init/syslogd/syslogd.h

/* SPDX-License-Identifier: GPL-3.0-or-later */
/*
 * Copyright (C) 2018 - David Oberhollenzer
 *
 * 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 <https://www.gnu.org/licenses/>.
 */
#ifndef SYSLOGD_H
#define SYSLOGD_H


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

#include "config.h"


#define SYSLOG_SOCKET PREFIXPATH "/dev/log"
#define SYSLOG_PATH PREFIXPATH "/var/log"
#define DEFAULT_USER "syslogd"
#define DEFAULT_GROUP "syslogd"


/*
  encapsulates the split up data from a message received
  through the local syslog socket.
 */
typedef struct {
	int facility;
	int level;
	time_t timestamp;
	pid_t pid;
	const char *ident;
	const char *message;
} syslog_msg_t;


enum {
	/*
	  Rotate log data in a way that we still generate a continuous stream
	  of log data. E.g. in the case of log files, move the current log file
	  to one suffixed with a timestamp. We don't lose any log data.
	 */
	LOG_ROTATE_CONTINUOUS = 0x00,

	/*
	  Rotate log data by overwriting old data with more recent data.
	  E.g. in the case of log files, move the current log file to one
	  with a constant prefix, overwriting any existing data.
	 */
	LOG_ROTATE_OVERWRITE = 0x01,

	/*
	  Automatically do a log rotatation if a log stream reaches a preset
	  size limit.
	 */
	LOG_ROTATE_SIZE_LIMIT = 0x10,
};

typedef struct log_backend_t {
	int (*init)(struct log_backend_t *log, int flags, size_t sizelimit);

	void (*cleanup)(struct log_backend_t *log);

	int (*write)(struct log_backend_t *log, const syslog_msg_t *msg);

	void (*rotate)(struct log_backend_t *log);
} log_backend_t;


extern log_backend_t *logmgr;

/*
  Parse a message string received from the syslog socket and produce
  a split up representation for the message.
 */
int syslog_msg_parse(syslog_msg_t *msg, char *str);

#endif /* LOGFILE_H */