/*
 * Live variable collector
 * Copyright (C) 2024-2025  Nguyễn Gia Phong
 *
 * This file is part of taosc.
 *
 * Taosc is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Taosc is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with taosc.  If not, see <https://www.gnu.org/licenses/>.
 */

#include "stdlib.c"

static uint32_t stack_size;
static int output_file = -1;

/*
 * Get an environment variable and parse as a number.
 * Return 0 on error.
 */
uint32_t getenvul(const char *name)
{
	const char *const str = getenv(name);
	if (str == NULL)
		return 0ULL;
	errno = 0;
	const uint32_t ul = strtoul(str, NULL, 0);
	if (errno)
		return 0ULL;
	return ul;
}

void init(int argc, const char *const *argv, char **envp)
{
	environ = envp;
	stack_size = getenvul("TAOSC_STACK_SIZE");
	const char *const path = getenv("TAOSC_OUTPUT");
	if (path != NULL)
		output_file = open(path, O_WRONLY | O_CREAT, 0644);
	if (output_file == -1) {
		const char *msg = "cannot open $TAOSC_OUTPUT for writing\n";
		write(2, msg, strlen(msg));
		fsync(2);
		exit(128);
	}
}

void log(const struct STATE *state)
{

	static mutex_t mutex = MUTEX_INITIALIZER;
	while (mutex_lock(&mutex) < 0);
	write(output_file, (const char *)state, sizeof(struct STATE));
	write(output_file, (const char *)state->rsp, stack_size);
	fsync(output_file);
	mutex_unlock(&mutex);
}