arch/um/drivers/mconsole_kern.c

   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/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 <linux/mutex.h>
  21 #include <asm/uaccess.h>
  22
  23 #include "init.h"
  24 #include "irq_kern.h"
  25 #include "irq_user.h"
  26 #include "kern_util.h"
  27 #include "mconsole.h"
  28 #include "mconsole_kern.h"
  29 #include "os.h"
  30
  31 static int do_unlink_socket(struct notifier_block *notifier,
  32                             unsigned long what, void *data)
  33 {
  34         return mconsole_unlink_socket();
  35 }
  36
  37
  38 static struct notifier_block reboot_notifier = {
  39         .notifier_call          = do_unlink_socket,
  40         .priority               = 0,
  41 };
  42
  43 /* Safe without explicit locking for now.  Tasklets provide their own
  44  * locking, and the interrupt handler is safe because it can't interrupt
  45  * itself and it can only happen on CPU 0.
  46  */
  47
  48 static LIST_HEAD(mc_requests);
  49
  50 static void mc_work_proc(struct work_struct *unused)
  51 {
  52         struct mconsole_entry *req;
  53         unsigned long flags;
  54
  55         while (!list_empty(&mc_requests)) {
  56                 local_irq_save(flags);
  57                 req = list_entry(mc_requests.next, struct mconsole_entry, list);
  58                 list_del(&req->list);
  59                 local_irq_restore(flags);
  60                 req->request.cmd->handler(&req->request);
  61                 kfree(req);
  62         }
  63 }
  64
  65 static DECLARE_WORK(mconsole_work, mc_work_proc);
  66
  67 static irqreturn_t mconsole_interrupt(int irq, void *dev_id)
  68 {
  69         /* long to avoid size mismatch warnings from gcc */
  70         long fd;
  71         struct mconsole_entry *new;
  72         static struct mc_request req;   /* that's OK */
  73
  74         fd = (long) dev_id;
  75         while (mconsole_get_request(fd, &req)) {
  76                 if (req.cmd->context == MCONSOLE_INTR)
  77                         (*req.cmd->handler)(&req);
  78                 else {
  79                         new = kmalloc(sizeof(*new), GFP_NOWAIT);
  80                         if (new == NULL)
  81                                 mconsole_reply(&req, "Out of memory", 1, 0);
  82                         else {
  83                                 new->request = req;
  84                                 new->request.regs = get_irq_regs()->regs;
  85                                 list_add(&new->list, &mc_requests);
  86                         }
  87                 }
  88         }
  89         if (!list_empty(&mc_requests))
  90                 schedule_work(&mconsole_work);
  91         reactivate_fd(fd, MCONSOLE_IRQ);
  92         return IRQ_HANDLED;
  93 }
  94
  95 void mconsole_version(struct mc_request *req)
  96 {
  97         char version[256];
  98
  99         sprintf(version, "%s %s %s %s %s", utsname()->sysname,
 100                 utsname()->nodename, utsname()->release, utsname()->version,
 101                 utsname()->machine);
 102         mconsole_reply(req, version, 0, 0);
 103 }
 104
 105 void mconsole_log(struct mc_request *req)
 106 {
 107         int len;
 108         char *ptr = req->request.data;
 109
 110         ptr += strlen("log ");
 111
 112         len = req->len - (ptr - req->request.data);
 113         printk(KERN_WARNING "%.*s", len, ptr);
 114         mconsole_reply(req, "", 0, 0);
 115 }
 116
 117 /* This is a more convoluted version of mconsole_proc, which has some stability
 118  * problems; however, we need it fixed, because it is expected that UML users
 119  * mount HPPFS instead of procfs on /proc. And we want mconsole_proc to still
 120  * show the real procfs content, not the ones from hppfs.*/
 121 #if 0
 122 void mconsole_proc(struct mc_request *req)
 123 {
 124         struct nameidata nd;
 125         struct file_system_type *proc;
 126         struct super_block *super;
 127         struct file *file;
 128         int n, err;
 129         char *ptr = req->request.data, *buf;
 130
 131         ptr += strlen("proc");
 132         while (isspace(*ptr)) ptr++;
 133
 134         proc = get_fs_type("proc");
 135         if (proc == NULL) {
 136                 mconsole_reply(req, "procfs not registered", 1, 0);
 137                 goto out;
 138         }
 139
