corosync/exec/logsys.c

/*
 * Copyright (c) 2002-2004 MontaVista Software, Inc.
 * Copyright (c) 2006-2009 Red Hat, Inc.
 *
 * Author: Steven Dake (sdake@redhat.com)
 * Author: Lon Hohberger (lhh@redhat.com)
 * Author: Fabio M. Di Nitto (fdinitto@redhat.com)
 *
 * All rights reserved.
 *
 * This software licensed under BSD license, the text of which follows:
 *
 * 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 the MontaVista Software, 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.
 */

#include <config.h>

#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <stdarg.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <time.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#if defined(COROSYNC_LINUX)
#include <linux/un.h>
#endif
#if defined(COROSYNC_BSD) || defined(COROSYNC_DARWIN)
#include <sys/un.h>
#endif
#define SYSLOG_NAMES
#include <syslog.h>
#include <stdlib.h>
#include <pthread.h>
#include <limits.h>

#include <corosync/engine/logsys.h>

#define YIELD_AFTER_LOG_OPS 10

/*
 * similar to syslog facilities/priorities tables,
 * make a tag table for internal use
 */

#ifdef SYSLOG_NAMES
struct syslog_names {
	const char *c_name;
	int c_val;
};

struct syslog_names tagnames[] =
{
	{ "log", LOGSYS_TAG_LOG },
	{ "enter", LOGSYS_TAG_ENTER },
	{ "leave", LOGSYS_TAG_LEAVE },
	{ "trace1", LOGSYS_TAG_TRACE1 },
	{ "trace2", LOGSYS_TAG_TRACE2 },
	{ "trace3", LOGSYS_TAG_TRACE3 },
	{ "trace4", LOGSYS_TAG_TRACE4 },
	{ "trace5", LOGSYS_TAG_TRACE5 },
	{ "trace6", LOGSYS_TAG_TRACE6 },
	{ "trace7", LOGSYS_TAG_TRACE7 },
	{ "trace8", LOGSYS_TAG_TRACE8 },
	{ NULL, -1 }
};
#endif

/*
 * These are not static so they can be read from the core file
 */
int *flt_data;

int flt_data_size;

#define COMBINE_BUFFER_SIZE 2048

/* values for logsys_logger init_status */
#define LOGSYS_LOGGER_INIT_DONE		0
#define LOGSYS_LOGGER_NEEDS_INIT	1

static int logsys_system_needs_init = LOGSYS_LOGGER_NEEDS_INIT;

static int logsys_after_log_ops_yield = 10;

/*
 * need unlogical order to preserve 64bit alignment
 */
struct logsys_logger {
	char subsys[LOGSYS_MAX_SUBSYS_NAMELEN];	/* subsystem name */
	char *logfile;				/* log to file */
	FILE *logfile_fp;			/* track file descriptor */
	unsigned int mode;			/* subsystem mode */
	unsigned int debug;			/* debug on|off */
	unsigned int tags;			/* trace tags */
	int syslog_facility;			/* facility */
	int syslog_priority;			/* priority */
	int logfile_priority;			/* priority to file */
	int init_status;			/* internal field to handle init queues
						   for subsystems */
};

/*
 * operating global variables
 */

static struct logsys_logger logsys_loggers[LOGSYS_MAX_SUBSYS_COUNT + 1];

static int wthread_active = 0;

static int wthread_should_exit = 0;

static pthread_mutex_t logsys_config_mutex = PTHREAD_MUTEX_INITIALIZER;

static unsigned int records_written = 1;

static pthread_t logsys_thread_id;

static pthread_cond_t logsys_cond;

static pthread_mutex_t logsys_cond_mutex;

#if defined(HAVE_PTHREAD_SPIN_LOCK)
static pthread_spinlock_t logsys_idx_spinlock;
#else
static pthread_mutex_t logsys_idx_mutex = PTHREAD_MUTEX_INITIALIZER;
#endif

static unsigned int log_rec_idx;

static int logsys_buffer_full = 0;

static char *format_buffer=NULL;

static int log_requests_pending = 0;

static int log_requests_lost = 0;

void *logsys_rec_end;

#define FDHEAD_INDEX	(flt_data_size)

#define FDTAIL_INDEX 	(flt_data_size + 1)

/* forward declarations */
static void logsys_close_logfile(int subsysid);

#ifdef LOGSYS_DEBUG
static char *decode_mode(int subsysid, char *buf, size_t buflen)
{
	memset(buf, 0, buflen);

	if (logsys_loggers[subsysid].mode & LOGSYS_MODE_OUTPUT_FILE)
		snprintf(buf+strlen(buf), buflen, "FILE,");

	if (logsys_loggers[subsysid].mode & LOGSYS_MODE_OUTPUT_STDERR)
		snprintf(buf+strlen(buf), buflen, "STDERR,");

	if (logsys_loggers[subsysid].mode & LOGSYS_MODE_OUTPUT_SYSLOG)
		snprintf(buf+strlen(buf), buflen, "SYSLOG,");

	if (subsysid == LOGSYS_MAX_SUBSYS_COUNT) {
		if (logsys_loggers[subsysid].mode & LOGSYS_MODE_FORK)
			snprintf(buf+strlen(buf), buflen, "FORK,");

		if (logsys_loggers[subsysid].mode & LOGSYS_MODE_THREADED)
			snprintf(buf+strlen(buf), buflen, "THREADED,");
	}

	memset(buf+strlen(buf)-1,0,1);

	return buf;
}

static char *decode_tags(int subsysid, char *buf, size_t buflen)
{
	unsigned int i;

	memset(buf, 0, buflen);

	for (i = 0; tagnames[i].c_name != NULL; i++) {
		if (logsys_loggers[subsysid].tags & tagnames[i].c_val) {
			snprintf(buf+strlen(buf), buflen, "%s,", tagnames[i].c_name);
		}
	}

	memset(buf+strlen(buf)-1,0,1);

	return buf;
}

static const char *decode_debug(int subsysid)
{
	if (logsys_loggers[subsysid].debug)
		return "on";

