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 "kern_util.h"
  29 #include "kern.h"
  30 #include "mconsole.h"
  31 #include "mconsole_kern.h"
  32 #include "irq_user.h"
  33 #include "init.h"
  34 #include "os.h"
  35 #include "irq_kern.h"
  36 #include "choose-mode.h"
  37
  38 static int do_unlink_socket(struct notifier_block *notifier,
  39                             unsigned long what, void *data)
  40 {
  41         return(mconsole_unlink_socket());
  42 }
  43
  44
  45 static struct notifier_block reboot_notifier = {
  46         .notifier_call          = do_unlink_socket,
  47         .priority               = 0,
  48 };
  49
  50 /* Safe without explicit locking for now.  Tasklets provide their own
  51  * locking, and the interrupt handler is safe because it can't interrupt
  52  * itself and it can only happen on CPU 0.
  53  */
  54
  55 static LIST_HEAD(mc_requests);
  56
  57 static void mc_work_proc(struct work_struct *unused)
  58 {
  59         struct mconsole_entry *req;
  60         unsigned long flags;
  61
  62         while(!list_empty(&mc_requests)){
  63                 local_irq_save(flags);
  64                 req = list_entry(mc_requests.next, struct mconsole_entry,
  65                                  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,
 109                 utsname()->version, 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("%.*s", len, ptr);
 122         mconsole_reply(req, "", 0, 0);
 123 }
 124
 125 /* This is a more convoluted version of mconsole_proc, which has some stability
 126  * problems; however, we need it fixed, because it is expected that UML users
 127  * mount HPPFS instead of procfs on /proc. And we want mconsole_proc to still
 128  * show the real procfs content, not the ones from hppfs.*/
 129 #if 0
 130 void mconsole_proc(struct mc_request *req)
 131 {
 132         struct nameidata nd;
 133         struct file_system_type *proc;
 134         struct super_block *super;
 135         struct file *file;
 136         int n, err;
 137         char *ptr = req->request.data, *buf;
 138
 139         ptr += strlen("proc");
 140         while(isspace(*ptr)) ptr++;
 141
 142         proc = get_fs_type("proc");
 143         if(proc == NULL){
 144                 mconsole_reply(req, "procfs not registered", 1, 0);
 145                 goto out;
 146         }
 147
 148         super = (*proc->get_sb)(proc, 0, NULL, NULL);
 149         put_filesystem(proc);
 150         if(super == NULL){
 151                 mconsole_reply(req, "Failed to get procfs superblock", 1, 0);
 152                 goto out;
 153         }
 154         up_write(&super->s_umount);
 155
 156         nd.dentry = super->s_root;
 157         nd.mnt = NULL;
 158         nd.flags = O_RDONLY + 1;
 159         nd.last_type = LAST_ROOT;
 160
 161         /* START: it was experienced that the stability problems are closed
 162          * if commenting out these two calls + the below read cycle. To
 163          * make UML crash again, it was enough to readd either one.*/
 164         err = link_path_walk(ptr, &nd);
 165         if(err){
 166                 mconsole_reply(req, "Failed to look up file", 1, 0);
 167                 goto out_kill;
 168         }
 169
 170         file = dentry_open(nd.dentry, nd.mnt, O_RDONLY);
 171         if(IS_ERR(file)){
 172                 mconsole_reply(req, "Failed to open file", 1, 0);
 173                 goto out_kill;
 174         }
 175         /*END*/
 176
 177         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
 178         if(buf == NULL){
 179                 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
 180                 goto out_fput;
 181         }
 182
 183         if((file->f_op != NULL) && (file->f_op->read != NULL)){
 184                 do {
 185                         n = (*file->f_op->read)(file, buf, PAGE_SIZE - 1,
 186                                                 &file->f_pos);
 187                         if(n >= 0){
 188                                 buf[n] = '\0';
 189                                 mconsole_reply(req, buf, 0, (n > 0));
 190                         }
 191                         else {
 192                                 mconsole_reply(req, "Read of file failed",
 193                                                1, 0);
 194                                 goto out_free;
 195                         }
 196                 } while(n > 0);
 197         }
