runtime/runtime_linux.cc - platform/art - Gitiles

 /*
  * Copyright (C) 2011 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include "runtime.h"

 #include <signal.h>
 #include <string.h>
 #include <sys/utsname.h>
 #include <inttypes.h>

 #include "base/logging.h"
 #include "base/mutex.h"
 #include "base/stringprintf.h"
 #include "thread-inl.h"
 #include "utils.h"

 namespace art {

 static constexpr bool kDumpHeapObjectOnSigsevg = false;

 struct Backtrace {
   void Dump(std::ostream& os) {
     DumpNativeStack(os, GetTid(), "\t", true);
   }
 };

 struct OsInfo {
   void Dump(std::ostream& os) {
     utsname info;
     uname(&info);
     // Linux 2.6.38.8-gg784 (x86_64)
     // Darwin 11.4.0 (x86_64)
     os << info.sysname << " " << info.release << " (" << info.machine << ")";
   }
 };

 static const char* GetSignalName(int signal_number) {
   switch (signal_number) {
     case SIGABRT: return "SIGABRT";
     case SIGBUS: return "SIGBUS";
     case SIGFPE: return "SIGFPE";
     case SIGILL: return "SIGILL";
     case SIGPIPE: return "SIGPIPE";
     case SIGSEGV: return "SIGSEGV";
 #if defined(SIGSTKFLT)
     case SIGSTKFLT: return "SIGSTKFLT";
 #endif
     case SIGTRAP: return "SIGTRAP";
   }
   return "??";
 }

 static const char* GetSignalCodeName(int signal_number, int signal_code) {
   // Try the signal-specific codes...
   switch (signal_number) {
     case SIGILL:
       switch (signal_code) {
         case ILL_ILLOPC: return "ILL_ILLOPC";
         case ILL_ILLOPN: return "ILL_ILLOPN";
         case ILL_ILLADR: return "ILL_ILLADR";
         case ILL_ILLTRP: return "ILL_ILLTRP";
         case ILL_PRVOPC: return "ILL_PRVOPC";
         case ILL_PRVREG: return "ILL_PRVREG";
         case ILL_COPROC: return "ILL_COPROC";
         case ILL_BADSTK: return "ILL_BADSTK";
       }
       break;
     case SIGBUS:
       switch (signal_code) {
         case BUS_ADRALN: return "BUS_ADRALN";
         case BUS_ADRERR: return "BUS_ADRERR";
         case BUS_OBJERR: return "BUS_OBJERR";
       }
       break;
     case SIGFPE:
       switch (signal_code) {
         case FPE_INTDIV: return "FPE_INTDIV";
         case FPE_INTOVF: return "FPE_INTOVF";
         case FPE_FLTDIV: return "FPE_FLTDIV";
         case FPE_FLTOVF: return "FPE_FLTOVF";
         case FPE_FLTUND: return "FPE_FLTUND";
         case FPE_FLTRES: return "FPE_FLTRES";
         case FPE_FLTINV: return "FPE_FLTINV";
         case FPE_FLTSUB: return "FPE_FLTSUB";
       }
       break;
     case SIGSEGV:
       switch (signal_code) {
         case SEGV_MAPERR: return "SEGV_MAPERR";
         case SEGV_ACCERR: return "SEGV_ACCERR";
       }
       break;
     case SIGTRAP:
       switch (signal_code) {
         case TRAP_BRKPT: return "TRAP_BRKPT";
         case TRAP_TRACE: return "TRAP_TRACE";
       }
       break;
   }
   // Then the other codes...
   switch (signal_code) {
     case SI_USER:     return "SI_USER";
 #if defined(SI_KERNEL)
     case SI_KERNEL:   return "SI_KERNEL";
 #endif
     case SI_QUEUE:    return "SI_QUEUE";
     case SI_TIMER:    return "SI_TIMER";
     case SI_MESGQ:    return "SI_MESGQ";
     case SI_ASYNCIO:  return "SI_ASYNCIO";
 #if defined(SI_SIGIO)
     case SI_SIGIO:    return "SI_SIGIO";
 #endif
 #if defined(SI_TKILL)
     case SI_TKILL:    return "SI_TKILL";
 #endif
   }
   // Then give up...
   return "?";
 }

 struct UContext {
   explicit UContext(void* raw_context) : context(reinterpret_cast<ucontext_t*>(raw_context)->uc_mcontext) {}

   void Dump(std::ostream& os) {
     // TODO: support non-x86 hosts (not urgent because this code doesn't run on targets).
 #if defined(__APPLE__) && defined(__i386__)
     DumpRegister32(os, "eax", context->__ss.__eax);
     DumpRegister32(os, "ebx", context->__ss.__ebx);
     DumpRegister32(os, "ecx", context->__ss.__ecx);
     DumpRegister32(os, "edx", context->__ss.__edx);
     os << '\n';

