1 //===-- MachException.cpp ---------------------------------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // Created by Greg Clayton on 6/18/07. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "MachException.h" 15 #include "DNB.h" 16 #include "DNBError.h" 17 #include "DNBLog.h" 18 #include "MachProcess.h" 19 #include "PThreadMutex.h" 20 #include "SysSignal.h" 21 #include <errno.h> 22 #include <sys/ptrace.h> 23 #include <sys/types.h> 24 25 // Routine mach_exception_raise 26 extern "C" kern_return_t 27 catch_mach_exception_raise(mach_port_t exception_port, mach_port_t thread, 28 mach_port_t task, exception_type_t exception, 29 mach_exception_data_t code, 30 mach_msg_type_number_t codeCnt); 31 32 extern "C" kern_return_t catch_mach_exception_raise_state( 33 mach_port_t exception_port, exception_type_t exception, 34 const mach_exception_data_t code, mach_msg_type_number_t codeCnt, 35 int *flavor, const thread_state_t old_state, 36 mach_msg_type_number_t old_stateCnt, thread_state_t new_state, 37 mach_msg_type_number_t *new_stateCnt); 38 39 // Routine mach_exception_raise_state_identity 40 extern "C" kern_return_t catch_mach_exception_raise_state_identity( 41 mach_port_t exception_port, mach_port_t thread, mach_port_t task, 42 exception_type_t exception, mach_exception_data_t code, 43 mach_msg_type_number_t codeCnt, int *flavor, thread_state_t old_state, 44 mach_msg_type_number_t old_stateCnt, thread_state_t new_state, 45 mach_msg_type_number_t *new_stateCnt); 46 47 extern "C" boolean_t mach_exc_server(mach_msg_header_t *InHeadP, 48 mach_msg_header_t *OutHeadP); 49 50 // Note: g_message points to the storage allocated to catch the data from 51 // catching the current exception raise. It's populated when we catch a raised 52 // exception which can't immediately be replied to. 53 // 54 // If it becomes possible to catch exceptions from multiple threads 55 // simultaneously, accesses to g_message would need to be mutually exclusive. 56 static MachException::Data *g_message = NULL; 57 58 extern "C" kern_return_t catch_mach_exception_raise_state( 59 mach_port_t exc_port, exception_type_t exc_type, 60 const mach_exception_data_t exc_data, mach_msg_type_number_t exc_data_count, 61 int *flavor, const thread_state_t old_state, 62 mach_msg_type_number_t old_stateCnt, thread_state_t new_state, 63 mach_msg_type_number_t *new_stateCnt) { 64 if (DNBLogCheckLogBit(LOG_EXCEPTIONS)) { 65 DNBLogThreaded("::%s ( exc_port = 0x%4.4x, exc_type = %d ( %s ), exc_data " 66 "= 0x%llx, exc_data_count = %d)", 67 __FUNCTION__, exc_port, exc_type, 68 MachException::Name(exc_type), (uint64_t)exc_data, 69 exc_data_count); 70 } 71 return KERN_FAILURE; 72 } 73 74 extern "C" kern_return_t catch_mach_exception_raise_state_identity( 75 mach_port_t exc_port, mach_port_t thread_port, mach_port_t task_port, 76 exception_type_t exc_type, mach_exception_data_t exc_data, 77 mach_msg_type_number_t exc_data_count, int *flavor, 78 thread_state_t old_state, mach_msg_type_number_t old_stateCnt, 79 thread_state_t new_state, mach_msg_type_number_t *new_stateCnt) { 80 if (DNBLogCheckLogBit(LOG_EXCEPTIONS)) { 81 DNBLogThreaded("::%s ( exc_port = 0x%4.4x, thd_port = 0x%4.4x, tsk_port = " 82 "0x%4.4x, exc_type = %d ( %s ), exc_data[%d] = { 0x%llx, " 83 "0x%llx })", 84 __FUNCTION__, exc_port, thread_port, task_port, exc_type, 85 MachException::Name(exc_type), exc_data_count, 86 (uint64_t)(exc_data_count > 0 ? exc_data[0] : 0xBADDBADD), 87 (uint64_t)(exc_data_count > 1 ? exc_data[1] : 0xBADDBADD)); 88 } 89 mach_port_deallocate(mach_task_self(), task_port); 90 mach_port_deallocate(mach_task_self(), thread_port); 91 92 return KERN_FAILURE; 93 } 94 95 extern "C" kern_return_t 96 catch_mach_exception_raise(mach_port_t exc_port, mach_port_t thread_port, 97 mach_port_t task_port, exception_type_t exc_type, 98 mach_exception_data_t exc_data, 99 mach_msg_type_number_t exc_data_count) { 100 if (DNBLogCheckLogBit(LOG_EXCEPTIONS)) { 101 DNBLogThreaded("::%s ( exc_port = 0x%4.4x, thd_port = 0x%4.4x, tsk_port = " 102 "0x%4.4x, exc_type = %d ( %s ), exc_data[%d] = { 0x%llx, " 103 "0x%llx })", 104 __FUNCTION__, exc_port, thread_port, task_port, exc_type, 105 MachException::Name(exc_type), exc_data_count, 106 (uint64_t)(exc_data_count > 0 ? exc_data[0] : 0xBADDBADD), 107 (uint64_t)(exc_data_count > 1 ? exc_data[1] : 0xBADDBADD)); 108 } 109 g_message->exc_type = 0; 110 g_message->exc_data.clear(); 111 112 if (task_port == g_message->task_port) { 113 g_message->task_port = task_port; 114 g_message->thread_port = thread_port; 115 g_message->exc_type = exc_type; 116 g_message->AppendExceptionData(exc_data, exc_data_count); 117 return KERN_SUCCESS; 118 } else if (!MachTask::IsValid(g_message->task_port)) { 119 // Our original exception port isn't valid anymore check for a SIGTRAP 120 if (exc_type == EXC_SOFTWARE && exc_data_count == 2 && 121 exc_data[0] == EXC_SOFT_SIGNAL && exc_data[1] == SIGTRAP) { 122 // We got a SIGTRAP which indicates we might have exec'ed and possibly 123 // lost our old task port during the exec, so we just need to switch over 124 // to using this new task port 125 g_message->task_port = task_port; 126 g_message->thread_port = thread_port; 127 g_message->exc_type = exc_type; 128 g_message->AppendExceptionData(exc_data, exc_data_count); 129 return KERN_SUCCESS; 130 } 131 } 132 return KERN_FAILURE; 133 } 134 135 void MachException::Message::Dump() const { 136 DNBLogThreadedIf(LOG_EXCEPTIONS, " exc_msg { bits = 0x%8.8x size = 0x%8.8x " 137 "remote-port = 0x%8.8x local-port = 0x%8.8x " 138 "reserved = 0x%8.8x id = 0x%8.8x } ", 139 exc_msg.hdr.msgh_bits, exc_msg.hdr.msgh_size, 140 exc_msg.hdr.msgh_remote_port, exc_msg.hdr.msgh_local_port, 141 exc_msg.hdr.msgh_reserved, exc_msg.hdr.msgh_id); 142 143 DNBLogThreadedIf(LOG_EXCEPTIONS, "reply_msg { bits = 0x%8.8x size = 0x%8.8x " 144 "remote-port = 0x%8.8x local-port = 0x%8.8x " 145 "reserved = 0x%8.8x id = 0x%8.8x }", 146 reply_msg.hdr.msgh_bits, reply_msg.hdr.msgh_size, 147 reply_msg.hdr.msgh_remote_port, 148 reply_msg.hdr.msgh_local_port, reply_msg.hdr.msgh_reserved, 149 reply_msg.hdr.msgh_id); 150 151 state.Dump(); 152 } 153 154 bool MachException::Data::GetStopInfo( 155 struct DNBThreadStopInfo *stop_info) const { 156 // Zero out the structure. 