488 static int mem_remove(int n, char **error_out)
 489 {
 490         *error_out = "Memory doesn't support the remove operation";
 491         return -EBUSY;
 492 }
 493
 494 static struct mc_device mem_mc = {
 495         .list           = LIST_HEAD_INIT(mem_mc.list),
 496         .name           = "mem",
 497         .config         = mem_config,
 498         .get_config     = mem_get_config,
 499         .id             = mem_id,
 500         .remove         = mem_remove,
 501 };
 502
 503 static int mem_mc_init(void)
 504 {
 505         if(can_drop_memory())
 506                 mconsole_register_dev(&mem_mc);
 507         else printk("Can't release memory to the host - memory hotplug won't "
 508                     "be supported\n");
 509         return 0;
 510 }
 511
 512 __initcall(mem_mc_init);
 513
 514 #define CONFIG_BUF_SIZE 64
 515
 516 static void mconsole_get_config(int (*get_config)(char *, char *, int,
 517                                                   char **),
 518                                 struct mc_request *req, char *name)
 519 {
 520         char default_buf[CONFIG_BUF_SIZE], *error, *buf;
 521         int n, size;
 522
 523         if(get_config == NULL){
 524                 mconsole_reply(req, "No get_config routine defined", 1, 0);
 525                 return;
 526         }
 527
 528         error = NULL;
 529         size = ARRAY_SIZE(default_buf);
 530         buf = default_buf;
 531
 532         while(1){
 533                 n = (*get_config)(name, buf, size, &error);
 534                 if(error != NULL){
 535                         mconsole_reply(req, error, 1, 0);
 536                         goto out;
 537                 }
 538
 539                 if(n <= size){
 540                         mconsole_reply(req, buf, 0, 0);
 541                         goto out;
 542                 }
 543
 544                 if(buf != default_buf)
 545                         kfree(buf);
 546
 547                 size = n;
 548                 buf = kmalloc(size, GFP_KERNEL);
 549                 if(buf == NULL){
 550                         mconsole_reply(req, "Failed to allocate buffer", 1, 0);
 551                         return;
 552                 }
 553         }
 554  out:
 555         if(buf != default_buf)
 556                 kfree(buf);
 557 }
 558
 559 void mconsole_config(struct mc_request *req)
 560 {
 561         struct mc_device *dev;
 562         char *ptr = req->request.data, *name, *error_string = "";
 563         int err;
 564
 565         ptr += strlen("config");
 566         while(isspace(*ptr)) ptr++;
 567         dev = mconsole_find_dev(ptr);
 568         if(dev == NULL){
 569                 mconsole_reply(req, "Bad configuration option", 1, 0);
 570                 return;
 571         }
 572
 573         name = &ptr[strlen(dev->name)];
 574         ptr = name;
 575         while((*ptr != '=') && (*ptr != '\0'))
 576                 ptr++;
 577
 578         if(*ptr == '='){
 579                 err = (*dev->config)(name, &error_string);
 580                 mconsole_reply(req, error_string, err, 0);
 581         }
 582         else mconsole_get_config(dev->get_config, req, name);
 583 }
 584
 585 void mconsole_remove(struct mc_request *req)
 586 {
 587         struct mc_device *dev;
 588         char *ptr = req->request.data, *err_msg = "";
 589         char error[256];
 590         int err, start, end, n;
 591
 592         ptr += strlen("remove");
 593         while(isspace(*ptr)) ptr++;
 594         dev = mconsole_find_dev(ptr);
 595         if(dev == NULL){
 596                 mconsole_reply(req, "Bad remove option", 1, 0);
 597                 return;
 598         }
 599
 600         ptr = &ptr[strlen(dev->name)];
 601
 602         err = 1;
 603         n = (*dev->id)(&ptr, &start, &end);
 604         if(n < 0){
 605                 err_msg = "Couldn't parse device number";
 606                 goto out;
 607         }
 608         else if((n < start) || (n > end)){
 609                 sprintf(error, "Invalid device number - must be between "
 610                         "%d and %d", start, end);
 611                 err_msg = error;
 612                 goto out;
 613         }
 614
 615         err_msg = NULL;
 616         err = (*dev->remove)(n, &err_msg);
 617         switch(err){
 618         case 0:
 619                 err_msg = "";
 620                 break;
 621         case -ENODEV:
 622                 if(err_msg == NULL)
 623                         err_msg = "Device doesn't exist";
 624                 break;
 625         case -EBUSY:
 626                 if(err_msg == NULL)
 627                         err_msg = "Device is currently open";
 628                 break;
 629         default:
 630                 break;
 631         }
 632 out:
 633         mconsole_reply(req, err_msg, err, 0);
 634 }
 635
 636 struct mconsole_output {
 637         struct list_head list;
 638         struct mc_request *req;
 639 };
 640
 641 static DEFINE_SPINLOCK(client_lock);
 642 static LIST_HEAD(clients);