     DumpRegister32(os, "edi", context->__ss.__edi);
     DumpRegister32(os, "esi", context->__ss.__esi);
     DumpRegister32(os, "ebp", context->__ss.__ebp);
     DumpRegister32(os, "esp", context->__ss.__esp);
     os << '\n';

     DumpRegister32(os, "eip", context->__ss.__eip);
     os << "                   ";
     DumpRegister32(os, "eflags", context->__ss.__eflags);
     DumpX86Flags(os, context->__ss.__eflags);
     os << '\n';

     DumpRegister32(os, "cs",  context->__ss.__cs);
     DumpRegister32(os, "ds",  context->__ss.__ds);
     DumpRegister32(os, "es",  context->__ss.__es);
     DumpRegister32(os, "fs",  context->__ss.__fs);
     os << '\n';
     DumpRegister32(os, "gs",  context->__ss.__gs);
     DumpRegister32(os, "ss",  context->__ss.__ss);
 #elif defined(__linux__) && defined(__i386__)
     DumpRegister32(os, "eax", context.gregs[REG_EAX]);
     DumpRegister32(os, "ebx", context.gregs[REG_EBX]);
     DumpRegister32(os, "ecx", context.gregs[REG_ECX]);
     DumpRegister32(os, "edx", context.gregs[REG_EDX]);
     os << '\n';

     DumpRegister32(os, "edi", context.gregs[REG_EDI]);
     DumpRegister32(os, "esi", context.gregs[REG_ESI]);
     DumpRegister32(os, "ebp", context.gregs[REG_EBP]);
     DumpRegister32(os, "esp", context.gregs[REG_ESP]);
     os << '\n';

     DumpRegister32(os, "eip", context.gregs[REG_EIP]);
     os << "                   ";
     DumpRegister32(os, "eflags", context.gregs[REG_EFL]);
     DumpX86Flags(os, context.gregs[REG_EFL]);
     os << '\n';

     DumpRegister32(os, "cs",  context.gregs[REG_CS]);
     DumpRegister32(os, "ds",  context.gregs[REG_DS]);
     DumpRegister32(os, "es",  context.gregs[REG_ES]);
     DumpRegister32(os, "fs",  context.gregs[REG_FS]);
     os << '\n';
     DumpRegister32(os, "gs",  context.gregs[REG_GS]);
     DumpRegister32(os, "ss",  context.gregs[REG_SS]);
 #elif defined(__linux__) && defined(__x86_64__)
     DumpRegister64(os, "rax", context.gregs[REG_RAX]);
     DumpRegister64(os, "rbx", context.gregs[REG_RBX]);
     DumpRegister64(os, "rcx", context.gregs[REG_RCX]);
     DumpRegister64(os, "rdx", context.gregs[REG_RDX]);
     os << '\n';

     DumpRegister64(os, "rdi", context.gregs[REG_RDI]);
     DumpRegister64(os, "rsi", context.gregs[REG_RSI]);
     DumpRegister64(os, "rbp", context.gregs[REG_RBP]);
     DumpRegister64(os, "rsp", context.gregs[REG_RSP]);
     os << '\n';

     DumpRegister64(os, "r8 ", context.gregs[REG_R8]);
     DumpRegister64(os, "r9 ", context.gregs[REG_R9]);
     DumpRegister64(os, "r10", context.gregs[REG_R10]);
     DumpRegister64(os, "r11", context.gregs[REG_R11]);
     os << '\n';

     DumpRegister64(os, "r12", context.gregs[REG_R12]);
     DumpRegister64(os, "r13", context.gregs[REG_R13]);
     DumpRegister64(os, "r14", context.gregs[REG_R14]);
     DumpRegister64(os, "r15", context.gregs[REG_R15]);
     os << '\n';