157 memset(stop_info, 0, sizeof(struct DNBThreadStopInfo)); 158 159 if (exc_type == 0) { 160 stop_info->reason = eStopTypeInvalid; 161 return true; 162 } 163 164 // We always stop with a mach exceptions 165 stop_info->reason = eStopTypeException; 166 // Save the EXC_XXXX exception type 167 stop_info->details.exception.type = exc_type; 168 169 // Fill in a text description 170 const char *exc_name = MachException::Name(exc_type); 171 char *desc = stop_info->description; 172 const char *end_desc = desc + DNB_THREAD_STOP_INFO_MAX_DESC_LENGTH; 173 if (exc_name) 174 desc += 175 snprintf(desc, DNB_THREAD_STOP_INFO_MAX_DESC_LENGTH, "%s", exc_name); 176 else 177 desc += 178 snprintf(desc, DNB_THREAD_STOP_INFO_MAX_DESC_LENGTH, "%i", exc_type); 179 180 stop_info->details.exception.data_count = exc_data.size(); 181 182 int soft_signal = SoftSignal(); 183 if (soft_signal) { 184 if (desc < end_desc) { 185 const char *sig_str = SysSignal::Name(soft_signal); 186 snprintf(desc, end_desc - desc, " EXC_SOFT_SIGNAL( %i ( %s ))", 187 soft_signal, sig_str ? sig_str : "unknown signal"); 188 } 189 } else { 190 // No special disassembly for exception data, just 191 size_t idx; 192 if (desc < end_desc) { 193 desc += snprintf(desc, end_desc - desc, " data[%llu] = {", 194 (uint64_t)stop_info->details.exception.data_count); 195 196 for (idx = 0; 197 desc < end_desc && idx < stop_info->details.exception.data_count; 198 ++idx) 199 desc += snprintf( 200 desc, end_desc - desc, "0x%llx%c", (uint64_t)exc_data[idx], 201 ((idx + 1 == stop_info->details.exception.data_count) ? '}' : ',')); 202 } 203 } 204 205 // Copy the exception data 206 size_t i; 207 for (i = 0; i < stop_info->details.exception.data_count; i++) 208 stop_info->details.exception.data[i] = exc_data[i]; 209 210 return true; 211 } 212 213 void MachException::Data::DumpStopReason() const { 214 int soft_signal = SoftSignal(); 215 if (soft_signal) { 216 const char *signal_str = SysSignal::Name(soft_signal); 217 if (signal_str) 218 DNBLog("signal(%s)", signal_str); 219 else 220 DNBLog("signal(%i)", soft_signal); 221 return; 222 } 223 DNBLog("%s", Name(exc_type)); 224 } 225 226 kern_return_t MachException::Message::Receive(mach_port_t port, 227 mach_msg_option_t options, 228 mach_msg_timeout_t timeout, 229 mach_port_t notify_port) { 230 DNBError err; 231 const bool log_exceptions = DNBLogCheckLogBit(LOG_EXCEPTIONS); 232 mach_msg_timeout_t mach_msg_timeout = 233 options & MACH_RCV_TIMEOUT ? timeout : 0; 234 if (log_exceptions && ((options & MACH_RCV_TIMEOUT) == 0)) { 235 // Dump this log message if we have no timeout in case it never returns 236 DNBLogThreaded("::mach_msg ( msg->{bits = %#x, size = %u remote_port = " 237 "%#x, local_port = %#x, reserved = 0x%x, id = 0x%x}, option " 238 "= %#x, send_size = 0, rcv_size = %llu, rcv_name = %#x, " 239 "timeout = %u, notify = %#x)", 240 exc_msg.hdr.msgh_bits, exc_msg.hdr.msgh_size, 241 exc_msg.hdr.msgh_remote_port, exc_msg.hdr.msgh_local_port, 242 exc_msg.hdr.msgh_reserved, exc_msg.hdr.msgh_id, options, 