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 for (mach_msg_type_number_t i=0; i<exc_data_count; ++i) 117 g_message->exc_data.push_back(exc_data[i]); 118 return KERN_SUCCESS; 119 } else if (!MachTask::IsValid(g_message->task_port)) { 120 // Our original exception port isn't valid anymore check for a SIGTRAP 121 if (exc_type == EXC_SOFTWARE && exc_data_count == 2 && 122 exc_data[0] == EXC_SOFT_SIGNAL && exc_data[1] == SIGTRAP) { 123 // We got a SIGTRAP which indicates we might have exec'ed and possibly 124 // lost our old task port during the exec, so we just need to switch over 125 // to using this new task port 126 g_message->task_port = task_port; 127 g_message->thread_port = thread_port; 128 g_message->exc_type = exc_type; 129 for (mach_msg_type_number_t i=0; i<exc_data_count; ++i) 130 g_message->exc_data.push_back(exc_data[i]); 131 return KERN_SUCCESS; 132 } 133 } 134 return KERN_FAILURE; 135 } 136 137 void MachException::Message::Dump() const { 138 DNBLogThreadedIf(LOG_EXCEPTIONS, " exc_msg { bits = 0x%8.8x size = 0x%8.8x " 139 "remote-port = 0x%8.8x local-port = 0x%8.8x " 140 "reserved = 0x%8.8x id = 0x%8.8x } ", 141 exc_msg.hdr.msgh_bits, exc_msg.hdr.msgh_size, 142 exc_msg.hdr.msgh_remote_port, exc_msg.hdr.msgh_local_port, 143 exc_msg.hdr.msgh_reserved, exc_msg.hdr.msgh_id); 144 145 DNBLogThreadedIf(LOG_EXCEPTIONS, "reply_msg { bits = 0x%8.8x size = 0x%8.8x " 146 "remote-port = 0x%8.8x local-port = 0x%8.8x " 147 "reserved = 0x%8.8x id = 0x%8.8x }", 148 reply_msg.hdr.msgh_bits, reply_msg.hdr.msgh_size, 149 reply_msg.hdr.msgh_remote_port, 150 reply_msg.hdr.msgh_local_port, reply_msg.hdr.msgh_reserved, 151 reply_msg.hdr.msgh_id); 152 153 state.Dump(); 154 } 155 156 bool MachException::Data::GetStopInfo( 157 struct DNBThreadStopInfo *stop_info) const { 158 // Zero out the structure. 159 memset(stop_info, 0, sizeof(struct DNBThreadStopInfo)); 160 161 if (exc_type == 0) { 162 stop_info->reason = eStopTypeInvalid; 163 return true; 164 } 165 166 // We always stop with a mach exceptions 167 stop_info->reason = eStopTypeException; 168 // Save the EXC_XXXX exception type 169 stop_info->details.exception.type = exc_type; 170 171 // Fill in a text description 172 const char *exc_name = MachException::Name(exc_type); 173 char *desc = stop_info->description; 174 const char *end_desc = desc + DNB_THREAD_STOP_INFO_MAX_DESC_LENGTH; 175 if (exc_name) 176 desc += 177 snprintf(desc, DNB_THREAD_STOP_INFO_MAX_DESC_LENGTH, "%s", exc_name); 178 else 179 desc += 180 snprintf(desc, DNB_THREAD_STOP_INFO_MAX_DESC_LENGTH, "%i", exc_type); 181 182 stop_info->details.exception.data_count = exc_data.size(); 183 184 int soft_signal = SoftSignal(); 185 if (soft_signal) { 186 if (desc < end_desc) { 187 const char *sig_str = SysSignal::Name(soft_signal); 188 snprintf(desc, end_desc - desc, " EXC_SOFT_SIGNAL( %i ( %s ))", 189 soft_signal, sig_str ? sig_str : "unknown signal"); 190 } 191 } else { 192 // No special disassembly for exception data, just 193 size_t idx; 194 if (desc < end_desc) { 195 desc += snprintf(desc, end_desc - desc, " data[%llu] = {", 196 (uint64_t)stop_info->details.exception.data_count); 197 198 for (idx = 0; 199 desc < end_desc && idx < stop_info->details.exception.data_count; 200 ++idx) 201 desc += snprintf( 202 desc, end_desc - desc, "0x%llx%c", (uint64_t)exc_data[idx], 203 ((idx + 1 == stop_info->details.exception.data_count) ? '}' : ',')); 204 } 205 } 206 207 // Copy the exception data 208 size_t i; 209 for (i = 0; i < stop_info->details.exception.data_count; i++) 