diff options
Diffstat (limited to 'contrib/llvm/lib/Support/Unix/Signals.inc')
| -rw-r--r-- | contrib/llvm/lib/Support/Unix/Signals.inc | 390 |
1 files changed, 390 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Support/Unix/Signals.inc b/contrib/llvm/lib/Support/Unix/Signals.inc new file mode 100644 index 000000000000..b4c78d69f77e --- /dev/null +++ b/contrib/llvm/lib/Support/Unix/Signals.inc @@ -0,0 +1,390 @@ +//===- 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/Mutex.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 + +using namespace llvm; + +static RETSIGTYPE SignalHandler(int Sig); // defined below. + +static SmartMutex<true> SignalsMutex; + +/// InterruptFunction - The function to call if ctrl-c is pressed. +static void (*InterruptFunction)() = 0; + +static std::vector<std::string> FilesToRemove; +static 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 +}; +static const int *const IntSigsEnd = array_endof(IntSigs); + +// 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 const int *const KillSigsEnd = array_endof(KillSigs); + +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; + + std::for_each(IntSigs, IntSigsEnd, RegisterHandler); + std::for_each(KillSigs, KillSigsEnd, RegisterHandler); +} + +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, 0); + 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. + for (unsigned i = 0, e = FilesToRemove.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 = FilesToRemove[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, 0); + + SignalsMutex.acquire(); + RemoveFilesToRemove(); + + if (std::find(IntSigs, IntSigsEnd, Sig) != IntSigsEnd) { + if (InterruptFunction) { + void (*IF)() = InterruptFunction; + SignalsMutex.release(); + InterruptFunction = 0; + IF(); // run the interrupt function. + return; + } + + SignalsMutex.release(); + raise(Sig); // Execute the default handler. + return; + } + + SignalsMutex.release(); + + // Otherwise if it is a fault (like SEGV) run any handler. + for (unsigned i = 0, e = CallBacksToRun.size(); i != e; ++i) + CallBacksToRun[i].first(CallBacksToRun[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() { + SignalsMutex.acquire(); + RemoveFilesToRemove(); + SignalsMutex.release(); +} + +void llvm::sys::SetInterruptFunction(void (*IF)()) { + SignalsMutex.acquire(); + InterruptFunction = IF; + SignalsMutex.release(); + RegisterHandlers(); +} + +// RemoveFileOnSignal - The public API +bool llvm::sys::RemoveFileOnSignal(StringRef Filename, + std::string* ErrMsg) { + SignalsMutex.acquire(); + std::string *OldPtr = FilesToRemove.empty() ? 0 : &FilesToRemove[0]; + FilesToRemove.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 == &FilesToRemove[0]) + FilesToRemove.back().c_str(); + else + for (unsigned i = 0, e = FilesToRemove.size(); i != e; ++i) + FilesToRemove[i].c_str(); + + SignalsMutex.release(); + + RegisterHandlers(); + return false; +} + +// DontRemoveFileOnSignal - The public API +void llvm::sys::DontRemoveFileOnSignal(StringRef Filename) { + SignalsMutex.acquire(); + 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(); + + SignalsMutex.release(); +} + +/// 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(); +} + + +// 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 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(FD, "%-2d", i); + + const char* name = strrchr(dlinfo.dli_fname, '/'); + if (name == NULL) 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 != NULL) { + fputc(' ', FD); +# if HAVE_CXXABI_H + int res; + char* d = abi::__cxa_demangle(dlinfo.dli_sname, NULL, NULL, &res); +# else + char* d = NULL; +# endif + if (d == NULL) 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, 0); + +#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 |