     DumpRegister64(os, "rip", context.gregs[REG_RIP]);
     os << "   ";
     DumpRegister32(os, "eflags", context.gregs[REG_EFL]);
     DumpX86Flags(os, context.gregs[REG_EFL]);
     os << '\n';

     DumpRegister32(os, "cs",  (context.gregs[REG_CSGSFS]) & 0x0FFFF);
     DumpRegister32(os, "gs",  (context.gregs[REG_CSGSFS] >> 16) & 0x0FFFF);
     DumpRegister32(os, "fs",  (context.gregs[REG_CSGSFS] >> 32) & 0x0FFFF);
     os << '\n';
 #else
     os << "Unknown architecture/word size/OS in ucontext dump";
 #endif
   }

   void DumpRegister32(std::ostream& os, const char* name, uint32_t value) {
     os << StringPrintf(" %6s: 0x%08x", name, value);
   }

   void DumpRegister64(std::ostream& os, const char* name, uint64_t value) {
     os << StringPrintf(" %6s: 0x%016" PRIx64, name, value);
   }

   void DumpX86Flags(std::ostream& os, uint32_t flags) {
     os << " [";
     if ((flags & (1 << 0)) != 0) {
       os << " CF";
     }
     if ((flags & (1 << 2)) != 0) {
       os << " PF";
     }
     if ((flags & (1 << 4)) != 0) {
       os << " AF";
     }
     if ((flags & (1 << 6)) != 0) {
       os << " ZF";
     }
     if ((flags & (1 << 7)) != 0) {
       os << " SF";
     }
     if ((flags & (1 << 8)) != 0) {
       os << " TF";
     }
     if ((flags & (1 << 9)) != 0) {
       os << " IF";
     }
     if ((flags & (1 << 10)) != 0) {
       os << " DF";
     }
     if ((flags & (1 << 11)) != 0) {
       os << " OF";
     }
     os << " ]";
   }

   mcontext_t& context;
 };

 void HandleUnexpectedSignal(int signal_number, siginfo_t* info, void* raw_context) {
   static bool handlingUnexpectedSignal = false;
   if (handlingUnexpectedSignal) {
     LogMessageData data(__FILE__, __LINE__, INTERNAL_FATAL, -1);
     LogMessage::LogLine(data, "HandleUnexpectedSignal reentered\n");
     _exit(1);
   }
   handlingUnexpectedSignal = true;

   gAborting++;  // set before taking any locks
   MutexLock mu(Thread::Current(), *Locks::unexpected_signal_lock_);

   bool has_address = (signal_number == SIGILL || signal_number == SIGBUS ||
                       signal_number == SIGFPE || signal_number == SIGSEGV);

   OsInfo os_info;
   const char* cmd_line = GetCmdLine();
   if (cmd_line == NULL) {
     cmd_line = "<unset>";  // Because no-one called InitLogging.
   }
   pid_t tid = GetTid();
   std::string thread_name(GetThreadName(tid));
   UContext thread_context(raw_context);
   Backtrace thread_backtrace;

   LOG(INTERNAL_FATAL) << "*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***\n"
                       << StringPrintf("Fatal signal %d (%s), code %d (%s)",
                                       signal_number, GetSignalName(signal_number),
                                       info->si_code,
                                       GetSignalCodeName(signal_number, info->si_code))
                       << (has_address ? StringPrintf(" fault addr %p", info->si_addr) : "") << "\n"
                       << "OS: " << Dumpable<OsInfo>(os_info) << "\n"
                       << "Cmdline: " << cmd_line << "\n"
                       << "Thread: " << tid << " \"" << thread_name << "\"\n"
                       << "Registers:\n" << Dumpable<UContext>(thread_context) << "\n"
                       << "Backtrace:\n" << Dumpable<Backtrace>(thread_backtrace);
   Runtime* runtime = Runtime::Current();
   if (runtime != nullptr) {
     gc::Heap* heap = runtime->GetHeap();
     LOG(INTERNAL_FATAL) << "Fault message: " << runtime->GetFaultMessage();
     if (kDumpHeapObjectOnSigsevg && heap != nullptr && info != nullptr) {
       LOG(INTERNAL_FATAL) << "Dump heap object at fault address: ";
       heap->DumpObject(LOG(INTERNAL_FATAL), reinterpret_cast<mirror::Object*>(info->si_addr));
     }
   }
   if (getenv("debug_db_uid") != NULL || getenv("art_wait_for_gdb_on_crash") != NULL) {
     LOG(INTERNAL_FATAL) << "********************************************************\n"
                         << "* Process " << getpid() << " thread " << tid << " \"" << thread_name << "\""
                         << " has been suspended while crashing.\n"
                         << "* Attach gdb:\n"
                         << "*     gdb -p " << tid << "\n"
                         << "********************************************************\n";
     // Wait for debugger to attach.
     while (true) {
     }
   }

