UnixSignal.cpp

/* CommonLibs/UnixSignal.cpp */
/*-
 * Copyright 2014 Range Networks, Inc.
 *
 * This software is distributed under the terms of the GNU Affero Public License.
 * See the COPYING file in the main directory for details.
 *
 * This use of this software may be subject to additional restrictions.
 * See the LEGAL file in the main directory for details.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/**@file Module for managing Linux signals and allowing multiple handlers per signal. */

#include <sys/types.h>
#include <sys/stat.h>

#include <unistd.h>

#include <cerrno>
#include <cstdio>
#include <cstdlib>
#include <cstring>

#include <google/coredumper.h>

#include "Logger.h"
#include "UnixSignal.h"

// UnixSignal gSigVec;

static void _sigHandler(int sig)
{
	signal(sig, SIG_IGN);
	if (sig <= 0 || sig >= UnixSignal::C_NSIG) {
		LOG(ERR) << "Signal Handler for signal " << sig << " (out of range)";
		return;
	}
	// work around C++ issue with function pointers and class based function pointers
	gSigVec.Handler(sig);
	signal(sig, SIG_DFL);
	printf("Rethrowing signal %d\n", sig);
	kill(getpid(), sig);
}

void UnixSignal::Handler(int sig)
{
	// Only write core files for the signals that need core
	switch (sig) {
	case SIGQUIT:
	case SIGILL:
	case SIGABRT:
	case SIGFPE:
	case SIGSEGV:
	case SIGBUS:
	case SIGSYS:
	case SIGTRAP:
	case SIGXCPU:
	case SIGXFSZ: {
		char buf[BUFSIZ];
		if (mAddPid)
			snprintf(buf, sizeof(buf) - 1, "%s.%d", mCoreFile.c_str(), getpid());
		else
			snprintf(buf, sizeof(buf) - 1, "%s", mCoreFile.c_str());
		WriteCoreDump(buf);

		// and save the files if needed
		if (mSaveFiles) {
			char buf[BUFSIZ];
			std::string s;
			std::string p;
			sprintf(buf, "%d", getpid());
			p = buf;
			s = "rm -rf /tmp/staging.";
			s += p;
			s += "/ ; ";
			s += "mkdir /tmp/staging.";
			s += p;
			s += "/ ; ";
			s += "cp --parents /etc/issue /tmp/staging.";
			s += p;
			s += "/ ; ";
			s += "cp --parents /proc/cpuinfo /proc/interrupts /proc/iomem /proc/ioports /proc/diskstats "
			     "/proc/loadavg /proc/locks /proc/meminfo /proc/softirqs /proc/stat /proc/uptime "
			     "/proc/version /proc/version_signature /proc/vmstat /tmp/staging.";
			s += p;
			s += "/ ; ";

			s += "for i in cmdline cpuset environ io limits maps net/tcp net/udp net/tcp6 net/udp6 "
			     "net/unix net/netstat sched schedstat smaps stat statm status ; ";
			s += "do cp --parents /proc/";
			s += p;
			s += "/$i /tmp/staging.";
			s += p;
			s += "/ ; ";
			s += "cp --parents /proc/";
			s += p;
			s += "/task/*/stat* /tmp/staging.";
			s += p;
			s += "/ ; ";
			s += "done ; ";
			s += "tar --create --verbose --file=- --directory=/proc/";
			s += p;
			s += " fd | ( cd /tmp/staging.";
			s += p;
			s += "/proc/";
			s += p;
			s += "/ ; tar xpvf - ) ; ";
			s += "tar --create --verbose --file=- --directory=/tmp/staging.";
			s += p;
			s += "/ . | gzip > ";
			s += mTarFile;
			s += " ; ";
			s += "rm -rf /tmp/staging.";
			s += p;
			printf("Running '%s'\n", s.c_str());
			int retcode = system(s.c_str());
			if (retcode != 0) {
				printf("Command failed: %s\n", strerror(errno));
			}
		}
	} break;
	default:
		break;
	}

	printf("Processing signal vector for sig %d\n", sig);
	mLock[sig].lock();
	for (std::list<sighandler_t>::iterator i = mListHandlers[sig].begin(); i != mListHandlers[sig].end(); i++) {
		(*i)(sig);
	}
	mLock[sig].unlock();
	printf("Done processing signal vector for sig %d\n", sig);
}

UnixSignal::UnixSignal(void)
{
	for (int i = 0; i < C_NSIG; i++) {
		mListHandlers[i].clear();
		// signal(i, _sigHandler);
	}
	mAddPid = false;
	mCoreFile = "core";
}

UnixSignal::~UnixSignal(void)
{
	for (int i = 0; i < C_NSIG; i++) {
		mListHandlers[i].clear();
		signal(i, SIG_DFL);
	}
}

void UnixSignal::Register(sighandler_t handler, int sig) // register the handler to the signal
{
	if (sig <= 0 || sig >= C_NSIG) {
		LOG(ERR) << "Unable to register callback for UnixSignal " << sig << " (out of range)";
		return;
	}
	mLock[sig].lock();
	signal(sig, _sigHandler); // only catch signals that have been registered
	mListHandlers[sig].insert(mListHandlers[sig].end(), handler);
	mLock[sig].unlock();
}

void UnixSignal::Dump(void)
{
	for (int sig = 0; sig < C_NSIG; sig++) {
		mLock[sig].lock();
		if (mListHandlers[sig].size() != 0) {
			printf("Signal vectors for signal %d: ", sig);
			for (std::list<sighandler_t>::iterator i = mListHandlers[sig].begin();
				i != mListHandlers[sig].end(); i++) {
				printf("%s0x%p", i == mListHandlers[sig].begin() ? "" : ", ", *i);
			}
			printf("\n");
		}
		mLock[sig].unlock();
	}
}