#define _POSIX_C_SOURCE 200809L

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

char *readpass(char *prompt) {
	FILE *term;
	struct termios saved, noecho;
	char *termpath, *pass = 0;;
	int fd;
	size_t len = 0;
	ssize_t res;

	termpath = ctermid(0);
	if (!*termpath) {
		errno = ENOTTY;
		return 0;
	}
	term = fopen(termpath, "r+");
	if (!term) {
		return 0;
	}

	fd = fileno(term);

	if (tcgetattr(fd, &saved) != 0) {
		return 0;
	}
	noecho = saved;
	noecho.c_lflag &= ~ECHO;

	if (tcsetattr(fd, TCSAFLUSH, &noecho) != 0) {
		return 0;
	}

	if (prompt) {
		fprintf(term, "%s", prompt);
		fflush(term);
	}

	/* Read the password. */
	res = getline(&pass, &len, term);
	fprintf(term, "\n");
	fflush(term);
	fclose(term);

	if (res == -1) {
		free(pass);
		return 0;
	}

	if (res == 0) {
		/* should be impossible */
		free(pass);
		return 0;
	}

	pass[res-1] = 0;

	/* Restore terminal. */
	tcsetattr(fd, TCSAFLUSH, &saved);

	return pass;
}