   // Remove our signal handler for this signal...
   struct sigaction action;
   memset(&action, 0, sizeof(action));
   sigemptyset(&action.sa_mask);
   action.sa_handler = SIG_DFL;
   sigaction(signal_number, &action, NULL);
   // ...and re-raise so we die with the appropriate status.
   kill(getpid(), signal_number);
 }

 void Runtime::InitPlatformSignalHandlers() {
   // On the host, we don't have debuggerd to dump a stack for us when something unexpected happens.
   struct sigaction action;
   memset(&action, 0, sizeof(action));
   sigemptyset(&action.sa_mask);
   action.sa_sigaction = HandleUnexpectedSignal;
   // Use the three-argument sa_sigaction handler.
   action.sa_flags |= SA_SIGINFO;
   // Use the alternate signal stack so we can catch stack overflows.
   action.sa_flags |= SA_ONSTACK;

   int rc = 0;
   rc += sigaction(SIGABRT, &action, NULL);
   rc += sigaction(SIGBUS, &action, NULL);
   rc += sigaction(SIGFPE, &action, NULL);
   rc += sigaction(SIGILL, &action, NULL);
   rc += sigaction(SIGPIPE, &action, NULL);
   rc += sigaction(SIGSEGV, &action, NULL);
 #if defined(SIGSTKFLT)
   rc += sigaction(SIGSTKFLT, &action, NULL);
 #endif
   rc += sigaction(SIGTRAP, &action, NULL);
   CHECK_EQ(rc, 0);
 }

 }  // namespace art
	/*
	* Copyright (C) 2011 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include "runtime.h"

	#include <signal.h>
	#include <string.h>
	#include <sys/utsname.h>
	#include <inttypes.h>

	#include "base/logging.h"
	#include "base/mutex.h"
	#include "base/stringprintf.h"
	#include "thread-inl.h"
	#include "utils.h"

	namespace art {

	static constexpr bool kDumpHeapObjectOnSigsevg = false;

	struct Backtrace {
	void Dump(std::ostream& os) {
	DumpNativeStack(os, GetTid(), "\t", true);
	}
	};

	struct OsInfo {
	void Dump(std::ostream& os) {
	utsname info;
	uname(&info);
	// Linux 2.6.38.8-gg784 (x86_64)
	// Darwin 11.4.0 (x86_64)
	os << info.sysname << " " << info.release << " (" << info.machine << ")";
	}
	};

	static const char* GetSignalName(int signal_number) {
	switch (signal_number) {
	case SIGABRT: return "SIGABRT";
	case SIGBUS: return "SIGBUS";
	case SIGFPE: return "SIGFPE";
	case SIGILL: return "SIGILL";
	case SIGPIPE: return "SIGPIPE";
	case SIGSEGV: return "SIGSEGV";
	#if defined(SIGSTKFLT)
	case SIGSTKFLT: return "SIGSTKFLT";
	#endif
	case SIGTRAP: return "SIGTRAP";
	}
	return "??";
	}

