/*	$OpenBSD: log.c,v 1.13 2016/10/12 11:57:31 reyk Exp $	*/

/*
 * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

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

int		 debug;
int		 verbose;
const char	*log_procname;

void	log_init(int, int);
void	log_procinit(const char *);
void	log_verbose(int);
void	log_warn(const char *, ...)
	    __attribute__((__format__ (printf, 1, 2)));
void	log_warnx(const char *, ...)
	    __attribute__((__format__ (printf, 1, 2)));
void	log_info(const char *, ...)
	    __attribute__((__format__ (printf, 1, 2)));
void	log_debug(const char *, ...)
	    __attribute__((__format__ (printf, 1, 2)));
void	logit(int, const char *, ...)
	    __attribute__((__format__ (printf, 2, 3)));
void	vlog(int, const char *, va_list)
	    __attribute__((__format__ (printf, 2, 0)));
__dead void fatal(const char *, ...)
	    __attribute__((__format__ (printf, 1, 2)));
__dead void fatalx(const char *, ...)
	    __attribute__((__format__ (printf, 1, 2)));

void
log_init(int n_debug, int facility)
{
	extern char	*__progname;

	debug = n_debug;
	verbose = n_debug;
	log_procinit(__progname);

	if (!debug)
		openlog(__progname, LOG_PID | LOG_NDELAY, facility);

	tzset();
}

void
log_procinit(const char *procname)
{
	if (procname != NULL)
		log_procname = procname;
}

void
log_verbose(int v)
{
	verbose = v;
}

void
logit(int pri, const char *fmt, ...)
{
	va_list	ap;

	va_start(ap, fmt);
	vlog(pri, fmt, ap);
	va_end(ap);
}

void
vlog(int pri, const char *fmt, va_list ap)
{
	char	*nfmt;

	if (debug) {
		/* best effort in out of mem situations */
		if (asprintf(&nfmt, "%s\n", fmt) == -1) {
			vfprintf(stderr, fmt, ap);
			fprintf(stderr, "\n");
		} else {
			vfprintf(stderr, nfmt, ap);
			free(nfmt);
		}
		fflush(stderr);
	} else
		vsyslog(pri, fmt, ap);
}


void
log_warn(const char *emsg, ...)
{
	char		*nfmt;
	va_list		 ap;
	int		 saved_errno = errno;

	/* best effort to even work in out of memory situations */
	if (emsg == NULL)
		logit(LOG_CRIT, "%s", strerror(saved_errno));
	else {
		va_start(ap, emsg);

		if (asprintf(&nfmt, "%s: %s", emsg,
		    strerror(saved_errno)) == -1) {
			/* we tried it... */
			vlog(LOG_CRIT, emsg, ap);
			logit(LOG_CRIT, "%s", strerror(saved_errno));
		} else {
			vlog(LOG_CRIT, nfmt, ap);
			free(nfmt);
		}
		va_end(ap);
	}
}

void
log_warnx(const char *emsg, ...)
{
	va_list	 ap;

	va_start(ap, emsg);
	vlog(LOG_CRIT, emsg, ap);
	va_end(ap);
}

void
log_info(const char *emsg, ...)
{
	va_list	 ap;

	va_start(ap, emsg);
	vlog(LOG_INFO, emsg, ap);
	va_end(ap);
}

void
log_debug(const char *emsg, ...)
{
	va_list	 ap;

	if (verbose > 1) {
		va_start(ap, emsg);
		vlog(LOG_DEBUG, emsg, ap);
		va_end(ap);
	}
}

static void
vfatal(const char *emsg, va_list ap)
{
	static char	s[BUFSIZ];
	const char	*sep;
	int		 saved_errno = errno;

	if (emsg != NULL) {
		(void)vsnprintf(s, sizeof(s), emsg, ap);
		sep = ": ";
	} else {
		s[0] = '\0';
		sep = "";
	}
	if (saved_errno)
		logit(LOG_CRIT, "%s: %s%s%s",
		    log_procname, s, sep, strerror(saved_errno));
	else
		logit(LOG_CRIT, "%s%s%s", log_procname, sep, s);
}

void
fatal(const char *emsg, ...)
{
	va_list	ap;

	va_start(ap, emsg);
	vfatal(emsg, ap);
	va_end(ap);
	exit(1);
}

void
fatalx(const char *emsg, ...)
{
	va_list	ap;

	errno = 0;
	va_start(ap, emsg);
	vfatal(emsg, ap);
	va_end(ap);
	exit(1);
}