243 (uint64_t)sizeof(exc_msg.data), port, mach_msg_timeout, 244 notify_port); 245 } 246 247 err = ::mach_msg(&exc_msg.hdr, 248 options, // options 249 0, // Send size 250 sizeof(exc_msg.data), // Receive size 251 port, // exception port to watch for exception on 252 mach_msg_timeout, // timeout in msec (obeyed only if 253 // MACH_RCV_TIMEOUT is ORed into the 254 // options parameter) 255 notify_port); 256 257 // Dump any errors we get 258 if (log_exceptions) { 259 err.LogThreaded("::mach_msg ( msg->{bits = %#x, size = %u remote_port = " 260 "%#x, local_port = %#x, reserved = 0x%x, id = 0x%x}, " 261 "option = %#x, send_size = %u, rcv_size = %u, rcv_name = " 262 "%#x, timeout = %u, notify = %#x)", 263 exc_msg.hdr.msgh_bits, exc_msg.hdr.msgh_size, 264 exc_msg.hdr.msgh_remote_port, exc_msg.hdr.msgh_local_port, 265 exc_msg.hdr.msgh_reserved, exc_msg.hdr.msgh_id, options, 0, 266 sizeof(exc_msg.data), port, mach_msg_timeout, notify_port); 267 } 268 return err.Status(); 269 } 270 271 bool MachException::Message::CatchExceptionRaise(task_t task) { 272 bool success = false; 273 state.task_port = task; 274 g_message = &state; 275 // The exc_server function is the MIG generated server handling function 276 // to handle messages from the kernel relating to the occurrence of an 277 // exception in a thread. Such messages are delivered to the exception port 278 // set via thread_set_exception_ports or task_set_exception_ports. When an 279 // exception occurs in a thread, the thread sends an exception message to 280 // its exception port, blocking in the kernel waiting for the receipt of a 281 // reply. The exc_server function performs all necessary argument handling 282 // for this kernel message and calls catch_exception_raise, 283 // catch_exception_raise_state or catch_exception_raise_state_identity, 284 // which should handle the exception. If the called routine returns 285 // KERN_SUCCESS, a reply message will be sent, allowing the thread to 286 // continue from the point of the exception; otherwise, no reply message 287 // is sent and the called routine must have dealt with the exception 288 // thread directly. 289 if (mach_exc_server(&exc_msg.hdr, &reply_msg.hdr)) { 290 success = true; 291 } else if (DNBLogCheckLogBit(LOG_EXCEPTIONS)) { 292 DNBLogThreaded("mach_exc_server returned zero..."); 293 } 294 g_message = NULL; 295 return success; 296 } 297 298 kern_return_t MachException::Message::Reply(MachProcess *process, int signal) { 299 // Reply to the exception... 300 DNBError err; 301 302 // If we had a soft signal, we need to update the thread first so it can 303 // continue without signaling 304 int soft_signal = state.SoftSignal(); 305 if (soft_signal) { 306 int state_pid = -1; 307 if (process->Task().TaskPort() == state.task_port) { 308 // This is our task, so we can update the signal to send to it 309 state_pid = process->ProcessID(); 310 soft_signal = signal; 311 } else { 312 err = ::pid_for_task(state.task_port, &state_pid); 313 } 314 315 assert(state_pid != -1); 316 if (state_pid != -1) { 317 errno = 0; 318 if (::ptrace(PT_THUPDATE, state_pid, 319 (caddr_t)((uintptr_t)state.thread_port), soft_signal) != 0) 320 err.SetError(errno, DNBError::POSIX); 321 else 322 err.Clear(); 323 324 if (DNBLogCheckLogBit(LOG_EXCEPTIONS) || err.Fail()) 325 err.LogThreaded("::ptrace (request = PT_THUPDATE, pid = 0x%4.4x, tid = " 326 "0x%4.4x, signal = %i)", 327 state_pid, state.thread_port, soft_signal); 328 } 329 } 330 331 DNBLogThreadedIf( 332 LOG_EXCEPTIONS, "::mach_msg ( msg->{bits = %#x, size = %u, remote_port = " 333 "%#x, local_port = %#x, reserved = 0x%x, id = 0x%x}, " 334 "option = %#x, send_size = %u, rcv_size = %u, rcv_name = " 335 "%#x, timeout = %u, notify = %#x)", 336 reply_msg.hdr.msgh_bits, reply_msg.hdr.msgh_size, 337 reply_msg.hdr.msgh_remote_port, reply_msg.hdr.msgh_local_port, 338 reply_msg.hdr.msgh_reserved, reply_msg.hdr.msgh_id, 339 MACH_SEND_MSG | MACH_SEND_INTERRUPT, reply_msg.hdr.msgh_size, 0, 340 MACH_PORT_NULL, MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL); 341 342 err = ::mach_msg(&reply_msg.hdr, MACH_SEND_MSG | MACH_SEND_INTERRUPT, 343 reply_msg.hdr.msgh_size, 0, MACH_PORT_NULL, 344 MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL); 345 346 if (err.Fail()) { 347 if (err.Status() == MACH_SEND_INTERRUPTED) { 348 if (DNBLogCheckLogBit(LOG_EXCEPTIONS)) 349 err.LogThreaded("::mach_msg() - send interrupted"); 350 // TODO: keep retrying to reply??? 351 } else { 352 if (state.task_port == process->Task().TaskPort()) { 353 DNBLogThreaded("error: mach_msg() returned an error when replying to a " 354 "mach exception: error = %u", 355 err.Status()); 356 } else { 357 if (DNBLogCheckLogBit(LOG_EXCEPTIONS)) 358 err.LogThreaded("::mach_msg() - failed (child of task)"); 359 } 360 } 361 } 362 363 return err.Status(); 364 } 365 366 void MachException::Data::Dump() const { 367 const char *exc_type_name = MachException::Name(exc_type); 368 DNBLogThreadedIf( 369 LOG_EXCEPTIONS, " state { task_port = 0x%4.4x, thread_port = " 370 "0x%4.4x, exc_type = %i (%s) ...", 371 task_port, thread_port, exc_type, exc_type_name ? exc_type_name : "???"); 372 373 const size_t exc_data_count = exc_data.size(); 374 // Dump any special exception data contents 375 int soft_signal = SoftSignal(); 376 if (soft_signal != 0) { 377 const char *sig_str = SysSignal::Name(soft_signal); 378 DNBLogThreadedIf(LOG_EXCEPTIONS, 379 " exc_data: EXC_SOFT_SIGNAL (%i (%s))", 380 soft_signal, sig_str ? sig_str : "unknown signal"); 381 } else { 382 // No special disassembly for this data, just dump the data 383 size_t idx; 384 for (idx = 0; idx < exc_data_count; ++idx) { 385 DNBLogThreadedIf(LOG_EXCEPTIONS, " exc_data[%llu]: 0x%llx", 386 (uint64_t)idx, (uint64_t)exc_data[idx]); 387 } 388 } 389 } 390 391 #define PREV_EXC_MASK_ALL \ 392 (EXC_MASK_BAD_ACCESS | EXC_MASK_BAD_INSTRUCTION | EXC_MASK_ARITHMETIC | \ 393 EXC_MASK_EMULATION | EXC_MASK_SOFTWARE | EXC_MASK_BREAKPOINT | \ 394 EXC_MASK_SYSCALL | EXC_MASK_MACH_SYSCALL | EXC_MASK_RPC_ALERT | \ 395 EXC_MASK_MACHINE) 396 397 // Don't listen for EXC_RESOURCE, it should really get handled by the system 398 // handler. 