source: MondoRescue/branches/2.2.5/mindi-busybox/libbb/bb_askpass.c

/* vi: set sw=4 ts=4: */
/*
 * Ask for a password
 * I use a static buffer in this function.  Plan accordingly.
 *
 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

#include <termios.h>

#include "libbb.h"

/* do nothing signal handler */
static void askpass_timeout(int ATTRIBUTE_UNUSED ignore)
{
}

char *bb_askpass(int timeout, const char * prompt)
{
    /* Was static char[BIGNUM] */
    enum { sizeof_passwd = 128 };
    static char *passwd;

    char *ret;
    int i;
    struct sigaction sa;
    struct termios old, new;

    if (!passwd)
        passwd = xmalloc(sizeof_passwd);
    memset(passwd, 0, sizeof_passwd);

    tcgetattr(STDIN_FILENO, &old);
    tcflush(STDIN_FILENO, TCIFLUSH);

    fputs(prompt, stdout);
    fflush(stdout);

    tcgetattr(STDIN_FILENO, &new);
    new.c_iflag &= ~(IUCLC|IXON|IXOFF|IXANY);
    new.c_lflag &= ~(ECHO|ECHOE|ECHOK|ECHONL|TOSTOP);
    tcsetattr(STDIN_FILENO, TCSANOW, &new);

    if (timeout) {
        sa.sa_flags = 0;
        sa.sa_handler = askpass_timeout;
        sigaction(SIGALRM, &sa, NULL);
        alarm(timeout);
    }

    ret = NULL;
    /* On timeout, read will hopefully be interrupted by SIGALRM,
     * and we return NULL */
    if (read(STDIN_FILENO, passwd, sizeof_passwd-1) > 0) {
        ret = passwd;
        i = 0;
        /* Last byte is guaranteed to be 0
           (read did not overwrite it) */
        do {
            if (passwd[i] == '\r' || passwd[i] == '\n')
                passwd[i] = '\0';
        } while (passwd[i++]);
    }

    if (timeout) {
        alarm(0);
    }

    tcsetattr(STDIN_FILENO, TCSANOW, &old);
    putchar('\n');
    fflush(stdout);
    return ret;
}