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Diffstat (limited to 'extern/glog/src/signalhandler.cc')
| -rw-r--r-- | extern/glog/src/signalhandler.cc | 375 |
1 files changed, 375 insertions, 0 deletions
diff --git a/extern/glog/src/signalhandler.cc b/extern/glog/src/signalhandler.cc new file mode 100644 index 00000000000..a7aef8b99d2 --- /dev/null +++ b/extern/glog/src/signalhandler.cc @@ -0,0 +1,375 @@ +// Copyright (c) 2008, Google Inc. +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above +// copyright notice, this list of conditions and the following disclaimer +// in the documentation and/or other materials provided with the +// distribution. +// * Neither the name of Google Inc. nor the names of its +// contributors may be used to endorse or promote products derived from +// this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +// +// Author: Satoru Takabayashi +// +// Implementation of InstallFailureSignalHandler(). + +#include "utilities.h" +#include "stacktrace.h" +#include "symbolize.h" +#include "glog/logging.h" + +#include <signal.h> +#include <time.h> +#ifdef HAVE_UCONTEXT_H +# include <ucontext.h> +#endif +#ifdef HAVE_SYS_UCONTEXT_H +# include <sys/ucontext.h> +#endif +#include <algorithm> + +_START_GOOGLE_NAMESPACE_ + +// TOOD(hamaji): Use signal instead of sigaction? +#ifdef HAVE_SIGACTION + +namespace { + +// We'll install the failure signal handler for these signals. We could +// use strsignal() to get signal names, but we don't use it to avoid +// introducing yet another #ifdef complication. +// +// The list should be synced with the comment in signalhandler.h. +const struct { + int number; + const char *name; +} kFailureSignals[] = { + { SIGSEGV, "SIGSEGV" }, + { SIGILL, "SIGILL" }, + { SIGFPE, "SIGFPE" }, + { SIGABRT, "SIGABRT" }, + { SIGBUS, "SIGBUS" }, + { SIGTERM, "SIGTERM" }, +}; + +// Returns the program counter from signal context, NULL if unknown. +void* GetPC(void* ucontext_in_void) { +#if (defined(HAVE_UCONTEXT_H) || defined(HAVE_SYS_UCONTEXT_H)) && defined(PC_FROM_UCONTEXT) + if (ucontext_in_void != NULL) { + ucontext_t *context = reinterpret_cast<ucontext_t *>(ucontext_in_void); + return (void*)context->PC_FROM_UCONTEXT; + } +#endif + return NULL; +} + +// The class is used for formatting error messages. We don't use printf() +// as it's not async signal safe. +class MinimalFormatter { + public: + MinimalFormatter(char *buffer, int size) + : buffer_(buffer), + cursor_(buffer), + end_(buffer + size) { + } + + // Returns the number of bytes written in the buffer. + int num_bytes_written() const { return cursor_ - buffer_; } + + // Appends string from "str" and updates the internal cursor. + void AppendString(const char* str) { + int i = 0; + while (str[i] != '\0' && cursor_ + i < end_) { + cursor_[i] = str[i]; + ++i; + } + cursor_ += i; + } + + // Formats "number" in "radix" and updates the internal cursor. + // Lowercase letters are used for 'a' - 'z'. + void AppendUint64(uint64 number, int radix) { + int i = 0; + while (cursor_ + i < end_) { + const int tmp = number % radix; + number /= radix; + cursor_[i] = (tmp < 10 ? '0' + tmp : 'a' + tmp - 10); + ++i; + if (number == 0) { + break; + } + } + // Reverse the bytes written. + std::reverse(cursor_, cursor_ + i); + cursor_ += i; + } + + // Formats "number" as hexadecimal number, and updates the internal + // cursor. Padding will be added in front if needed. + void AppendHexWithPadding(uint64 number, int width) { + char* start = cursor_; + AppendString("0x"); + AppendUint64(number, 16); + // Move to right and add padding in front if needed. + if (cursor_ < start + width) { + const int64 delta = start + width - cursor_; + std::copy(start, cursor_, start + delta); + std::fill(start, start + delta, ' '); + cursor_ = start + width; + } + } + + private: + char *buffer_; + char *cursor_; + const char * const end_; +}; + +// Writes the given data with the size to the standard error. +void WriteToStderr(const char* data, int size) { + if (write(STDERR_FILENO, data, size) < 