SO1_TERMINAL_02

/*
Napisz program, który wyłączy echo, czyli wypisywanie znaków wprowadzonych z klawiatury na ekran. Po ponownym uruchomieniu program powinien
*/

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <termios.h>
#include <ctype.h>
#include <string.h>

#define BUFFER_SIZE 128

void restore_settings(struct termios default_settings)
{
    if(tcsetattr(STDIN_FILENO, TCSANOW, &default_settings) == -1) {
        perror("tcsetattr restore_settings");
        exit(EXIT_FAILURE);
    }
}

void set_no_echo_mode(void)
{
    struct termios no_echo_attr;

    if(tcgetattr(STDIN_FILENO, &no_echo_attr) == -1) {
        perror("tcgetattr set_no_echo_mode");
        exit(EXIT_FAILURE);
    }

    no_echo_attr.c_lflag &= ~(ICANON | ECHO);
    no_echo_attr.c_cc[VMIN] = 1;
    no_echo_attr.c_cc[VTIME] = 0;

    if(tcsetattr(STDIN_FILENO, TCSANOW, &no_echo_attr) == -1) {
        perror("tcsetattr set_no_echo_mode");
        exit(EXIT_FAILURE);
    }
}

int main(void)
{
    struct termios default_settings;
    char ch_buffer, asterisk = '*';
    char passwd_buffer[BUFFER_SIZE];
    unsigned int i = 0;
    const char *enter_password = "Podaj haslo: ";

    if(!isatty(STDIN_FILENO)) {
        perror("isatty");
        return EXIT_FAILURE;
    }

    if(tcgetattr(STDIN_FILENO, &default_settings) == -1) {
        perror("tcgetattr");
        return EXIT_FAILURE;
    }

    write(STDOUT_FILENO, enter_password, strlen(enter_password));

    set_no_echo_mode();
    while(read(STDIN_FILENO, &ch_buffer, 1) && (isalnum(ch_buffer) || (ispunct(ch_buffer))) && i < sizeof(passwd_buffer) -2) {
        passwd_buffer[i++] = ch_buffer;
        write(STDOUT_FILENO, &asterisk, 1);
    }
    passwd_buffer[i] = '\0';

    printf("\nPodane haslo: %s\n", passwd_buffer);

    restore_settings(default_settings);
    return EXIT_SUCCESS;
}