path: root/02_exercise/shell.c

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

#include <fcntl.h>
#include <signal.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>

#include "array.h"
#include "errno.h"
#include "stdbool.h"

void print_prompt(char const *const original_wd, char const *current_wd);

// Returns the return code of the executed programm
int exec_command(char *command);

int main(void) {
    // the directory is specified without a / at the end
    char const *const original_wd = get_current_dir_name();
    char const *current_wd = get_current_dir_name();

    while (true) {
        char *command = NULL;
        size_t cap = 0;
        size_t length = 0;

        print_prompt(original_wd, current_wd);
        if ((length = getline(&command, &cap, stdin)) < 0) {
            fprintf(stderr, "Failed to read from STDIN");
            exit(-1);
        }
        if (strstr(command, "cd") != NULL) {
            printf("Changing dirs \n");
            chdir("beispiele");
            free((void *) current_wd);
            current_wd = get_current_dir_name();
        } else if (strcmp(command, "exit\n") == 0) {
            exit(0);
        } else {
            exec_command(command);
        }
        free((void *)command);
    }
    // Gotta cast to void otherwise we discard qualifiers
    free((void *)original_wd);
    free((void *)current_wd);
}

void print_prompt(char const *const original_wd, char const *const current_wd) {
    // easiest case first
    {
        int result = strcmp(original_wd, current_wd);
        if (result == 0) {
            printf(".> ");
            return;
        }
    }
    printf("%s > ", current_wd);
    // Now checking for substrings aka are we in a subdir
    {
        size_t dirlen = strlen(original_wd);
        char *const orig_dir_with_slash = malloc(dirlen + 2);
        if (orig_dir_with_slash == NULL) {
            fprintf(stderr, "Failed to allocate for prompt");
            exit(ENOMEM);
        }
        memcpy(orig_dir_with_slash, original_wd, dirlen);
        orig_dir_with_slash[dirlen] = '/';
        orig_dir_with_slash[dirlen + 1] = '\0';
        char const *const result = strstr(current_wd, original_wd);
        if (result != NULL) {
            printf(".%s > ", current_wd + dirlen);
            return;
        }
    }
}

int exec_command(char *command) { return 0; }