	return "off";
}

static const char *decode_status(int subsysid)
{
	if (!logsys_loggers[subsysid].init_status)
		return "INIT_DONE";

	return "NEEDS_INIT";
}

static void dump_subsys_config(int subsysid)
{
	char modebuf[1024];
	char tagbuf[1024];

	fprintf(stderr,
		"ID: %d\n"
		"subsys: %s\n"
		"logfile: %s\n"
		"logfile_fp: %p\n"
		"mode: %s\n"
		"debug: %s\n"
		"tags: %s\n"
		"syslog_fac: %s\n"
		"syslog_pri: %s\n"
		"logfile_pri: %s\n"
		"init_status: %s\n",
		subsysid,
		logsys_loggers[subsysid].subsys,
		logsys_loggers[subsysid].logfile,
		logsys_loggers[subsysid].logfile_fp,
		decode_mode(subsysid, modebuf, sizeof(modebuf)),
		decode_debug(subsysid),
		decode_tags(subsysid, tagbuf, sizeof(tagbuf)),
		logsys_facility_name_get(logsys_loggers[subsysid].syslog_facility),
		logsys_priority_name_get(logsys_loggers[subsysid].syslog_priority),
		logsys_priority_name_get(logsys_loggers[subsysid].logfile_priority),
		decode_status(subsysid));
}

static void dump_full_config(void)
{
	int i;

	for (i = 0; i <= LOGSYS_MAX_SUBSYS_COUNT; i++) {
		if (strlen(logsys_loggers[i].subsys) > 0)
			dump_subsys_config(i);
	}
}
#endif

/*
 * Helpers for _logsys_log_rec functionality
 */
static inline void my_memcpy_32bit (int *dest, const int *src, unsigned int words)
{
	unsigned int word_idx;
	for (word_idx = 0; word_idx < words; word_idx++) {
		dest[word_idx] = src[word_idx];
	}
}

static inline void my_memcpy_8bit (char *dest, const char *src,
				   unsigned int bytes)
{
	unsigned int byte_idx;

	for (byte_idx = 0; byte_idx < bytes; byte_idx++) {
		dest[byte_idx] = src[byte_idx];
	}
}

#if defined(HAVE_PTHREAD_SPIN_LOCK)
static void logsys_lock (void)
{
	pthread_spin_lock (&logsys_idx_spinlock);
}
static void logsys_unlock (void)
{
	pthread_spin_unlock (&logsys_idx_spinlock);
}
#else
static void logsys_lock (void)
{
	pthread_mutex_lock (&logsys_idx_mutex);
}
static void logsys_unlock (void)
{
	pthread_mutex_unlock (&logsys_idx_mutex);
}
#endif

/*
 * Before any write operation, a reclaim on the buffer area must be executed
 */
static inline void records_reclaim (unsigned int idx, unsigned int words)
{
	unsigned int should_reclaim;

	should_reclaim = 0;

	if ((idx + words) >= flt_data_size) {
		logsys_buffer_full = 1;
	}
	if (logsys_buffer_full == 0) {
		return;
	}

	logsys_lock();
	if (flt_data[FDTAIL_INDEX] > flt_data[FDHEAD_INDEX]) {
		if (idx + words >= flt_data[FDTAIL_INDEX]) {
			should_reclaim = 1;
		}
	} else {
		if ((idx + words) >= (flt_data[FDTAIL_INDEX] + flt_data_size)) {
			should_reclaim = 1;
		}
	}

	if (should_reclaim) {
		int words_needed = 0;

		words_needed = words + 1;
		do {
			unsigned int old_tail;

			words_needed -= flt_data[flt_data[FDTAIL_INDEX]];
			old_tail = flt_data[FDTAIL_INDEX];
			flt_data[FDTAIL_INDEX] =
				(flt_data[FDTAIL_INDEX] +
				flt_data[flt_data[FDTAIL_INDEX]]) % (flt_data_size);
			if (log_rec_idx == old_tail) {
				log_requests_lost += 1;
				log_rec_idx = flt_data[FDTAIL_INDEX];
			}
		} while (words_needed > 0);
	}
	logsys_unlock();
}

#define idx_word_step(idx)						\
do {									\
	if (idx > (flt_data_size - 1)) {				\
		idx = 0;						\
	}								\
} while (0);

#define idx_buffer_step(idx)						\
do {									\
	if (idx > (flt_data_size - 1)) {				\
		idx = ((idx) % (flt_data_size));			\
	}								\
} while (0);

/*
 * Internal threaded logging implementation
 */
static inline int strcpy_cutoff (char *dest, const char *src, int cutoff)
{
	if (cutoff <= 0) {
		size_t len = strlen (src);
		memcpy (dest, src, len + 1);
		return (len);
	} else {
		size_t len;
		strncpy (dest, src, cutoff);
		dest[cutoff] = '\0';
		len = strlen (dest);
		if (len != cutoff) {
			memset (&dest[len], ' ', cutoff - len);
		}
	}
	return (cutoff);
}

/*
 * %s SUBSYSTEM
 * %n FUNCTION NAME
 * %f FILENAME
 * %l FILELINE
 * %p PRIORITY
 * %t TIMESTAMP
 * %b BUFFER
 *
 * any number between % and character specify field length to pad or chop
*/
static void log_printf_to_logs (
	const char *subsys,
	const char *file_name,
	const char *function_name,
	int file_line,
	unsigned int level,
	const char *buffer)
{
	char output_buffer[COMBINE_BUFFER_SIZE];
	char char_time[128];
	char line_no[30];
	unsigned int format_buffer_idx = 0;
	unsigned int output_buffer_idx = 0;
	struct timeval tv;
	int cutoff;
	unsigned int len;
	int subsysid;

	subsysid = _logsys_config_subsys_get(subsys);
	if (subsysid <= - 1) {
		return;
	}

	while (format_buffer[format_buffer_idx]) {
		cutoff = -1;
		if (format_buffer[format_buffer_idx] == '%') {
			format_buffer_idx += 1;
			if (isdigit (format_buffer[format_buffer_idx])) {
				cutoff = atoi (&format_buffer[format_buffer_idx]);
			}
			while (isdigit (format_buffer[format_buffer_idx])) {
				format_buffer_idx += 1;
			}

