main.c

#include "headers.h"

#define USER_LENGTH 257 // max size of username in linux + 1 for NULL character

char home_dir[PATH_MAX];     // beginning path
int child_pids[1000] = {-1}; // pids of child processes
int child_current_idx = 0;   // index of the current child id

void die(const char *s) {
    perror(s);
    exit(1);
}

struct termios orig_termios;

void disableRawMode() {
    if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &orig_termios) == -1)
        die("tcsetattr");
}

void enableRawMode() {
    if (tcgetattr(STDIN_FILENO, &orig_termios) == -1)
        die("tcgetattr");
    atexit(disableRawMode);
    struct termios raw = orig_termios;
    raw.c_lflag &= ~(ICANON | ECHO);
    if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw) == -1)
        die("tcsetattr");
}

// forground
int foreground = 0; // if process running on the foreground

int main() {
    printf("Welcome to aksh -- akshit shell\n\n");
    past pastevents = init_past();

    char username[USER_LENGTH];
    char hostname[USER_LENGTH];

    getlogin_r(username, USER_LENGTH);
    gethostname(hostname, USER_LENGTH);
    getcwd(home_dir, PATH_MAX);

    // input stuff
    char *input = malloc(sizeof(char) * 100);
    char c;

    char last[100] = "None";

    // child processes list
    child main_process = create_node(getpid(), "main");

    int index_cmd = 0; // index of the command

    // Keep accepting commands
    // only run if no command in foreground
    while (1) {
        if (getpid() == main_process->pid) {
            setbuf(stdout, NULL);
            enableRawMode();
            // when no foreground process
            char *save_ptr;
            int tabbed = 0;
            char *rel_pathname = getrpath(home_dir);
            // Print appropriate prompt with username, systemname and
            // directory before accepting input
            //			printf("asd");
            prompt(username, hostname, rel_pathname);

            memset(input, '\0', 100);

            int i = 0;
            int pt = 0;

            while (read(STDIN_FILENO, &c, 1) == 1) {
                if (iscntrl(c)) {
                    if (c == 10)
                        break;
                    else if (c == 27) {
                        char buf[3];
                        buf[2] = 0;
                        if (read(STDIN_FILENO, buf, 2) ==
                            2) { // length of escape code
                            printf("");
                        }
                    } else if (c == 127) { // backspace
                        if (pt > 0) {
                            if (input[pt - 1] == 9) {
                                for (int i = 0; i < 7; i++) {
                                    printf("\b");
                                }
                            }
                            input[--pt] = '\0';
                            printf("\b \b");
                        }
                    } else if (c == 9) { // TAB character
                        input[pt++] = c;
                        tabbed = 1;

                    } else if (c == 4) {
                        exit(0);
                    } else {
                        printf("%d\n", c);
                    }
                } else {
                    input[pt++] = c;
                    printf("%c", c);
                }
            }
            disableRawMode();

            if (tabbed == 0) {

                add_event_past(pastevents, input);
                stripspace(input);

                // check if ";"
                char *semicolon_ptr;
                char *expr = strtok_r(input, ";",
                                      &semicolon_ptr); // the first expression

                // run for every segment
                while (expr != NULL) {
                    run(expr, save_ptr, home_dir, pastevents, &foreground,
                        main_process, username, hostname, rel_pathname);
                    expr = strtok_r(NULL, ";", &semicolon_ptr);
                }
            }

            strcpy(last, input);
            // reset input
            strcpy(input, "");

            // next prompt
            fputc('\n', stdout);
            // foreground = 0;
        }
    }
    // in child process
}