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| #include <string.h> | |
| #include <unistd.h> | |
| #include <stdlib.h> | |
| #include <sys/wait.h> | |
| enum { | |
| READ, | |
| WRITE | |
| }; | |
| enum { | |
| CHILD, | |
| }; | |
| void ft_putstr_fd(char *str, int fd) { | |
| int len = 0; | |
| while (str[len]) | |
| len++; | |
| write(fd, str, len); | |
| } | |
| void fatal_err() { | |
| ft_putstr_fd("error: fatal\n", 2) | |
| exit(1); | |
| } | |
| void exec_cmd(char **cmd, char **env, int *pipe_fd, int *prev_pipe_read) { | |
| if (cmd && cmd[0] && env && pipe_fd && prev_pipe_read) { | |
| if (strcmp(cmd[0], "cd") == 0) { | |
| if (cmd[1] == NULL || cmd[2] != NULL) | |
| ft_putstr_fd("error: cd: bad arguments\n", 2) | |
| else if (chdir(cmd[1]) != 0) { | |
| ft_putstr_fd("error: cd: cannot change directory to ", 2); | |
| ft_putstr_fd(cmd[1], 2); | |
| ft_putstr_fd("\n", 2); | |
| } | |
| } | |
| else { | |
| pid_t pid = fork(); | |
| if (pid == -1) | |
| fatal_err(); | |
| if (pid == CHILD) { | |
| if (*prev_pipe_read != -1) | |
| dup2(*prev_pipe_read, STDIN_FILENO); | |
| if (pipe_fd[WRITE] != -1) | |
| dup2(pipe_fd[WRITE], STDOUT_FILENO); | |
| if (execve(cmd[0], cmd, env) == -1) { | |
| ft_putstr_fd("error: cannot execute ", 2); | |
| ft_putstr_fd(cmd[0], 2); | |
| ft_putstr_fd("\n", 2); | |
| } | |
| exit(0); | |
| } | |
| else { | |
| waitpid(pid, NULL, 0); | |
| if (*prev_pipe_read != -1) { | |
| close(*prev_pipe_read); | |
| *prev_pipe_read = -1; | |
| } | |
| if (pipe_fd[WRITE] != -1) { | |
| close(pipe_fd[WRITE]); | |
| pipe_fd[WRITE] = -1; | |
| } | |
| if (pipe_fd[READ] != -1) { | |
| *prev_pipe_read = pipe_fd[READ]; | |
| pipe_fd[READ] = -1; | |
| } | |
| } | |
| } | |
| } | |
| } | |
| int main(int argc, char **argv, char **env) { | |
| if (argc > 1) { | |
| int start = 1; | |
| int pipe_fd[2] = {-1, -1}; | |
| int prev_pipe_read = -1; | |
| for (int i = 1; argv[i]; i++) { | |
| if (strcmp(argv[i], "|") == 0 || strcmp(argv[i], ";") == 0) { | |
| if (strcmp(argv[i], "|") == 0) { | |
| if (pipe(pipe_fd) == -1) | |
| fatal_err(); | |
| } | |
| argv[i] = NULL; | |
| exec_cmd(&(argv[start]), env, pipe_fd, &prev_pipe_read); | |
| start = i + 1; | |
| } | |
| } | |
| exec_cmd(&(argv[start]), env, pipe_fd, &prev_pipe_read); | |
| } | |
| } |
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