arch/um/drivers/mconsole_kern.c

   1 /*
   2  * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org)
   3  * Copyright (C) 2001 - 2003 Jeff Dike (jdike@addtoit.com)
   4  * Licensed under the GPL
   5  */
   6
   7 #include "linux/kernel.h"
   8 #include "linux/slab.h"
   9 #include "linux/init.h"
  10 #include "linux/notifier.h"
  11 #include "linux/reboot.h"
  12 #include "linux/utsname.h"
  13 #include "linux/ctype.h"
  14 #include "linux/interrupt.h"
  15 #include "linux/sysrq.h"
  16 #include "linux/workqueue.h"
  17 #include "linux/module.h"
  18 #include "linux/file.h"
  19 #include "linux/fs.h"
  20 #include "linux/namei.h"
  21 #include "linux/proc_fs.h"
  22 #include "linux/syscalls.h"
  23 #include "asm/irq.h"
  24 #include "asm/uaccess.h"
  25 #include "user_util.h"
  26 #include "kern_util.h"
  27 #include "kern.h"
  28 #include "mconsole.h"
  29 #include "mconsole_kern.h"
  30 #include "irq_user.h"
  31 #include "init.h"
  32 #include "os.h"
  33 #include "umid.h"
  34 #include "irq_kern.h"
  35 #include "choose-mode.h"
  36
  37 static int do_unlink_socket(struct notifier_block *notifier,
  38                             unsigned long what, void *data)
  39 {
  40         return(mconsole_unlink_socket());
  41 }
  42
  43
  44 static struct notifier_block reboot_notifier = {
  45         .notifier_call          = do_unlink_socket,
  46         .priority               = 0,
  47 };
  48
  49 /* Safe without explicit locking for now.  Tasklets provide their own
  50  * locking, and the interrupt handler is safe because it can't interrupt
  51  * itself and it can only happen on CPU 0.
  52  */
  53
  54 LIST_HEAD(mc_requests);
  55
  56 static void mc_work_proc(void *unused)
  57 {
  58         struct mconsole_entry *req;
  59         unsigned long flags;
  60
  61         while(!list_empty(&mc_requests)){
  62                 local_save_flags(flags);
  63                 req = list_entry(mc_requests.next, struct mconsole_entry,
  64                                  list);
  65                 list_del(&req->list);
  66                 local_irq_restore(flags);
  67                 req->request.cmd->handler(&req->request);
  68                 kfree(req);
  69         }
  70 }
  71
  72 DECLARE_WORK(mconsole_work, mc_work_proc, NULL);
  73
  74 static irqreturn_t mconsole_interrupt(int irq, void *dev_id,
  75                                       struct pt_regs *regs)
  76 {
  77         /* long to avoid size mismatch warnings from gcc */
  78         long fd;
  79         struct mconsole_entry *new;
  80         struct mc_request req;
  81
  82         fd = (long) dev_id;
  83         while (mconsole_get_request(fd, &req)){
  84                 if(req.cmd->context == MCONSOLE_INTR)
  85                         (*req.cmd->handler)(&req);
  86                 else {
  87                         new = kmalloc(sizeof(*new), GFP_ATOMIC);
  88                         if(new == NULL)
  89                                 mconsole_reply(&req, "Out of memory", 1, 0);
  90                         else {
  91                                 new->request = req;
  92                                 list_add(&new->list, &mc_requests);
  93                         }
  94                 }
  95         }
  96         if(!list_empty(&mc_requests))
  97                 schedule_work(&mconsole_work);
  98         reactivate_fd(fd, MCONSOLE_IRQ);
  99         return(IRQ_HANDLED);
 100 }
 101
 102 void mconsole_version(struct mc_request *req)
 103 {
 104         char version[256];
 105
 106         sprintf(version, "%s %s %s %s %s", system_utsname.sysname,
 107                 system_utsname.nodename, system_utsname.release,
 108                 system_utsname.version, system_utsname.machine);
 109         mconsole_reply(req, version, 0, 0);
 110 }
 111
 112 void mconsole_log(struct mc_request *req)
 113 {
 114         int len;
 115         char *ptr = req->request.data;
 116
 117         ptr += strlen("log ");
 118
 119         len = req->len - (ptr - req->request.data);
 120         printk("%.*s", len, ptr);
 121         mconsole_reply(req, "", 0, 0);