 140         super = (*proc->get_sb)(proc, 0, NULL, NULL);
 141         put_filesystem(proc);
 142         if (super == NULL) {
 143                 mconsole_reply(req, "Failed to get procfs superblock", 1, 0);
 144                 goto out;
 145         }
 146         up_write(&super->s_umount);
 147
 148         nd.path.dentry = super->s_root;
 149         nd.path.mnt = NULL;
 150         nd.flags = O_RDONLY + 1;
 151         nd.last_type = LAST_ROOT;
 152
 153         /* START: it was experienced that the stability problems are closed
 154          * if commenting out these two calls + the below read cycle. To
 155          * make UML crash again, it was enough to readd either one.*/
 156         err = link_path_walk(ptr, &nd);
 157         if (err) {
 158                 mconsole_reply(req, "Failed to look up file", 1, 0);
 159                 goto out_kill;
 160         }
 161
 162         file = dentry_open(nd.path.dentry, nd.path.mnt, O_RDONLY);
 163         if (IS_ERR(file)) {
 164                 mconsole_reply(req, "Failed to open file", 1, 0);
 165                 goto out_kill;
 166         }
 167         /*END*/
 168
 169         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
 170         if (buf == NULL) {
 171                 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
 172                 goto out_fput;
 173         }
 174
 175         if ((file->f_op != NULL) && (file->f_op->read != NULL)) {
 176                 do {
 177                         n = (*file->f_op->read)(file, buf, PAGE_SIZE - 1,
 178                                                 &file->f_pos);
 179                         if (n >= 0) {
 180                                 buf[n] = '\0';
 181                                 mconsole_reply(req, buf, 0, (n > 0));
 182                         }
 183                         else {
 184                                 mconsole_reply(req, "Read of file failed",
 185                                                1, 0);
 186                                 goto out_free;
 187                         }
 188                 } while (n > 0);
 189         }
 190         else mconsole_reply(req, "", 0, 0);
 191
 192  out_free:
 193         kfree(buf);
 194  out_fput:
 195         fput(file);
 196  out_kill:
 197         deactivate_super(super);
 198  out: ;
 199 }
 200 #endif
 201
 202 void mconsole_proc(struct mc_request *req)
 203 {
 204         char path[64];
 205         char *buf;
 206         int len;
 207         int fd;
 208         int first_chunk = 1;
 209         char *ptr = req->request.data;
 210
 211         ptr += strlen("proc");
 212         while (isspace(*ptr))
 213                 ptr++;
 214         snprintf(path, sizeof(path), "/proc/%s", ptr);
 215
 216         fd = sys_open(path, 0, 0);
 217         if (fd < 0) {
 218                 mconsole_reply(req, "Failed to open file", 1, 0);
 219                 printk(KERN_ERR "open %s: %d\n",path,fd);
 220                 goto out;
 221         }
 222
 223         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
 224         if (buf == NULL) {
 225                 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
 226                 goto out_close;
 227         }
 228
 229         for (;;) {
 230                 len = sys_read(fd, buf, PAGE_SIZE-1);
 231                 if (len < 0) {
 232                         mconsole_reply(req, "Read of file failed", 1, 0);
 233                         goto out_free;
 234                 }
 235                 /* Begin the file content on his own line. */
 236                 if (first_chunk) {
 237                         mconsole_reply(req, "\n", 0, 1);
 238                         first_chunk = 0;
 239                 }
 240                 if (len == PAGE_SIZE-1) {
 241                         buf[len] = '\0';
 242                         mconsole_reply(req, buf, 0, 1);
 243                 } else {
 244                         buf[len] = '\0';
 245                         mconsole_reply(req, buf, 0, 0);
 246                         break;
 247                 }
 248         }
 249
 250  out_free:
 251         kfree(buf);
 252  out_close:
 253         sys_close(fd);
 254  out:
 255         /* nothing */;
 256 }
 257
 258 #define UML_MCONSOLE_HELPTEXT \
 259 "Commands: \n\
 260     version - Get kernel version \n\
 261     help - Print this message \n\
 262     halt - Halt UML \n\