			switch (format_buffer[format_buffer_idx]) {
				case 's':
					len = strcpy_cutoff (&output_buffer[output_buffer_idx], subsys, cutoff);
					output_buffer_idx += len;
					break;

				case 'n':
					len = strcpy_cutoff (&output_buffer[output_buffer_idx], function_name, cutoff);
					output_buffer_idx += len;
					break;

				case 'f':
					len = strcpy_cutoff (&output_buffer[output_buffer_idx], file_name, cutoff);
					output_buffer_idx += len;
					break;

				case 'l':
					sprintf (line_no, "%d", file_line);
					len = strcpy_cutoff (&output_buffer[output_buffer_idx], line_no, cutoff);
					output_buffer_idx += len;
					break;

				case 'p':
					break;

				case 't':
					gettimeofday (&tv, NULL);
					(void)strftime (char_time, sizeof (char_time), "%b %d %T", localtime ((time_t *)&tv.tv_sec));
					len = strcpy_cutoff (&output_buffer[output_buffer_idx], char_time, cutoff);
					output_buffer_idx += len;
					break;

				case 'b':
					len = strcpy_cutoff (&output_buffer[output_buffer_idx], buffer, cutoff);
					output_buffer_idx += len;
					break;
			}
			format_buffer_idx += 1;
		} else {
			output_buffer[output_buffer_idx++] = format_buffer[format_buffer_idx++];
		}
	}

	output_buffer[output_buffer_idx] = '\0';

	/*
	 * Output to syslog
	 */
	if ((logsys_loggers[subsysid].mode & LOGSYS_MODE_OUTPUT_SYSLOG) &&
	     ((level <= logsys_loggers[subsysid].syslog_priority) ||
	     (logsys_loggers[subsysid].debug != 0))) {
		syslog (level | logsys_loggers[subsysid].syslog_facility, "%s", output_buffer);
	}

	/*
	 * Terminate string with \n \0
	 */
	output_buffer[output_buffer_idx++] = '\n';
	output_buffer[output_buffer_idx] = '\0';

	/*
	 * Output to configured file
	 */
	if (((logsys_loggers[subsysid].mode & LOGSYS_MODE_OUTPUT_FILE) &&
	     (logsys_loggers[subsysid].logfile_fp != NULL)) &&
	    ((level <= logsys_loggers[subsysid].logfile_priority) ||
	     (logsys_loggers[subsysid].debug != 0))) {
		/*
		 * Output to a file
		 */
		if ((fwrite (output_buffer, strlen (output_buffer), 1,
			    logsys_loggers[subsysid].logfile_fp) < 1) ||
		    (fflush (logsys_loggers[subsysid].logfile_fp) == EOF)) {
			char tmpbuffer[1024];
			/*
			 * if we are here, it's bad.. it's really really bad.
			 * Best thing would be to light a candle in a church
			 * and pray.
			 */
			snprintf(tmpbuffer, sizeof(tmpbuffer),
				"LOGSYS EMERGENCY: %s Unable to write to %s.",
				logsys_loggers[subsysid].subsys,
				logsys_loggers[subsysid].logfile);
			pthread_mutex_lock (&logsys_config_mutex);
			logsys_close_logfile(subsysid);
			logsys_loggers[subsysid].mode &= ~LOGSYS_MODE_OUTPUT_FILE;
			pthread_mutex_unlock (&logsys_config_mutex);
			log_printf_to_logs(logsys_loggers[subsysid].subsys,
					   __FILE__, __FUNCTION__, __LINE__,
					   LOGSYS_LEVEL_EMERG, tmpbuffer);
		}
	}

	/*
	 * Output to stderr
	 */
	if ((logsys_loggers[subsysid].mode & LOGSYS_MODE_OUTPUT_STDERR) &&
	     ((level <= logsys_loggers[subsysid].logfile_priority) ||
	     (logsys_loggers[subsysid].debug != 0))) {
		if (write (STDERR_FILENO, output_buffer, strlen (output_buffer)) < 0) {
			char tmpbuffer[1024];
			/*
			 * if we are here, it's bad.. it's really really bad.
			 * Best thing would be to light 20 candles for each saint
			 * in the calendar and pray a lot...
			 */
			pthread_mutex_lock (&logsys_config_mutex);
			logsys_loggers[subsysid].mode &= ~LOGSYS_MODE_OUTPUT_STDERR;
			pthread_mutex_unlock (&logsys_config_mutex);
			snprintf(tmpbuffer, sizeof(tmpbuffer),
				"LOGSYS EMERGENCY: %s Unable to write to STDERR.",
				logsys_loggers[subsysid].subsys);
			log_printf_to_logs(logsys_loggers[subsysid].subsys,
				__FILE__, __FUNCTION__, __LINE__,
				LOGSYS_LEVEL_EMERG, tmpbuffer);
		}
	}
}

static void record_print (const char *buf)
{
	const int *buf_uint32t = (const int *)buf;
	unsigned int rec_size = buf_uint32t[0];
	unsigned int rec_ident = buf_uint32t[1];
	unsigned int file_line = buf_uint32t[2];
	unsigned int level = rec_ident >> 28;
	unsigned int i;
	unsigned int words_processed;
	unsigned int arg_size_idx;
	const void *arguments[64];
	unsigned int arg_count;

	arg_size_idx = 4;
	words_processed = 4;
	arg_count = 0;

	for (i = 0; words_processed < rec_size; i++) {
		arguments[arg_count++] = &buf_uint32t[arg_size_idx + 1];
		arg_size_idx += buf_uint32t[arg_size_idx] + 1;
		words_processed += buf_uint32t[arg_size_idx] + 1;
	}