 122 }
 123
 124 /* This is a more convoluted version of mconsole_proc, which has some stability
 125  * problems; however, we need it fixed, because it is expected that UML users
 126  * mount HPPFS instead of procfs on /proc. And we want mconsole_proc to still
 127  * show the real procfs content, not the ones from hppfs.*/
 128 #if 0
 129 void mconsole_proc(struct mc_request *req)
 130 {
 131         struct nameidata nd;
 132         struct file_system_type *proc;
 133         struct super_block *super;
 134         struct file *file;
 135         int n, err;
 136         char *ptr = req->request.data, *buf;
 137
 138         ptr += strlen("proc");
 139         while(isspace(*ptr)) ptr++;
 140
 141         proc = get_fs_type("proc");
 142         if(proc == NULL){
 143                 mconsole_reply(req, "procfs not registered", 1, 0);
 144                 goto out;
 145         }
 146
 147         super = (*proc->get_sb)(proc, 0, NULL, NULL);
 148         put_filesystem(proc);
 149         if(super == NULL){
 150                 mconsole_reply(req, "Failed to get procfs superblock", 1, 0);
 151                 goto out;
 152         }
 153         up_write(&super->s_umount);
 154
 155         nd.dentry = super->s_root;
 156         nd.mnt = NULL;
 157         nd.flags = O_RDONLY + 1;
 158         nd.last_type = LAST_ROOT;
 159
 160         /* START: it was experienced that the stability problems are closed
 161          * if commenting out these two calls + the below read cycle. To
 162          * make UML crash again, it was enough to readd either one.*/
 163         err = link_path_walk(ptr, &nd);
 164         if(err){
 165                 mconsole_reply(req, "Failed to look up file", 1, 0);
 166                 goto out_kill;
 167         }
 168
 169         file = dentry_open(nd.dentry, nd.mnt, O_RDONLY);
 170         if(IS_ERR(file)){
 171                 mconsole_reply(req, "Failed to open file", 1, 0);
 172                 goto out_kill;
 173         }
 174         /*END*/
 175
 176         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
 177         if(buf == NULL){
 178                 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
 179                 goto out_fput;
 180         }
 181
 182         if((file->f_op != NULL) && (file->f_op->read != NULL)){
 183                 do {
 184                         n = (*file->f_op->read)(file, buf, PAGE_SIZE - 1,
 185                                                 &file->f_pos);
 186                         if(n >= 0){
 187                                 buf[n] = '\0';
 188                                 mconsole_reply(req, buf, 0, (n > 0));
 189                         }
 190                         else {
 191                                 mconsole_reply(req, "Read of file failed",
 192                                                1, 0);
 193                                 goto out_free;
 194                         }
 195                 } while(n > 0);
 196         }
 197         else mconsole_reply(req, "", 0, 0);
 198
 199  out_free:
 200         kfree(buf);
 201  out_fput:
 202         fput(file);
 203  out_kill:
 204         deactivate_super(super);
 205  out: ;
 206 }
 207 #endif
 208
 209 void mconsole_proc(struct mc_request *req)
 210 {
 211         char path[64];
 212         char *buf;
 213         int len;
 214         int fd;
 215         int first_chunk = 1;
 216         char *ptr = req->request.data;
 217
 218         ptr += strlen("proc");
 219         while(isspace(*ptr)) ptr++;
 220         snprintf(path, sizeof(path), "/proc/%s", ptr);
 221
 222         fd = sys_open(path, 0, 0);
 223         if (fd < 0) {
 224                 mconsole_reply(req, "Failed to open file", 1, 0);
 225                 printk("open %s: %d\n",path,fd);
 226                 goto out;
 227         }
 228
 229         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
 230         if(buf == NULL){
 231                 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
 232                 goto out_close;
 233         }
 234
 235         for (;;) {
 236                 len = sys_read(fd, buf, PAGE_SIZE-1);
