libliftoff/log.c

#include <errno.h>
#include <stdio.h>
#include <string.h>
#include "log.h"

static enum liftoff_log_priority log_priority = LIFTOFF_ERROR;

static void
log_stderr(enum liftoff_log_priority priority, const char *fmt, va_list args)
{
	vfprintf(stderr, fmt, args);
	fprintf(stderr, "\n");
}

static liftoff_log_handler log_handler = log_stderr;

void
liftoff_log_set_priority(enum liftoff_log_priority priority)
{
	log_priority = priority;
}

void
liftoff_log_set_handler(liftoff_log_handler handler) {
	if (handler) {
		log_handler = handler;
	} else {
		log_handler = log_stderr;
	}
}

bool
log_has(enum liftoff_log_priority priority)
{
	return priority <= log_priority;
}

void
liftoff_log(enum liftoff_log_priority priority, const char *fmt, ...)
{
	if (!log_has(priority)) {
		return;
	}

	va_list args;
	va_start(args, fmt);
	log_handler(priority, fmt, args);
	va_end(args);
}

void
liftoff_log_errno(enum liftoff_log_priority priority, const char *msg)
{
	// Ensure errno is still set to its original value when we return
	int prev_errno = errno;
	liftoff_log(priority, "%s: %s", msg, strerror(errno));
	errno = prev_errno;
}