	/*
	 * (char *)arguments[0] -> subsystem
	 * (char *)arguments[1] -> file_name
	 * (char *)arguments[2] -> function_name
	 * (char *)arguments[3] -> message
	 */

	log_printf_to_logs (
		(char *)arguments[0],
		(char *)arguments[1],
		(char *)arguments[2],
		file_line,
		(level-1),
		(char *)arguments[3]);
}

static int record_read (char *buf, int rec_idx, int *log_msg) {
        unsigned int rec_size;
        unsigned int rec_ident;
        int firstcopy, secondcopy;

	rec_size = flt_data[rec_idx];
	rec_ident = flt_data[(rec_idx + 1) % flt_data_size];

	/*
	 * Not a log record
	 */
	if ((rec_ident & LOGSYS_TAG_LOG) == 0) {
		*log_msg = 0;
        	return ((rec_idx + rec_size) % flt_data_size);
	}

	/*
	 * A log record
	 */
	*log_msg = 1;

        firstcopy = rec_size;
        secondcopy = 0;
        if (firstcopy + rec_idx > flt_data_size) {
                firstcopy = flt_data_size - rec_idx;
                secondcopy -= firstcopy - rec_size;
        }
        memcpy (&buf[0], &flt_data[rec_idx], firstcopy << 2);
        if (secondcopy) {
                memcpy (&buf[(firstcopy << 2)], &flt_data[0], secondcopy << 2);
        }
        return ((rec_idx + rec_size) % flt_data_size);
}

static inline void wthread_signal (void)
{
	if (wthread_active == 0) {
		return;
	}
	pthread_mutex_lock (&logsys_cond_mutex);
	pthread_cond_signal (&logsys_cond);
	pthread_mutex_unlock (&logsys_cond_mutex);
}

static inline void wthread_wait (void)
{
	pthread_mutex_lock (&logsys_cond_mutex);
	pthread_cond_wait (&logsys_cond, &logsys_cond_mutex);
	pthread_mutex_unlock (&logsys_cond_mutex);
}

static inline void wthread_wait_locked (void)
{
	pthread_cond_wait (&logsys_cond, &logsys_cond_mutex);
	pthread_mutex_unlock (&logsys_cond_mutex);
}

static void *logsys_worker_thread (void *data) __attribute__((__noreturn__));
static void *logsys_worker_thread (void *data)
{
	int log_msg;
	char buf[COMBINE_BUFFER_SIZE];

	/*
	 * Signal wthread_create that the initialization process may continue
	 */
	wthread_signal ();
	logsys_lock();
	log_rec_idx = flt_data[FDTAIL_INDEX];
	logsys_unlock();

	for (;;) {
		wthread_wait ();
		/*
		 * Read and copy the logging record index position
		 * It may have been updated by records_reclaim if
		 * messages were lost or or log_rec on the first new
		 * logging record available
		 */
		/*
		 * Process any pending log messages here
		 */
		for (;;) {
			int yield_counter = 1;
			
			logsys_lock();
			if (log_requests_lost > 0) {
				printf ("lost %d log requests\n", log_requests_lost);
				log_requests_pending -= log_requests_lost;
				log_requests_lost = 0;
			}
			if (log_requests_pending == 0) {
				logsys_unlock();
				break;
			}
			log_rec_idx = record_read (buf, log_rec_idx, &log_msg);
			if (log_msg) {
				log_requests_pending -= 1;
			}
			logsys_unlock();

			/*
			 * print the stored buffer
			 */
			if (log_msg) {
				record_print (buf);
				if (yield_counter++ > logsys_after_log_ops_yield) {
					yield_counter = 0;
					sched_yield ();
				}
			}
		}

		if (wthread_should_exit) {
			pthread_exit (NULL);
		}
	}
}

static void wthread_create (void)
{
	int res;

	if (wthread_active) {
		return;
	}

	wthread_active = 1;

	pthread_mutex_init (&logsys_cond_mutex, NULL);
	pthread_cond_init (&logsys_cond, NULL);
	pthread_mutex_lock (&logsys_cond_mutex);
	res = pthread_create (&logsys_thread_id, NULL,
		logsys_worker_thread, NULL);


	/*
	 * Wait for thread to be started
	 */
	wthread_wait_locked ();
}

static int _logsys_config_subsys_get_unlocked (const char *subsys)
{
	unsigned int i;

	if (!subsys) {
		return LOGSYS_MAX_SUBSYS_COUNT;
	}

 	for (i = 0; i <= LOGSYS_MAX_SUBSYS_COUNT; i++) {
		if (strcmp (logsys_loggers[i].subsys, subsys) == 0) {
			pthread_mutex_unlock (&logsys_config_mutex);
			return i;
		}
	}

	return (-1);
}

static void syslog_facility_reconf (void)
{
	closelog();
	openlog(logsys_loggers[LOGSYS_MAX_SUBSYS_COUNT].subsys,
		LOG_CONS|LOG_PID,
		logsys_loggers[LOGSYS_MAX_SUBSYS_COUNT].syslog_facility);
}

/*
 * this is always invoked within the mutex, so it's safe to parse the
 * whole thing as we need.
 */
static void logsys_close_logfile (
	int subsysid)
{
	int i;

	if ((logsys_loggers[subsysid].logfile_fp == NULL) &&
	    (logsys_loggers[subsysid].logfile == NULL)) {
		return;
	}

	/*
	 * if there is another subsystem or system using the same fp,
	 * then we clean our own structs, but we can't close the file
	 * as it is in use by somebody else.
	 * Only the last users will be allowed to perform the fclose.
	 */
 	for (i = 0; i <= LOGSYS_MAX_SUBSYS_COUNT; i++) {
		if ((logsys_loggers[i].logfile_fp == logsys_loggers[subsysid].logfile_fp) &&
		    (i != subsysid)) {
			logsys_loggers[subsysid].logfile = NULL;
			logsys_loggers[subsysid].logfile_fp = NULL;
			return;
		}
	}

	/*
	 * if we are here, we are the last users of that fp, so we can safely
	 * close it.
	 */
	fclose (logsys_loggers[subsysid].logfile_fp);
	logsys_loggers[subsysid].logfile_fp = NULL;
	free (logsys_loggers[subsysid].logfile);
	logsys_loggers[subsysid].logfile = NULL;
}

