init/lib/util/argv_exec.c

/* SPDX-License-Identifier: ISC */
#include "service.h"

#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <stdio.h>

int setup_tty(const char *tty, bool truncate)
{
	int fd;

	if (tty == NULL)
		return 0;

	fd = open(tty, O_RDWR);
	if (fd < 0) {
		perror(tty);
		return -1;
	}

	if (truncate)
		ftruncate(fd, 0);

	close(STDIN_FILENO);
	close(STDOUT_FILENO);
	close(STDERR_FILENO);

	setsid();

	dup2(fd, STDIN_FILENO);
	dup2(fd, STDOUT_FILENO);
	dup2(fd, STDERR_FILENO);
	close(fd);
	return 0;
}

void argv_exec(exec_t *e)
{
	char **argv = alloca(sizeof(char *) * (e->argc + 1)), *ptr;
	int i;

	for (ptr = e->args, i = 0; i < e->argc; ++i, ptr += strlen(ptr) + 1)
		argv[i] = ptr;

	argv[i] = NULL;
	execvp(argv[0], argv);
	perror(argv[0]);
	exit(EXIT_FAILURE);
}