 263     reboot - Reboot UML \n\
 264     config <dev>=<config> - Add a new device to UML;  \n\
 265         same syntax as command line \n\
 266     config <dev> - Query the configuration of a device \n\
 267     remove <dev> - Remove a device from UML \n\
 268     sysrq <letter> - Performs the SysRq action controlled by the letter \n\
 269     cad - invoke the Ctrl-Alt-Del handler \n\
 270     stop - pause the UML; it will do nothing until it receives a 'go' \n\
 271     go - continue the UML after a 'stop' \n\
 272     log <string> - make UML enter <string> into the kernel log\n\
 273     proc <file> - returns the contents of the UML's /proc/<file>\n\
 274     stack <pid> - returns the stack of the specified pid\n\
 275 "
 276
 277 void mconsole_help(struct mc_request *req)
 278 {
 279         mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0);
 280 }
 281
 282 void mconsole_halt(struct mc_request *req)
 283 {
 284         mconsole_reply(req, "", 0, 0);
 285         machine_halt();
 286 }
 287
 288 void mconsole_reboot(struct mc_request *req)
 289 {
 290         mconsole_reply(req, "", 0, 0);
 291         machine_restart(NULL);
 292 }
 293
 294 void mconsole_cad(struct mc_request *req)
 295 {
 296         mconsole_reply(req, "", 0, 0);
 297         ctrl_alt_del();
 298 }
 299
 300 void mconsole_go(struct mc_request *req)
 301 {
 302         mconsole_reply(req, "Not stopped", 1, 0);
 303 }
 304
 305 void mconsole_stop(struct mc_request *req)
 306 {
 307         deactivate_fd(req->originating_fd, MCONSOLE_IRQ);
 308         os_set_fd_block(req->originating_fd, 1);
 309         mconsole_reply(req, "stopped", 0, 0);
 310         for (;;) {
 311                 if (!mconsole_get_request(req->originating_fd, req))
 312                         continue;
 313                 if (req->cmd->handler == mconsole_go)
 314                         break;
 315                 if (req->cmd->handler == mconsole_stop) {
 316                         mconsole_reply(req, "Already stopped", 1, 0);
 317                         continue;
 318                 }
 319                 if (req->cmd->handler == mconsole_sysrq) {
 320                         struct pt_regs *old_regs;
 321                         old_regs = set_irq_regs((struct pt_regs *)&req->regs);
 322                         mconsole_sysrq(req);
 323                         set_irq_regs(old_regs);
 324                         continue;
 325                 }
 326                 (*req->cmd->handler)(req);
 327         }
 328         os_set_fd_block(req->originating_fd, 0);
 329         reactivate_fd(req->originating_fd, MCONSOLE_IRQ);
 330         mconsole_reply(req, "", 0, 0);
 331 }
 332
 333 static DEFINE_SPINLOCK(mc_devices_lock);
 334 static LIST_HEAD(mconsole_devices);
 335
 336 void mconsole_register_dev(struct mc_device *new)
 337 {
 338         spin_lock(&mc_devices_lock);
 339         BUG_ON(!list_empty(&new->list));
 340         list_add(&new->list, &mconsole_devices);
 341         spin_unlock(&mc_devices_lock);
 342 }
 343
 344 static struct mc_device *mconsole_find_dev(char *name)
 345 {
 346         struct list_head *ele;
 347         struct mc_device *dev;
 348
 349         list_for_each(ele, &mconsole_devices) {
 350                 dev = list_entry(ele, struct mc_device, list);
 351                 if (!strncmp(name, dev->name, strlen(dev->name)))
 352                         return dev;
 353         }
 354         return NULL;
 355 }
 356
 357 #define UNPLUGGED_PER_PAGE \
 358         ((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long))
 359
 360 struct unplugged_pages {
 361         struct list_head list;
 362         void *pages[UNPLUGGED_PER_PAGE];
 363 };
 364
 365 static DEFINE_MUTEX(plug_mem_mutex);
 366 static unsigned long long unplugged_pages_count = 0;
 367 static LIST_HEAD(unplugged_pages);
 368 static int unplug_index = UNPLUGGED_PER_PAGE;
 369
 370 static int mem_config(char *str, char **error_out)
 371 {
 372         unsigned long long diff;
 373         int err = -EINVAL, i, add;
 374         char *ret;
 375
 376         if (str[0] != '=') {
 377                 *error_out = "Expected '=' after 'mem'";
 378                 goto out;
 379         }
 380
 381         str++;
 382         if (str[0] == '-')
 383                 add = 0;
 384         else if (str[0] == '+') {
 385                 add = 1;
 386         }