/*
 * we need a version that can work when somebody else is already
 * holding a config mutex lock or we will never get out of here
 */
static int logsys_config_file_set_unlocked (
		int subsysid,
		const char **error_string,
		const char *file)
{
	static char error_string_response[512];
	int i;

	logsys_close_logfile(subsysid);

	if ((file == NULL) ||
	    (strcmp(logsys_loggers[subsysid].subsys, "") == 0)) {
		return (0);
	}

	if (strlen(file) >= PATH_MAX) {
		snprintf (error_string_response,
			sizeof(error_string_response),
			"%s: logfile name exceed maximum system filename lenght\n",
			logsys_loggers[subsysid].subsys);
		*error_string = error_string_response;
		return (-1);
	}

	for (i = 0; i <= LOGSYS_MAX_SUBSYS_COUNT; i++) {
		if ((logsys_loggers[i].logfile != NULL) &&
			(strcmp (logsys_loggers[i].logfile, file) == 0) &&
			(i != subsysid)) {
				logsys_loggers[subsysid].logfile =
					logsys_loggers[i].logfile;
				logsys_loggers[subsysid].logfile_fp =
					logsys_loggers[i].logfile_fp;
				return (0);
		}
	}

	logsys_loggers[subsysid].logfile = strdup(file);
	if (logsys_loggers[subsysid].logfile == NULL) {
		snprintf (error_string_response,
			sizeof(error_string_response),
			"Unable to allocate memory for logfile '%s'\n",
			file);
		*error_string = error_string_response;
		return (-1);
	}

	logsys_loggers[subsysid].logfile_fp = fopen (file, "a+");
	if (logsys_loggers[subsysid].logfile_fp == NULL) {
		free(logsys_loggers[subsysid].logfile);
		logsys_loggers[subsysid].logfile = NULL;
		snprintf (error_string_response,
			sizeof(error_string_response),
			"Can't open logfile '%s' for reason (%s).\n",
				 file, strerror (errno));
		*error_string = error_string_response;
		return (-1);
	}

	return (0);
}

static void logsys_subsys_init (
		const char *subsys,
		int subsysid)
{
	if (logsys_system_needs_init == LOGSYS_LOGGER_NEEDS_INIT) {
		logsys_loggers[subsysid].init_status =
			LOGSYS_LOGGER_NEEDS_INIT;
	} else {
		memcpy(&logsys_loggers[subsysid],
		       &logsys_loggers[LOGSYS_MAX_SUBSYS_COUNT],
		       sizeof(logsys_loggers[LOGSYS_MAX_SUBSYS_COUNT]));
		logsys_loggers[subsysid].tags = LOGSYS_TAG_LOG;
		logsys_loggers[subsysid].init_status =
			LOGSYS_LOGGER_INIT_DONE;
	}
	strncpy (logsys_loggers[subsysid].subsys, subsys,
		LOGSYS_MAX_SUBSYS_NAMELEN);
}

/*
 * Internal API - exported
 */

int _logsys_system_setup(
	const char *mainsystem,
	unsigned int mode,
	unsigned int debug,
	const char *logfile,
	int logfile_priority,
	int syslog_facility,
	int syslog_priority,
	unsigned int tags)
{
	int i;
	const char *errstr;
	char tempsubsys[LOGSYS_MAX_SUBSYS_NAMELEN];

	if ((mainsystem == NULL) ||
	    (strlen(mainsystem) >= LOGSYS_MAX_SUBSYS_NAMELEN)) {
		return -1;
	}

	i = LOGSYS_MAX_SUBSYS_COUNT;

	pthread_mutex_lock (&logsys_config_mutex);

	snprintf(logsys_loggers[i].subsys,
		 LOGSYS_MAX_SUBSYS_NAMELEN,
		"%s", mainsystem);

	logsys_loggers[i].mode = mode;

	logsys_loggers[i].debug = debug;

	if (logsys_config_file_set_unlocked (i, &errstr, logfile) < 0) {
		pthread_mutex_unlock (&logsys_config_mutex);
		return (-1);
	}
	logsys_loggers[i].logfile_priority = logfile_priority;

	logsys_loggers[i].syslog_facility = syslog_facility;
	logsys_loggers[i].syslog_priority = syslog_priority;
	syslog_facility_reconf();

	logsys_loggers[i].tags = tags;

	logsys_loggers[i].init_status = LOGSYS_LOGGER_INIT_DONE;

	logsys_system_needs_init = LOGSYS_LOGGER_INIT_DONE;

	for (i = 0; i < LOGSYS_MAX_SUBSYS_COUNT; i++) {
		if ((strcmp (logsys_loggers[i].subsys, "") != 0) &&
			(logsys_loggers[i].init_status ==
			 LOGSYS_LOGGER_NEEDS_INIT)) {
				strncpy (tempsubsys, logsys_loggers[i].subsys,
					LOGSYS_MAX_SUBSYS_NAMELEN);
				logsys_subsys_init(tempsubsys, i);
		}
	}

	pthread_mutex_unlock (&logsys_config_mutex);

	return (0);
}

unsigned int _logsys_subsys_create (const char *subsys)
{
	int i;

	if ((subsys == NULL) ||
	    (strlen(subsys) >= LOGSYS_MAX_SUBSYS_NAMELEN)) {
		return -1;
	}

	pthread_mutex_lock (&logsys_config_mutex);

	i = _logsys_config_subsys_get_unlocked (subsys);
	if ((i > -1) && (i < LOGSYS_MAX_SUBSYS_COUNT)) {
		pthread_mutex_unlock (&logsys_config_mutex);
		return i;
	}

	for (i = 0; i < LOGSYS_MAX_SUBSYS_COUNT; i++) {
		if (strcmp (logsys_loggers[i].subsys, "") == 0) {
			logsys_subsys_init(subsys, i);
			break;
		}
	}

	if (i >= LOGSYS_MAX_SUBSYS_COUNT) {
		i = -1;
	}

	pthread_mutex_unlock (&logsys_config_mutex);
	return i;
}

int _logsys_wthread_create (void)
{
	if (((logsys_loggers[LOGSYS_MAX_SUBSYS_COUNT].mode & LOGSYS_MODE_FORK) == 0) &&
		((logsys_loggers[LOGSYS_MAX_SUBSYS_COUNT].mode & LOGSYS_MODE_THREADED) != 0)) {
		wthread_create();
		atexit (logsys_atexit);
	}
	return (0);
}

int _logsys_rec_init (unsigned int size)
{
	/*
	 * First record starts at zero
	 * Last record ends at zero
	 */
	flt_data = malloc ((size + 2) * sizeof (unsigned int));
	if (flt_data == NULL) {
		return (-1);
	}
	flt_data_size = size;
	flt_data[FDHEAD_INDEX] = 0;
	flt_data[FDTAIL_INDEX] = 0;

