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llvm-mirror/lib/Support/Unix/Signals.inc
Pete Cooper 8aef527f4f Add boolean to PrintStackTraceOnErrorSignal to disable crash reporting.
The current crash reporting on Mac OS is only disabled via an environment variable.
This adds a boolean (default false) which can also disable crash reporting.

The only client right now is the unittests which don't ever want crash reporting, but do want to detect killed programs.

Reduces the time to run the APFloat unittests on my machine from

[----------] 47 tests from APFloatTest (51250 ms total)

to

[----------] 47 tests from APFloatTest (765 ms total)

Reviewed by Reid Kleckner and Justin Bogner

llvm-svn: 234353
2015-04-07 20:43:23 +00:00

547 lines
18 KiB
C++

//===- Signals.cpp - Generic Unix Signals Implementation -----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines some helpful functions for dealing with the possibility of
// Unix signals occurring while your program is running.
//
//===----------------------------------------------------------------------===//
#include "Unix.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/FileUtilities.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Mutex.h"
#include "llvm/Support/Program.h"
#include "llvm/Support/UniqueLock.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <string>
#include <vector>
#if HAVE_EXECINFO_H
# include <execinfo.h> // For backtrace().
#endif
#if HAVE_SIGNAL_H
#include <signal.h>
#endif
#if HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#if HAVE_CXXABI_H
#include <cxxabi.h>
#endif
#if HAVE_DLFCN_H
#include <dlfcn.h>
#endif
#if HAVE_MACH_MACH_H
#include <mach/mach.h>
#endif
#if HAVE_LINK_H
#include <link.h>
#endif
using namespace llvm;
static RETSIGTYPE SignalHandler(int Sig); // defined below.
static ManagedStatic<SmartMutex<true> > SignalsMutex;
/// InterruptFunction - The function to call if ctrl-c is pressed.
static void (*InterruptFunction)() = nullptr;
static ManagedStatic<std::vector<std::string>> FilesToRemove;
static ManagedStatic<std::vector<std::pair<void (*)(void *), void *>>>
CallBacksToRun;
// IntSigs - Signals that represent requested termination. There's no bug
// or failure, or if there is, it's not our direct responsibility. For whatever
// reason, our continued execution is no longer desirable.
static const int IntSigs[] = {
SIGHUP, SIGINT, SIGPIPE, SIGTERM, SIGUSR1, SIGUSR2
};
// KillSigs - Signals that represent that we have a bug, and our prompt
// termination has been ordered.
static const int KillSigs[] = {
SIGILL, SIGTRAP, SIGABRT, SIGFPE, SIGBUS, SIGSEGV, SIGQUIT
#ifdef SIGSYS
, SIGSYS
#endif
#ifdef SIGXCPU
, SIGXCPU
#endif
#ifdef SIGXFSZ
, SIGXFSZ
#endif
#ifdef SIGEMT
, SIGEMT
#endif
};
static unsigned NumRegisteredSignals = 0;
static struct {
struct sigaction SA;
int SigNo;
} RegisteredSignalInfo[(sizeof(IntSigs)+sizeof(KillSigs))/sizeof(KillSigs[0])];
static void RegisterHandler(int Signal) {
assert(NumRegisteredSignals <
sizeof(RegisteredSignalInfo)/sizeof(RegisteredSignalInfo[0]) &&
"Out of space for signal handlers!");
struct sigaction NewHandler;
NewHandler.sa_handler = SignalHandler;
NewHandler.sa_flags = SA_NODEFER|SA_RESETHAND;
sigemptyset(&NewHandler.sa_mask);
// Install the new handler, save the old one in RegisteredSignalInfo.
sigaction(Signal, &NewHandler,
&RegisteredSignalInfo[NumRegisteredSignals].SA);
