log.c

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <syslog.h>
#include <time.h>
#include "timespec.h"
#include "log.h"

static FILE *log_file = NULL;
static int priority_max_level = LOG_NOTICE;

static struct {
	char *name;
	int val;
} priority_names[] = {
	{ "emerg", LOG_EMERG },	/* system in unusable */
	{ "alert", LOG_ALERT },	/* action must be taken immediately */
	{ "crit", LOG_CRIT },	/* critical conditions */
	{ "err", LOG_ERR },	/* error conditions */
	{ "warning", LOG_WARNING }, /* warning conditions */
	{ "notice", LOG_NOTICE },   /* normal but significant condition */
	{ "info", LOG_INFO },       /* informational */
	{ "debug", LOG_DEBUG },     /* debug-level messages */
	{ NULL, -1 }
};

int
log_priority_from_name(char *name)
{
	int i = 0;

	if (name == NULL)
		return (-1);
	while (priority_names[i].name) {
		if (strcmp(priority_names[i].name, name) == 0)
			break;
		++i;
	}
	return (priority_names[i].val);
}

char *
log_name_from_priority(int priority)
{
	if (priority < 0 || priority > LOG_DEBUG)
		return ("unknown");
	if (priority_names[priority].val == priority)
		return (priority_names[priority].name);
	return ("unknown");
}

void
log_set_priority_max_level(int priority)
{
	priority_max_level = priority;
}

static void
log_time(char *s, int size)
{
	struct timespec ts;

	clock_gettime(CLOCK_REALTIME, &ts);
	timespec_str(&ts, s, size);
}

static void
log_msg_syslog(int priority, const char *buf)
{
	syslog(priority, "%s", buf);
}

#define TIMEBUF_SIZE	256

static void
log_msg_stderr(int priority, const char *buf)
{
	char tb[TIMEBUF_SIZE];

	log_time(tb, TIMEBUF_SIZE);
	fprintf(stderr, "%s: <%s> %s\n", tb, log_name_from_priority(priority),
		buf);
}

static void
log_msg_file(int priority, const char *buf)
{
	char tb[TIMEBUF_SIZE];

	log_time(tb, TIMEBUF_SIZE);
	fprintf(log_file, "%s: <%s> %s\n", tb, log_name_from_priority(priority),
		buf);
}

static void
(*log_msg)(int priority, const char *buf)
	= log_msg_stderr;

static void
log_vmessage(int priority, const char *format, va_list ap)
{
	char buffer[2048];

	if (priority > priority_max_level)
		return;
	vsnprintf(buffer, sizeof buffer, format, ap);
	log_msg(priority, buffer);
}

void
log_message(int priority, const char *format, ...)
{
	va_list ap;

	va_start(ap, format);
	log_vmessage(priority, format, ap);
	va_end(ap);
}

void
log_error(const char *format, ...)
{
	va_list ap;

	va_start(ap, format);
	log_vmessage(LOG_ERR, format, ap);
	va_end(ap);
}

void
log_warning(const char *format, ...)
{
	va_list ap;

	va_start(ap, format);
	log_vmessage(LOG_WARNING, format, ap);
	va_end(ap);
}

void
log_notice(const char *format, ...)
{
	va_list ap;

	va_start(ap, format);
	log_vmessage(LOG_NOTICE, format, ap);
	va_end(ap);
}

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

	va_start(ap, format);
	log_vmessage(LOG_INFO, format, ap);
	va_end(ap);
}

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

	va_start(ap, format);
	log_vmessage(LOG_DEBUG, format, ap);
	va_end(ap);
}

void
log_fatal(const char *format, ...)
{
	va_list ap;

	va_start(ap, format);
	log_vmessage(LOG_ERR, format, ap);
	va_end(ap);
	exit(2);
}

void
log_syslog_open(const char *log_identifier, int option, int facility)
{
	openlog(log_identifier, option, facility);
	log_msg = log_msg_syslog;
}

int
log_file_open(const char *path)
{
	FILE *f;

	f = fopen(path, "a");
	if (f == NULL)
		return (-1);
	if (log_file != NULL)
		fclose(log_file);
	setbuf(f, NULL);
	log_file = f;
	log_msg = log_msg_file;
	return (0);
}

void
log_term()
{
	if (log_file)
		fclose(log_file);
	log_file = NULL;
	log_msg = log_msg_stderr;
}