bsd/uxkern/ux_exception.c

   1 /*
   2  * Copyright (c) 2000-2008 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * Mach Operating System
  30  * Copyright (c) 1987 Carnegie-Mellon University
  31  * All rights reserved.  The CMU software License Agreement specifies
  32  * the terms and conditions for use and redistribution.
  33  */
  34
  35 /*
  36  *********************************************************************
  37  * HISTORY
  38  **********************************************************************
  39  */
  40
  41 #include <sys/param.h>
  42
  43 #include <mach/boolean.h>
  44 #include <mach/exception.h>
  45 #include <mach/kern_return.h>
  46 #include <mach/message.h>
  47 #include <mach/port.h>
  48 #include <mach/mach_port.h>
  49 #include <mach/mig_errors.h>
  50 #include <mach/exc_server.h>
  51 #include <mach/mach_exc_server.h>
  52 #include <kern/task.h>
  53 #include <kern/thread.h>
  54 #include <kern/sched_prim.h>
  55 #include <kern/kalloc.h>
  56
  57 #include <sys/proc.h>
  58 #include <sys/user.h>
  59 #include <sys/systm.h>
  60 #include <sys/ux_exception.h>
  61 #include <sys/vmparam.h>        /* MAXSSIZ */
  62
  63 #include <vm/vm_protos.h>       /* get_task_ipcspace() */
  64 /*
  65  * XXX Things that should be retrieved from Mach headers, but aren't
  66  */
  67 struct ipc_object;
  68 extern kern_return_t ipc_object_copyin(ipc_space_t space, mach_port_name_t name,
  69                 mach_msg_type_name_t msgt_name, struct ipc_object **objectp);
  70 extern mach_msg_return_t mach_msg_receive(mach_msg_header_t *msg,
  71                 mach_msg_option_t option, mach_msg_size_t rcv_size,
  72                 mach_port_name_t rcv_name, mach_msg_timeout_t rcv_timeout,
  73                 void (*continuation)(mach_msg_return_t),
  74                 mach_msg_size_t slist_size);
  75 extern mach_msg_return_t mach_msg_send(mach_msg_header_t *msg,
  76                 mach_msg_option_t option, mach_msg_size_t send_size,
  77                 mach_msg_timeout_t send_timeout, mach_port_name_t notify);
  78 extern thread_t convert_port_to_thread(ipc_port_t port);
  79 extern void ipc_port_release(ipc_port_t);
  80
  81
  82
  83
  84
  85 /*
  86  *      Unix exception handler.
  87  */
  88
  89 static void     ux_exception(int exception, mach_exception_code_t code,
  90                                 mach_exception_subcode_t subcode,
  91                                 int *ux_signal, mach_exception_code_t *ux_code);
  92
  93 #if defined(__x86_64__)
  94 mach_port_t                     ux_exception_port;
  95 #else
  96 mach_port_name_t                ux_exception_port;
  97 #endif /* __x86_64__ */
  98
  99 static task_t                   ux_handler_self;
 100
 101 static
 102 void
 103 ux_handler(void)
 104 {
 105     task_t              self = current_task();
 106     mach_port_name_t    exc_port_name;
 107     mach_port_name_t    exc_set_name;
 108
 109     /* self->kernel_vm_space = TRUE; */
 110     ux_handler_self = self;
 111
 112
 113     /*
 114      *  Allocate a port set that we will receive on.
 115      */
 116     if (mach_port_allocate(get_task_ipcspace(ux_handler_self), MACH_PORT_RIGHT_PORT_SET,  &exc_set_name) != MACH_MSG_SUCCESS)
 117             panic("ux_handler: port_set_allocate failed");
 118
 119     /*
 120      *  Allocate an exception port and use object_copyin to
 121      *  translate it to the global name.  Put it into the set.