 387         else {
 388                 *error_out = "Expected increment to start with '-' or '+'";
 389                 goto out;
 390         }
 391
 392         str++;
 393         diff = memparse(str, &ret);
 394         if (*ret != '\0') {
 395                 *error_out = "Failed to parse memory increment";
 396                 goto out;
 397         }
 398
 399         diff /= PAGE_SIZE;
 400
 401         mutex_lock(&plug_mem_mutex);
 402         for (i = 0; i < diff; i++) {
 403                 struct unplugged_pages *unplugged;
 404                 void *addr;
 405
 406                 if (add) {
 407                         if (list_empty(&unplugged_pages))
 408                                 break;
 409
 410                         unplugged = list_entry(unplugged_pages.next,
 411                                                struct unplugged_pages, list);
 412                         if (unplug_index > 0)
 413                                 addr = unplugged->pages[--unplug_index];
 414                         else {
 415                                 list_del(&unplugged->list);
 416                                 addr = unplugged;
 417                                 unplug_index = UNPLUGGED_PER_PAGE;
 418                         }
 419
 420                         free_page((unsigned long) addr);
 421                         unplugged_pages_count--;
 422                 }
 423                 else {
 424                         struct page *page;
 425
 426                         page = alloc_page(GFP_ATOMIC);
 427                         if (page == NULL)
 428                                 break;
 429
 430                         unplugged = page_address(page);
 431                         if (unplug_index == UNPLUGGED_PER_PAGE) {
 432                                 list_add(&unplugged->list, &unplugged_pages);
 433                                 unplug_index = 0;
 434                         }
 435                         else {
 436                                 struct list_head *entry = unplugged_pages.next;
 437                                 addr = unplugged;
 438
 439                                 unplugged = list_entry(entry,
 440                                                        struct unplugged_pages,
 441                                                        list);
 442                                 err = os_drop_memory(addr, PAGE_SIZE);
 443                                 if (err) {
 444                                         printk(KERN_ERR "Failed to release "
 445                                                "memory - errno = %d\n", err);
 446                                         *error_out = "Failed to release memory";
 447                                         goto out_unlock;
 448                                 }
 449                                 unplugged->pages[unplug_index++] = addr;
 450                         }
 451
 452                         unplugged_pages_count++;
 453                 }
 454         }
 455
 456         err = 0;
 457 out_unlock:
 458         mutex_unlock(&plug_mem_mutex);
 459 out:
 460         return err;
 461 }
 462
 463 static int mem_get_config(char *name, char *str, int size, char **error_out)
 464 {
 465         char buf[sizeof("18446744073709551615")];
 466         int len = 0;
 467
 468         sprintf(buf, "%ld", uml_physmem);
 469         CONFIG_CHUNK(str, size, len, buf, 1);
 470
 471         return len;
 472 }
 473
 474 static int mem_id(char **str, int *start_out, int *end_out)
 475 {
 476         *start_out = 0;
 477         *end_out = 0;
 478
 479         return 0;
 480 }
 481
 482 static int mem_remove(int n, char **error_out)
 483 {
 484         *error_out = "Memory doesn't support the remove operation";
 485         return -EBUSY;
 486 }
 487
 488 static struct mc_device mem_mc = {
 489         .list           = LIST_HEAD_INIT(mem_mc.list),
 490         .name           = "mem",
 491         .config         = mem_config,
 492         .get_config     = mem_get_config,
 493         .id             = mem_id,
 494         .remove         = mem_remove,
 495 };
 496
 497 static int __init mem_mc_init(void)
 498 {
 499         if (can_drop_memory())
 500                 mconsole_register_dev(&mem_mc);
 501         else printk(KERN_ERR "Can't release memory to the host - memory "
 502                     "hotplug won't be supported\n");
