log.c

#include <sys/errno.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#define TIMEBUF_LEN 32 /* this should fit %c for all locales */

int
psircd_log(const char *level, const char *fname, int lineno, const char *fxname, const char *fmt, ...) {
	char *log_prefix = NULL;
	char *log_line = NULL;
	char *log_complete = NULL;
	char *timestr = NULL;
	struct tm *tptr = NULL;
	va_list ap;
	time_t now;
	int ret = -1;

	va_start(ap, fmt);

	now = time(NULL);
	if((time_t)-1 == now)
		goto cleanup; /* time(3) does not necessarily set errno */

	tptr = malloc(sizeof(struct tm));
	if(NULL == tptr)
		goto fail;
	if(NULL == gmtime_r(&now, tptr))
		goto fail;

	timestr = malloc(TIMEBUF_LEN*sizeof(char));
	if(NULL == timestr)
		goto fail;
	if(0 == strftime(timestr, TIMEBUF_LEN, "%c", tptr))
	{
		fprintf(stderr, "Logging failed: Formatted time did not for buffer.\n");
		goto cleanup;
	}

	ret = asprintf(&log_prefix, "[%.24s %s] %s - %s:%d, %s:",
		timestr, tptr->tm_zone, level, fname, lineno, fxname);
	if(-1 == ret)
		goto fail;
	
	ret = vasprintf(&log_line, fmt, ap);
	if(-1 == ret)
		goto fail;

	ret = asprintf(&log_complete, "%s %s", log_prefix, log_line);
	if(-1 == ret)
		goto fail;

	printf("%s", log_complete);

fail:
	if(errno)
		fprintf(stderr, "Logging failed: (%d) %s\n", errno, strerror(errno));

cleanup:
	free(timestr);
	free(log_prefix);
	free(log_line);
	free(log_complete);

	va_end(ap);

	return ret;
}