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