 237                 if (len < 0) {
 238                         mconsole_reply(req, "Read of file failed", 1, 0);
 239                         goto out_free;
 240                 }
 241                 /*Begin the file content on his own line.*/
 242                 if (first_chunk) {
 243                         mconsole_reply(req, "\n", 0, 1);
 244                         first_chunk = 0;
 245                 }
 246                 if (len == PAGE_SIZE-1) {
 247                         buf[len] = '\0';
 248                         mconsole_reply(req, buf, 0, 1);
 249                 } else {
 250                         buf[len] = '\0';
 251                         mconsole_reply(req, buf, 0, 0);
 252                         break;
 253                 }
 254         }
 255
 256  out_free:
 257         kfree(buf);
 258  out_close:
 259         sys_close(fd);
 260  out:
 261         /* nothing */;
 262 }
 263
 264 #define UML_MCONSOLE_HELPTEXT \
 265 "Commands: \n\
 266     version - Get kernel version \n\
 267     help - Print this message \n\
 268     halt - Halt UML \n\
 269     reboot - Reboot UML \n\
 270     config <dev>=<config> - Add a new device to UML;  \n\
 271         same syntax as command line \n\
 272     config <dev> - Query the configuration of a device \n\
 273     remove <dev> - Remove a device from UML \n\
 274     sysrq <letter> - Performs the SysRq action controlled by the letter \n\
 275     cad - invoke the Ctl-Alt-Del handler \n\
 276     stop - pause the UML; it will do nothing until it receives a 'go' \n\
 277     go - continue the UML after a 'stop' \n\
 278     log <string> - make UML enter <string> into the kernel log\n\
 279     proc <file> - returns the contents of the UML's /proc/<file>\n\
 280     stack <pid> - returns the stack of the specified pid\n\
 281 "
 282
 283 void mconsole_help(struct mc_request *req)
 284 {
 285         mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0);
 286 }
 287
 288 void mconsole_halt(struct mc_request *req)
 289 {
 290         mconsole_reply(req, "", 0, 0);
 291         machine_halt();
 292 }
 293
 294 void mconsole_reboot(struct mc_request *req)
 295 {
 296         mconsole_reply(req, "", 0, 0);
 297         machine_restart(NULL);
 298 }
 299
 300 extern void ctrl_alt_del(void);
 301
 302 void mconsole_cad(struct mc_request *req)
 303 {
 304         mconsole_reply(req, "", 0, 0);
 305         ctrl_alt_del();
 306 }
 307
 308 void mconsole_go(struct mc_request *req)
 309 {
 310         mconsole_reply(req, "Not stopped", 1, 0);
 311 }
 312
 313 void mconsole_stop(struct mc_request *req)
 314 {
 315         deactivate_fd(req->originating_fd, MCONSOLE_IRQ);
 316         os_set_fd_block(req->originating_fd, 1);
 317         mconsole_reply(req, "", 0, 0);
 318         while(mconsole_get_request(req->originating_fd, req)){
 319                 if(req->cmd->handler == mconsole_go) break;
 320                 (*req->cmd->handler)(req);
 321         }
 322         os_set_fd_block(req->originating_fd, 0);
 323         reactivate_fd(req->originating_fd, MCONSOLE_IRQ);
 324         mconsole_reply(req, "", 0, 0);
 325 }
 326
 327 /* This list is populated by __initcall routines. */
 328
 329 LIST_HEAD(mconsole_devices);
 330
 331 void mconsole_register_dev(struct mc_device *new)
 332 {
 333         list_add(&new->list, &mconsole_devices);
 334 }
 335
 336 static struct mc_device *mconsole_find_dev(char *name)
 337 {
 338         struct list_head *ele;
 339         struct mc_device *dev;
 340
 341         list_for_each(ele, &mconsole_devices){
 342                 dev = list_entry(ele, struct mc_device, list);
 343                 if(!strncmp(name, dev->name, strlen(dev->name)))
 344                         return(dev);
 345         }
 346         return(NULL);
 347 }
 348
 349 #define CONFIG_BUF_SIZE 64
 350
 351 static void mconsole_get_config(int (*get_config)(char *, char *, int,
 352                                                   char **),
 353                                 struct mc_request *req, char *name)
 354 {
 355         char default_buf[CONFIG_BUF_SIZE], *error, *buf;