 503         return 0;
 504 }
 505
 506 __initcall(mem_mc_init);
 507
 508 #define CONFIG_BUF_SIZE 64
 509
 510 static void mconsole_get_config(int (*get_config)(char *, char *, int,
 511                                                   char **),
 512                                 struct mc_request *req, char *name)
 513 {
 514         char default_buf[CONFIG_BUF_SIZE], *error, *buf;
 515         int n, size;
 516
 517         if (get_config == NULL) {
 518                 mconsole_reply(req, "No get_config routine defined", 1, 0);
 519                 return;
 520         }
 521
 522         error = NULL;
 523         size = ARRAY_SIZE(default_buf);
 524         buf = default_buf;
 525
 526         while (1) {
 527                 n = (*get_config)(name, buf, size, &error);
 528                 if (error != NULL) {
 529                         mconsole_reply(req, error, 1, 0);
 530                         goto out;
 531                 }
 532
 533                 if (n <= size) {
 534                         mconsole_reply(req, buf, 0, 0);
 535                         goto out;
 536                 }
 537
 538                 if (buf != default_buf)
 539                         kfree(buf);
 540
 541                 size = n;
 542                 buf = kmalloc(size, GFP_KERNEL);
 543                 if (buf == NULL) {
 544                         mconsole_reply(req, "Failed to allocate buffer", 1, 0);
 545                         return;
 546                 }
 547         }
 548  out:
 549         if (buf != default_buf)
 550                 kfree(buf);
 551 }
 552
 553 void mconsole_config(struct mc_request *req)
 554 {
 555         struct mc_device *dev;
 556         char *ptr = req->request.data, *name, *error_string = "";
 557         int err;
 558
 559         ptr += strlen("config");
 560         while (isspace(*ptr))
 561                 ptr++;
 562         dev = mconsole_find_dev(ptr);
 563         if (dev == NULL) {
 564                 mconsole_reply(req, "Bad configuration option", 1, 0);
 565                 return;
 566         }
 567
 568         name = &ptr[strlen(dev->name)];
 569         ptr = name;
 570         while ((*ptr != '=') && (*ptr != '\0'))
 571                 ptr++;
 572
 573         if (*ptr == '=') {
 574                 err = (*dev->config)(name, &error_string);
 575                 mconsole_reply(req, error_string, err, 0);
 576         }
 577         else mconsole_get_config(dev->get_config, req, name);
 578 }
 579
 580 void mconsole_remove(struct mc_request *req)
 581 {
 582         struct mc_device *dev;
 583         char *ptr = req->request.data, *err_msg = "";
 584         char error[256];
 585         int err, start, end, n;
 586
 587         ptr += strlen("remove");
 588         while (isspace(*ptr)) ptr++;
 589         dev = mconsole_find_dev(ptr);
 590         if (dev == NULL) {
 591                 mconsole_reply(req, "Bad remove option", 1, 0);
 592                 return;
 593         }
 594
 595         ptr = &ptr[strlen(dev->name)];
 596
 597         err = 1;
 598         n = (*dev->id)(&ptr, &start, &end);
 599         if (n < 0) {
 600                 err_msg = "Couldn't parse device number";
 601                 goto out;
 602         }
 603         else if ((n < start) || (n > end)) {
 604                 sprintf(error, "Invalid device number - must be between "
 605                         "%d and %d", start, end);
 606                 err_msg = error;
 607                 goto out;
 608         }
 609
 610         err_msg = NULL;
 611         err = (*dev->remove)(n, &err_msg);
 612         switch(err) {
 613         case 0:
 614                 err_msg = "";
 615                 break;
 616         case -ENODEV:
 617                 if (err_msg == NULL)
 618                         err_msg = "Device doesn't exist";
 619                 break;
 620         case -EBUSY:
 621                 if (err_msg == NULL)
 622                         err_msg = "Device is currently open";
 623                 break;
 624         default:
 625                 break;
 626         }
 627 out:
 628         mconsole_reply(req, err_msg, err, 0);
 629 }
 630
 631 struct mconsole_output {
 632         struct list_head list;
 633         struct mc_request *req;
 634 };
 635
 636 static DEFINE_SPINLOCK(client_lock);
 637 static LIST_HEAD(clients);
