haraldwolff
/
collabora-online
mirror of https://github.com/CollaboraOnline/online.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity
collabora-online/common/SigUtil.cpp

386 lines
9.5 KiB
C++
Raw Blame History

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
/*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
#include <config.h>
#include "SigUtil.hpp"
#if !defined(__ANDROID__)
# include <execinfo.h>
#endif
#include <csignal>
#include <sys/poll.h>
#include <sys/uio.h>
#include <unistd.h>
#include <atomic>
#include <cassert>
#include <chrono>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <fstream>
#include <iomanip>
#include <iostream>
#include <mutex>
#include <sstream>
#include <string>
#include <thread>
#include <Socket.hpp>
#include "Common.hpp"
#include "Log.hpp"
#ifndef IOS
static std::atomic<bool> TerminationFlag(false);
static std::atomic<bool> DumpGlobalState(false);
static std::atomic<bool> ShutdownRequestFlag(false);
#endif
namespace SigUtil
{
#ifndef IOS
bool getShutdownRequestFlag()
{
return ShutdownRequestFlag;
}
bool getTerminationFlag()
{
return TerminationFlag;
}
void setTerminationFlag()
{
TerminationFlag = true;
}
#if MOBILEAPP
void resetTerminationFlag()
{
TerminationFlag = false;
}
#endif
#endif // !IOS
void checkDumpGlobalState(GlobalDumpStateFn dumpState)
{
#if !MOBILEAPP
if (DumpGlobalState)
{
dumpState();
DumpGlobalState = false;
}
#endif
}
#if !MOBILEAPP
/// This traps the signal-handler so we don't _Exit
/// while dumping stack trace. It's re-entrant.
/// Used to safely increment and decrement the signal-handler trap.
class SigHandlerTrap
{
static std::atomic<int> SigHandling;
public:
SigHandlerTrap() { ++SigHandlerTrap::SigHandling; }
~SigHandlerTrap() { --SigHandlerTrap::SigHandling; }
/// Check that we have exclusive access to the trap.
/// Otherwise, there is another signal in progress.
bool isExclusive() const
{
// Return true if we are alone.
return SigHandlerTrap::SigHandling == 1;
}
/// Wait for the trap to clear.
static void wait()
{
while (SigHandlerTrap::SigHandling)
sleep(1);
}
};
std::atomic<int> SigHandlerTrap::SigHandling;
void waitSigHandlerTrap()
{
SigHandlerTrap::wait();
}
const char *signalName(const int signo)
{
switch (signo)
{
#define CASE(x) case SIG##x: return "SIG" #x
CASE(HUP);
CASE(INT);
CASE(QUIT);
CASE(ILL);
CASE(ABRT);
CASE(FPE);
CASE(KILL);
CASE(SEGV);
CASE(PIPE);
CASE(ALRM);
CASE(TERM);
CASE(USR1);
CASE(USR2);
CASE(CHLD);
CASE(CONT);
CASE(STOP);
CASE(TSTP);
CASE(TTIN);
CASE(TTOU);
CASE(BUS);
#ifdef SIGPOLL
CASE(POLL);
#endif
CASE(PROF);
CASE(SYS);
CASE(TRAP);
CASE(URG);
CASE(VTALRM);
CASE(XCPU);
CASE(XFSZ);
#ifdef SIGEMT
CASE(EMT);
#endif
#ifdef SIGSTKFLT
CASE(STKFLT);
#endif
#if defined(SIGIO) && SIGIO != SIGPOLL
CASE(IO);
#endif
#ifdef SIGPWR
CASE(PWR);
#endif
#ifdef SIGLOST
CASE(LOST);
#endif
CASE(WINCH);
#if defined(SIGINFO) && SIGINFO != SIGPWR
CASE(INFO);
#endif
#undef CASE
default:
return "unknown";
}
}
static
void handleTerminationSignal(const int signal)
{
bool hardExit = false;
const char *domain;
if (!ShutdownRequestFlag && (signal == SIGINT || signal == SIGTERM))
{
domain = " Shutdown signal received: ";
ShutdownRequestFlag = true;
}
else if (!TerminationFlag)
{
domain = " Forced-Termination signal received: ";
TerminationFlag = true;
}
else
{
domain = " ok, ok - hard-termination signal received: ";
hardExit = true;
}
Log::signalLogPrefix();
Log::signalLog(domain);
Log::signalLog(signalName(signal));
Log::signalLog("\n");
if (!hardExit)
SocketPoll::wakeupWorld();
else
{
::signal (signal, SIG_DFL);
::raise (signal);
}
}
void requestShutdown()
{
ShutdownRequestFlag = true;
SocketPoll::wakeupWorld();
}
void setTerminationSignals()
{
struct sigaction action;
sigemptyset(&action.sa_mask);
action.sa_flags = 0;
action.sa_handler = handleTerminationSignal;
sigaction(SIGINT, &action, nullptr);
sigaction(SIGTERM, &action, nullptr);
sigaction(SIGQUIT, &action, nullptr);
sigaction(SIGHUP, &action, nullptr);
}
static char FatalGdbString[256] = { '\0' };
static
void handleFatalSignal(const int signal)
{
SigHandlerTrap guard;
bool bReEntered = !guard.isExclusive();
Log::signalLogPrefix();
// Heap corruption can re-enter through backtrace.
