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//===- 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 occuring while your program is running.
//
//===----------------------------------------------------------------------===//
#include "Unix.h"
#include "llvm/ADT/STLExtras.h"
#include <vector>
#include <algorithm>
#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_DLFCN_H && __GNUG__
#include <dlfcn.h>
#include <cxxabi.h>
#endif
using namespace llvm;
/// InterruptFunction - The function to call if ctrl-c is pressed.
static void (*InterruptFunction)() = 0;
static std::vector<sys::Path> *FilesToRemove = 0;
static std::vector<std::pair<void(*)(void*), void*> > *CallBacksToRun = 0;
// IntSigs - Signals that may interrupt the program at any time.
static const int IntSigs[] = {
SIGHUP, SIGINT, SIGQUIT, SIGPIPE, SIGTERM, SIGUSR1, SIGUSR2
};
static const int *const IntSigsEnd =
IntSigs + sizeof(IntSigs) / sizeof(IntSigs[0]);
// KillSigs - Signals that are synchronous with the program that will cause it
// to die.
static const int KillSigs[] = {
SIGILL, SIGTRAP, SIGABRT, SIGFPE, SIGBUS, SIGSEGV, SIGSYS, SIGXCPU, SIGXFSZ
#ifdef SIGEMT
, SIGEMT
#endif
};
static const int *const KillSigsEnd =
KillSigs + sizeof(KillSigs) / sizeof(KillSigs[0]);
static void UnregisterHandler(int Signal) {
signal(Signal, SIG_DFL);
}
// 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.
std::for_each(KillSigs, KillSigsEnd, UnregisterHandler);
// Unmask all potentially blocked kill signals.
sigset_t SigMask;
sigfillset(&SigMask);
sigprocmask(SIG_UNBLOCK, &SigMask, 0);
if (FilesToRemove != 0)
while (!FilesToRemove->empty()) {
FilesToRemove->back().eraseFromDisk(true);
FilesToRemove->pop_back();
}
if (std::find(IntSigs, IntSigsEnd, Sig) != IntSigsEnd) {
if (InterruptFunction) {
void (*IF)() = InterruptFunction;
InterruptFunction = 0;
IF(); // run the interrupt function.
return;
}
exit(1); // If this is an interrupt signal, exit the program
}
// Otherwise if it is a fault (like SEGV) run any handler.
if (CallBacksToRun)
for (unsigned i = 0, e = CallBacksToRun->size(); i != e; ++i)
(*CallBacksToRun)[i].first((*CallBacksToRun)[i].second);
}
// Just call signal
static void RegisterHandler(int Signal) {
signal(Signal, SignalHandler);
}
void llvm::sys::SetInterruptFunction(void (*IF)()) {
InterruptFunction = IF;
RegisterHandler(SIGINT);
}
// RemoveFileOnSignal - The public API
bool llvm::sys::RemoveFileOnSignal(const sys::Path &Filename,
std::string* ErrMsg) {
if (FilesToRemove == 0)
FilesToRemove = new std::vector<sys::Path>();
FilesToRemove->push_back(Filename);
std::for_each(IntSigs, IntSigsEnd, RegisterHandler);
std::for_each(KillSigs, KillSigsEnd, RegisterHandler);
return false;
}
/// 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) {
if (CallBacksToRun == 0)
CallBacksToRun = new std::vector<std::pair<void(*)(void*), void*> >();
CallBacksToRun->push_back(std::make_pair(FnPtr, Cookie));
std::for_each(KillSigs, KillSigsEnd, RegisterHandler);
}
// 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.
static void PrintStackTrace(void *) {
#ifdef HAVE_BACKTRACE
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 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 == NULL) 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(stderr, "%-3d", i);
const char* name = strrchr(dlinfo.dli_fname, '/');
if (name == NULL) fprintf(stderr, " %-*s", width, dlinfo.dli_fname);
else fprintf(stderr, " %-*s", width, name+1);
fprintf(stderr, " %#0*lx",
(int)(sizeof(void*) * 2) + 2, (unsigned long)StackTrace[i]);
if (dlinfo.dli_sname != NULL) {
int res;
fputc(' ', stderr);
char* d = abi::__cxa_demangle(dlinfo.dli_sname, NULL, NULL, &res);
if (d == NULL) fputs(dlinfo.dli_sname, stderr);
else fputs(d, stderr);
free(d);
fprintf(stderr, " + %tu",(char*)StackTrace[i]-(char*)dlinfo.dli_saddr);
}
fputc('\n', stderr);
}
#else
backtrace_symbols_fd(StackTrace, depth, STDERR_FILENO);
#endif
#endif
}
/// PrintStackTraceOnErrorSignal - When an error signal (such as SIBABRT or
/// SIGSEGV) is delivered to the process, print a stack trace and then exit.
void llvm::sys::PrintStackTraceOnErrorSignal() {
AddSignalHandler(PrintStackTrace, 0);
}
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