log.c

/* redsocks - transparent TCP-to-proxy redirector
 * Copyright (C) 2007-2008 Leonid Evdokimov <leon@darkk.net.ru>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <sys/time.h>
#include <sys/types.h>
#include <event.h>
#include "utils.h"
#include "log.h"

static const char *lowmem = "<Can't print error, not enough memory>";

typedef void (*log_func)(const char *file, int line, const char *func, int priority, const char *message, const char *appendix);

static void stderr_msg(const char *file, int line, const char *func, int priority, const char *message, const char *appendix)
{
	struct timeval tv = { };
	gettimeofday(&tv, 0);

	if (appendix)
		fprintf(stderr, "%lu.%6.6lu %s:%u %s(...) %s: %s\n", tv.tv_sec, tv.tv_usec, file, line, func, message, appendix);
	else
		fprintf(stderr, "%lu.%6.6lu %s:%u %s(...) %s\n", tv.tv_sec, tv.tv_usec, file, line, func, message);
}

static void syslog_msg(const char *file, int line, const char *func, int priority, const char *message, const char *appendix)
{
	if (appendix)
		syslog(priority, "%s: %s\n", message, appendix);
	else
		syslog(priority, "%s\n", message);
}

static log_func log_msg = stderr_msg;
static log_func log_msg_next = NULL;


int log_preopen(const char *dst, bool log_debug, bool log_info)
{
	const char *syslog_prefix = "syslog:";
	if (strcmp(dst, "stderr") == 0) {
		log_msg_next = stderr_msg;
	}
	else if (strncmp(dst, syslog_prefix, strlen(syslog_prefix)) == 0) {
		const char *facility_name = dst + strlen(syslog_prefix);
		int facility = -1;
		int logmask;
		struct {
			char *name; int value;
		} *ptpl, tpl[] = {
			{ "daemon", LOG_DAEMON },
			{ "local0", LOG_LOCAL0 },
			{ "local1", LOG_LOCAL1 },
			{ "local2", LOG_LOCAL2 },
			{ "local3", LOG_LOCAL3 },
			{ "local4", LOG_LOCAL4 },
			{ "local5", LOG_LOCAL5 },
			{ "local6", LOG_LOCAL6 },
			{ "local7", LOG_LOCAL7 },
		};

		FOREACH(ptpl, tpl)
			if (strcmp(facility_name, ptpl->name) == 0) {
				facility = ptpl->value;
				break;
			}
		if (facility == -1) {
			log_error(LOG_ERR, "log_preopen(%s, ...): unknown syslog facility", dst);
			return -1;
		}

		openlog("redsocks", LOG_NDELAY | LOG_PID, facility);

		logmask = setlogmask(0);
		if (!log_debug)
			logmask &= ~(LOG_MASK(LOG_DEBUG));
		if (!log_info)
			logmask &= ~(LOG_MASK(LOG_INFO));
		setlogmask(logmask);

		log_msg_next = syslog_msg;
	}
	else {
		log_error(LOG_ERR, "log_preopen(%s, ...): unknown destination", dst);
		return -1;
	}
	return 0;
}

void log_open()
{
	log_msg = log_msg_next;
	log_msg_next = NULL;
}

void _log_vwrite(const char *file, int line, const char *func, int do_errno, int priority, const char *fmt, va_list ap)
{
	int saved_errno = errno;
	struct evbuffer *buff = evbuffer_new();
	const char *message;

	if (buff) {
		evbuffer_add_vprintf(buff, fmt, ap);
		message = buff->buffer;
	}
	else
		message = lowmem;

	log_msg(file, line, func, priority, message, do_errno ? strerror(saved_errno) : NULL);

	if (buff)
		evbuffer_free(buff);
}

void _log_write(const char *file, int line, const char *func, int do_errno, int priority, const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	_log_vwrite(file, line, func, do_errno, priority, fmt, ap);
	va_end(ap);
}

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