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