	static const char* GetSignalCodeName(int signal_number, int signal_code) {
	// Try the signal-specific codes...
	switch (signal_number) {
	case SIGILL:
	switch (signal_code) {
	case ILL_ILLOPC: return "ILL_ILLOPC";
	case ILL_ILLOPN: return "ILL_ILLOPN";
	case ILL_ILLADR: return "ILL_ILLADR";
	case ILL_ILLTRP: return "ILL_ILLTRP";
	case ILL_PRVOPC: return "ILL_PRVOPC";
	case ILL_PRVREG: return "ILL_PRVREG";
	case ILL_COPROC: return "ILL_COPROC";
	case ILL_BADSTK: return "ILL_BADSTK";
	}
	break;
	case SIGBUS:
	switch (signal_code) {
	case BUS_ADRALN: return "BUS_ADRALN";
	case BUS_ADRERR: return "BUS_ADRERR";
	case BUS_OBJERR: return "BUS_OBJERR";
	}
	break;
	case SIGFPE:
	switch (signal_code) {
	case FPE_INTDIV: return "FPE_INTDIV";
	case FPE_INTOVF: return "FPE_INTOVF";
	case FPE_FLTDIV: return "FPE_FLTDIV";
	case FPE_FLTOVF: return "FPE_FLTOVF";
	case FPE_FLTUND: return "FPE_FLTUND";
	case FPE_FLTRES: return "FPE_FLTRES";
	case FPE_FLTINV: return "FPE_FLTINV";
	case FPE_FLTSUB: return "FPE_FLTSUB";
	}
	break;
	case SIGSEGV:
	switch (signal_code) {
	case SEGV_MAPERR: return "SEGV_MAPERR";
	case SEGV_ACCERR: return "SEGV_ACCERR";
	}
	break;
	case SIGTRAP:
	switch (signal_code) {
	case TRAP_BRKPT: return "TRAP_BRKPT";
	case TRAP_TRACE: return "TRAP_TRACE";
	}
	break;
	}
	// Then the other codes...
	switch (signal_code) {
	case SI_USER: return "SI_USER";
	#if defined(SI_KERNEL)
	case SI_KERNEL: return "SI_KERNEL";
	#endif
	case SI_QUEUE: return "SI_QUEUE";
	case SI_TIMER: return "SI_TIMER";
	case SI_MESGQ: return "SI_MESGQ";
	case SI_ASYNCIO: return "SI_ASYNCIO";
	#if defined(SI_SIGIO)
	case SI_SIGIO: return "SI_SIGIO";
	#endif
	#if defined(SI_TKILL)
	case SI_TKILL: return "SI_TKILL";
	#endif
	}
	// Then give up...
	return "?";
	}

	struct UContext {
	explicit UContext(void* raw_context) : context(reinterpret_cast<ucontext_t*>(raw_context)->uc_mcontext) {}

	void Dump(std::ostream& os) {
	// TODO: support non-x86 hosts (not urgent because this code doesn't run on targets).
	#if defined(__APPLE__) && defined(__i386__)
	DumpRegister32(os, "eax", context->__ss.__eax);
	DumpRegister32(os, "ebx", context->__ss.__ebx);
	DumpRegister32(os, "ecx", context->__ss.__ecx);
	DumpRegister32(os, "edx", context->__ss.__edx);
	os << '\n';

	DumpRegister32(os, "edi", context->__ss.__edi);
	DumpRegister32(os, "esi", context->__ss.__esi);
	DumpRegister32(os, "ebp", context->__ss.__ebp);
	DumpRegister32(os, "esp", context->__ss.__esp);
	os << '\n';

	DumpRegister32(os, "eip", context->__ss.__eip);
	os << " ";
	DumpRegister32(os, "eflags", context->__ss.__eflags);
	DumpX86Flags(os, context->__ss.__eflags);
	os << '\n';

	DumpRegister32(os, "cs", context->__ss.__cs);
	DumpRegister32(os, "ds", context->__ss.__ds);
	DumpRegister32(os, "es", context->__ss.__es);
	DumpRegister32(os, "fs", context->__ss.__fs);
	os << '\n';
	DumpRegister32(os, "gs", context->__ss.__gs);
	DumpRegister32(os, "ss", context->__ss.__ss);
	#elif defined(__linux__) && defined(__i386__)
	DumpRegister32(os, "eax", context.gregs[REG_EAX]);
	DumpRegister32(os, "ebx", context.gregs[REG_EBX]);
	DumpRegister32(os, "ecx", context.gregs[REG_ECX]);
	DumpRegister32(os, "edx", context.gregs[REG_EDX]);
	os << '\n';

	DumpRegister32(os, "edi", context.gregs[REG_EDI]);
	DumpRegister32(os, "esi", context.gregs[REG_ESI]);
	DumpRegister32(os, "ebp", context.gregs[REG_EBP]);
	DumpRegister32(os, "esp", context.gregs[REG_ESP]);
	os << '\n';