399 400 #ifndef EXC_RESOURCE 401 #define EXC_RESOURCE 11 402 #endif 403 404 #ifndef EXC_MASK_RESOURCE 405 #define EXC_MASK_RESOURCE (1 << EXC_RESOURCE) 406 #endif 407 408 #define LLDB_EXC_MASK (EXC_MASK_ALL & ~EXC_MASK_RESOURCE) 409 410 kern_return_t MachException::PortInfo::Save(task_t task) { 411 DNBLogThreadedIf(LOG_EXCEPTIONS | LOG_VERBOSE, 412 "MachException::PortInfo::Save ( task = 0x%4.4x )", task); 413 // Be careful to be able to have debugserver built on a newer OS than what 414 // it is currently running on by being able to start with all exceptions 415 // and back off to just what is supported on the current system 416 DNBError err; 417 418 mask = LLDB_EXC_MASK; 419 420 count = (sizeof(ports) / sizeof(ports[0])); 421 err = ::task_get_exception_ports(task, mask, masks, &count, ports, behaviors, 422 flavors); 423 if (DNBLogCheckLogBit(LOG_EXCEPTIONS) || err.Fail()) 424 err.LogThreaded("::task_get_exception_ports ( task = 0x%4.4x, mask = 0x%x, " 425 "maskCnt => %u, ports, behaviors, flavors )", 426 task, mask, count); 427 428 if (err.Status() == KERN_INVALID_ARGUMENT && mask != PREV_EXC_MASK_ALL) { 429 mask = PREV_EXC_MASK_ALL; 430 count = (sizeof(ports) / sizeof(ports[0])); 431 err = ::task_get_exception_ports(task, mask, masks, &count, ports, 432 behaviors, flavors); 433 if (DNBLogCheckLogBit(LOG_EXCEPTIONS) || err.Fail()) 434 err.LogThreaded("::task_get_exception_ports ( task = 0x%4.4x, mask = " 435 "0x%x, maskCnt => %u, ports, behaviors, flavors )", 436 task, mask, count); 437 } 438 if (err.Fail()) { 439 mask = 0; 440 count = 0; 441 } 442 return err.Status(); 443 } 444 445 kern_return_t MachException::PortInfo::Restore(task_t task) { 446 DNBLogThreadedIf(LOG_EXCEPTIONS | LOG_VERBOSE, 447 "MachException::PortInfo::Restore( task = 0x%4.4x )", task); 448 uint32_t i = 0; 449 DNBError err; 450 if (count > 0) { 451 for (i = 0; i < count; i++) { 452 err = ::task_set_exception_ports(task, masks[i], ports[i], behaviors[i], 453 flavors[i]); 454 if (DNBLogCheckLogBit(LOG_EXCEPTIONS) || err.Fail()) { 455 err.LogThreaded("::task_set_exception_ports ( task = 0x%4.4x, " 456 "exception_mask = 0x%8.8x, new_port = 0x%4.4x, " 457 "behavior = 0x%8.8x, new_flavor = 0x%8.8x )", 458 task, masks[i], ports[i], behaviors[i], flavors[i]); 459 // Bail if we encounter any errors 460 } 461 462 if (err.Fail()) 463 break; 464 } 465 } 466 count = 0; 467 return err.Status(); 468 } 469 470 const char *MachException::Name(exception_type_t exc_type) { 471 switch (exc_type) { 472 case EXC_BAD_ACCESS: 473 return "EXC_BAD_ACCESS"; 474 case EXC_BAD_INSTRUCTION: 475 return "EXC_BAD_INSTRUCTION"; 476 case EXC_ARITHMETIC: 477 return "EXC_ARITHMETIC"; 478 case EXC_EMULATION: 479 return "EXC_EMULATION"; 480 case EXC_SOFTWARE: 481 return "EXC_SOFTWARE"; 482 case EXC_BREAKPOINT: 483 return "EXC_BREAKPOINT"; 484 case EXC_SYSCALL: 485 return "EXC_SYSCALL"; 486 case EXC_MACH_SYSCALL: 487 return "EXC_MACH_SYSCALL"; 488 case EXC_RPC_ALERT: 489 return "EXC_RPC_ALERT"; 490 #ifdef EXC_CRASH 491 case EXC_CRASH: 492 return "EXC_CRASH"; 493 #endif 494 default: 495 break; 496 } 497 return NULL; 498 } 499