 122      */
 123     if (mach_port_allocate(get_task_ipcspace(ux_handler_self), MACH_PORT_RIGHT_RECEIVE, &exc_port_name) != MACH_MSG_SUCCESS)
 124         panic("ux_handler: port_allocate failed");
 125     if (mach_port_move_member(get_task_ipcspace(ux_handler_self),
 126                         exc_port_name,  exc_set_name) != MACH_MSG_SUCCESS)
 127         panic("ux_handler: port_set_add failed");
 128
 129     if (ipc_object_copyin(get_task_ipcspace(self), exc_port_name,
 130                         MACH_MSG_TYPE_MAKE_SEND,
 131                         (void *) &ux_exception_port) != MACH_MSG_SUCCESS)
 132                 panic("ux_handler: object_copyin(ux_exception_port) failed");
 133
 134     proc_list_lock();
 135     thread_wakeup(&ux_exception_port);
 136     proc_list_unlock();
 137
 138     /* Message handling loop. */
 139
 140     for (;;) {
 141         struct rep_msg {
 142                 mach_msg_header_t Head;
 143                 NDR_record_t NDR;
 144                 kern_return_t RetCode;
 145         } rep_msg;
 146         struct exc_msg {
 147                 mach_msg_header_t Head;
 148                 /* start of the kernel processed data */
 149                 mach_msg_body_t msgh_body;
 150                 mach_msg_port_descriptor_t thread;
 151                 mach_msg_port_descriptor_t task;
 152                 /* end of the kernel processed data */
 153                 NDR_record_t NDR;
 154                 exception_type_t exception;
 155                 mach_msg_type_number_t codeCnt;
 156                 mach_exception_data_t code;
 157                 /* some times RCV_TO_LARGE probs */
 158                 char pad[512];
 159         } exc_msg;
 160         mach_port_name_t        reply_port;
 161         kern_return_t    result;
 162
 163         exc_msg.Head.msgh_local_port = CAST_MACH_NAME_TO_PORT(exc_set_name);
 164         exc_msg.Head.msgh_size = sizeof (exc_msg);
 165 #if 0
 166         result = mach_msg_receive(&exc_msg.Head);
 167 #else
 168         result = mach_msg_receive(&exc_msg.Head, MACH_RCV_MSG,
 169                              sizeof (exc_msg), exc_set_name,
 170                              MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL,
 171                              0);
 172 #endif
 173         if (result == MACH_MSG_SUCCESS) {
 174             reply_port = CAST_MACH_PORT_TO_NAME(exc_msg.Head.msgh_remote_port);
 175
 176             if (mach_exc_server(&exc_msg.Head, &rep_msg.Head)) {
 177                 result = mach_msg_send(&rep_msg.Head, MACH_SEND_MSG,
 178                         sizeof (rep_msg),MACH_MSG_TIMEOUT_NONE,MACH_PORT_NULL);
 179                 if (reply_port != 0 && result != MACH_MSG_SUCCESS)
 180                         mach_port_deallocate(get_task_ipcspace(ux_handler_self), reply_port);
 181             }
 182
 183         }
 184         else if (result == MACH_RCV_TOO_LARGE)
 185                 /* ignore oversized messages */;
 186         else
 187                 panic("exception_handler");
 188     }
 189 }
 190
 191 void
 192 ux_handler_init(void)
 193 {
 194         thread_t        thread = THREAD_NULL;
 195
 196         ux_exception_port = MACH_PORT_NULL;
 197         (void) kernel_thread_start((thread_continue_t)ux_handler, NULL, &thread);
 198         thread_deallocate(thread);
 199         proc_list_lock();
 200         if (ux_exception_port == MACH_PORT_NULL)  {
 201                 (void)msleep(&ux_exception_port, proc_list_mlock, 0, "ux_handler_wait", 0);
 202         }
 203         proc_list_unlock();
 204 }
 205
 206 kern_return_t
 207 catch_exception_raise(
 208         __unused mach_port_t exception_port,
 209         mach_port_t thread,
 210         mach_port_t task,
 211         exception_type_t exception,
 212         exception_data_t code,
 213         __unused mach_msg_type_number_t codeCnt
 214 )
 215 {
 216         mach_exception_data_type_t big_code[EXCEPTION_CODE_MAX];
 217         big_code[0] = code[0];
 218         big_code[1] = code[1];
 219
 220         return catch_mach_exception_raise(exception_port,
 221                         thread,
 222                         task,
 223                         exception,
 224                         big_code,
 225                         codeCnt);
 226
 227 }
 228
 229 kern_return_t
 230 catch_mach_exception_raise(
 231         __unused mach_port_t exception_port,
 232         mach_port_t thread,
 233         mach_port_t task,
 234         exception_type_t exception,
 235         mach_exception_data_t code,
 236         __unused mach_msg_type_number_t codeCnt
 237 )
 238 {
 239         task_t                  self = current_task();
 240         thread_t                th_act;
 241         ipc_port_t              thread_port;
 242         struct proc             *p;
 243         kern_return_t           result = MACH_MSG_SUCCESS;
 244         int                     ux_signal = 0;
 245         mach_exception_code_t   ucode = 0;
 246         struct uthread          *ut;
 247         mach_port_name_t thread_name = CAST_MACH_PORT_TO_NAME(thread);
 248         mach_port_name_t task_name = CAST_MACH_PORT_TO_NAME(task);
 249
 250         /*
 251          *      Convert local thread name to global port.