210 stop_info->details.exception.data[i] = exc_data[i]; 211 212 return true; 213 } 214 215 void MachException::Data::DumpStopReason() const { 216 int soft_signal = SoftSignal(); 217 if (soft_signal) { 218 const char *signal_str = SysSignal::Name(soft_signal); 219 if (signal_str) 220 DNBLog("signal(%s)", signal_str); 221 else 222 DNBLog("signal(%i)", soft_signal); 223 return; 224 } 225 DNBLog("%s", Name(exc_type)); 226 } 227 228 kern_return_t MachException::Message::Receive(mach_port_t port, 229 mach_msg_option_t options, 230 mach_msg_timeout_t timeout, 231 mach_port_t notify_port) { 232 DNBError err; 233 const bool log_exceptions = DNBLogCheckLogBit(LOG_EXCEPTIONS); 234 mach_msg_timeout_t mach_msg_timeout = 235 options & MACH_RCV_TIMEOUT ? timeout : 0; 236 if (log_exceptions && ((options & MACH_RCV_TIMEOUT) == 0)) { 237 // Dump this log message if we have no timeout in case it never returns 238 DNBLogThreaded("::mach_msg ( msg->{bits = %#x, size = %u remote_port = " 239 "%#x, local_port = %#x, reserved = 0x%x, id = 0x%x}, option " 240 "= %#x, send_size = 0, rcv_size = %llu, rcv_name = %#x, " 241 "timeout = %u, notify = %#x)", 242 exc_msg.hdr.msgh_bits, exc_msg.hdr.msgh_size, 243 exc_msg.hdr.msgh_remote_port, exc_msg.hdr.msgh_local_port, 244 exc_msg.hdr.msgh_reserved, exc_msg.hdr.msgh_id, options, 245 (uint64_t)sizeof(exc_msg.data), port, mach_msg_timeout, 246 notify_port); 247 } 248 249 err = ::mach_msg(&exc_msg.hdr, 250 options, // options 251 0, // Send size 252 sizeof(exc_msg.data), // Receive size 253 port, // exception port to watch for exception on 254 mach_msg_timeout, // timeout in msec (obeyed only if 255 // MACH_RCV_TIMEOUT is ORed into the 256 // options parameter) 257 notify_port); 258 259 // Dump any errors we get 260 if (log_exceptions) { 261 err.LogThreaded("::mach_msg ( msg->{bits = %#x, size = %u remote_port = " 262 "%#x, local_port = %#x, reserved = 0x%x, id = 0x%x}, " 263 "option = %#x, send_size = %u, rcv_size = %u, rcv_name = " 264 "%#x, timeout = %u, notify = %#x)", 265 exc_msg.hdr.msgh_bits, exc_msg.hdr.msgh_size, 266 exc_msg.hdr.msgh_remote_port, exc_msg.hdr.msgh_local_port, 267 exc_msg.hdr.msgh_reserved, exc_msg.hdr.msgh_id, options, 0, 268 sizeof(exc_msg.data), port, mach_msg_timeout, notify_port); 269 } 270 return err.Status(); 271 } 272 273 bool MachException::Message::CatchExceptionRaise(task_t task) { 274 bool success = false; 275 state.task_port = task; 276 g_message = &state; 277 // The exc_server function is the MIG generated server handling function 278 // to handle messages from the kernel relating to the occurrence of an 279 // exception in a thread. Such messages are delivered to the exception port 280 // set via thread_set_exception_ports or task_set_exception_ports. When an 281 // exception occurs in a thread, the thread sends an exception message to 282 // its exception port, blocking in the kernel waiting for the receipt of a 283 // reply. The exc_server function performs all necessary argument handling 284 // for this kernel message and calls catch_exception_raise, 285 // catch_exception_raise_state or catch_exception_raise_state_identity, 286 // which should handle the exception. If the called routine returns 287 // KERN_SUCCESS, a reply message will be sent, allowing the thread to 288 // continue from the point of the exception; otherwise, no reply message 289 // is sent and the called routine must have dealt with the exception 290 // thread directly. 