RegisteredSignalInfo[NumRegisteredSignals].SigNo = Signal;
++NumRegisteredSignals;
}
static void RegisterHandlers() {
// If the handlers are already registered, we're done.
if (NumRegisteredSignals != 0) return;
for (auto S : IntSigs) RegisterHandler(S);
for (auto S : KillSigs) RegisterHandler(S);
}
static void UnregisterHandlers() {
// Restore all of the signal handlers to how they were before we showed up.
for (unsigned i = 0, e = NumRegisteredSignals; i != e; ++i)
sigaction(RegisteredSignalInfo[i].SigNo,
&RegisteredSignalInfo[i].SA, nullptr);
NumRegisteredSignals = 0;
}
/// RemoveFilesToRemove - Process the FilesToRemove list. This function
/// should be called with the SignalsMutex lock held.
/// NB: This must be an async signal safe function. It cannot allocate or free
/// memory, even in debug builds.
static void RemoveFilesToRemove() {
// We avoid iterators in case of debug iterators that allocate or release
// memory.
std::vector<std::string>& FilesToRemoveRef = *FilesToRemove;
for (unsigned i = 0, e = FilesToRemoveRef.size(); i != e; ++i) {
// We rely on a std::string implementation for which repeated calls to
// 'c_str()' don't allocate memory. We pre-call 'c_str()' on all of these
// strings to try to ensure this is safe.
const char *path = FilesToRemoveRef[i].c_str();
// Get the status so we can determine if it's a file or directory. If we
// can't stat the file, ignore it.
struct stat buf;
if (stat(path, &buf) != 0)
continue;
// If this is not a regular file, ignore it. We want to prevent removal of
// special files like /dev/null, even if the compiler is being run with the
// super-user permissions.
if (!S_ISREG(buf.st_mode))
continue;
// Otherwise, remove the file. We ignore any errors here as there is nothing
// else we can do.
unlink(path);
}
}
// SignalHandler - The signal handler that runs.
static RETSIGTYPE SignalHandler(int Sig) {
// Restore the signal behavior to default, so that the program actually
// crashes when we return and the signal reissues. This also ensures that if
// we crash in our signal handler that the program will terminate immediately
// instead of recursing in the signal handler.
UnregisterHandlers();
// Unmask all potentially blocked kill signals.
sigset_t SigMask;
sigfillset(&SigMask);
sigprocmask(SIG_UNBLOCK, &SigMask, nullptr);
{
unique_lock<SmartMutex<true>> Guard(*SignalsMutex);
RemoveFilesToRemove();
if (std::find(std::begin(IntSigs), std::end(IntSigs), Sig)
!= std::end(IntSigs)) {
if (InterruptFunction) {
void (*IF)() = InterruptFunction;
Guard.unlock();
InterruptFunction = nullptr;
IF(); // run the interrupt function.
return;
}
Guard.unlock();
raise(Sig); // Execute the default handler.
return;
}
}
// Otherwise if it is a fault (like SEGV) run any handler.
std::vector<std::pair<void (*)(void *), void *>>& CallBacksToRunRef =
*CallBacksToRun;
for (unsigned i = 0, e = CallBacksToRun->size(); i != e; ++i)
CallBacksToRunRef[i].first(CallBacksToRunRef[i].second);
#ifdef __s390__
// On S/390, certain signals are delivered with PSW Address pointing to
// *after* the faulting instruction. Simply returning from the signal
// handler would continue execution after that point, instead of
// re-raising the signal. Raise the signal manually in those cases.
if (Sig == SIGILL || Sig == SIGFPE || Sig == SIGTRAP)
raise(Sig);
#endif
}
void llvm::sys::RunInterruptHandlers() {