 638 static char console_buf[MCONSOLE_MAX_DATA];
 639
 640 static void console_write(struct console *console, const char *string,
 641                           unsigned int len)
 642 {
 643         struct list_head *ele;
 644         int n;
 645
 646         if (list_empty(&clients))
 647                 return;
 648
 649         while (len > 0) {
 650                 n = min((size_t) len, ARRAY_SIZE(console_buf));
 651                 strncpy(console_buf, string, n);
 652                 string += n;
 653                 len -= n;
 654
 655                 list_for_each(ele, &clients) {
 656                         struct mconsole_output *entry;
 657
 658                         entry = list_entry(ele, struct mconsole_output, list);
 659                         mconsole_reply_len(entry->req, console_buf, n, 0, 1);
 660                 }
 661         }
 662 }
 663
 664 static struct console mc_console = { .name      = "mc",
 665                                      .write     = console_write,
 666                                      .flags     = CON_ENABLED,
 667                                      .index     = -1 };
 668
 669 static int mc_add_console(void)
 670 {
 671         register_console(&mc_console);
 672         return 0;
 673 }
 674
 675 late_initcall(mc_add_console);
 676
 677 static void with_console(struct mc_request *req, void (*proc)(void *),
 678                          void *arg)
 679 {
 680         struct mconsole_output entry;
 681         unsigned long flags;
 682
 683         entry.req = req;
 684         spin_lock_irqsave(&client_lock, flags);
 685         list_add(&entry.list, &clients);
 686         spin_unlock_irqrestore(&client_lock, flags);
 687
 688         (*proc)(arg);
 689
 690         mconsole_reply_len(req, "", 0, 0, 0);
 691
 692         spin_lock_irqsave(&client_lock, flags);
 693         list_del(&entry.list);
 694         spin_unlock_irqrestore(&client_lock, flags);
 695 }
 696
 697 #ifdef CONFIG_MAGIC_SYSRQ
 698
 699 #include <linux/sysrq.h>
 700
 701 static void sysrq_proc(void *arg)
 702 {
 703         char *op = arg;
 704         handle_sysrq(*op, NULL);
 705 }
 706
 707 void mconsole_sysrq(struct mc_request *req)
 708 {
 709         char *ptr = req->request.data;
 710
 711         ptr += strlen("sysrq");
 712         while (isspace(*ptr)) ptr++;
 713
 714         /*
 715          * With 'b', the system will shut down without a chance to reply,
 716          * so in this case, we reply first.
 717          */
 718         if (*ptr == 'b')
 719                 mconsole_reply(req, "", 0, 0);
 720
 721         with_console(req, sysrq_proc, ptr);
 722 }
 723 #else
 724 void mconsole_sysrq(struct mc_request *req)
 725 {
 726         mconsole_reply(req, "Sysrq not compiled in", 1, 0);
 727 }
 728 #endif
 729
 730 static void stack_proc(void *arg)
 731 {
 732         struct task_struct *from = current, *to = arg;
 733
 734         to->thread.saved_task = from;
 735         switch_to(from, to, from);
 736 }
 737
 738 /*
 739  * Mconsole stack trace
 740  *  Added by Allan Graves, Jeff Dike
 741  *  Dumps a stacks registers to the linux console.
 742  *  Usage stack <pid>.
 743  */
 744 void mconsole_stack(struct mc_request *req)
 745 {
 746         char *ptr = req->request.data;
 747         int pid_requested= -1;
 748         struct task_struct *to = NULL;
 749
 750         /*
 751          * Would be nice:
 752          * 1) Send showregs output to mconsole.
 753          * 2) Add a way to stack dump all pids.
 754          */
 755
 756         ptr += strlen("stack");
 757         while (isspace(*ptr))
 758                 ptr++;
 759
 760         /*
 761          * Should really check for multiple pids or reject bad args here
 762          */
 763         /* What do the arguments in mconsole_reply mean? */
 764         if (sscanf(ptr, "%d", &pid_requested) == 0) {
 765                 mconsole_reply(req, "Please specify a pid", 1, 0);
 766                 return;
 767         }
 768
 769         to = find_task_by_pid_ns(pid_requested, &init_pid_ns);
 770         if ((to == NULL) || (pid_requested == 0)) {
 771                 mconsole_reply(req, "Couldn't find that pid", 1, 0);
 772                 return;
 773         }
 774         with_console(req, stack_proc, to);
 775 }
 776
 777 /*
 778  * Changed by mconsole_setup, which is __setup, and called before SMP is
 779  * active.