291 if (mach_exc_server(&exc_msg.hdr, &reply_msg.hdr)) { 292 success = true; 293 } else if (DNBLogCheckLogBit(LOG_EXCEPTIONS)) { 294 DNBLogThreaded("mach_exc_server returned zero..."); 295 } 296 g_message = NULL; 297 return success; 298 } 299 300 kern_return_t MachException::Message::Reply(MachProcess *process, int signal) { 301 // Reply to the exception... 302 DNBError err; 303 304 // If we had a soft signal, we need to update the thread first so it can 305 // continue without signaling 306 int soft_signal = state.SoftSignal(); 307 if (soft_signal) { 308 int state_pid = -1; 309 if (process->Task().TaskPort() == state.task_port) { 310 // This is our task, so we can update the signal to send to it 311 state_pid = process->ProcessID(); 312 soft_signal = signal; 313 } else { 314 err = ::pid_for_task(state.task_port, &state_pid); 315 } 316 317 assert(state_pid != -1); 318 if (state_pid != -1) { 319 errno = 0; 320 if (::ptrace(PT_THUPDATE, state_pid, 321 (caddr_t)((uintptr_t)state.thread_port), soft_signal) != 0) 322 err.SetError(errno, DNBError::POSIX); 323 else 324 err.Clear(); 325 326 if (DNBLogCheckLogBit(LOG_EXCEPTIONS) || err.Fail()) 327 err.LogThreaded("::ptrace (request = PT_THUPDATE, pid = 0x%4.4x, tid = " 328 "0x%4.4x, signal = %i)", 329 state_pid, state.thread_port, soft_signal); 330 } 331 } 332 333 DNBLogThreadedIf( 334 LOG_EXCEPTIONS, "::mach_msg ( msg->{bits = %#x, size = %u, remote_port = " 335 "%#x, local_port = %#x, reserved = 0x%x, id = 0x%x}, " 336 "option = %#x, send_size = %u, rcv_size = %u, rcv_name = " 337 "%#x, timeout = %u, notify = %#x)", 338 reply_msg.hdr.msgh_bits, reply_msg.hdr.msgh_size, 339 reply_msg.hdr.msgh_remote_port, reply_msg.hdr.msgh_local_port, 340 reply_msg.hdr.msgh_reserved, reply_msg.hdr.msgh_id, 341 MACH_SEND_MSG | MACH_SEND_INTERRUPT, reply_msg.hdr.msgh_size, 0, 342 MACH_PORT_NULL, MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL); 343 344 err = ::mach_msg(&reply_msg.hdr, MACH_SEND_MSG | MACH_SEND_INTERRUPT, 345 reply_msg.hdr.msgh_size, 0, MACH_PORT_NULL, 346 MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL); 347 348 if (err.Fail()) { 349 if (err.Status() == MACH_SEND_INTERRUPTED) { 350 if (DNBLogCheckLogBit(LOG_EXCEPTIONS)) 351 err.LogThreaded("::mach_msg() - send interrupted"); 352 // TODO: keep retrying to reply??? 353 } else { 354 if (state.task_port == process->Task().TaskPort()) { 355 DNBLogThreaded("error: mach_msg() returned an error when replying to a " 356 "mach exception: error = %u", 357 err.Status()); 358 } else { 359 if (DNBLogCheckLogBit(LOG_EXCEPTIONS)) 360 err.LogThreaded("::mach_msg() - failed (child of task)"); 361 } 362 } 363 } 364 365 return err.Status(); 366 } 367 368 void MachException::Data::Dump() const { 369 const char *exc_type_name = MachException::Name(exc_type); 370 DNBLogThreadedIf( 371 LOG_EXCEPTIONS, " state { task_port = 0x%4.4x, thread_port = " 372 "0x%4.4x, exc_type = %i (%s) ...", 373 task_port, thread_port, exc_type, exc_type_name ? exc_type_name : "???"); 374 375 const size_t exc_data_count = exc_data.size(); 376 // Dump any special exception data contents 377 int soft_signal = SoftSignal(); 378 if (soft_signal != 0) { 379 const char *sig_str = SysSignal::Name(soft_signal); 380 DNBLogThreadedIf(LOG_EXCEPTIONS, 381 " exc_data: EXC_SOFT_SIGNAL (%i (%s))", 382 soft_signal, sig_str ? sig_str : "unknown signal"); 383 } else { 384 // No special disassembly for this data, just dump the data 385 size_t idx; 386 for (idx = 0; idx < exc_data_count; ++idx) { 387 DNBLogThreadedIf(LOG_EXCEPTIONS, " exc_data[%llu]: 0x%llx", 388 (uint64_t)idx, (uint64_t)exc_data[idx]); 389 } 390 } 391 } 392 393 #define PREV_EXC_MASK_ALL \ 394 (EXC_MASK_BAD_ACCESS | EXC_MASK_BAD_INSTRUCTION | EXC_MASK_ARITHMETIC | \ 395 EXC_MASK_EMULATION | EXC_MASK_SOFTWARE | EXC_MASK_BREAKPOINT | \ 396 EXC_MASK_SYSCALL | EXC_MASK_MACH_SYSCALL | EXC_MASK_RPC_ALERT | \ 397 EXC_MASK_MACHINE) 398 399 // Don't listen for EXC_RESOURCE, it should really get handled by the system 400 // handler. 