maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity
llvm-project/llvm/lib/Support/Unix/Signals.inc

543 lines
18 KiB
C++
Raw Blame History

//===- 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/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, FILE *FD) {
// 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]) {
fprintf(FD, "#%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;
fprintf(FD, "#%d %p ", frame_no++, StackTrace[i]);
if (!FunctionName.startswith("??"))
fprintf(FD, "%s ", FunctionName.str().c_str());
if (CurLine == Lines.end())
return false;
StringRef FileLineInfo = *CurLine++;
if (!FileLineInfo.startswith("??"))
fprintf(FD, "%s", FileLineInfo.str().c_str());
else
fprintf(FD, "(%s+%p)", Modules[i], (void *)Offsets[i]);
fprintf(FD, "\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(FILE *FD) {
#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, FD))
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);
fprintf(FD, "%-2d", i);
const char* name = strrchr(dlinfo.dli_fname, '/');
if (!name) fprintf(FD, " %-*s", width, dlinfo.dli_fname);
else fprintf(FD, " %-*s", width, name+1);
fprintf(FD, " %#0*lx",
(int)(sizeof(void*) * 2) + 2, (unsigned long)StackTrace[i]);
if (dlinfo.dli_sname != nullptr) {
fputc(' ', FD);
# if HAVE_CXXABI_H
int res;
char* d = abi::__cxa_demangle(dlinfo.dli_sname, nullptr, nullptr, &res);
# else
char* d = NULL;
# endif
if (!d) fputs(dlinfo.dli_sname, FD);
else fputs(d, FD);
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.
fprintf(FD, " + %u",(unsigned)((char*)StackTrace[i]-
(char*)dlinfo.dli_saddr));
}
fputc('\n', FD);
}
#else
backtrace_symbols_fd(StackTrace, depth, STDERR_FILENO);
#endif
#endif
}
static void PrintStackTraceSignalHandler(void *) {
PrintStackTrace(stderr);
}
/// 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() {
AddSignalHandler(PrintStackTraceSignalHandler, nullptr);
#if defined(__APPLE__) && defined(ENABLE_CRASH_OVERRIDES)
// Environment variable to disable any kind of crash dialog.
if (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
Reference in New Issue View Git Blame Copy Permalink