	DumpRegister32(os, "eip", context.gregs[REG_EIP]);
	os << " ";
	DumpRegister32(os, "eflags", context.gregs[REG_EFL]);
	DumpX86Flags(os, context.gregs[REG_EFL]);
	os << '\n';

	DumpRegister32(os, "cs", context.gregs[REG_CS]);
	DumpRegister32(os, "ds", context.gregs[REG_DS]);
	DumpRegister32(os, "es", context.gregs[REG_ES]);
	DumpRegister32(os, "fs", context.gregs[REG_FS]);
	os << '\n';
	DumpRegister32(os, "gs", context.gregs[REG_GS]);
	DumpRegister32(os, "ss", context.gregs[REG_SS]);
	#elif defined(__linux__) && defined(__x86_64__)
	DumpRegister64(os, "rax", context.gregs[REG_RAX]);
	DumpRegister64(os, "rbx", context.gregs[REG_RBX]);
	DumpRegister64(os, "rcx", context.gregs[REG_RCX]);
	DumpRegister64(os, "rdx", context.gregs[REG_RDX]);
	os << '\n';

	DumpRegister64(os, "rdi", context.gregs[REG_RDI]);
	DumpRegister64(os, "rsi", context.gregs[REG_RSI]);
	DumpRegister64(os, "rbp", context.gregs[REG_RBP]);
	DumpRegister64(os, "rsp", context.gregs[REG_RSP]);
	os << '\n';

	DumpRegister64(os, "r8 ", context.gregs[REG_R8]);
	DumpRegister64(os, "r9 ", context.gregs[REG_R9]);
	DumpRegister64(os, "r10", context.gregs[REG_R10]);
	DumpRegister64(os, "r11", context.gregs[REG_R11]);
	os << '\n';

	DumpRegister64(os, "r12", context.gregs[REG_R12]);
	DumpRegister64(os, "r13", context.gregs[REG_R13]);
	DumpRegister64(os, "r14", context.gregs[REG_R14]);
	DumpRegister64(os, "r15", context.gregs[REG_R15]);
	os << '\n';

	DumpRegister64(os, "rip", context.gregs[REG_RIP]);
	os << " ";
	DumpRegister32(os, "eflags", context.gregs[REG_EFL]);
	DumpX86Flags(os, context.gregs[REG_EFL]);
	os << '\n';

	DumpRegister32(os, "cs", (context.gregs[REG_CSGSFS]) & 0x0FFFF);
	DumpRegister32(os, "gs", (context.gregs[REG_CSGSFS] >> 16) & 0x0FFFF);
	DumpRegister32(os, "fs", (context.gregs[REG_CSGSFS] >> 32) & 0x0FFFF);
	os << '\n';
	#else
	os << "Unknown architecture/word size/OS in ucontext dump";
	#endif
	}

	void DumpRegister32(std::ostream& os, const char* name, uint32_t value) {
	os << StringPrintf(" %6s: 0x%08x", name, value);
	}

	void DumpRegister64(std::ostream& os, const char* name, uint64_t value) {
	os << StringPrintf(" %6s: 0x%016" PRIx64, name, value);
	}

	void DumpX86Flags(std::ostream& os, uint32_t flags) {
	os << " [";
	if ((flags & (1 << 0)) != 0) {
	os << " CF";
	}
	if ((flags & (1 << 2)) != 0) {
	os << " PF";
	}
	if ((flags & (1 << 4)) != 0) {
	os << " AF";
	}
	if ((flags & (1 << 6)) != 0) {
	os << " ZF";
	}
	if ((flags & (1 << 7)) != 0) {
	os << " SF";
	}
	if ((flags & (1 << 8)) != 0) {
	os << " TF";
	}
	if ((flags & (1 << 9)) != 0) {
	os << " IF";
	}
	if ((flags & (1 << 10)) != 0) {
	os << " DF";
	}
	if ((flags & (1 << 11)) != 0) {
	os << " OF";
	}
	os << " ]";
	}

	mcontext_t& context;
	};

	void HandleUnexpectedSignal(int signal_number, siginfo_t* info, void* raw_context) {
	static bool handlingUnexpectedSignal = false;
	if (handlingUnexpectedSignal) {
	LogMessageData data(__FILE__, __LINE__, INTERNAL_FATAL, -1);
	LogMessage::LogLine(data, "HandleUnexpectedSignal reentered\n");
	_exit(1);
	}
	handlingUnexpectedSignal = true;

	gAborting++; // set before taking any locks
	MutexLock mu(Thread::Current(), *Locks::unexpected_signal_lock_);

	bool has_address = (signal_number == SIGILL \|\| signal_number == SIGBUS \|\|
	signal_number == SIGFPE \|\| signal_number == SIGSEGV);