401 402 #ifndef EXC_RESOURCE 403 #define EXC_RESOURCE 11 404 #endif 405 406 #ifndef EXC_MASK_RESOURCE 407 #define EXC_MASK_RESOURCE (1 << EXC_RESOURCE) 408 #endif 409 410 #define LLDB_EXC_MASK (EXC_MASK_ALL & ~EXC_MASK_RESOURCE) 411 412 kern_return_t MachException::PortInfo::Save(task_t task) { 413 DNBLogThreadedIf(LOG_EXCEPTIONS | LOG_VERBOSE, 414 "MachException::PortInfo::Save ( task = 0x%4.4x )", task); 415 // Be careful to be able to have debugserver built on a newer OS than what 416 // it is currently running on by being able to start with all exceptions 417 // and back off to just what is supported on the current system 418 DNBError err; 419 420 mask = LLDB_EXC_MASK; 421 422 count = (sizeof(ports) / sizeof(ports[0])); 423 err = ::task_get_exception_ports(task, mask, masks, &count, ports, behaviors, 424 flavors); 425 if (DNBLogCheckLogBit(LOG_EXCEPTIONS) || err.Fail()) 426 err.LogThreaded("::task_get_exception_ports ( task = 0x%4.4x, mask = 0x%x, " 427 "maskCnt => %u, ports, behaviors, flavors )", 428 task, mask, count); 429 430 if (err.Status() == KERN_INVALID_ARGUMENT && mask != PREV_EXC_MASK_ALL) { 431 mask = PREV_EXC_MASK_ALL; 432 count = (sizeof(ports) / sizeof(ports[0])); 433 err = ::task_get_exception_ports(task, mask, masks, &count, ports, 434 behaviors, flavors); 435 if (DNBLogCheckLogBit(LOG_EXCEPTIONS) || err.Fail()) 436 err.LogThreaded("::task_get_exception_ports ( task = 0x%4.4x, mask = " 437 "0x%x, maskCnt => %u, ports, behaviors, flavors )", 438 task, mask, count); 439 } 440 if (err.Fail()) { 441 mask = 0; 442 count = 0; 443 } 444 return err.Status(); 445 } 446 447 kern_return_t MachException::PortInfo::Restore(task_t task) { 448 DNBLogThreadedIf(LOG_EXCEPTIONS | LOG_VERBOSE, 449 "MachException::PortInfo::Restore( task = 0x%4.4x )", task); 450 uint32_t i = 0; 451 DNBError err; 452 if (count > 0) { 453 for (i = 0; i < count; i++) { 454 err = ::task_set_exception_ports(task, masks[i], ports[i], behaviors[i], 455 flavors[i]); 456 if (DNBLogCheckLogBit(LOG_EXCEPTIONS) || err.Fail()) { 457 err.LogThreaded("::task_set_exception_ports ( task = 0x%4.4x, " 458 "exception_mask = 0x%8.8x, new_port = 0x%4.4x, " 459 "behavior = 0x%8.8x, new_flavor = 0x%8.8x )", 460 task, masks[i], ports[i], behaviors[i], flavors[i]); 461 // Bail if we encounter any errors 462 } 463 464 if (err.Fail()) 465 break; 466 } 467 } 468 count = 0; 469 return err.Status(); 470 } 471 472 const char *MachException::Name(exception_type_t exc_type) { 473 switch (exc_type) { 474 case EXC_BAD_ACCESS: 475 return "EXC_BAD_ACCESS"; 476 case EXC_BAD_INSTRUCTION: 477 return "EXC_BAD_INSTRUCTION"; 478 case EXC_ARITHMETIC: 479 return "EXC_ARITHMETIC"; 480 case EXC_EMULATION: 481 return "EXC_EMULATION"; 482 case EXC_SOFTWARE: 483 return "EXC_SOFTWARE"; 484 case EXC_BREAKPOINT: 485 return "EXC_BREAKPOINT"; 486 case EXC_SYSCALL: 487 return "EXC_SYSCALL"; 488 case EXC_MACH_SYSCALL: 489 return "EXC_MACH_SYSCALL"; 490 case EXC_RPC_ALERT: 491 return "EXC_RPC_ALERT"; 492 #ifdef EXC_CRASH 493 case EXC_CRASH: 494 return "EXC_CRASH"; 495 #endif 496 default: 497 break; 498 } 499 return NULL; 500 } 501