 643 static char console_buf[MCONSOLE_MAX_DATA];
 644 static int console_index = 0;
 645
 646 static void console_write(struct console *console, const char *string,
 647                           unsigned len)
 648 {
 649         struct list_head *ele;
 650         int n;
 651
 652         if(list_empty(&clients))
 653                 return;
 654
 655         while(1){
 656                 n = min((size_t) len, ARRAY_SIZE(console_buf) - console_index);
 657                 strncpy(&console_buf[console_index], string, n);
 658                 console_index += n;
 659                 string += n;
 660                 len -= n;
 661                 if(len == 0)
 662                         return;
 663
 664                 list_for_each(ele, &clients){
 665                         struct mconsole_output *entry;
 666
 667                         entry = list_entry(ele, struct mconsole_output, list);
 668                         mconsole_reply_len(entry->req, console_buf,
 669                                            console_index, 0, 1);
 670                 }
 671
 672                 console_index = 0;
 673         }
 674 }
 675
 676 static struct console mc_console = { .name      = "mc",
 677                                      .write     = console_write,
 678                                      .flags     = CON_ENABLED,
 679                                      .index     = -1 };
 680
 681 static int mc_add_console(void)
 682 {
 683         register_console(&mc_console);
 684         return 0;
 685 }
 686
 687 late_initcall(mc_add_console);
 688
 689 static void with_console(struct mc_request *req, void (*proc)(void *),
 690                          void *arg)
 691 {
 692         struct mconsole_output entry;
 693         unsigned long flags;
 694
 695         entry.req = req;
 696         spin_lock_irqsave(&client_lock, flags);
 697         list_add(&entry.list, &clients);
 698         spin_unlock_irqrestore(&client_lock, flags);
 699
 700         (*proc)(arg);
 701
 702         mconsole_reply_len(req, console_buf, console_index, 0, 0);
 703         console_index = 0;
 704
 705         spin_lock_irqsave(&client_lock, flags);
 706         list_del(&entry.list);
 707         spin_unlock_irqrestore(&client_lock, flags);
 708 }
 709
 710 #ifdef CONFIG_MAGIC_SYSRQ
 711 static void sysrq_proc(void *arg)
 712 {
 713         char *op = arg;
 714         handle_sysrq(*op, NULL);
 715 }
 716
 717 void mconsole_sysrq(struct mc_request *req)
 718 {
 719         char *ptr = req->request.data;
 720
 721         ptr += strlen("sysrq");
 722         while(isspace(*ptr)) ptr++;
 723
 724         /* With 'b', the system will shut down without a chance to reply,
 725          * so in this case, we reply first.
 726          */
 727         if(*ptr == 'b')
 728                 mconsole_reply(req, "", 0, 0);
 729
 730         with_console(req, sysrq_proc, ptr);
 731 }
 732 #else
 733 void mconsole_sysrq(struct mc_request *req)
 734 {
 735         mconsole_reply(req, "Sysrq not compiled in", 1, 0);
 736 }
 737 #endif
 738
 739 #ifdef CONFIG_MODE_SKAS
 740
 741 static void stack_proc(void *arg)
 742 {
 743         struct task_struct *from = current, *to = arg;
 744
 745         to->thread.saved_task = from;
 746         switch_to(from, to, from);
 747 }
 748
 749 /* Mconsole stack trace
 750  *  Added by Allan Graves, Jeff Dike
 751  *  Dumps a stacks registers to the linux console.
 752  *  Usage stack <pid>.
 753  */
 754 static void do_stack_trace(struct mc_request *req)
 755 {
 756         char *ptr = req->request.data;
 757         int pid_requested= -1;
 758         struct task_struct *from = NULL;
 759         struct task_struct *to = NULL;
 760
 761         /* Would be nice:
 762          * 1) Send showregs output to mconsole.
 763          * 2) Add a way to stack dump all pids.
 764          */
 765
 766         ptr += strlen("stack");
 767         while(isspace(*ptr)) ptr++;
 768
 769         /* Should really check for multiple pids or reject bad args here */
 770         /* What do the arguments in mconsole_reply mean? */
 771         if(sscanf(ptr, "%d", &pid_requested) == 0){
 772                 mconsole_reply(req, "Please specify a pid", 1, 0);
 773                 return;
 774         }
 775
 776         from = current;
 777
 778         to = find_task_by_pid(pid_requested);
 779         if((to == NULL) || (pid_requested == 0)) {
 780                 mconsole_reply(req, "Couldn't find that pid", 1, 0);
 781                 return;
 782         }
 783         with_console(req, stack_proc, to);
 784 }
 785 #endif /* CONFIG_MODE_SKAS */
 786
 787 void mconsole_stack(struct mc_request *req)
 788 {
 789         /* This command doesn't work in TT mode, so let's check and then
 790          * get out of here
 791          */
 792         CHOOSE_MODE(mconsole_reply(req, "Sorry, this doesn't work in TT mode",
 793                                    1, 0),
 794                     do_stack_trace(req));
 795 }
 796
 797 /* Changed by mconsole_setup, which is __setup, and called before SMP is
 798  * active.