if (bReEntered)
Log::signalLog(" Fatal double signal received: ");
else
Log::signalLog(" Fatal signal received: ");
Log::signalLog(signalName(signal));
struct sigaction action;
sigemptyset(&action.sa_mask);
action.sa_flags = 0;
action.sa_handler = SIG_DFL;
sigaction(signal, &action, nullptr);
if (!bReEntered)
dumpBacktrace();
// let default handler process the signal
::raise(signal);
}
void dumpBacktrace()
{
#if !defined(__ANDROID__)
Log::signalLog("\nBacktrace ");
Log::signalLogNumber(getpid());
Log::signalLog(":\n");
const int maxSlots = 50;
void *backtraceBuffer[maxSlots];
const int numSlots = backtrace(backtraceBuffer, maxSlots);
if (numSlots > 0)
{
backtrace_symbols_fd(backtraceBuffer, numSlots, STDERR_FILENO);
}
#else
LOG_SYS("Backtrace not available on Android.");
#endif
if (std::getenv("LOOL_DEBUG"))
{
Log::signalLog(FatalGdbString);
LOG_ERR("Sleeping 30s to allow debugging.");
sleep(30);
}
}
void setFatalSignals()
{
struct sigaction action;
sigemptyset(&action.sa_mask);
action.sa_flags = 0;
action.sa_handler = handleFatalSignal;
sigaction(SIGSEGV, &action, nullptr);
sigaction(SIGBUS, &action, nullptr);
sigaction(SIGABRT, &action, nullptr);
sigaction(SIGILL, &action, nullptr);
sigaction(SIGFPE, &action, nullptr);
// Prepare this in advance just in case.
std::ostringstream stream;
stream << "\nERROR: Fatal signal! Attach debugger with:\n"
<< "sudo gdb --pid=" << getpid() << "\n or \n"
<< "sudo gdb --q --n --ex 'thread apply all backtrace full' --batch --pid="
<< getpid() << '\n';
std::string streamStr = stream.str();
assert (sizeof (FatalGdbString) > strlen(streamStr.c_str()) + 1);
strncpy(FatalGdbString, streamStr.c_str(), sizeof(FatalGdbString)-1);
FatalGdbString[sizeof(FatalGdbString)-1] = '\0';
}
static
void handleUserSignal(const int signal)
{
Log::signalLogPrefix();
Log::signalLog(" User signal received: ");
Log::signalLog(signalName(signal));
Log::signalLog("\n");
if (signal == SIGUSR1)
{
DumpGlobalState = true;
SocketPoll::wakeupWorld();
}
}
static
void handleDebuggerSignal(const int /*signal*/)
{}
void setUserSignals()
{
struct sigaction action;
sigemptyset(&action.sa_mask);
action.sa_flags = 0;
action.sa_handler = handleUserSignal;
sigaction(SIGUSR1, &action, nullptr);
}
void setDebuggerSignal()
{
struct sigaction action;
sigemptyset(&action.sa_mask);
action.sa_flags = 0;
action.sa_handler = handleDebuggerSignal;
sigaction(SIGUSR1, &action, nullptr);
}
/// Kill the given pid with SIGKILL as default. Returns true when the pid does not exist any more.
bool killChild(const int pid, const int signal)
{
LOG_DBG("Killing PID: " << pid);
// Don't kill anything in the fuzzer case: pid == 0 would kill the fuzzer itself, and
// killing random other processes is not a great idea, either.
if (Util::isFuzzing() || kill(pid, signal) == 0 || errno == ESRCH)
{
// Killed or doesn't exist.
return true;
}
LOG_SYS("Error when trying to kill PID: " << pid << ". Will wait for termination.");
const int sleepMs = 50;
const int count = std::max(CHILD_REBALANCE_INTERVAL_MS / sleepMs, 2);
for (int i = 0; i < count; ++i)
{
if (kill(pid, 0) == 0 || errno == ESRCH)
{
// Doesn't exist.
return true;
}
std::this_thread::sleep_for(std::chrono::milliseconds(sleepMs));
}
return false;
}
#endif // !MOBILEAPP
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
Reference in New Issue View Git Blame Copy Permalink