 252          */
 253    if (MACH_PORT_VALID(thread_name) &&
 254        (ipc_object_copyin(get_task_ipcspace(self), thread_name,
 255                        MACH_MSG_TYPE_PORT_SEND,
 256                        (void *) &thread_port) == MACH_MSG_SUCCESS)) {
 257         if (IPC_PORT_VALID(thread_port)) {
 258            th_act = convert_port_to_thread(thread_port);
 259            ipc_port_release(thread_port);
 260         } else {
 261            th_act = THREAD_NULL;
 262         }
 263
 264         /*
 265          *      Catch bogus ports
 266          */
 267         if (th_act != THREAD_NULL) {
 268
 269             /*
 270              *  Convert exception to unix signal and code.
 271              */
 272             ux_exception(exception, code[0], code[1], &ux_signal, &ucode);
 273
 274             ut = get_bsdthread_info(th_act);
 275             p = proc_findthread(th_act);
 276
 277             /* Can't deliver a signal without a bsd process reference */
 278             if (p == NULL) {
 279                     ux_signal = 0;
 280                     result = KERN_FAILURE;
 281             }
 282
 283             /*
 284              * Stack overflow should result in a SIGSEGV signal
 285              * on the alternate stack.
 286              * but we have one or more guard pages after the
 287              * stack top, so we would get a KERN_PROTECTION_FAILURE
 288              * exception instead of KERN_INVALID_ADDRESS, resulting in
 289              * a SIGBUS signal.
 290              * Detect that situation and select the correct signal.
 291              */
 292             if (code[0] == KERN_PROTECTION_FAILURE &&
 293                 ux_signal == SIGBUS) {
 294                     user_addr_t         sp, stack_min, stack_max;
 295                     int                 mask;
 296                     struct sigacts      *ps;
 297
 298                     sp = code[1];
 299
 300                     stack_max = p->user_stack;
 301                     stack_min = p->user_stack - MAXSSIZ;
 302                     if (sp >= stack_min &&
 303                         sp < stack_max) {
 304                             /*
 305                              * This is indeed a stack overflow.  Deliver a
 306                              * SIGSEGV signal.
 307                              */
 308                             ux_signal = SIGSEGV;
 309
 310                             /*
 311                              * If the thread/process is not ready to handle
 312                              * SIGSEGV on an alternate stack, force-deliver
 313                              * SIGSEGV with a SIG_DFL handler.
 314                              */
 315                             mask = sigmask(ux_signal);
 316                             ps = p->p_sigacts;
 317                             if ((p->p_sigignore & mask) ||
 318                                 (ut->uu_sigwait & mask) ||
 319                                 (ut->uu_sigmask & mask) ||
 320                                 (ps->ps_sigact[SIGSEGV] == SIG_IGN) ||
 321                                 (! (ps->ps_sigonstack & mask))) {
 322                                     p->p_sigignore &= ~mask;
 323                                     p->p_sigcatch &= ~mask;
 324                                     ps->ps_sigact[SIGSEGV] = SIG_DFL;
 325                                     ut->uu_sigwait &= ~mask;
 326                                     ut->uu_sigmask &= ~mask;
 327                             }
 328                     }
 329             }
 330             /*
 331              *  Send signal.
 332              */
 333             if (ux_signal != 0) {
 334                         ut->uu_exception = exception;
 335                         //ut->uu_code = code[0]; // filled in by threadsignal
 336                         ut->uu_subcode = code[1];
 337                         threadsignal(th_act, ux_signal, code[0]);
 338             }
 339             if (p != NULL)
 340                     proc_rele(p);
 341             thread_deallocate(th_act);
 342         }
 343         else
 344             result = KERN_INVALID_ARGUMENT;
 345     }
 346     else
 347         result = KERN_INVALID_ARGUMENT;
 348
 349     /*
 350      *  Delete our send rights to the task port.