 356         int n, size;
 357
 358         if(get_config == NULL){
 359                 mconsole_reply(req, "No get_config routine defined", 1, 0);
 360                 return;
 361         }
 362
 363         error = NULL;
 364         size = sizeof(default_buf)/sizeof(default_buf[0]);
 365         buf = default_buf;
 366
 367         while(1){
 368                 n = (*get_config)(name, buf, size, &error);
 369                 if(error != NULL){
 370                         mconsole_reply(req, error, 1, 0);
 371                         goto out;
 372                 }
 373
 374                 if(n <= size){
 375                         mconsole_reply(req, buf, 0, 0);
 376                         goto out;
 377                 }
 378
 379                 if(buf != default_buf)
 380                         kfree(buf);
 381
 382                 size = n;
 383                 buf = kmalloc(size, GFP_KERNEL);
 384                 if(buf == NULL){
 385                         mconsole_reply(req, "Failed to allocate buffer", 1, 0);
 386                         return;
 387                 }
 388         }
 389  out:
 390         if(buf != default_buf)
 391                 kfree(buf);
 392
 393 }
 394
 395 void mconsole_config(struct mc_request *req)
 396 {
 397         struct mc_device *dev;
 398         char *ptr = req->request.data, *name;
 399         int err;
 400
 401         ptr += strlen("config");
 402         while(isspace(*ptr)) ptr++;
 403         dev = mconsole_find_dev(ptr);
 404         if(dev == NULL){
 405                 mconsole_reply(req, "Bad configuration option", 1, 0);
 406                 return;
 407         }
 408
 409         name = &ptr[strlen(dev->name)];
 410         ptr = name;
 411         while((*ptr != '=') && (*ptr != '\0'))
 412                 ptr++;
 413
 414         if(*ptr == '='){
 415                 err = (*dev->config)(name);
 416                 mconsole_reply(req, "", err, 0);
 417         }
 418         else mconsole_get_config(dev->get_config, req, name);
 419 }
 420
 421 void mconsole_remove(struct mc_request *req)
 422 {
 423         struct mc_device *dev;
 424         char *ptr = req->request.data, *err_msg = "";
 425         char error[256];
 426         int err, start, end, n;
 427
 428         ptr += strlen("remove");
 429         while(isspace(*ptr)) ptr++;
 430         dev = mconsole_find_dev(ptr);
 431         if(dev == NULL){
 432                 mconsole_reply(req, "Bad remove option", 1, 0);
 433                 return;
 434         }
 435
 436         ptr = &ptr[strlen(dev->name)];
 437
 438         err = 1;
 439         n = (*dev->id)(&ptr, &start, &end);
 440         if(n < 0){
 441                 err_msg = "Couldn't parse device number";
 442                 goto out;
 443         }
 444         else if((n < start) || (n > end)){
 445                 sprintf(error, "Invalid device number - must be between "
 446                         "%d and %d", start, end);
 447                 err_msg = error;
 448                 goto out;
 449         }
 450
 451         err = (*dev->remove)(n);
 452         switch(err){
 453         case -ENODEV:
 454                 err_msg = "Device doesn't exist";
 455                 break;
 456         case -EBUSY:
 457                 err_msg = "Device is currently open";
 458                 break;
 459         default:
 460                 break;
 461         }
 462  out:
 463         mconsole_reply(req, err_msg, err, 0);
 464 }
 465
 466 #ifdef CONFIG_MAGIC_SYSRQ
 467 void mconsole_sysrq(struct mc_request *req)
 468 {
 469         char *ptr = req->request.data;
 470
 471         ptr += strlen("sysrq");
 472         while(isspace(*ptr)) ptr++;
 473
 474         mconsole_reply(req, "", 0, 0);
 475         handle_sysrq(*ptr, &current->thread.regs, NULL);
 476 }
 477 #else
 478 void mconsole_sysrq(struct mc_request *req)
 479 {
 480         mconsole_reply(req, "Sysrq not compiled in", 1, 0);
 481 }
 482 #endif
 483
 484 /* Mconsole stack trace
 485  *  Added by Allan Graves, Jeff Dike
 486  *  Dumps a stacks registers to the linux console.