 780  */
 781 static char *notify_socket = NULL;
 782
 783 static int __init mconsole_init(void)
 784 {
 785         /* long to avoid size mismatch warnings from gcc */
 786         long sock;
 787         int err;
 788         char file[256];
 789
 790         if (umid_file_name("mconsole", file, sizeof(file)))
 791                 return -1;
 792         snprintf(mconsole_socket_name, sizeof(file), "%s", file);
 793
 794         sock = os_create_unix_socket(file, sizeof(file), 1);
 795         if (sock < 0) {
 796                 printk(KERN_ERR "Failed to initialize management console\n");
 797                 return 1;
 798         }
 799         if (os_set_fd_block(sock, 0))
 800                 goto out;
 801
 802         register_reboot_notifier(&reboot_notifier);
 803
 804         err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
 805                              IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
 806                              "mconsole", (void *)sock);
 807         if (err) {
 808                 printk(KERN_ERR "Failed to get IRQ for management console\n");
 809                 goto out;
 810         }
 811
 812         if (notify_socket != NULL) {
 813                 notify_socket = kstrdup(notify_socket, GFP_KERNEL);
 814                 if (notify_socket != NULL)
 815                         mconsole_notify(notify_socket, MCONSOLE_SOCKET,
 816                                         mconsole_socket_name,
 817                                         strlen(mconsole_socket_name) + 1);
 818                 else printk(KERN_ERR "mconsole_setup failed to strdup "
 819                             "string\n");
 820         }
 821
 822         printk(KERN_INFO "mconsole (version %d) initialized on %s\n",
 823                MCONSOLE_VERSION, mconsole_socket_name);
 824         return 0;
 825
 826  out:
 827         os_close_file(sock);
 828         return 1;
 829 }
 830
 831 __initcall(mconsole_init);
 832
 833 static int write_proc_mconsole(struct file *file, const char __user *buffer,
 834                                unsigned long count, void *data)
 835 {
 836         char *buf;
 837
 838         buf = kmalloc(count + 1, GFP_KERNEL);
 839         if (buf == NULL)
 840                 return -ENOMEM;
 841
 842         if (copy_from_user(buf, buffer, count)) {
 843                 count = -EFAULT;
 844                 goto out;
 845         }
 846
 847         buf[count] = '\0';
 848
 849         mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count);
 850  out:
 851         kfree(buf);
 852         return count;
 853 }
 854
 855 static int create_proc_mconsole(void)
 856 {
 857         struct proc_dir_entry *ent;
 858
 859         if (notify_socket == NULL)
 860                 return 0;
 861
 862         ent = create_proc_entry("mconsole", S_IFREG | 0200, NULL);
 863         if (ent == NULL) {
 864                 printk(KERN_INFO "create_proc_mconsole : create_proc_entry "
 865                        "failed\n");
 866                 return 0;
 867         }
 868
 869         ent->read_proc = NULL;
 870         ent->write_proc = write_proc_mconsole;
 871         return 0;
 872 }
 873
 874 static DEFINE_SPINLOCK(notify_spinlock);
 875
 876 void lock_notify(void)
 877 {
 878         spin_lock(&notify_spinlock);
 879 }
 880
 881 void unlock_notify(void)
 882 {
 883         spin_unlock(&notify_spinlock);
 884 }
 885
 886 __initcall(create_proc_mconsole);
 887
 888 #define NOTIFY "notify:"
 889
 890 static int mconsole_setup(char *str)
 891 {
 892         if (!strncmp(str, NOTIFY, strlen(NOTIFY))) {
 893                 str += strlen(NOTIFY);
 894                 notify_socket = str;
 895         }
 896         else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str);
 897         return 1;
 898 }
 899
 900 __setup("mconsole=", mconsole_setup);
 901
 902 __uml_help(mconsole_setup,
 903 "mconsole=notify:<socket>\n"
 904 "    Requests that the mconsole driver send a message to the named Unix\n"
 905 "    socket containing the name of the mconsole socket.  This also serves\n"
 906 "    to notify outside processes when UML has booted far enough to respond\n"
 907 "    to mconsole requests.\n\n"
 908 );
 909
 910 static int notify_panic(struct notifier_block *self, unsigned long unused1,
 911                         void *ptr)
 912 {
 913         char *message = ptr;
 914
 915         if (notify_socket == NULL)
 916                 return 0;
 917
 918         mconsole_notify(notify_socket, MCONSOLE_PANIC, message,
 919                         strlen(message) + 1);
 920         return 0;
 921 }
 922
 923 static struct notifier_block panic_exit_notifier = {
 924         .notifier_call          = notify_panic,
 925         .next                   = NULL,
 926         .priority               = 1
 927 };
 928
 929 static int add_notifier(void)
 930 {
 931         atomic_notifier_chain_register(&panic_notifier_list,
 932                         &panic_exit_notifier);
 933         return 0;
 934 }
 935
 936 __initcall(add_notifier);
 937
 938 char *mconsole_notify_socket(void)
 939 {
 940         return notify_socket;
 941 }
 942
 943 EXPORT_SYMBOL(mconsole_notify_socket);