bsd/uxkern/ux_exception.c

   1 /*
   2  * Copyright (c) 2000-2004 Apple Computer, 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 mach_port_name_t                ux_exception_port;
  94 static task_t                   ux_handler_self;
  95
  96 static
  97 void
  98 ux_handler(void)
  99 {
 100     task_t              self = current_task();
 101     mach_port_name_t    exc_port_name;
 102     mach_port_name_t    exc_set_name;
 103
 104     /* self->kernel_vm_space = TRUE; */
 105     ux_handler_self = self;
 106
 107
 108     /*
 109      *  Allocate a port set that we will receive on.
 110      */
 111     if (mach_port_allocate(get_task_ipcspace(ux_handler_self), MACH_PORT_RIGHT_PORT_SET,  &exc_set_name) != MACH_MSG_SUCCESS)
 112             panic("ux_handler: port_set_allocate failed");
 113
 114     /*
 115      *  Allocate an exception port and use object_copyin to
 116      *  translate it to the global name.  Put it into the set.
 117      */
 118     if (mach_port_allocate(get_task_ipcspace(ux_handler_self), MACH_PORT_RIGHT_RECEIVE, &exc_port_name) != MACH_MSG_SUCCESS)
 119         panic("ux_handler: port_allocate failed");
 120     if (mach_port_move_member(get_task_ipcspace(ux_handler_self),
 121                         exc_port_name,  exc_set_name) != MACH_MSG_SUCCESS)
 122         panic("ux_handler: port_set_add failed");
 123
 124     if (ipc_object_copyin(get_task_ipcspace(self), exc_port_name,
 125                         MACH_MSG_TYPE_MAKE_SEND,
 126                         (void *) &ux_exception_port) != MACH_MSG_SUCCESS)
 127                 panic("ux_handler: object_copyin(ux_exception_port) failed");
 128
 129     proc_list_lock();
 130     thread_wakeup(&ux_exception_port);
 131     proc_list_unlock();
 132
 133     /* Message handling loop. */
 134
 135     for (;;) {
 136         struct rep_msg {
 137                 mach_msg_header_t Head;
 138                 NDR_record_t NDR;
 139                 kern_return_t RetCode;
 140         } rep_msg;
 141         struct exc_msg {
 142                 mach_msg_header_t Head;
 143                 /* start of the kernel processed data */
 144                 mach_msg_body_t msgh_body;
 145                 mach_msg_port_descriptor_t thread;
 146                 mach_msg_port_descriptor_t task;
 147                 /* end of the kernel processed data */
 148                 NDR_record_t NDR;
 149                 exception_type_t exception;
 150                 mach_msg_type_number_t codeCnt;
 151                 mach_exception_data_t code;
 152                 /* some times RCV_TO_LARGE probs */
 153                 char pad[512];
 154         } exc_msg;
 155         mach_port_name_t        reply_port;
 156         kern_return_t    result;
 157
 158         exc_msg.Head.msgh_local_port = (mach_port_t)exc_set_name;
 159         exc_msg.Head.msgh_size = sizeof (exc_msg);
 160 #if 0
 161         result = mach_msg_receive(&exc_msg.Head);
 162 #else
 163         result = mach_msg_receive(&exc_msg.Head, MACH_RCV_MSG,
 164                              sizeof (exc_msg), exc_set_name,
 165                              MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL,
 166                              0);
 167 #endif
 168         if (result == MACH_MSG_SUCCESS) {
 169             reply_port = (mach_port_name_t)exc_msg.Head.msgh_remote_port;
 170
 171             if (mach_exc_server(&exc_msg.Head, &rep_msg.Head))
 172                 (void) mach_msg_send(&rep_msg.Head, MACH_SEND_MSG,
 173                         sizeof (rep_msg),MACH_MSG_TIMEOUT_NONE,MACH_PORT_NULL);
 174
 175             if (reply_port != MACH_PORT_NULL)
 176                 (void) mach_port_deallocate(get_task_ipcspace(ux_handler_self), reply_port);
 177         }
 178         else if (result == MACH_RCV_TOO_LARGE)
 179                 /* ignore oversized messages */;
 180         else
 181                 panic("exception_handler");
 182     }
 183 }
 184
 185 void
 186 ux_handler_init(void)
 187 {
 188         ux_exception_port = MACH_PORT_NULL;
 189         (void) kernel_thread(kernel_task, ux_handler);
 190         proc_list_lock();
 191         if (ux_exception_port == MACH_PORT_NULL)  {
 192                 (void)msleep(&ux_exception_port, proc_list_mlock, 0, "ux_handler_wait", 0);
 193         }
 194         proc_list_unlock();
 195 }
 196
 197 kern_return_t
 198 catch_exception_raise(
 199         __unused mach_port_t exception_port,
 200         mach_port_t thread,
 201         mach_port_t task,
 202         exception_type_t exception,
 203         exception_data_t code,
 204         __unused mach_msg_type_number_t codeCnt
 205 )
 206 {
 207         mach_exception_data_type_t big_code[EXCEPTION_CODE_MAX];
 208         big_code[0] = code[0];
 209         big_code[1] = code[1];
 210
 211         return catch_mach_exception_raise(exception_port,
 212                         thread,
 213                         task,
 214                         exception,
 215                         big_code,
 216                         codeCnt);
 217
 218 }
 219
 220 kern_return_t
 221 catch_mach_exception_raise(
 222         __unused mach_port_t exception_port,
 223         mach_port_t thread,
 224         mach_port_t task,
 225         exception_type_t exception,
 226         mach_exception_data_t code,
 227         __unused mach_msg_type_number_t codeCnt
 228 )
 229 {
 230         task_t                  self = current_task();
 231         thread_t                th_act;
 232         ipc_port_t              thread_port;
 233         struct task             *sig_task;
 234         struct proc             *p;
 235         kern_return_t           result = MACH_MSG_SUCCESS;
 236         int                     ux_signal = 0;
 237         mach_exception_code_t   ucode = 0;
 238         struct uthread          *ut;
 239         mach_port_name_t thread_name = (mach_port_name_t)thread; /* XXX */
 240         mach_port_name_t task_name = (mach_port_name_t)task;    /* XXX */
 241
 242         /*
 243          *      Convert local thread name to global port.