 198         else mconsole_reply(req, "", 0, 0);
 199
 200  out_free:
 201         kfree(buf);
 202  out_fput:
 203         fput(file);
 204  out_kill:
 205         deactivate_super(super);
 206  out: ;
 207 }
 208 #endif
 209
 210 void mconsole_proc(struct mc_request *req)
 211 {
 212         char path[64];
 213         char *buf;
 214         int len;
 215         int fd;
 216         int first_chunk = 1;
 217         char *ptr = req->request.data;
 218
 219         ptr += strlen("proc");
 220         while(isspace(*ptr)) ptr++;
 221         snprintf(path, sizeof(path), "/proc/%s", ptr);
 222
 223         fd = sys_open(path, 0, 0);
 224         if (fd < 0) {
 225                 mconsole_reply(req, "Failed to open file", 1, 0);
 226                 printk("open %s: %d\n",path,fd);
 227                 goto out;
 228         }
 229
 230         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
 231         if(buf == NULL){
 232                 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
 233                 goto out_close;
 234         }
 235
 236         for (;;) {
 237                 len = sys_read(fd, buf, PAGE_SIZE-1);
 238                 if (len < 0) {
 239                         mconsole_reply(req, "Read of file failed", 1, 0);
 240                         goto out_free;
 241                 }
 242                 /*Begin the file content on his own line.*/
 243                 if (first_chunk) {
 244                         mconsole_reply(req, "\n", 0, 1);
 245                         first_chunk = 0;
 246                 }
 247                 if (len == PAGE_SIZE-1) {
 248                         buf[len] = '\0';
 249                         mconsole_reply(req, buf, 0, 1);
 250                 } else {
 251                         buf[len] = '\0';
 252                         mconsole_reply(req, buf, 0, 0);
 253                         break;
 254                 }
 255         }
 256
 257  out_free:
 258         kfree(buf);
 259  out_close:
 260         sys_close(fd);
 261  out:
 262         /* nothing */;
 263 }
 264
 265 #define UML_MCONSOLE_HELPTEXT \
 266 "Commands: \n\
 267     version - Get kernel version \n\
 268     help - Print this message \n\
 269     halt - Halt UML \n\
 270     reboot - Reboot UML \n\
 271     config <dev>=<config> - Add a new device to UML;  \n\
 272         same syntax as command line \n\
 273     config <dev> - Query the configuration of a device \n\
 274     remove <dev> - Remove a device from UML \n\
 275     sysrq <letter> - Performs the SysRq action controlled by the letter \n\
 276     cad - invoke the Ctrl-Alt-Del handler \n\
 277     stop - pause the UML; it will do nothing until it receives a 'go' \n\
 278     go - continue the UML after a 'stop' \n\
 279     log <string> - make UML enter <string> into the kernel log\n\
 280     proc <file> - returns the contents of the UML's /proc/<file>\n\
 281     stack <pid> - returns the stack of the specified pid\n\
 282 "
 283
 284 void mconsole_help(struct mc_request *req)
 285 {
 286         mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0);
 287 }
 288
 289 void mconsole_halt(struct mc_request *req)
 290 {
 291         mconsole_reply(req, "", 0, 0);
 292         machine_halt();
 293 }
 294
 295 void mconsole_reboot(struct mc_request *req)
 296 {
 297         mconsole_reply(req, "", 0, 0);
 298         machine_restart(NULL);
 299 }
 300
 301 void mconsole_cad(struct mc_request *req)
 302 {
 303         mconsole_reply(req, "", 0, 0);
 304         ctrl_alt_del();
 305 }
 306
 307 void mconsole_go(struct mc_request *req)
 308 {
 309         mconsole_reply(req, "Not stopped", 1, 0);
 310 }
 311
 312 void mconsole_stop(struct mc_request *req)
 313 {
 314         deactivate_fd(req->originating_fd, MCONSOLE_IRQ);
 315         os_set_fd_block(req->originating_fd, 1);
 316         mconsole_reply(req, "stopped", 0, 0);
 317         while (mconsole_get_request(req->originating_fd, req)) {
 318                 if (req->cmd->handler == mconsole_go)
 319                         break;
 320                 if (req->cmd->handler == mconsole_stop) {
 321                         mconsole_reply(req, "Already stopped", 1, 0);
 322                         continue;
 323                 }
 324                 if (req->cmd->handler == mconsole_sysrq) {
 325                         struct pt_regs *old_regs;
 326                         old_regs = set_irq_regs((struct pt_regs *)&req->regs);
 327                         mconsole_sysrq(req);
