release/src/router/busybox/libbb/bb_askpass.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Ask for a password
   4  * I use a static buffer in this function.  Plan accordingly.
   5  *
   6  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
   7  *
   8  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
   9  */
  10
  11 #include "libbb.h"
  12
  13 /* do nothing signal handler */
  14 static void askpass_timeout(int UNUSED_PARAM ignore)
  15 {
  16 }
  17
  18 char* FAST_FUNC bb_ask_stdin(const char *prompt)
  19 {
  20         return bb_ask(STDIN_FILENO, 0, prompt);
  21 }
  22 char* FAST_FUNC bb_ask(const int fd, int timeout, const char *prompt)
  23 {
  24         /* Was static char[BIGNUM] */
  25         enum { sizeof_passwd = 128 };
  26         static char *passwd;
  27
  28         char *ret;
  29         int i;
  30         struct sigaction sa, oldsa;
  31         struct termios tio, oldtio;
  32
  33         if (!passwd)
  34                 passwd = xmalloc(sizeof_passwd);
  35         memset(passwd, 0, sizeof_passwd);
  36
  37         tcgetattr(fd, &oldtio);
  38         tcflush(fd, TCIFLUSH);
  39         tio = oldtio;
  40         tio.c_iflag &= ~(IUCLC|IXON|IXOFF|IXANY);
  41         tio.c_lflag &= ~(ECHO|ECHOE|ECHOK|ECHONL|TOSTOP);
  42         tcsetattr_stdin_TCSANOW(&tio);
  43
  44         memset(&sa, 0, sizeof(sa));
  45         /* sa.sa_flags = 0; - no SA_RESTART! */
  46         /* SIGINT and SIGALRM will interrupt read below */
  47         sa.sa_handler = askpass_timeout;
  48         sigaction(SIGINT, &sa, &oldsa);
  49         if (timeout) {
  50                 sigaction_set(SIGALRM, &sa);
  51                 alarm(timeout);
  52         }
  53
  54         fputs(prompt, stdout);
  55         fflush(stdout);
  56         ret = NULL;
  57         /* On timeout or Ctrl-C, read will hopefully be interrupted,
  58          * and we return NULL */
  59         if (read(fd, passwd, sizeof_passwd - 1) > 0) {
  60                 ret = passwd;
  61                 i = 0;
  62                 /* Last byte is guaranteed to be 0
  63                    (read did not overwrite it) */
  64                 do {
  65                         if (passwd[i] == '\r' || passwd[i] == '\n')
  66                                 passwd[i] = '\0';
  67                 } while (passwd[i++]);
  68         }
  69
  70         if (timeout) {
  71                 alarm(0);
  72         }
  73         sigaction_set(SIGINT, &oldsa);
  74
  75         tcsetattr_stdin_TCSANOW(&oldtio);
  76         bb_putchar('\n');
  77         fflush(stdout);
  78         return ret;
  79 }