 487  *  Usage stack <pid>.
 488  */
 489 void do_stack(struct mc_request *req)
 490 {
 491         char *ptr = req->request.data;
 492         int pid_requested= -1;
 493         struct task_struct *from = NULL;
 494         struct task_struct *to = NULL;
 495
 496         /* Would be nice:
 497          * 1) Send showregs output to mconsole.
 498          * 2) Add a way to stack dump all pids.
 499          */
 500
 501         ptr += strlen("stack");
 502         while(isspace(*ptr)) ptr++;
 503
 504         /* Should really check for multiple pids or reject bad args here */
 505         /* What do the arguments in mconsole_reply mean? */
 506         if(sscanf(ptr, "%d", &pid_requested) == 0){
 507                 mconsole_reply(req, "Please specify a pid", 1, 0);
 508                 return;
 509         }
 510
 511         from = current;
 512         to = find_task_by_pid(pid_requested);
 513
 514         if((to == NULL) || (pid_requested == 0)) {
 515                 mconsole_reply(req, "Couldn't find that pid", 1, 0);
 516                 return;
 517         }
 518         to->thread.saved_task = current;
 519
 520         switch_to(from, to, from);
 521         mconsole_reply(req, "Stack Dumped to console and message log", 0, 0);
 522 }
 523
 524 void mconsole_stack(struct mc_request *req)
 525 {
 526         /* This command doesn't work in TT mode, so let's check and then
 527          * get out of here
 528          */
 529         CHOOSE_MODE(mconsole_reply(req, "Sorry, this doesn't work in TT mode",
 530                                    1, 0),
 531                     do_stack(req));
 532 }
 533
 534 /* Changed by mconsole_setup, which is __setup, and called before SMP is
 535  * active.
 536  */
 537 static char *notify_socket = NULL;
 538
 539 int mconsole_init(void)
 540 {
 541         /* long to avoid size mismatch warnings from gcc */
 542         long sock;
 543         int err;
 544         char file[256];
 545
 546         if(umid_file_name("mconsole", file, sizeof(file))) return(-1);
 547         snprintf(mconsole_socket_name, sizeof(file), "%s", file);
 548
 549         sock = os_create_unix_socket(file, sizeof(file), 1);
 550         if (sock < 0){
 551                 printk("Failed to initialize management console\n");
 552                 return(1);
 553         }
 554
 555         register_reboot_notifier(&reboot_notifier);
 556
 557         err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
 558                              SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM,
 559                              "mconsole", (void *)sock);
 560         if (err){
 561                 printk("Failed to get IRQ for management console\n");
 562                 return(1);
 563         }
 564
 565         if(notify_socket != NULL){
 566                 notify_socket = uml_strdup(notify_socket);
 567                 if(notify_socket != NULL)
 568                         mconsole_notify(notify_socket, MCONSOLE_SOCKET,
 569                                         mconsole_socket_name,
 570                                         strlen(mconsole_socket_name) + 1);
 571                 else printk(KERN_ERR "mconsole_setup failed to strdup "
 572                             "string\n");
 573         }
 574
 575         printk("mconsole (version %d) initialized on %s\n",
 576                MCONSOLE_VERSION, mconsole_socket_name);
 577         return(0);
 578 }
 579
 580 __initcall(mconsole_init);
 581