0) { + // Ignore errors. + } +} + +// The writer function can be changed by InstallFailureWriter(). +void (*g_failure_writer)(const char* data, int size) = WriteToStderr; + +// Dumps time information. We don't dump human-readable time information +// as localtime() is not guaranteed to be async signal safe. +void DumpTimeInfo() { + time_t time_in_sec = time(NULL); + char buf[256]; // Big enough for time info. + MinimalFormatter formatter(buf, sizeof(buf)); + formatter.AppendString("*** Aborted at "); + formatter.AppendUint64(time_in_sec, 10); + formatter.AppendString(" (unix time)"); + formatter.AppendString(" try \"date -d @"); + formatter.AppendUint64(time_in_sec, 10); + formatter.AppendString("\" if you are using GNU date ***\n"); + g_failure_writer(buf, formatter.num_bytes_written()); +} + +// Dumps information about the signal to STDERR. +void DumpSignalInfo(int signal_number, siginfo_t *siginfo) { + // Get the signal name. + const char* signal_name = NULL; + for (size_t i = 0; i < ARRAYSIZE(kFailureSignals); ++i) { + if (signal_number == kFailureSignals[i].number) { + signal_name = kFailureSignals[i].name; + } + } + + char buf[256]; // Big enough for signal info. + MinimalFormatter formatter(buf, sizeof(buf)); + + formatter.AppendString("*** "); + if (signal_name) { + formatter.AppendString(signal_name); + } else { + // Use the signal number if the name is unknown. The signal name + // should be known, but just in case. + formatter.AppendString("Signal "); + formatter.AppendUint64(signal_number, 10); + } + formatter.AppendString(" (@0x"); + formatter.AppendUint64(reinterpret_cast<uintptr_t>(siginfo->si_addr), 16); + formatter.AppendString(")"); + formatter.AppendString(" received by PID "); + formatter.AppendUint64(getpid(), 10); + formatter.AppendString(" (TID 0x"); + // We assume pthread_t is an integral number or a pointer, rather + // than a complex struct. In some environments, pthread_self() + // returns an uint64 but in some other environments pthread_self() + // returns a pointer. Hence we use C-style cast here, rather than + // reinterpret/static_cast, to support both types of environments. + formatter.AppendUint64((uintptr_t)pthread_self(), 16); + formatter.AppendString(") "); + // Only linux has the PID of the signal sender in si_pid. +#ifdef OS_LINUX + formatter.AppendString("from PID "); + formatter.AppendUint64(siginfo->si_pid, 10); + formatter.AppendString("; "); +#endif + formatter.AppendString("stack trace: ***\n"); + g_failure_writer(buf, formatter.num_bytes_written()); +} + +// Dumps information about the stack frame to STDERR. +void DumpStackFrameInfo(const char* prefix, void* pc) { + // Get the symbol name. + const char *symbol = "(unknown)"; + char symbolized[1024]; // Big enough for a sane symbol. + // Symbolizes the previous address of pc because pc may be in the + // next function. + if (Symbolize(reinterpret_cast<char *>(pc) - 1, + symbolized, sizeof(symbolized))) { + symbol = symbolized; + } + + char buf[1024]; // Big enough for stack frame info. + MinimalFormatter formatter(buf, sizeof(buf)); + + formatter.AppendString(prefix); + formatter.AppendString("@ "); + const int width = 2 * sizeof(void*) + 2; // + 2 for "0x". + formatter.AppendHexWithPadding(reinterpret_cast<uintptr_t>(pc), width); + formatter.AppendString(" "); + formatter.AppendString(symbol); + formatter.AppendString("\n"); + g_failure_writer(buf, formatter.num_bytes_written()); +} + +// Invoke the default signal handler. +void InvokeDefaultSignalHandler(int signal_number) { + struct sigaction sig_action; + memset(&sig_action, 0, sizeof(sig_action)); + sigemptyset(&sig_action.sa_mask); + sig_action.sa_handler = SIG_DFL; + sigaction(signal_number, &sig_action, NULL); + kill(getpid(), signal_number); +} + +// This variable is used for protecting FailureSignalHandler() from +// dumping stuff while another thread is doing it. Our policy is to let +// the first thread dump stuff and let other threads wait. +// See also comments in FailureSignalHandler(). +static pthread_t* g_entered_thread_id_pointer = NULL; + +// Dumps signal and stack frame information, and invokes the default +// signal handler once our job is done. +void FailureSignalHandler(int signal_number, + siginfo_t *signal_info, + void *ucontext) { + // First check if we've already entered the function. We use an atomic + // compare and swap operation for platforms that support it. For other + // platforms, we use a naive method that could lead to a subtle race. + + // We assume pthread_self() is async signal safe, though it's not + // officially guaranteed. + pthread_t my_thread_id = pthread_self(); + // NOTE: We could simply use pthread_t rather than pthread_t* for this, + // if pthread_self() is guaranteed to return non-zero value for thread + // ids, but there is no such guarantee. We need to distinguish if the + // old value (value returned from __sync_val_compare_and_swap) is + // different from the original value (in this case NULL). + pthread_t* old_thread_id_pointer = + glog_internal_namespace_::sync_val_compare_and_swap( + &g_entered_thread_id_pointer, + static_cast<pthread_t*>(NULL), + &my_thread_id); + if (old_thread_id_pointer != NULL) { + // We've already entered the signal handler. What should we do? + if (pthread_equal(my_thread_id, *g_entered_thread_id_pointer)) { + // It looks the current thread is reentering the signal handler. + // Something must be going wrong (maybe we are reentering by another + // type of signal?). Kill ourself by the default signal handler. + InvokeDefaultSignalHandler(signal_number); + } + // Another thread is dumping stuff. Let's wait until that thread + // finishes the job and kills the process. + while (true) { + sleep(1); + } + } + // This is the first time we enter the signal handler. We are going to + // do some interesting stuff from here. + // TODO(satorux): We might want to set timeout here using alarm(), but + // mixing alarm() and sleep() can be a bad idea. + + // First dump time info. + DumpTimeInfo(); + + // Get the program counter from ucontext. + void *pc = GetPC(ucontext); + DumpStackFrameInfo("PC: ", pc); + +#ifdef HAVE_STACKTRACE + // Get the stack traces. + void *stack[32]; + // +1 to exclude this function. + const int depth = GetStackTrace(stack, ARRAYSIZE(stack), 1); + DumpSignalInfo(signal_number, signal_info); + // Dump the stack traces. + for (int i = 0; i < depth; ++i) { + DumpStackFrameInfo(" ", stack[i]); + } +#endif + + // *** TRANSITION *** + // + // BEFORE this point, all code must be async-termination-safe! + // (See WARNING above.) + // + // AFTER this point, we do unsafe things, like using LOG()! + // The process could be terminated or hung at any time. We try to + // do more useful things first and riskier things later. + + // Flush the logs before we do anything in case 'anything' + // causes problems. + FlushLogFilesUnsafe(0); + + // Kill ourself by the default signal handler. + InvokeDefaultSignalHandler(signal_number); +} + +} // namespace + +#endif // HAVE_SIGACTION + +namespace glog_internal_namespace_ { + +bool IsFailureSignalHandlerInstalled() { +#ifdef HAVE_SIGACTION + struct sigaction sig_action; + memset(&sig_action, 0, sizeof(sig_action)); + sigemptyset(&sig_action.sa_mask); + sigaction(SIGABRT, NULL, &sig_action); + if (sig_action.sa_sigaction == &FailureSignalHandler) + return true; +#endif // HAVE_SIGACTION + return false; +} + +} // namespace glog_internal_namespace_ + +void InstallFailureSignalHandler() { +#ifdef HAVE_SIGACTION + // Build the sigaction struct. + struct sigaction sig_action; + memset(&sig_action, 0, sizeof(sig_action)); + sigemptyset(&sig_action.sa_mask); + sig_action.sa_flags |= SA_SIGINFO; + sig_action.sa_sigaction = &FailureSignalHandler; + + for (size_t i = 0; i < ARRAYSIZE(kFailureSignals); ++i) { + CHECK_ERR(sigaction(kFailureSignals[i].number, &sig_action, NULL)); + } +#endif // HAVE_SIGACTION +} + +void InstallFailureWriter(void (*writer)(const char* data, int size)) { +#ifdef HAVE_SIGACTION + g_failure_writer = writer; +#endif // HAVE_SIGACTION +} + +_END_GOOGLE_NAMESPACE_ |