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