 351      */
 352     (void)mach_port_deallocate(get_task_ipcspace(ux_handler_self), task_name);
 353
 354     return (result);
 355 }
 356
 357 kern_return_t
 358 catch_exception_raise_state(
 359         __unused mach_port_t exception_port,
 360         __unused exception_type_t exception,
 361         __unused const exception_data_t code,
 362         __unused mach_msg_type_number_t codeCnt,
 363         __unused int *flavor,
 364         __unused const thread_state_t old_state,
 365         __unused mach_msg_type_number_t old_stateCnt,
 366         __unused thread_state_t new_state,
 367         __unused mach_msg_type_number_t *new_stateCnt)
 368 {
 369         return(KERN_INVALID_ARGUMENT);
 370 }
 371
 372 kern_return_t
 373 catch_mach_exception_raise_state(
 374         __unused mach_port_t exception_port,
 375         __unused exception_type_t exception,
 376         __unused const mach_exception_data_t code,
 377         __unused mach_msg_type_number_t codeCnt,
 378         __unused int *flavor,
 379         __unused const thread_state_t old_state,
 380         __unused mach_msg_type_number_t old_stateCnt,
 381         __unused thread_state_t new_state,
 382         __unused mach_msg_type_number_t *new_stateCnt)
 383 {
 384         return(KERN_INVALID_ARGUMENT);
 385 }
 386
 387 kern_return_t
 388 catch_exception_raise_state_identity(
 389         __unused mach_port_t exception_port,
 390         __unused mach_port_t thread,
 391         __unused mach_port_t task,
 392         __unused exception_type_t exception,
 393         __unused exception_data_t code,
 394         __unused mach_msg_type_number_t codeCnt,
 395         __unused int *flavor,
 396         __unused thread_state_t old_state,
 397         __unused mach_msg_type_number_t old_stateCnt,
 398         __unused thread_state_t new_state,
 399         __unused mach_msg_type_number_t *new_stateCnt)
 400 {
 401         return(KERN_INVALID_ARGUMENT);
 402 }
 403
 404 kern_return_t
 405 catch_mach_exception_raise_state_identity(
 406         __unused mach_port_t exception_port,
 407         __unused mach_port_t thread,
 408         __unused mach_port_t task,
 409         __unused exception_type_t exception,
 410         __unused mach_exception_data_t code,
 411         __unused mach_msg_type_number_t codeCnt,
 412         __unused int *flavor,
 413         __unused thread_state_t old_state,
 414         __unused mach_msg_type_number_t old_stateCnt,
 415         __unused thread_state_t new_state,
 416         __unused mach_msg_type_number_t *new_stateCnt)
 417 {
 418         return(KERN_INVALID_ARGUMENT);
 419 }
 420
 421
 422 /*
 423  *      ux_exception translates a mach exception, code and subcode to
 424  *      a signal and u.u_code.  Calls machine_exception (machine dependent)
 425  *      to attempt translation first.
 426  */
 427
 428 static
 429 void ux_exception(
 430                 int                     exception,
 431                 mach_exception_code_t   code,
 432                 mach_exception_subcode_t subcode,
 433                 int                     *ux_signal,
 434                 mach_exception_code_t   *ux_code)
 435 {
 436     /*
 437      *  Try machine-dependent translation first.
 438      */
 439     if (machine_exception(exception, code, subcode, ux_signal, ux_code))
 440         return;
 441
 442     switch(exception) {
 443
 444         case EXC_BAD_ACCESS:
 445                 if (code == KERN_INVALID_ADDRESS)
 446                         *ux_signal = SIGSEGV;
 447                 else
 448                         *ux_signal = SIGBUS;
 449                 break;
 450
 451         case EXC_BAD_INSTRUCTION:
 452             *ux_signal = SIGILL;
 453             break;
 454
 455         case EXC_ARITHMETIC:
 456             *ux_signal = SIGFPE;
 457             break;
 458
 459         case EXC_EMULATION:
 460             *ux_signal = SIGEMT;
 461             break;
 462
 463         case EXC_SOFTWARE:
 464             switch (code) {
 465
 466             case EXC_UNIX_BAD_SYSCALL:
 467                 *ux_signal = SIGSYS;
 468                 break;
 469             case EXC_UNIX_BAD_PIPE:
 470                 *ux_signal = SIGPIPE;
 471                 break;
 472             case EXC_UNIX_ABORT:
 473                 *ux_signal = SIGABRT;
 474                 break;
 475             case EXC_SOFT_SIGNAL:
 476                 *ux_signal = SIGKILL;
 477                 break;
 478             }
 479             break;
 480
 481         case EXC_BREAKPOINT:
 482             *ux_signal = SIGTRAP;
 483             break;
 484     }
 485 }