 244          */
 245    if (MACH_PORT_VALID(thread_name) &&
 246        (ipc_object_copyin(get_task_ipcspace(self), thread_name,
 247                        MACH_MSG_TYPE_PORT_SEND,
 248                        (void *) &thread_port) == MACH_MSG_SUCCESS)) {
 249         if (IPC_PORT_VALID(thread_port)) {
 250            th_act = convert_port_to_thread(thread_port);
 251            ipc_port_release(thread_port);
 252         } else {
 253            th_act = THREAD_NULL;
 254         }
 255
 256         /*
 257          *      Catch bogus ports
 258          */
 259         if (th_act != THREAD_NULL) {
 260
 261             /*
 262              *  Convert exception to unix signal and code.
 263              */
 264             ux_exception(exception, code[0], code[1], &ux_signal, &ucode);
 265
 266             ut = get_bsdthread_info(th_act);
 267             sig_task = get_threadtask(th_act);
 268             p = (struct proc *) get_bsdtask_info(sig_task);
 269
 270             /* Can't deliver a signal without a bsd process */
 271             if (p == NULL) {
 272                     ux_signal = 0;
 273                     result = KERN_FAILURE;
 274             }
 275
 276             /*
 277              * Stack overflow should result in a SIGSEGV signal
 278              * on the alternate stack.
 279              * but we have one or more guard pages after the
 280              * stack top, so we would get a KERN_PROTECTION_FAILURE
 281              * exception instead of KERN_INVALID_ADDRESS, resulting in
 282              * a SIGBUS signal.
 283              * Detect that situation and select the correct signal.
 284              */
 285             if (code[0] == KERN_PROTECTION_FAILURE &&
 286                 ux_signal == SIGBUS) {
 287                     user_addr_t         sp, stack_min, stack_max;
 288                     int                 mask;
 289                     struct sigacts      *ps;
 290
 291                     sp = code[1];
 292                     if (ut && (ut->uu_flag & UT_VFORK))
 293                             p = ut->uu_proc;
 294 #if STACK_GROWTH_UP
 295                     stack_min = p->user_stack;
 296                     stack_max = p->user_stack + MAXSSIZ;
 297 #else /* STACK_GROWTH_UP */
 298                     stack_max = p->user_stack;
 299                     stack_min = p->user_stack - MAXSSIZ;
 300 #endif /* STACK_GROWTH_UP */
 301                     if (sp >= stack_min &&
 302                         sp < stack_max) {
 303                             /*
 304                              * This is indeed a stack overflow.  Deliver a
 305                              * SIGSEGV signal.
 306                              */
 307                             ux_signal = SIGSEGV;
 308
 309                             /*
 310                              * If the thread/process is not ready to handle
 311                              * SIGSEGV on an alternate stack, force-deliver
 312                              * SIGSEGV with a SIG_DFL handler.
 313                              */
 314                             mask = sigmask(ux_signal);
 315                             ps = p->p_sigacts;
 316                             if ((p->p_sigignore & mask) ||
 317                                 (ut->uu_sigwait & mask) ||
 318                                 (ut->uu_sigmask & mask) ||
 319                                 (ps->ps_sigact[SIGSEGV] == SIG_IGN) ||
 320                                 (! (ps->ps_sigonstack & mask))) {
 321                                     p->p_sigignore &= ~mask;
 322                                     p->p_sigcatch &= ~mask;
 323                                     ps->ps_sigact[SIGSEGV] = SIG_DFL;
 324                                     ut->uu_sigwait &= ~mask;
 325                                     ut->uu_sigmask &= ~mask;
 326                             }
 327                     }
 328             }
 329             /*
 330              *  Send signal.
 331              */
 332             if (ux_signal != 0) {
 333                         ut->uu_exception = exception;
 334                         //ut->uu_code = code[0]; // filled in by threadsignal
 335                         ut->uu_subcode = code[1];
 336                         threadsignal(th_act, ux_signal, code[0]);
 337             }
 338
 339             thread_deallocate(th_act);
 340         }
 341         else
 342             result = KERN_INVALID_ARGUMENT;
 343     }
 344     else
 345         result = KERN_INVALID_ARGUMENT;
 346
 347     /*
 348      *  Delete our send rights to the task and thread ports.