 799  */
 800 static char *notify_socket = NULL;
 801
 802 static int mconsole_init(void)
 803 {
 804         /* long to avoid size mismatch warnings from gcc */
 805         long sock;
 806         int err;
 807         char file[256];
 808
 809         if(umid_file_name("mconsole", file, sizeof(file))) return(-1);
 810         snprintf(mconsole_socket_name, sizeof(file), "%s", file);
 811
 812         sock = os_create_unix_socket(file, sizeof(file), 1);
 813         if (sock < 0){
 814                 printk("Failed to initialize management console\n");
 815                 return(1);
 816         }
 817
 818         register_reboot_notifier(&reboot_notifier);
 819
 820         err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
 821                              IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
 822                              "mconsole", (void *)sock);
 823         if (err){
 824                 printk("Failed to get IRQ for management console\n");
 825                 return(1);
 826         }
 827
 828         if(notify_socket != NULL){
 829                 notify_socket = kstrdup(notify_socket, GFP_KERNEL);
 830                 if(notify_socket != NULL)
 831                         mconsole_notify(notify_socket, MCONSOLE_SOCKET,
 832                                         mconsole_socket_name,
 833                                         strlen(mconsole_socket_name) + 1);
 834                 else printk(KERN_ERR "mconsole_setup failed to strdup "
 835                             "string\n");
 836         }
 837
 838         printk("mconsole (version %d) initialized on %s\n",
 839                MCONSOLE_VERSION, mconsole_socket_name);
 840         return(0);
 841 }
 842
 843 __initcall(mconsole_init);
 844
 845 static int write_proc_mconsole(struct file *file, const char __user *buffer,
 846                                unsigned long count, void *data)
 847 {
 848         char *buf;
 849
 850         buf = kmalloc(count + 1, GFP_KERNEL);
 851         if(buf == NULL)
 852                 return(-ENOMEM);
 853
 854         if(copy_from_user(buf, buffer, count)){
 855                 count = -EFAULT;
 856                 goto out;
 857         }
 858
 859         buf[count] = '\0';
 860
 861         mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count);
 862  out:
 863         kfree(buf);
 864         return(count);
 865 }
 866
 867 static int create_proc_mconsole(void)
 868 {
 869         struct proc_dir_entry *ent;
 870
 871         if(notify_socket == NULL) return(0);
 872
 873         ent = create_proc_entry("mconsole", S_IFREG | 0200, NULL);
 874         if(ent == NULL){
 875                 printk(KERN_INFO "create_proc_mconsole : create_proc_entry failed\n");
 876                 return(0);
 877         }
 878
 879         ent->read_proc = NULL;
 880         ent->write_proc = write_proc_mconsole;
 881         return(0);
 882 }
 883
 884 static DEFINE_SPINLOCK(notify_spinlock);
 885
 886 void lock_notify(void)
 887 {
 888         spin_lock(&notify_spinlock);
 889 }
 890
 891 void unlock_notify(void)
 892 {
 893         spin_unlock(&notify_spinlock);
 894 }
 895
 896 __initcall(create_proc_mconsole);
 897
 898 #define NOTIFY "=notify:"
 899
 900 static int mconsole_setup(char *str)
 901 {
 902         if(!strncmp(str, NOTIFY, strlen(NOTIFY))){
 903                 str += strlen(NOTIFY);
 904                 notify_socket = str;
 905         }
 906         else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str);
 907         return(1);
 908 }
 909
 910 __setup("mconsole", mconsole_setup);
 911
 912 __uml_help(mconsole_setup,
 913 "mconsole=notify:<socket>\n"
 914 "    Requests that the mconsole driver send a message to the named Unix\n"
 915 "    socket containing the name of the mconsole socket.  This also serves\n"
 916 "    to notify outside processes when UML has booted far enough to respond\n"
 917 "    to mconsole requests.\n\n"
 918 );
 919
 920 static int notify_panic(struct notifier_block *self, unsigned long unused1,
 921                         void *ptr)
 922 {
 923         char *message = ptr;
 924
 925         if(notify_socket == NULL) return(0);
 926
 927         mconsole_notify(notify_socket, MCONSOLE_PANIC, message,
 928                         strlen(message) + 1);
 929         return(0);
 930 }
 931
 932 static struct notifier_block panic_exit_notifier = {
 933         .notifier_call          = notify_panic,
 934         .next                   = NULL,
 935         .priority               = 1
 936 };
 937
 938 static int add_notifier(void)
 939 {
 940         atomic_notifier_chain_register(&panic_notifier_list,
 941                         &panic_exit_notifier);
 942         return(0);
 943 }
 944
 945 __initcall(add_notifier);
 946
 947 char *mconsole_notify_socket(void)
 948 {
 949         return(notify_socket);
 950 }
 951
 952 EXPORT_SYMBOL(mconsole_notify_socket);