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