 328                         set_irq_regs(old_regs);
 329                         continue;
 330                 }
 331                 (*req->cmd->handler)(req);
 332         }
 333         os_set_fd_block(req->originating_fd, 0);
 334         reactivate_fd(req->originating_fd, MCONSOLE_IRQ);
 335         mconsole_reply(req, "", 0, 0);
 336 }
 337
 338 static DEFINE_SPINLOCK(mc_devices_lock);
 339 static LIST_HEAD(mconsole_devices);
 340
 341 void mconsole_register_dev(struct mc_device *new)
 342 {
 343         spin_lock(&mc_devices_lock);
 344         BUG_ON(!list_empty(&new->list));
 345         list_add(&new->list, &mconsole_devices);
 346         spin_unlock(&mc_devices_lock);
 347 }
 348
 349 static struct mc_device *mconsole_find_dev(char *name)
 350 {
 351         struct list_head *ele;
 352         struct mc_device *dev;
 353
 354         list_for_each(ele, &mconsole_devices){
 355                 dev = list_entry(ele, struct mc_device, list);
 356                 if(!strncmp(name, dev->name, strlen(dev->name)))
 357                         return(dev);
 358         }
 359         return(NULL);
 360 }
 361
 362 #define UNPLUGGED_PER_PAGE \
 363         ((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long))
 364
 365 struct unplugged_pages {
 366         struct list_head list;
 367         void *pages[UNPLUGGED_PER_PAGE];
 368 };
 369
 370 static DECLARE_MUTEX(plug_mem_mutex);
 371 static unsigned long long unplugged_pages_count = 0;
 372 static LIST_HEAD(unplugged_pages);
 373 static int unplug_index = UNPLUGGED_PER_PAGE;
 374
 375 static int mem_config(char *str, char **error_out)
 376 {
 377         unsigned long long diff;
 378         int err = -EINVAL, i, add;
 379         char *ret;
 380
 381         if(str[0] != '='){
 382                 *error_out = "Expected '=' after 'mem'";
 383                 goto out;
 384         }
 385
 386         str++;
 387         if(str[0] == '-')
 388                 add = 0;
 389         else if(str[0] == '+'){
 390                 add = 1;
 391         }
 392         else {
 393                 *error_out = "Expected increment to start with '-' or '+'";
 394                 goto out;
 395         }
 396
 397         str++;
 398         diff = memparse(str, &ret);
 399         if(*ret != '\0'){
 400                 *error_out = "Failed to parse memory increment";
 401                 goto out;
 402         }
 403
 404         diff /= PAGE_SIZE;
 405
 406         down(&plug_mem_mutex);
 407         for(i = 0; i < diff; i++){
 408                 struct unplugged_pages *unplugged;
 409                 void *addr;
 410
 411                 if(add){
 412                         if(list_empty(&unplugged_pages))
 413                                 break;
 414
 415                         unplugged = list_entry(unplugged_pages.next,
 416                                                struct unplugged_pages, list);
 417                         if(unplug_index > 0)
 418                                 addr = unplugged->pages[--unplug_index];
 419                         else {
 420                                 list_del(&unplugged->list);
 421                                 addr = unplugged;
 422                                 unplug_index = UNPLUGGED_PER_PAGE;
 423                         }
 424
 425                         free_page((unsigned long) addr);
 426                         unplugged_pages_count--;
 427                 }
 428                 else {
 429                         struct page *page;
 430
 431                         page = alloc_page(GFP_ATOMIC);
 432                         if(page == NULL)
 433                                 break;
 434
 435                         unplugged = page_address(page);
 436                         if(unplug_index == UNPLUGGED_PER_PAGE){
 437                                 list_add(&unplugged->list, &unplugged_pages);
 438                                 unplug_index = 0;
 439                         }
 440                         else {
 441                                 struct list_head *entry = unplugged_pages.next;
 442                                 addr = unplugged;
 443
 444                                 unplugged = list_entry(entry,
 445                                                        struct unplugged_pages,
 446                                                        list);
 447                                 err = os_drop_memory(addr, PAGE_SIZE);
 448                                 if(err){