	OsInfo os_info;
	const char* cmd_line = GetCmdLine();
	if (cmd_line == NULL) {
	cmd_line = "<unset>"; // Because no-one called InitLogging.
	}
	pid_t tid = GetTid();
	std::string thread_name(GetThreadName(tid));
	UContext thread_context(raw_context);
	Backtrace thread_backtrace;

	LOG(INTERNAL_FATAL) << "* * * * * * * * * * * * * * * *\n"
	<< StringPrintf("Fatal signal %d (%s), code %d (%s)",
	signal_number, GetSignalName(signal_number),
	info->si_code,
	GetSignalCodeName(signal_number, info->si_code))
	<< (has_address ? StringPrintf(" fault addr %p", info->si_addr) : "") << "\n"
	<< "OS: " << Dumpable<OsInfo>(os_info) << "\n"
	<< "Cmdline: " << cmd_line << "\n"
	<< "Thread: " << tid << " \"" << thread_name << "\"\n"
	<< "Registers:\n" << Dumpable<UContext>(thread_context) << "\n"
	<< "Backtrace:\n" << Dumpable<Backtrace>(thread_backtrace);
	Runtime* runtime = Runtime::Current();
	if (runtime != nullptr) {
	gc::Heap* heap = runtime->GetHeap();
	LOG(INTERNAL_FATAL) << "Fault message: " << runtime->GetFaultMessage();
	if (kDumpHeapObjectOnSigsevg && heap != nullptr && info != nullptr) {
	LOG(INTERNAL_FATAL) << "Dump heap object at fault address: ";
	heap->DumpObject(LOG(INTERNAL_FATAL), reinterpret_cast<mirror::Object*>(info->si_addr));
	}
	}
	if (getenv("debug_db_uid") != NULL \|\| getenv("art_wait_for_gdb_on_crash") != NULL) {
	LOG(INTERNAL_FATAL) << "********************************************************\n"
	<< "* Process " << getpid() << " thread " << tid << " \"" << thread_name << "\""
	<< " has been suspended while crashing.\n"
	<< "* Attach gdb:\n"
	<< "* gdb -p " << tid << "\n"
	<< "********************************************************\n";
	// Wait for debugger to attach.
	while (true) {
	}
	}

	// Remove our signal handler for this signal...
	struct sigaction action;
	memset(&action, 0, sizeof(action));
	sigemptyset(&action.sa_mask);
	action.sa_handler = SIG_DFL;
	sigaction(signal_number, &action, NULL);
	// ...and re-raise so we die with the appropriate status.
	kill(getpid(), signal_number);
	}

	void Runtime::InitPlatformSignalHandlers() {
	// On the host, we don't have debuggerd to dump a stack for us when something unexpected happens.
	struct sigaction action;
	memset(&action, 0, sizeof(action));
	sigemptyset(&action.sa_mask);
	action.sa_sigaction = HandleUnexpectedSignal;
	// Use the three-argument sa_sigaction handler.
	action.sa_flags \|= SA_SIGINFO;
	// Use the alternate signal stack so we can catch stack overflows.
	action.sa_flags \|= SA_ONSTACK;

	int rc = 0;
	rc += sigaction(SIGABRT, &action, NULL);
	rc += sigaction(SIGBUS, &action, NULL);
	rc += sigaction(SIGFPE, &action, NULL);
	rc += sigaction(SIGILL, &action, NULL);
	rc += sigaction(SIGPIPE, &action, NULL);
	rc += sigaction(SIGSEGV, &action, NULL);
	#if defined(SIGSTKFLT)
	rc += sigaction(SIGSTKFLT, &action, NULL);
	#endif
	rc += sigaction(SIGTRAP, &action, NULL);
	CHECK_EQ(rc, 0);
	}

	} // namespace art