 582 static int write_proc_mconsole(struct file *file, const char __user *buffer,
 583                                unsigned long count, void *data)
 584 {
 585         char *buf;
 586
 587         buf = kmalloc(count + 1, GFP_KERNEL);
 588         if(buf == NULL)
 589                 return(-ENOMEM);
 590
 591         if(copy_from_user(buf, buffer, count)){
 592                 count = -EFAULT;
 593                 goto out;
 594         }
 595
 596         buf[count] = '\0';
 597
 598         mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count);
 599  out:
 600         kfree(buf);
 601         return(count);
 602 }
 603
 604 static int create_proc_mconsole(void)
 605 {
 606         struct proc_dir_entry *ent;
 607
 608         if(notify_socket == NULL) return(0);
 609
 610         ent = create_proc_entry("mconsole", S_IFREG | 0200, NULL);
 611         if(ent == NULL){
 612                 printk(KERN_INFO "create_proc_mconsole : create_proc_entry failed\n");
 613                 return(0);
 614         }
 615
 616         ent->read_proc = NULL;
 617         ent->write_proc = write_proc_mconsole;
 618         return(0);
 619 }
 620
 621 static DEFINE_SPINLOCK(notify_spinlock);
 622
 623 void lock_notify(void)
 624 {
 625         spin_lock(&notify_spinlock);
 626 }
 627
 628 void unlock_notify(void)
 629 {
 630         spin_unlock(&notify_spinlock);
 631 }
 632
 633 __initcall(create_proc_mconsole);
 634
 635 #define NOTIFY "=notify:"
 636
 637 static int mconsole_setup(char *str)
 638 {
 639         if(!strncmp(str, NOTIFY, strlen(NOTIFY))){
 640                 str += strlen(NOTIFY);
 641                 notify_socket = str;
 642         }
 643         else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str);
 644         return(1);
 645 }
 646
 647 __setup("mconsole", mconsole_setup);
 648
 649 __uml_help(mconsole_setup,
 650 "mconsole=notify:<socket>\n"
 651 "    Requests that the mconsole driver send a message to the named Unix\n"
 652 "    socket containing the name of the mconsole socket.  This also serves\n"
 653 "    to notify outside processes when UML has booted far enough to respond\n"
 654 "    to mconsole requests.\n\n"
 655 );
 656
 657 static int notify_panic(struct notifier_block *self, unsigned long unused1,
 658                         void *ptr)
 659 {
 660         char *message = ptr;
 661
 662         if(notify_socket == NULL) return(0);
 663
 664         mconsole_notify(notify_socket, MCONSOLE_PANIC, message,
 665                         strlen(message) + 1);
 666         return(0);
 667 }
 668
 669 static struct notifier_block panic_exit_notifier = {
 670         .notifier_call          = notify_panic,
 671         .next                   = NULL,
 672         .priority               = 1
 673 };
 674
 675 static int add_notifier(void)
 676 {
 677         notifier_chain_register(&panic_notifier_list, &panic_exit_notifier);
 678         return(0);
 679 }
 680
 681 __initcall(add_notifier);
 682
 683 char *mconsole_notify_socket(void)
 684 {
 685         return(notify_socket);
 686 }
 687
 688 EXPORT_SYMBOL(mconsole_notify_socket);
 689
 690 /*
 691  * Overrides for Emacs so that we follow Linus's tabbing style.
 692  * Emacs will notice this stuff at the end of the file and automatically
 693  * adjust the settings for this buffer only.  This must remain at the end
 694  * of the file.
 695  * ---------------------------------------------------------------------------
 696  * Local variables:
 697  * c-file-style: "linux"
 698  * End:
 699  */