aboutsummaryrefslogtreecommitdiff
path: root/misc/getpass.c
blob: 62e56866a13078646816724e703c7699cc98fe4b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
/* Copyright (C) 1992-1999, 2001, 2003, 2004 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <stdio.h>
#include <stdio_ext.h>
#include <string.h>		/* For string function builtin redirect.  */
#include <termios.h>
#include <unistd.h>

#include <wchar.h>
#define flockfile(s) _IO_flockfile (s)
#define funlockfile(s) _IO_funlockfile (s)
#include <bits/libc-lock.h>

/* It is desirable to use this bit on systems that have it.
   The only bit of terminal state we want to twiddle is echoing, which is
   done in software; there is no need to change the state of the terminal
   hardware.  */

#ifndef TCSASOFT
#define TCSASOFT 0
#endif

static void
call_fclose (void *arg)
{
  if (arg != NULL)
    fclose (arg);
}

char *
getpass (prompt)
     const char *prompt;
{
  FILE *in, *out;
  struct termios s, t;
  int tty_changed;
  static char *buf;
  static size_t bufsize;
  ssize_t nread;

  /* Try to write to and read from the terminal if we can.
     If we can't open the terminal, use stderr and stdin.  */

  in = fopen ("/dev/tty", "w+c");
  if (in == NULL)
    {
      in = stdin;
      out = stderr;
    }
  else
    {
      /* We do the locking ourselves.  */
      __fsetlocking (in, FSETLOCKING_BYCALLER);

      out = in;
    }

  /* Make sure the stream we opened is closed even if the thread is
     canceled.  */
  __libc_cleanup_push (call_fclose, in == out ? in : NULL);

  flockfile (out);

  /* Turn echoing off if it is on now.  */

  if (__tcgetattr (fileno (in), &t) == 0)
    {
      /* Save the old one. */
      s = t;
      /* Tricky, tricky. */
      t.c_lflag &= ~(ECHO|ISIG);
      tty_changed = (tcsetattr (fileno (in), TCSAFLUSH|TCSASOFT, &t) == 0);
    }
  else
    tty_changed = 0;

  /* Write the prompt.  */
#ifdef USE_IN_LIBIO
  if (_IO_fwide (out, 0) > 0)
    __fwprintf (out, L"%s", prompt);
  else
#endif
    fputs_unlocked (prompt, out);
  fflush_unlocked (out);

  /* Read the password.  */
  nread = __getline (&buf, &bufsize, in);
  if (buf != NULL)
    {
      if (nread < 0)
	buf[0] = '\0';
      else if (buf[nread - 1] == '\n')
	{
	  /* Remove the newline.  */
	  buf[nread - 1] = '\0';
	  if (tty_changed)
	    {
	      /* Write the newline that was not echoed.  */
#ifdef USE_IN_LIBIO
	      if (_IO_fwide (out, 0) > 0)
		putwc_unlocked (L'\n', out);
	      else
#endif
		putc_unlocked ('\n', out);
	    }
	}
    }

  /* Restore the original setting.  */
  if (tty_changed)
    (void) tcsetattr (fileno (in), TCSAFLUSH|TCSASOFT, &s);

  funlockfile (out);

  __libc_cleanup_pop (0);

  if (in != stdin)
    /* We opened the terminal; now close it.  */
    fclose (in);

  return buf;
}