#if defined(HAVE_PTHREAD_SPIN_LOCK)
	pthread_spin_init (&logsys_idx_spinlock, 0);
#endif

	return (0);
}


/*
 * u32 RECORD SIZE
 * u32 record ident
 * u32 arg count
 * u32 file line
 * u32 subsys length
 * buffer null terminated subsys
 * u32 filename length
 * buffer null terminated filename
 * u32 filename length
 * buffer null terminated function
 * u32 arg1 length
 * buffer arg1
 * ... repeats length & arg
 */
void _logsys_log_rec (
	int subsysid,
	const char *function_name,
	const char *file_name,
	int file_line,
	unsigned int rec_ident,
	...)
{
	va_list ap;
	const void *buf_args[64];
	unsigned int buf_len[64];
	unsigned int i;
	unsigned int idx;
	unsigned int arguments = 0;
	unsigned int record_reclaim_size;
	unsigned int index_start;
	int words_written;

	record_reclaim_size = 0;

	/*
	 * Decode VA Args
	 */
	va_start (ap, rec_ident);
	arguments = 3;
	for (;;) {
		buf_args[arguments] = va_arg (ap, void *);
		if (buf_args[arguments] == LOGSYS_REC_END) {
			break;
		}
		buf_len[arguments] = va_arg (ap, int);
		record_reclaim_size += ((buf_len[arguments] + 3) >> 2) + 1;
		arguments++;
		if (arguments >= 64) {
			break;
		}
	}
	va_end (ap);

	/*
	 * Encode logsys subsystem identity, filename, and function
	 */
	buf_args[0] = logsys_loggers[subsysid].subsys;
	buf_len[0] = strlen (logsys_loggers[subsysid].subsys) + 1;
	buf_args[1] = file_name;
	buf_len[1] = strlen (file_name) + 1;
	buf_args[2] = function_name;
	buf_len[2] = strlen (function_name) + 1;
	for (i = 0; i < 3; i++) {
		record_reclaim_size += ((buf_len[i] + 3) >> 2) + 1;
	}

	idx = flt_data[FDHEAD_INDEX];
	index_start = idx;

	/*
	 * Reclaim data needed for record including 4 words for the header
	 */
	records_reclaim (idx, record_reclaim_size + 4);

	/*
	 * Write record size of zero and rest of header information
	 */
	flt_data[idx++] = 0;
	idx_word_step(idx);

	flt_data[idx++] = rec_ident;
	idx_word_step(idx);

	flt_data[idx++] = file_line;
	idx_word_step(idx);

	flt_data[idx++] = records_written;
	idx_word_step(idx);
	/*
	 * Encode all of the arguments into the log message
	 */
	for (i = 0; i < arguments; i++) {
		unsigned int bytes;
		unsigned int full_words;
		unsigned int total_words;

		bytes = buf_len[i];
		full_words = bytes >> 2;
		total_words = (bytes + 3) >> 2;

		flt_data[idx++] = total_words;
		idx_word_step(idx);

		/*
		 * determine if this is a wrapped write or normal write
		 */
		if (idx + total_words < flt_data_size) {
			/*
			 * dont need to wrap buffer
			 */
			my_memcpy_32bit (&flt_data[idx], buf_args[i], full_words);
			if (bytes % 4) {
				my_memcpy_8bit ((char *)&flt_data[idx + full_words],
					((const char *)buf_args[i]) + (full_words << 2), bytes % 4);
			}
		} else {
			/*
			 * need to wrap buffer
			 */
			unsigned int first;
			unsigned int second;

			first = flt_data_size - idx;
			if (first > full_words) {
				first = full_words;
			}
			second = full_words - first;
			my_memcpy_32bit (&flt_data[idx],
					 (const int *)buf_args[i], first);
			my_memcpy_32bit (&flt_data[0],
				(const int *)(((const unsigned char *)buf_args[i]) + (first << 2)),
				second);
			if (bytes % 4) {
				my_memcpy_8bit ((char *)&flt_data[0 + second],
					((const char *)buf_args[i]) + (full_words << 2), bytes % 4);
			}
		}
		idx += total_words;
		idx_buffer_step (idx);
	}
	words_written = idx - index_start;
	if (words_written < 0) {
		words_written += flt_data_size;
	}

	/*
	 * Commit the write of the record size now that the full record
	 * is in the memory buffer
	 */
	flt_data[index_start] = words_written;

	/*
	 * If the index of the current head equals the current log_rec_idx,
	 * and this is not a log_printf operation, set the log_rec_idx to
	 * the new head position and commit the new head.
	 */
	logsys_lock();
	if (rec_ident & LOGSYS_TAG_LOG) {
		log_requests_pending += 1;
	}
	if (log_requests_pending == 0) {
		log_rec_idx = idx;
	}
	flt_data[FDHEAD_INDEX] = idx;
	logsys_unlock();
	records_written++;
}

void _logsys_log_vprintf (
	int subsysid,
	const char *function_name,
	const char *file_name,
	int file_line,
	unsigned int level,
	const char *format,
	va_list ap)
{
	char logsys_print_buffer[COMBINE_BUFFER_SIZE];
	unsigned int len;

	if (subsysid <= -1) {
		subsysid = LOGSYS_MAX_SUBSYS_COUNT;
	}

	if ((level > logsys_loggers[subsysid].syslog_priority) &&
	    (level > logsys_loggers[subsysid].logfile_priority) &&
	    (logsys_loggers[subsysid].debug == 0)) {
		return;
	}

	len = vsprintf (logsys_print_buffer, format, ap);
	if (logsys_print_buffer[len - 1] == '\n') {
		logsys_print_buffer[len - 1] = '\0';
		len -= 1;
	}

