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