sys::SmartScopedLock<true> Guard(*SignalsMutex);
RemoveFilesToRemove();
}
void llvm::sys::SetInterruptFunction(void (*IF)()) {
{
sys::SmartScopedLock<true> Guard(*SignalsMutex);
InterruptFunction = IF;
}
RegisterHandlers();
}
// RemoveFileOnSignal - The public API
bool llvm::sys::RemoveFileOnSignal(StringRef Filename,
std::string* ErrMsg) {
{
sys::SmartScopedLock<true> Guard(*SignalsMutex);
std::vector<std::string>& FilesToRemoveRef = *FilesToRemove;
std::string *OldPtr =
FilesToRemoveRef.empty() ? nullptr : &FilesToRemoveRef[0];
FilesToRemoveRef.push_back(Filename);
// We want to call 'c_str()' on every std::string in this vector so that if
// the underlying implementation requires a re-allocation, it happens here
// rather than inside of the signal handler. If we see the vector grow, we
// have to call it on every entry. If it remains in place, we only need to
// call it on the latest one.
if (OldPtr == &FilesToRemoveRef[0])
FilesToRemoveRef.back().c_str();
else
for (unsigned i = 0, e = FilesToRemoveRef.size(); i != e; ++i)
FilesToRemoveRef[i].c_str();
}
RegisterHandlers();
return false;
}
// DontRemoveFileOnSignal - The public API
void llvm::sys::DontRemoveFileOnSignal(StringRef Filename) {
sys::SmartScopedLock<true> Guard(*SignalsMutex);
std::vector<std::string>::reverse_iterator RI =
std::find(FilesToRemove->rbegin(), FilesToRemove->rend(), Filename);
std::vector<std::string>::iterator I = FilesToRemove->end();
if (RI != FilesToRemove->rend())
I = FilesToRemove->erase(RI.base()-1);
// We need to call c_str() on every element which would have been moved by
// the erase. These elements, in a C++98 implementation where c_str()
// requires a reallocation on the first call may have had the call to c_str()
// made on insertion become invalid by being copied down an element.
for (std::vector<std::string>::iterator E = FilesToRemove->end(); I != E; ++I)
I->c_str();
}
/// AddSignalHandler - Add a function to be called when a signal is delivered
/// to the process. The handler can have a cookie passed to it to identify
/// what instance of the handler it is.
void llvm::sys::AddSignalHandler(void (*FnPtr)(void *), void *Cookie) {
CallBacksToRun->push_back(std::make_pair(FnPtr, Cookie));
RegisterHandlers();
}
#if defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)
#if HAVE_LINK_H && (defined(__linux__) || defined(__FreeBSD__) || \
defined(__FreeBSD_kernel__) || defined(__NetBSD__))
struct DlIteratePhdrData {
void **StackTrace;
int depth;
bool first;
const char **modules;
intptr_t *offsets;
const char *main_exec_name;
};
static int dl_iterate_phdr_cb(dl_phdr_info *info, size_t size, void *arg) {
DlIteratePhdrData *data = (DlIteratePhdrData*)arg;
const char *name = data->first ? data->main_exec_name : info->dlpi_name;
data->first = false;
for (int i = 0; i < info->dlpi_phnum; i++) {
const auto *phdr = &info->dlpi_phdr[i];
if (phdr->p_type != PT_LOAD)
continue;
intptr_t beg = info->dlpi_addr + phdr->p_vaddr;
intptr_t end = beg + phdr->p_memsz;
for (int j = 0; j < data->depth; j++) {
if (data->modules[j])
continue;
intptr_t addr = (intptr_t)data->StackTrace[j];
if (beg <= addr && addr < end) {
data->modules[j] = name;
data->offsets[j] = addr - info->dlpi_addr;
}
}
}
return 0;
}
static bool findModulesAndOffsets(void **StackTrace, int Depth,
const char **Modules, intptr_t *Offsets,
const char *MainExecutableName) {
DlIteratePhdrData data = {StackTrace, Depth, true,
