1 //===- Signals.cpp - Generic Unix Signals Implementation -----*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines some helpful functions for dealing with the possibility of
11 // Unix signals occuring while your program is running.
13 //===----------------------------------------------------------------------===//
16 #include "llvm/ADT/STLExtras.h"
20 # include <execinfo.h> // For backtrace().
28 #if HAVE_DLFCN_H && __GNUG__
34 static RETSIGTYPE SignalHandler(int Sig); // defined below.
36 /// InterruptFunction - The function to call if ctrl-c is pressed.
37 static void (*InterruptFunction)() = 0;
39 static std::vector<sys::Path> *FilesToRemove = 0;
40 static std::vector<std::pair<void(*)(void*), void*> > *CallBacksToRun = 0;
42 // IntSigs - Signals that may interrupt the program at any time.
43 static const int IntSigs[] = {
44 SIGHUP, SIGINT, SIGQUIT, SIGPIPE, SIGTERM, SIGUSR1, SIGUSR2
46 static const int *const IntSigsEnd =
47 IntSigs + sizeof(IntSigs) / sizeof(IntSigs[0]);
49 // KillSigs - Signals that are synchronous with the program that will cause it
51 static const int KillSigs[] = {
52 SIGILL, SIGTRAP, SIGABRT, SIGFPE, SIGBUS, SIGSEGV, SIGSYS, SIGXCPU, SIGXFSZ
57 static const int *const KillSigsEnd =
58 KillSigs + sizeof(KillSigs) / sizeof(KillSigs[0]);
60 static unsigned NumRegisteredSignals = 0;
64 } RegisteredSignalInfo[(sizeof(IntSigs)+sizeof(KillSigs))/sizeof(KillSigs[0])];
67 static void RegisterHandler(int Signal) {
68 assert(NumRegisteredSignals <
69 sizeof(RegisteredSignalInfo)/sizeof(RegisteredSignalInfo[0]) &&
70 "Out of space for signal handlers!");
72 struct sigaction NewHandler;
74 NewHandler.sa_handler = SignalHandler;
75 NewHandler.sa_flags = SA_NODEFER|SA_RESETHAND;
76 sigemptyset(&NewHandler.sa_mask);
78 // Install the new handler, save the old one in RegisteredSignalInfo.
79 sigaction(Signal, &NewHandler,
80 &RegisteredSignalInfo[NumRegisteredSignals].SA);
81 RegisteredSignalInfo[NumRegisteredSignals].SigNo = Signal;
82 ++NumRegisteredSignals;
85 static void RegisterHandlers() {
86 // If the handlers are already registered, we're done.
87 if (NumRegisteredSignals != 0) return;
89 std::for_each(IntSigs, IntSigsEnd, RegisterHandler);
90 std::for_each(KillSigs, KillSigsEnd, RegisterHandler);
93 static void UnregisterHandlers() {
94 // Restore all of the signal handlers to how they were before we showed up.
95 for (unsigned i = 0, e = NumRegisteredSignals; i != e; ++i)
96 sigaction(RegisteredSignalInfo[i].SigNo,
97 &RegisteredSignalInfo[i].SA, 0);
98 NumRegisteredSignals = 0;
103 // SignalHandler - The signal handler that runs.
104 static RETSIGTYPE SignalHandler(int Sig) {
105 // Restore the signal behavior to default, so that the program actually
106 // crashes when we return and the signal reissues. This also ensures that if
107 // we crash in our signal handler that the program will terminate immediately
108 // instead of recursing in the signal handler.
109 UnregisterHandlers();
111 // Unmask all potentially blocked kill signals.
113 sigfillset(&SigMask);
114 sigprocmask(SIG_UNBLOCK, &SigMask, 0);
116 if (FilesToRemove != 0)
117 while (!FilesToRemove->empty()) {
118 FilesToRemove->back().eraseFromDisk(true);
119 FilesToRemove->pop_back();
122 if (std::find(IntSigs, IntSigsEnd, Sig) != IntSigsEnd) {
123 if (InterruptFunction) {
124 void (*IF)() = InterruptFunction;
125 InterruptFunction = 0;
126 IF(); // run the interrupt function.
129 exit(1); // If this is an interrupt signal, exit the program
132 // Otherwise if it is a fault (like SEGV) run any handler.
134 for (unsigned i = 0, e = CallBacksToRun->size(); i != e; ++i)
135 (*CallBacksToRun)[i].first((*CallBacksToRun)[i].second);
140 void llvm::sys::SetInterruptFunction(void (*IF)()) {
141 InterruptFunction = IF;
145 // RemoveFileOnSignal - The public API
146 bool llvm::sys::RemoveFileOnSignal(const sys::Path &Filename,
147 std::string* ErrMsg) {
148 if (FilesToRemove == 0)
149 FilesToRemove = new std::vector<sys::Path>();
151 FilesToRemove->push_back(Filename);
157 /// AddSignalHandler - Add a function to be called when a signal is delivered
158 /// to the process. The handler can have a cookie passed to it to identify
159 /// what instance of the handler it is.
160 void llvm::sys::AddSignalHandler(void (*FnPtr)(void *), void *Cookie) {
161 if (CallBacksToRun == 0)
162 CallBacksToRun = new std::vector<std::pair<void(*)(void*), void*> >();
163 CallBacksToRun->push_back(std::make_pair(FnPtr, Cookie));
168 // PrintStackTrace - In the case of a program crash or fault, print out a stack
169 // trace so that the user has an indication of why and where we died.
171 // On glibc systems we have the 'backtrace' function, which works nicely, but
172 // doesn't demangle symbols.
173 static void PrintStackTrace(void *) {
174 #ifdef HAVE_BACKTRACE
175 static void* StackTrace[256];
176 // Use backtrace() to output a backtrace on Linux systems with glibc.
177 int depth = backtrace(StackTrace,
178 static_cast<int>(array_lengthof(StackTrace)));
179 #if HAVE_DLFCN_H && __GNUG__
181 for (int i = 0; i < depth; ++i) {
183 dladdr(StackTrace[i], &dlinfo);
184 const char* name = strrchr(dlinfo.dli_fname, '/');
187 if (name == NULL) nwidth = strlen(dlinfo.dli_fname);
188 else nwidth = strlen(name) - 1;
190 if (nwidth > width) width = nwidth;
193 for (int i = 0; i < depth; ++i) {
195 dladdr(StackTrace[i], &dlinfo);
197 fprintf(stderr, "%-3d", i);
199 const char* name = strrchr(dlinfo.dli_fname, '/');
200 if (name == NULL) fprintf(stderr, " %-*s", width, dlinfo.dli_fname);
201 else fprintf(stderr, " %-*s", width, name+1);
203 fprintf(stderr, " %#0*lx",
204 (int)(sizeof(void*) * 2) + 2, (unsigned long)StackTrace[i]);
206 if (dlinfo.dli_sname != NULL) {
209 char* d = abi::__cxa_demangle(dlinfo.dli_sname, NULL, NULL, &res);
210 if (d == NULL) fputs(dlinfo.dli_sname, stderr);
211 else fputs(d, stderr);
214 fprintf(stderr, " + %tu",(char*)StackTrace[i]-(char*)dlinfo.dli_saddr);
219 backtrace_symbols_fd(StackTrace, depth, STDERR_FILENO);
224 /// PrintStackTraceOnErrorSignal - When an error signal (such as SIBABRT or
225 /// SIGSEGV) is delivered to the process, print a stack trace and then exit.
226 void llvm::sys::PrintStackTraceOnErrorSignal() {
227 AddSignalHandler(PrintStackTrace, 0);