	/*
	 * Create a log record
	 */
	_logsys_log_rec (subsysid,
		function_name,
		file_name,
		file_line,
		(level+1) << 28,
		logsys_print_buffer, len + 1,
		LOGSYS_REC_END);

	if ((logsys_loggers[LOGSYS_MAX_SUBSYS_COUNT].mode & LOGSYS_MODE_THREADED) == 0) {
		/*
		 * Output (and block) if the log mode is not threaded otherwise
		 * expect the worker thread to output the log data once signaled
		 */
		log_printf_to_logs (logsys_loggers[subsysid].subsys,
			file_name, function_name, file_line, level,
			logsys_print_buffer);
	} else {
		/*
		 * Signal worker thread to display logging output
		 */
		wthread_signal ();
	}
}

void _logsys_log_printf (
	int subsysid,
	const char *function_name,
	const char *file_name,
	int file_line,
	unsigned int level,
	const char *format,
	...)
{
	char logsys_print_buffer[COMBINE_BUFFER_SIZE];
	unsigned int len;
	va_list ap;

	if (subsysid <= -1) {
		subsysid = LOGSYS_MAX_SUBSYS_COUNT;
	}

	if ((level > logsys_loggers[subsysid].syslog_priority) &&
	    (level > logsys_loggers[subsysid].logfile_priority) &&
	    (logsys_loggers[subsysid].debug == 0)) {
		return;
	}

	va_start (ap, format);
	len = vsprintf (logsys_print_buffer, format, ap);
	va_end (ap);
	if (logsys_print_buffer[len - 1] == '\n') {
		logsys_print_buffer[len - 1] = '\0';
		len -= 1;
	}

	/*
	 * Create a log record
	 */
	_logsys_log_rec (subsysid,
		function_name,
		file_name,
		file_line,
		(level+1) << 28,
		logsys_print_buffer, len + 1,
		LOGSYS_REC_END);

	if ((logsys_loggers[LOGSYS_MAX_SUBSYS_COUNT].mode & LOGSYS_MODE_THREADED) == 0) {
		/*
		 * Output (and block) if the log mode is not threaded otherwise
		 * expect the worker thread to output the log data once signaled
		 */
		log_printf_to_logs (logsys_loggers[subsysid].subsys,
			file_name, function_name, file_line, level,
			logsys_print_buffer);
	} else {
		/*
		 * Signal worker thread to display logging output
		 */
		wthread_signal ();
	}
}

int _logsys_config_subsys_get (const char *subsys)
{
	unsigned int i;

	pthread_mutex_lock (&logsys_config_mutex);

	i = _logsys_config_subsys_get_unlocked (subsys);

	pthread_mutex_unlock (&logsys_config_mutex);

	return i;
}

/*
 * External Configuration and Initialization API
 */
void logsys_fork_completed (void)
{
	logsys_loggers[LOGSYS_MAX_SUBSYS_COUNT].mode &= ~LOGSYS_MODE_FORK;
	_logsys_wthread_create ();
}

unsigned int logsys_config_mode_set (const char *subsys, unsigned int mode)
{
	int i;

	pthread_mutex_lock (&logsys_config_mutex);
	if (subsys != NULL) {
		i = _logsys_config_subsys_get_unlocked (subsys);
		if (i >= 0) {
			logsys_loggers[i].mode = mode;
			i = 0;
		}
	} else {
		for (i = 0; i <= LOGSYS_MAX_SUBSYS_COUNT; i++) {
			logsys_loggers[i].mode = mode;
		}
		i = 0;
	}
	pthread_mutex_unlock (&logsys_config_mutex);

	return i;
}

unsigned int logsys_config_mode_get (const char *subsys)
{
	int i;

	i = _logsys_config_subsys_get (subsys);
	if (i < 0) {
		return i;
	}

	return logsys_loggers[i].mode;
}

unsigned int logsys_config_tags_set (const char *subsys, unsigned int tags)
{
	int i;

	pthread_mutex_lock (&logsys_config_mutex);
	if (subsys != NULL) {
		i = _logsys_config_subsys_get_unlocked (subsys);
		if (i >= 0) {
			logsys_loggers[i].tags = tags;
			i = 0;
		}
	} else {
		for (i = 0; i <= LOGSYS_MAX_SUBSYS_COUNT; i++) {
			logsys_loggers[i].tags = tags;
		}
		i = 0;
	}
	pthread_mutex_unlock (&logsys_config_mutex);

	return i;
}

unsigned int logsys_config_tags_get (const char *subsys)
{
	int i;

	i = _logsys_config_subsys_get (subsys);
	if (i < 0) {
		return i;
	}

	return logsys_loggers[i].tags;
}

int logsys_config_file_set (
		const char *subsys,
		const char **error_string,
		const char *file)
{
	int i;
	int res;

	pthread_mutex_lock (&logsys_config_mutex);

	if (subsys != NULL) {
		i = _logsys_config_subsys_get_unlocked (subsys);
		if (i < 0) {
			res = i;
		} else {
			res = logsys_config_file_set_unlocked(i, error_string, file);
		}
	} else {
		for (i = 0; i <= LOGSYS_MAX_SUBSYS_COUNT; i++) {
			res = logsys_config_file_set_unlocked(i, error_string, file);
			if (res < 0) {
				break;
			}
		}
	}

	pthread_mutex_unlock (&logsys_config_mutex);
	return res;
}

int logsys_format_set (const char *format)
{
	int ret = 0;

	pthread_mutex_lock (&logsys_config_mutex);

