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 source tree.
   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         tcflush(fd, TCIFLUSH);
  34         /* Was buggy: was printing prompt *before* flushing input,
  35          * which was upsetting "expect" based scripts of some users.
  36          */
  37         fputs(prompt, stdout);
  38         fflush_all();
  39
  40         tcgetattr(fd, &oldtio);
  41         tio = oldtio;
  42 #if 0
  43         /* Switch off UPPERCASE->lowercase conversion (never used since 198x)
  44          * and XON/XOFF (why we want to mess with this??)
  45          */
  46 # ifndef IUCLC
  47 #  define IUCLC 0
  48 # endif
  49         tio.c_iflag &= ~(IUCLC|IXON|IXOFF|IXANY);
  50 #endif
  51         /* Switch off echo */
  52         tio.c_lflag &= ~(ECHO|ECHOE|ECHOK|ECHONL);
  53         tcsetattr(fd, TCSANOW, &tio);
  54
  55         memset(&sa, 0, sizeof(sa));
  56         /* sa.sa_flags = 0; - no SA_RESTART! */
  57         /* SIGINT and SIGALRM will interrupt reads below */
  58         sa.sa_handler = askpass_timeout;
  59         sigaction(SIGINT, &sa, &oldsa);
  60         if (timeout) {
  61                 sigaction_set(SIGALRM, &sa);
  62                 alarm(timeout);
  63         }
  64
  65         if (!passwd)
  66                 passwd = xmalloc(sizeof_passwd);
  67         ret = passwd;
  68         i = 0;
  69         while (1) {
  70                 int r = read(fd, &ret[i], 1);
  71                 if ((i == 0 && r == 0) /* EOF (^D) with no password */
  72                  || r < 0
  73                 ) {
  74                         /* read is interrupted by timeout or ^C */
  75                         ret = NULL;
  76                         break;
  77                 }
  78                 if (r == 0 /* EOF */
  79                  || ret[i] == '\r' || ret[i] == '\n' /* EOL */
  80                  || ++i == sizeof_passwd-1 /* line limit */
  81                 ) {
  82                         ret[i] = '\0';
  83                         break;
  84                 }
  85         }
  86
  87         if (timeout) {
  88                 alarm(0);
  89         }
  90         sigaction_set(SIGINT, &oldsa);
  91         tcsetattr(fd, TCSANOW, &oldtio);
  92         bb_putchar('\n');
  93         fflush_all();
  94         return ret;
  95 }