 349      */
 350     (void)mach_port_deallocate(get_task_ipcspace(ux_handler_self), task_name);
 351     (void)mach_port_deallocate(get_task_ipcspace(ux_handler_self), thread_name);
 352
 353     return (result);
 354 }
 355
 356 kern_return_t
 357 catch_exception_raise_state(
 358         __unused mach_port_t exception_port,
 359         __unused exception_type_t exception,
 360         __unused const exception_data_t code,
 361         __unused mach_msg_type_number_t codeCnt,
 362         __unused int *flavor,
 363         __unused const thread_state_t old_state,
 364         __unused mach_msg_type_number_t old_stateCnt,
 365         __unused thread_state_t new_state,
 366         __unused mach_msg_type_number_t *new_stateCnt)
 367 {
 368         return(KERN_INVALID_ARGUMENT);
 369 }
 370
 371 kern_return_t
 372 catch_mach_exception_raise_state(
 373         __unused mach_port_t exception_port,
 374         __unused exception_type_t exception,
 375         __unused const mach_exception_data_t code,
 376         __unused mach_msg_type_number_t codeCnt,
 377         __unused int *flavor,
 378         __unused const thread_state_t old_state,
 379         __unused mach_msg_type_number_t old_stateCnt,
 380         __unused thread_state_t new_state,
 381         __unused mach_msg_type_number_t *new_stateCnt)
 382 {
 383         return(KERN_INVALID_ARGUMENT);
 384 }
 385
 386 kern_return_t
 387 catch_exception_raise_state_identity(
 388         __unused mach_port_t exception_port,
 389         __unused mach_port_t thread,
 390         __unused mach_port_t task,
 391         __unused exception_type_t exception,
 392         __unused exception_data_t code,
 393         __unused mach_msg_type_number_t codeCnt,
 394         __unused int *flavor,
 395         __unused thread_state_t old_state,
 396         __unused mach_msg_type_number_t old_stateCnt,
 397         __unused thread_state_t new_state,
 398         __unused mach_msg_type_number_t *new_stateCnt)
 399 {
 400         return(KERN_INVALID_ARGUMENT);
 401 }
 402
 403 kern_return_t
 404 catch_mach_exception_raise_state_identity(
 405         __unused mach_port_t exception_port,
 406         __unused mach_port_t thread,
 407         __unused mach_port_t task,
 408         __unused exception_type_t exception,
 409         __unused mach_exception_data_t code,
 410         __unused mach_msg_type_number_t codeCnt,
 411         __unused int *flavor,
 412         __unused thread_state_t old_state,
 413         __unused mach_msg_type_number_t old_stateCnt,
 414         __unused thread_state_t new_state,
 415         __unused mach_msg_type_number_t *new_stateCnt)
 416 {
 417         return(KERN_INVALID_ARGUMENT);
 418 }
 419
 420
 421 /*
 422  *      ux_exception translates a mach exception, code and subcode to
 423  *      a signal and u.u_code.  Calls machine_exception (machine dependent)
 424  *      to attempt translation first.
 425  */
 426
 427 static
 428 void ux_exception(
 429                 int                     exception,
 430                 mach_exception_code_t   code,
 431                 mach_exception_subcode_t subcode,
 432                 int                     *ux_signal,
 433                 mach_exception_code_t   *ux_code)
 434 {
 435     /*
 436      *  Try machine-dependent translation first.
 437      */
 438     if (machine_exception(exception, code, subcode, ux_signal, ux_code))
 439         return;
 440
 441     switch(exception) {
 442
 443         case EXC_BAD_ACCESS:
 444                 if (code == KERN_INVALID_ADDRESS)
 445                         *ux_signal = SIGSEGV;
 446                 else
 447                         *ux_signal = SIGBUS;
 448                 break;
 449
 450         case EXC_BAD_INSTRUCTION:
 451             *ux_signal = SIGILL;
 452             break;
 453
 454         case EXC_ARITHMETIC:
 455             *ux_signal = SIGFPE;
 456             break;
 457
 458         case EXC_EMULATION:
 459             *ux_signal = SIGEMT;
 460             break;
 461
 462         case EXC_SOFTWARE:
 463             switch (code) {
 464
 465             case EXC_UNIX_BAD_SYSCALL:
 466                 *ux_signal = SIGSYS;
 467                 break;
 468             case EXC_UNIX_BAD_PIPE:
 469                 *ux_signal = SIGPIPE;
 470                 break;
 471             case EXC_UNIX_ABORT:
 472                 *ux_signal = SIGABRT;
 473                 break;
 474             case EXC_SOFT_SIGNAL:
 475                 *ux_signal = SIGKILL;
 476                 break;
 477             }
 478             break;
 479
 480         case EXC_BREAKPOINT:
 481             *ux_signal = SIGTRAP;
 482             break;
 483     }
 484 }