	if (format_buffer) {
		free(format_buffer);
		format_buffer = NULL;
	}

	format_buffer = strdup(format ? format : "[%6s] %b");
	if (format_buffer == NULL) {
		ret = -1;
	}

	pthread_mutex_unlock (&logsys_config_mutex);
	return ret;
}

char *logsys_format_get (void)
{
	return format_buffer;
}

unsigned int logsys_config_syslog_facility_set (
	const char *subsys,
	unsigned int facility)
{
	int i;

	pthread_mutex_lock (&logsys_config_mutex);
	if (subsys != NULL) {
		i = _logsys_config_subsys_get_unlocked (subsys);
		if (i >= 0) {
			logsys_loggers[i].syslog_facility = facility;
			if (i == LOGSYS_MAX_SUBSYS_COUNT) {
				syslog_facility_reconf();
			}
			i = 0;
		}
	} else {
		for (i = 0; i <= LOGSYS_MAX_SUBSYS_COUNT; i++) {
			logsys_loggers[i].syslog_facility = facility;
		}
		syslog_facility_reconf();
		i = 0;
	}
	pthread_mutex_unlock (&logsys_config_mutex);

	return i;
}

unsigned int logsys_config_syslog_priority_set (
	const char *subsys,
	unsigned int priority)
{
	int i;

	pthread_mutex_lock (&logsys_config_mutex);
	if (subsys != NULL) {
		i = _logsys_config_subsys_get_unlocked (subsys);
		if (i >= 0) {
			logsys_loggers[i].syslog_priority = priority;
			i = 0;
		}
	} else {
		for (i = 0; i <= LOGSYS_MAX_SUBSYS_COUNT; i++) {
			logsys_loggers[i].syslog_priority = priority;
		}
		i = 0;
	}
	pthread_mutex_unlock (&logsys_config_mutex);

	return i;
}

unsigned int logsys_config_logfile_priority_set (
	const char *subsys,
	unsigned int priority)
{
	int i;

	pthread_mutex_lock (&logsys_config_mutex);
	if (subsys != NULL) {
		i = _logsys_config_subsys_get_unlocked (subsys);
		if (i >= 0) {
			logsys_loggers[i].logfile_priority = priority;
			i = 0;
		}
	} else {
		for (i = 0; i <= LOGSYS_MAX_SUBSYS_COUNT; i++) {
			logsys_loggers[i].logfile_priority = priority;
		}
		i = 0;
	}
	pthread_mutex_unlock (&logsys_config_mutex);

	return i;
}

unsigned int logsys_config_debug_set (
	const char *subsys,
	unsigned int debug)
{
	int i;

	pthread_mutex_lock (&logsys_config_mutex);
	if (subsys != NULL) {
		i = _logsys_config_subsys_get_unlocked (subsys);
		if (i >= 0) {
			logsys_loggers[i].debug = debug;
			i = 0;
		}
	} else {
		for (i = 0; i <= LOGSYS_MAX_SUBSYS_COUNT; i++) {
			logsys_loggers[i].debug = debug;
		}
		i = 0;
	}
	pthread_mutex_unlock (&logsys_config_mutex);

	return i;
}

int logsys_facility_id_get (const char *name)
{
	unsigned int i;

	for (i = 0; facilitynames[i].c_name != NULL; i++) {
		if (strcasecmp(name, facilitynames[i].c_name) == 0) {
			return (facilitynames[i].c_val);
		}
	}
	return (-1);
}

const char *logsys_facility_name_get (unsigned int facility)
{
	unsigned int i;

	for (i = 0; facilitynames[i].c_name != NULL; i++) {
		if (facility == facilitynames[i].c_val) {
			return (facilitynames[i].c_name);
		}
	}
	return (NULL);
}

int logsys_priority_id_get (const char *name)
{
	unsigned int i;

	for (i = 0; prioritynames[i].c_name != NULL; i++) {
		if (strcasecmp(name, prioritynames[i].c_name) == 0) {
			return (prioritynames[i].c_val);
		}
	}
	return (-1);
}

const char *logsys_priority_name_get (unsigned int priority)
{
	unsigned int i;

	for (i = 0; prioritynames[i].c_name != NULL; i++) {
		if (priority == prioritynames[i].c_val) {
			return (prioritynames[i].c_name);
		}
	}
	return (NULL);
}

int logsys_tag_id_get (const char *name)
{
	unsigned int i;

	for (i = 0; tagnames[i].c_name != NULL; i++) {
		if (strcasecmp(name, tagnames[i].c_name) == 0) {
			return (tagnames[i].c_val);
		}
	}
	return (-1);
}

const char *logsys_tag_name_get (unsigned int tag)
{
	unsigned int i;

	for (i = 0; tagnames[i].c_name != NULL; i++) {
		if (tag == tagnames[i].c_val) {
			return (tagnames[i].c_name);
		}
	}
	return (NULL);
}

int logsys_thread_priority_set (
	int policy,
	const struct sched_param *param,
        unsigned int after_log_ops_yield)

{
	int res = 0;

	if (policy != SCHED_OTHER) {
		res = pthread_setschedparam (logsys_thread_id, policy, param);
	}
	if (after_log_ops_yield > 0) {
		logsys_after_log_ops_yield = after_log_ops_yield;
	}
	return (res);

}

int logsys_log_rec_store (const char *filename)
{
	int fd;
	ssize_t written_size;
	size_t size_to_write = (flt_data_size + 2) * sizeof (unsigned int);

	fd = open (filename, O_CREAT|O_RDWR, 0700);
	if (fd < 0) {
		return (-1);
	}

	written_size = write (fd, flt_data, size_to_write);
	if (close (fd) != 0)
		return (-1);
	if (written_size < 0) {
		return (-1);
	} else if ((size_t)written_size != size_to_write) {
		return (-1);
	}

	return (0);
}

void logsys_atexit (void)
{
	if (wthread_active) {
		wthread_should_exit = 1;
		wthread_signal ();
		pthread_join (logsys_thread_id, NULL);
	}
}

void logsys_flush (void)
{
	wthread_signal ();
}