 449                                         printk("Failed to release memory - "
 450                                                "errno = %d\n", err);
 451                                         *error_out = "Failed to release memory";
 452                                         goto out_unlock;
 453                                 }
 454                                 unplugged->pages[unplug_index++] = addr;
 455                         }
 456
 457                         unplugged_pages_count++;
 458                 }
 459         }
 460
 461         err = 0;
 462 out_unlock:
 463         up(&plug_mem_mutex);
 464 out:
 465         return err;
 466 }
 467
 468 static int mem_get_config(char *name, char *str, int size, char **error_out)
 469 {
 470         char buf[sizeof("18446744073709551615")];
 471         int len = 0;
 472
 473         sprintf(buf, "%ld", uml_physmem);
 474         CONFIG_CHUNK(str, size, len, buf, 1);
 475
 476         return len;
 477 }
 478
 479 static int mem_id(char **str, int *start_out, int *end_out)
 480 {
 481         *start_out = 0;
 482         *end_out = 0;
 483
 484         return 0;
 485 }
 486
 487 static int mem_remove(int n, char **error_out)
 488 {
 489         *error_out = "Memory doesn't support the remove operation";
 490         return -EBUSY;
 491 }
 492
 493 static struct mc_device mem_mc = {
 494         .list           = LIST_HEAD_INIT(mem_mc.list),
 495         .name           = "mem",
 496         .config         = mem_config,
 497         .get_config     = mem_get_config,
 498         .id             = mem_id,
 499         .remove         = mem_remove,
 500 };
 501
 502 static int mem_mc_init(void)
 503 {
 504         if(can_drop_memory())
 505                 mconsole_register_dev(&mem_mc);
 506         else printk("Can't release memory to the host - memory hotplug won't "
 507                     "be supported\n");
 508         return 0;
 509 }
 510
 511 __initcall(mem_mc_init);
 512
 513 #define CONFIG_BUF_SIZE 64
 514
 515 static void mconsole_get_config(int (*get_config)(char *, char *, int,
 516                                                   char **),
 517                                 struct mc_request *req, char *name)
 518 {
 519         char default_buf[CONFIG_BUF_SIZE], *error, *buf;
 520         int n, size;
 521
 522         if(get_config == NULL){
 523                 mconsole_reply(req, "No get_config routine defined", 1, 0);
 524                 return;
 525         }
 526
 527         error = NULL;
 528         size = ARRAY_SIZE(default_buf);
 529         buf = default_buf;
 530
 531         while(1){
 532                 n = (*get_config)(name, buf, size, &error);
 533                 if(error != NULL){
 534                         mconsole_reply(req, error, 1, 0);
 535                         goto out;
 536                 }
 537
 538                 if(n <= size){
 539                         mconsole_reply(req, buf, 0, 0);
 540                         goto out;
 541                 }
 542
 543                 if(buf != default_buf)
 544                         kfree(buf);
 545
 546                 size = n;
 547                 buf = kmalloc(size, GFP_KERNEL);
 548                 if(buf == NULL){
 549                         mconsole_reply(req, "Failed to allocate buffer", 1, 0);
 550                         return;
 551                 }
 552         }
 553  out:
 554         if(buf != default_buf)
 555                 kfree(buf);
 556 }
 557
 558 void mconsole_config(struct mc_request *req)
 559 {
 560         struct mc_device *dev;
 561         char *ptr = req->request.data, *name, *error_string = "";
 562         int err;
 563
 564         ptr += strlen("config");
 565         while(isspace(*ptr)) ptr++;
 566         dev = mconsole_find_dev(ptr);
 567         if(dev == NULL){
 568                 mconsole_reply(req, "Bad configuration option", 1, 0);
 569                 return;
 570         }
 571
 572         name = &ptr[strlen(dev->name)];
 573         ptr = name;
 574         while((*ptr != '=') && (*ptr != '\0'))
 575                 ptr++;
 576
 577         if(*ptr == '='){
 578                 err = (*dev->config)(name, &error_string);
 579                 mconsole_reply(req, error_string, err, 0);
 580         }
 581         else mconsole_get_config(dev->get_config, req, name);
 582 }
 583
 584 void mconsole_remove(struct mc_request *req)
 585 {
 586         struct mc_device *dev;
