source: MondoRescue/branches/3.3/mindi-busybox/libbb/bb_askpass.c@ 3621

/* vi: set sw=4 ts=4: */
/*
 * Ask for a password
 *
 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */

#include "libbb.h"

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

char* FAST_FUNC bb_ask_stdin(const char *prompt)
{
    return bb_ask(STDIN_FILENO, 0, prompt);
}
char* FAST_FUNC bb_ask(const int fd, int timeout, const char *prompt)
{
    /* Was static char[BIGNUM] */
    enum { sizeof_passwd = 128 };

    char *passwd;
    char *ret;
    int i;
    struct sigaction sa, oldsa;
    struct termios tio, oldtio;

    tcflush(fd, TCIFLUSH);
    /* Was buggy: was printing prompt *before* flushing input,
     * which was upsetting "expect" based scripts of some users.
     */
    fputs(prompt, stdout);
    fflush_all();

    tcgetattr(fd, &oldtio);
    tio = oldtio;
#if 0
    /* Switch off UPPERCASE->lowercase conversion (never used since 198x)
     * and XON/XOFF (why we want to mess with this??)
     */
# ifndef IUCLC
#  define IUCLC 0
# endif
    tio.c_iflag &= ~(IUCLC|IXON|IXOFF|IXANY);
#endif
    /* Switch off echo */
    tio.c_lflag &= ~(ECHO|ECHOE|ECHOK|ECHONL);
    tcsetattr(fd, TCSANOW, &tio);

    memset(&sa, 0, sizeof(sa));
    /* sa.sa_flags = 0; - no SA_RESTART! */
    /* SIGINT and SIGALRM will interrupt reads below */
    sa.sa_handler = askpass_timeout;
    sigaction(SIGINT, &sa, &oldsa);
    if (timeout) {
        sigaction_set(SIGALRM, &sa);
        alarm(timeout);
    }

    passwd = auto_string(xmalloc(sizeof_passwd));
    ret = passwd;
    i = 0;
    while (1) {
        int r = read(fd, &ret[i], 1);
        if ((i == 0 && r == 0) /* EOF (^D) with no password */
         || r < 0
        ) {
            /* read is interrupted by timeout or ^C */
            ret = NULL;
            break;
        }
        if (r == 0 /* EOF */
         || ret[i] == '\r' || ret[i] == '\n' /* EOL */
         || ++i == sizeof_passwd-1 /* line limit */
        ) {
            ret[i] = '\0';
            break;
        }
    }

    if (timeout) {
        alarm(0);
    }
    sigaction_set(SIGINT, &oldsa);
    tcsetattr(fd, TCSANOW, &oldtio);
    bb_putchar('\n');
    fflush_all();
    return ret;
}