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microshell.c

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+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   microshell.c                                       :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: astein <astein@student.42lisboa.com>       +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2021/12/15 12:15:17 by shackbei          #+#    #+#             */
+/*   Updated: 2023/12/06 23:29:19 by astein           ###   ########.fr       */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include <unistd.h>
+#include <sys/wait.h>
+#include <string.h>
+#include <stdlib.h>
+
+/*not needed in exam, but necessary if you want to use this tester:
+https://github.com/Glagan/42-exam-rank-04/blob/master/microshell/test.sh*/
+// #ifdef TEST_SH
+// # define TEST		1
+// #else
+// # define TEST		0
+// #endif
+
+void	ft_putstr_fd2(char *str, char *arg)
+{
+	while (*str)
+		write(2, str++, 1);
+	if (arg)
+		while(*arg)
+			write(2, arg++, 1);
+	write(2, "\n", 1);
+}
+
+void ft_execute(char *argv[], int i, int tmp_fd, char *env[])
+{
+	argv[i] = NULL;
+	dup2(tmp_fd, STDIN_FILENO);
+	close(tmp_fd);
+	execve(argv[0], argv, env);
+	ft_putstr_fd2("error: cannot execute ", argv[0]);
+	exit(1);
+}
+
+int	main(int argc, char *argv[], char *env[])
+{
+	int	i;
+	int fd[2];
+	int tmp_fd;
+	(void)argc;
+
+	i = 0;
+	tmp_fd = dup(STDIN_FILENO);
+	while (argv[i] && argv[i + 1])
+	{
+		argv = &argv[i + 1];
+		i = 0;
+		while (argv[i] && strcmp(argv[i], ";") && strcmp(argv[i], "|"))
+			i++;
+		if (strcmp(argv[0], "cd") == 0)
+		{
+			if (i != 2)
+				ft_putstr_fd2("error: cd: bad arguments", NULL);
+			else if (chdir(argv[1]) != 0)
+				ft_putstr_fd2("error: cd: cannot change directory to ", argv[1]	);
+		}
+		else if (i != 0 && (argv[i] == NULL || strcmp(argv[i], ";") == 0))
+		{
+			if ( fork() == 0)
+				ft_execute(argv, i, tmp_fd, env);
+			else
+			{
+				close(tmp_fd);
+				while(waitpid(-1, NULL, WUNTRACED) != -1)
+					;
+				tmp_fd = dup(STDIN_FILENO);
+			}
+		}
+		else if(i != 0 && strcmp(argv[i], "|") == 0)
+		{
+			pipe(fd);
+			if ( fork() == 0)
+			{
+				dup2(fd[1], STDOUT_FILENO);
+				close(fd[0]);
+				close(fd[1]);
+				ft_execute(argv, i, tmp_fd, env);
+			}
+			else
+			{
+				close(fd[1]);
+				close(tmp_fd);
+				tmp_fd = fd[0];
+			}
+		}
+	}
+	close(tmp_fd);
+	return (0);
+}