 587         char *ptr = req->request.data, *err_msg = "";
 588         char error[256];
 589         int err, start, end, n;
 590
 591         ptr += strlen("remove");
 592         while(isspace(*ptr)) ptr++;
 593         dev = mconsole_find_dev(ptr);
 594         if(dev == NULL){
 595                 mconsole_reply(req, "Bad remove option", 1, 0);
 596                 return;
 597         }
 598
 599         ptr = &ptr[strlen(dev->name)];
 600
 601         err = 1;
 602         n = (*dev->id)(&ptr, &start, &end);
 603         if(n < 0){
 604                 err_msg = "Couldn't parse device number";
 605                 goto out;
 606         }
 607         else if((n < start) || (n > end)){
 608                 sprintf(error, "Invalid device number - must be between "
 609                         "%d and %d", start, end);
 610                 err_msg = error;
 611                 goto out;
 612         }
 613
 614         err_msg = NULL;
 615         err = (*dev->remove)(n, &err_msg);
 616         switch(err){
 617         case 0:
 618                 err_msg = "";
 619                 break;
 620         case -ENODEV:
 621                 if(err_msg == NULL)
 622                         err_msg = "Device doesn't exist";
 623                 break;
 624         case -EBUSY:
 625                 if(err_msg == NULL)
 626                         err_msg = "Device is currently open";
 627                 break;
 628         default:
 629                 break;
 630         }
 631 out:
 632         mconsole_reply(req, err_msg, err, 0);
 633 }
 634
 635 struct mconsole_output {
 636         struct list_head list;
 637         struct mc_request *req;
 638 };
 639
 640 static DEFINE_SPINLOCK(client_lock);
 641 static LIST_HEAD(clients);
 642 static char console_buf[MCONSOLE_MAX_DATA];
 643 static int console_index = 0;
 644
 645 static void console_write(struct console *console, const char *string,
 646                           unsigned len)
 647 {
 648         struct list_head *ele;
 649         int n;
 650
 651         if(list_empty(&clients))
 652                 return;
 653
 654         while(1){
 655                 n = min((size_t) len, ARRAY_SIZE(console_buf) - console_index);
 656                 strncpy(&console_buf[console_index], string, n);
 657                 console_index += n;
 658                 string += n;
 659                 len -= n;
 660                 if(len == 0)
 661                         return;
 662
 663                 list_for_each(ele, &clients){
 664                         struct mconsole_output *entry;
 665
 666                         entry = list_entry(ele, struct mconsole_output, list);
 667                         mconsole_reply_len(entry->req, console_buf,
 668                                            console_index, 0, 1);
 669                 }
 670
 671                 console_index = 0;
 672         }
 673 }
 674
 675 static struct console mc_console = { .name      = "mc",
 676                                      .write     = console_write,
 677                                      .flags     = CON_ENABLED,
 678                                      .index     = -1 };
 679
 680 static int mc_add_console(void)
 681 {
 682         register_console(&mc_console);
 683         return 0;
 684 }
 685
 686 late_initcall(mc_add_console);
 687
 688 static void with_console(struct mc_request *req, void (*proc)(void *),
 689                          void *arg)
 690 {
 691         struct mconsole_output entry;
 692         unsigned long flags;
 693
 694         entry.req = req;
 695         spin_lock_irqsave(&client_lock, flags);
 696         list_add(&entry.list, &clients);
 697         spin_unlock_irqrestore(&client_lock, flags);
 698
 699         (*proc)(arg);
 700
 701         mconsole_reply_len(req, console_buf, console_index, 0, 0);
 702         console_index = 0;
 703
 704         spin_lock_irqsave(&client_lock, flags);
 705         list_del(&entry.list);
 706         spin_unlock_irqrestore(&client_lock, flags);
 707 }
 708
 709 #ifdef CONFIG_MAGIC_SYSRQ
 710 static void sysrq_proc(void *arg)
 711 {
 712         char *op = arg;
 713         handle_sysrq(*op, NULL);
 714 }
 715
 716 void mconsole_sysrq(struct mc_request *req)
 717 {
 718         char *ptr = req->request.data;
 719
 720         ptr += strlen("sysrq");
 721         while(isspace(*ptr)) ptr++;
 722
 723         /* With 'b', the system will shut down without a chance to reply,
 724          * so in this case, we reply first.
