lib/getpass.c

   1 /*
   2  * An implementation of getpass for systems that lack one.
   3  *
   4  * Copyright (C) 2013 Roman Donchenko
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; if not, visit the http://fsf.org website.
  18  */
  19
  20 #include <stdio.h>
  21 #include <string.h>
  22 #include <termios.h>
  23
  24 #include "rsync.h"
  25
  26 char *getpass(const char *prompt)
  27 {
  28         static char password[256];
  29
  30         BOOL tty_changed = False, read_success;
  31         struct termios tty_old, tty_new;
  32         FILE *in = stdin, *out = stderr;
  33         FILE *tty = fopen("/dev/tty", "w+");
  34
  35         if (tty)
  36                 in = out = tty;
  37
  38         if (tcgetattr(fileno(in), &tty_old) == 0) {
  39                 tty_new = tty_old;
  40                 tty_new.c_lflag &= ~(ECHO | ISIG);
  41
  42                 if (tcsetattr(fileno(in), TCSAFLUSH, &tty_new) == 0)
  43                         tty_changed = True;
  44         }
  45
  46         if (!tty_changed)
  47                 fputs("(WARNING: will be visible) ", out);
  48         fputs(prompt, out);
  49         fflush(out);
  50
  51         read_success = fgets(password, sizeof password, in) != NULL;
  52
  53         /* Print the newline that hasn't been echoed. */
  54         fputc('\n', out);
  55
  56         if (tty_changed)
  57                 tcsetattr(fileno(in), TCSAFLUSH, &tty_old);
  58
  59         if (tty)
  60                 fclose(tty);
  61
  62         if (read_success) {
  63                 /* Remove the trailing newline. */
  64                 size_t password_len = strlen(password);
  65                 if (password_len && password[password_len - 1] == '\n')
  66                         password[password_len - 1] = '\0';
  67
  68                 return password;
  69         }
  70
  71         return NULL;
  72 }