Modules, Offsets, MainExecutableName};
dl_iterate_phdr(dl_iterate_phdr_cb, &data);
return true;
}
#else
static bool findModulesAndOffsets(void **StackTrace, int Depth,
const char **Modules, intptr_t *Offsets,
const char *MainExecutableName) {
return false;
}
#endif
static bool printSymbolizedStackTrace(void **StackTrace, int Depth,
llvm::raw_ostream &OS) {
// FIXME: Subtract necessary number from StackTrace entries to turn return addresses
// into actual instruction addresses.
// Use llvm-symbolizer tool to symbolize the stack traces.
ErrorOr<std::string> LLVMSymbolizerPathOrErr =
sys::findProgramByName("llvm-symbolizer");
if (!LLVMSymbolizerPathOrErr)
return false;
const std::string &LLVMSymbolizerPath = *LLVMSymbolizerPathOrErr;
// We don't know argv0 or the address of main() at this point, but try
// to guess it anyway (it's possible on some platforms).
std::string MainExecutableName = sys::fs::getMainExecutable(nullptr, nullptr);
if (MainExecutableName.empty() ||
MainExecutableName.find("llvm-symbolizer") != std::string::npos)
return false;
std::vector<const char *> Modules(Depth, nullptr);
std::vector<intptr_t> Offsets(Depth, 0);
if (!findModulesAndOffsets(StackTrace, Depth, Modules.data(), Offsets.data(),
MainExecutableName.c_str()))
return false;
int InputFD;
SmallString<32> InputFile, OutputFile;
sys::fs::createTemporaryFile("symbolizer-input", "", InputFD, InputFile);
sys::fs::createTemporaryFile("symbolizer-output", "", OutputFile);
FileRemover InputRemover(InputFile.c_str());
FileRemover OutputRemover(OutputFile.c_str());
{
raw_fd_ostream Input(InputFD, true);
for (int i = 0; i < Depth; i++) {
if (Modules[i])
Input << Modules[i] << " " << (void*)Offsets[i] << "\n";
}
}
StringRef InputFileStr(InputFile);
StringRef OutputFileStr(OutputFile);
StringRef StderrFileStr;
const StringRef *Redirects[] = {&InputFileStr, &OutputFileStr,
&StderrFileStr};
const char *Args[] = {"llvm-symbolizer", "--functions=linkage", "--inlining",
"--demangle", nullptr};
int RunResult =
sys::ExecuteAndWait(LLVMSymbolizerPath, Args, nullptr, Redirects);
if (RunResult != 0)
return false;
auto OutputBuf = MemoryBuffer::getFile(OutputFile.c_str());
if (!OutputBuf)
return false;
StringRef Output = OutputBuf.get()->getBuffer();
SmallVector<StringRef, 32> Lines;
Output.split(Lines, "\n");
auto CurLine = Lines.begin();
int frame_no = 0;
for (int i = 0; i < Depth; i++) {
if (!Modules[i]) {
OS << format("#%d %p\n", frame_no++, StackTrace[i]);
continue;
}
// Read pairs of lines (function name and file/line info) until we
// encounter empty line.
for (;;) {
if (CurLine == Lines.end())
return false;
StringRef FunctionName = *CurLine++;
if (FunctionName.empty())
break;
OS << format("#%d %p ", frame_no++, StackTrace[i]);
if (!FunctionName.startswith("??"))
OS << format("%s ", FunctionName.str().c_str());
if (CurLine == Lines.end())
return false;
StringRef FileLineInfo = *CurLine++;
if (!FileLineInfo.startswith("??"))
OS << format("%s", FileLineInfo.str().c_str());
else
OS << format("(%s+%p)", Modules[i], (void *)Offsets[i]);
OS << "\n";
}
}
return true;
}
#endif // defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)
// PrintStackTrace - In the case of a program crash or fault, print out a stack
// trace so that the user has an indication of why and where we died.
//
// On glibc systems we have the 'backtrace' function, which works nicely, but