 725          */
 726         if(*ptr == 'b')
 727                 mconsole_reply(req, "", 0, 0);
 728
 729         with_console(req, sysrq_proc, ptr);
 730 }
 731 #else
 732 void mconsole_sysrq(struct mc_request *req)
 733 {
 734         mconsole_reply(req, "Sysrq not compiled in", 1, 0);
 735 }
 736 #endif
 737
 738 #ifdef CONFIG_MODE_SKAS
 739
 740 static void stack_proc(void *arg)
 741 {
 742         struct task_struct *from = current, *to = arg;
 743
 744         to->thread.saved_task = from;
 745         switch_to(from, to, from);
 746 }
 747
 748 /* Mconsole stack trace
 749  *  Added by Allan Graves, Jeff Dike
 750  *  Dumps a stacks registers to the linux console.
 751  *  Usage stack <pid>.
 752  */
 753 static void do_stack_trace(struct mc_request *req)
 754 {
 755         char *ptr = req->request.data;
 756         int pid_requested= -1;
 757         struct task_struct *from = NULL;
 758         struct task_struct *to = NULL;
 759
 760         /* Would be nice:
 761          * 1) Send showregs output to mconsole.
 762          * 2) Add a way to stack dump all pids.
 763          */
 764
 765         ptr += strlen("stack");
 766         while(isspace(*ptr)) ptr++;
 767
 768         /* Should really check for multiple pids or reject bad args here */
 769         /* What do the arguments in mconsole_reply mean? */
 770         if(sscanf(ptr, "%d", &pid_requested) == 0){
 771                 mconsole_reply(req, "Please specify a pid", 1, 0);
 772                 return;
 773         }
 774
 775         from = current;
 776
 777         to = find_task_by_pid(pid_requested);
 778         if((to == NULL) || (pid_requested == 0)) {
 779                 mconsole_reply(req, "Couldn't find that pid", 1, 0);
 780                 return;
 781         }
 782         with_console(req, stack_proc, to);
 783 }
 784 #endif /* CONFIG_MODE_SKAS */
 785
 786 void mconsole_stack(struct mc_request *req)
 787 {
 788         /* This command doesn't work in TT mode, so let's check and then
 789          * get out of here
 790          */
 791         CHOOSE_MODE(mconsole_reply(req, "Sorry, this doesn't work in TT mode",
 792                                    1, 0),
 793                     do_stack_trace(req));
 794 }
 795
 796 /* Changed by mconsole_setup, which is __setup, and called before SMP is
 797  * active.
 798  */
 799 static char *notify_socket = NULL;
 800
 801 static int mconsole_init(void)
 802 {
 803         /* long to avoid size mismatch warnings from gcc */
 804         long sock;
 805         int err;
 806         char file[256];
 807
 808         if(umid_file_name("mconsole", file, sizeof(file))) return(-1);
 809         snprintf(mconsole_socket_name, sizeof(file), "%s", file);
 810
 811         sock = os_create_unix_socket(file, sizeof(file), 1);
 812         if (sock < 0){
 813                 printk("Failed to initialize management console\n");
 814                 return(1);
 815         }
 816
 817         register_reboot_notifier(&reboot_notifier);
 818
 819         err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
 820                              IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
 821                              "mconsole", (void *)sock);
 822         if (err){
 823                 printk("Failed to get IRQ for management console\n");
 824                 return(1);
 825         }
 826
 827         if(notify_socket != NULL){
 828                 notify_socket = kstrdup(notify_socket, GFP_KERNEL);
 829                 if(notify_socket != NULL)
 830                         mconsole_notify(notify_socket, MCONSOLE_SOCKET,
 831                                         mconsole_socket_name,
 832                                         strlen(mconsole_socket_name) + 1);
 833                 else printk(KERN_ERR "mconsole_setup failed to strdup "
 834                             "string\n");
 835         }
 836
 837         printk("mconsole (version %d) initialized on %s\n",
 838                MCONSOLE_VERSION, mconsole_socket_name);
 839         return(0);
 840 }
 841
 842 __initcall(mconsole_init);
 843
 844 static int write_proc_mconsole(struct file *file, const char __user *buffer,
 845                                unsigned long count, void *data)
 846 {
 847         char *buf;
 848
 849         buf = kmalloc(count + 1, GFP_KERNEL);
 850         if(buf == NULL)
 851                 return(-ENOMEM);
 852
 853         if(copy_from_user(buf, buffer, count)){
 854                 count = -EFAULT;
 855                 goto out;
 856         }
 857
 858         buf[count] = '\0';
 859
 860         mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count);
 861  out:
 862         kfree(buf);
 863         return(count);
 864 }
 865
 866 static int create_proc_mconsole(void)
 867 {
 868         struct proc_dir_entry *ent;
 869
 870         if(notify_socket == NULL) return(0);
 871
 872         ent = create_proc_entry("mconsole", S_IFREG | 0200, NULL);
 873         if(ent == NULL){
 874                 printk(KERN_INFO "create_proc_mconsole : create_proc_entry failed\n");
 875                 return(0);
 876         }
 877
 878         ent->read_proc = NULL;
 879         ent->write_proc = write_proc_mconsole;
 880         return(0);
 881 }
 882
 883 static DEFINE_SPINLOCK(notify_spinlock);
 884
 885 void lock_notify(void)
 886 {
 887         spin_lock(&notify_spinlock);
 888 }
 889
 890 void unlock_notify(void)
 891 {
 892         spin_unlock(&notify_spinlock);
 893 }
 894
 895 __initcall(create_proc_mconsole);
 896
 897 #define NOTIFY "=notify:"
 898
 899 static int mconsole_setup(char *str)
 900 {
 901         if(!strncmp(str, NOTIFY, strlen(NOTIFY))){
 902                 str += strlen(NOTIFY);
 903                 notify_socket = str;
 904         }
 905         else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str);
 906         return(1);
 907 }
 908
 909 __setup("mconsole", mconsole_setup);
 910
 911 __uml_help(mconsole_setup,
 912 "mconsole=notify:<socket>\n"
 913 "    Requests that the mconsole driver send a message to the named Unix\n"
 914 "    socket containing the name of the mconsole socket.  This also serves\n"
 915 "    to notify outside processes when UML has booted far enough to respond\n"
 916 "    to mconsole requests.\n\n"
 917 );
 918
 919 static int notify_panic(struct notifier_block *self, unsigned long unused1,
 920                         void *ptr)
 921 {
 922         char *message = ptr;
 923
 924         if(notify_socket == NULL) return(0);
 925
 926         mconsole_notify(notify_socket, MCONSOLE_PANIC, message,
 927                         strlen(message) + 1);
 928         return(0);
 929 }
 930
 931 static struct notifier_block panic_exit_notifier = {
 932         .notifier_call          = notify_panic,
 933         .next                   = NULL,
 934         .priority               = 1
 935 };
 936
 937 static int add_notifier(void)
 938 {
 939         atomic_notifier_chain_register(&panic_notifier_list,
 940                         &panic_exit_notifier);
 941         return(0);
 942 }
 943
 944 __initcall(add_notifier);
 945
 946 char *mconsole_notify_socket(void)
 947 {
 948         return(notify_socket);
 949 }
 950
 951 EXPORT_SYMBOL(mconsole_notify_socket);