// doesn't demangle symbols.
void llvm::sys::PrintStackTrace(raw_ostream &OS) {
#if defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACES)
static void* StackTrace[256];
// Use backtrace() to output a backtrace on Linux systems with glibc.
int depth = backtrace(StackTrace,
static_cast<int>(array_lengthof(StackTrace)));
if (printSymbolizedStackTrace(StackTrace, depth, OS))
return;
#if HAVE_DLFCN_H && __GNUG__
int width = 0;
for (int i = 0; i < depth; ++i) {
Dl_info dlinfo;
dladdr(StackTrace[i], &dlinfo);
const char* name = strrchr(dlinfo.dli_fname, '/');
int nwidth;
if (!name) nwidth = strlen(dlinfo.dli_fname);
else nwidth = strlen(name) - 1;
if (nwidth > width) width = nwidth;
}
for (int i = 0; i < depth; ++i) {
Dl_info dlinfo;
dladdr(StackTrace[i], &dlinfo);
OS << format("%-2d", i);
const char* name = strrchr(dlinfo.dli_fname, '/');
if (!name) OS << format(" %-*s", width, dlinfo.dli_fname);
else OS << format(" %-*s", width, name+1);
OS << format(" %#0*lx", (int)(sizeof(void*) * 2) + 2,
(unsigned long)StackTrace[i]);
if (dlinfo.dli_sname != nullptr) {
OS << ' ';
# if HAVE_CXXABI_H
int res;
char* d = abi::__cxa_demangle(dlinfo.dli_sname, nullptr, nullptr, &res);
# else
char* d = NULL;
# endif
if (!d) OS << dlinfo.dli_sname;
else OS << d;
free(d);
// FIXME: When we move to C++11, use %t length modifier. It's not in
// C++03 and causes gcc to issue warnings. Losing the upper 32 bits of
// the stack offset for a stack dump isn't likely to cause any problems.
OS << format(" + %u",(unsigned)((char*)StackTrace[i]-
(char*)dlinfo.dli_saddr));
}
OS << '\n';
}
#else
backtrace_symbols_fd(StackTrace, depth, STDERR_FILENO);
#endif
#endif
}
static void PrintStackTraceSignalHandler(void *) {
PrintStackTrace(llvm::errs());
}
void llvm::sys::DisableSystemDialogsOnCrash() {}
/// PrintStackTraceOnErrorSignal - When an error signal (such as SIGABRT or
/// SIGSEGV) is delivered to the process, print a stack trace and then exit.
void llvm::sys::PrintStackTraceOnErrorSignal(bool DisableCrashReporting) {
AddSignalHandler(PrintStackTraceSignalHandler, nullptr);
#if defined(__APPLE__) && defined(ENABLE_CRASH_OVERRIDES)
// Environment variable to disable any kind of crash dialog.
if (DisableCrashReporting || getenv("LLVM_DISABLE_CRASH_REPORT")) {
mach_port_t self = mach_task_self();
exception_mask_t mask = EXC_MASK_CRASH;
kern_return_t ret = task_set_exception_ports(self,
mask,
MACH_PORT_NULL,
EXCEPTION_STATE_IDENTITY | MACH_EXCEPTION_CODES,
THREAD_STATE_NONE);
(void)ret;
}
#endif
}
/***/
// On Darwin, raise sends a signal to the main thread instead of the current
// thread. This has the unfortunate effect that assert() and abort() will end up
// bypassing our crash recovery attempts. We work around this for anything in
// the same linkage unit by just defining our own versions of the assert handler
// and abort.
#if defined(__APPLE__) && defined(ENABLE_CRASH_OVERRIDES)
#include <signal.h>
#include <pthread.h>
int raise(int sig) {
return pthread_kill(pthread_self(), sig);
}
void __assert_rtn(const char *func,
const char *file,
int line,
const char *expr) {
if (func)
fprintf(stderr, "Assertion failed: (%s), function %s, file %s, line %d.\n",
expr, func, file, line);
else
fprintf(stderr, "Assertion failed: (%s), file %s, line %d.\n",
expr, file, line);
abort();
}
void abort() {
raise(SIGABRT);
usleep(1000);
__builtin_trap();
}
#endif