1 /* Copyright (C) 1992-1999,2001,2003,2004,2005 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <http://www.gnu.org/licenses/>. */
17
18 #include <stdio.h>
19 #include <string.h>
20 #include <termios.h>
21 #include <unistd.h>
22
23 #if defined __USE_BSD || (defined __USE_XOPEN && !defined __USE_XOPEN2K)
24
25
26 /* It is desirable to use this bit on systems that have it.
27 The only bit of terminal state we want to twiddle is echoing, which is
28 done in software; there is no need to change the state of the terminal
29 hardware. */
30
31 #ifndef TCSASOFT
32 #define TCSASOFT 0
33 #endif
34 #define PWD_BUFFER_SIZE 256
35
getpass(const char * prompt)36 char * getpass (const char *prompt)
37 {
38 FILE *in, *out;
39 struct termios s, t;
40 int tty_changed;
41 static char buf[PWD_BUFFER_SIZE];
42 int nread;
43
44 /* Try to write to and read from the terminal if we can.
45 If we can't open the terminal, use stderr and stdin. */
46
47 out = in = fopen ("/dev/tty", "r+");
48 if (in == NULL)
49 {
50 in = stdin;
51 out = stderr;
52 }
53 else
54 {
55 /* Disable buffering for read/write FILE to prevent problems with
56 * fseek and buffering for read/write auto-transitioning. */
57 setvbuf(in, NULL, _IONBF, 0);
58 }
59
60 /* Turn echoing off if it is on now. */
61
62 tty_changed = 0;
63 if (tcgetattr (fileno (in), &t) == 0)
64 {
65 /* Save the old one. */
66 s = t;
67 /* Tricky, tricky. */
68 t.c_lflag &= ~(ECHO|ISIG);
69 tty_changed = (tcsetattr (fileno (in), TCSAFLUSH|TCSASOFT, &t) == 0);
70 }
71
72 /* Write the prompt. */
73 fputs(prompt, out);
74 fflush(out);
75
76 /* Read the password. */
77 if (!fgets (buf, sizeof(buf), in))
78 buf[0] = '\0';
79 nread = strlen(buf);
80 if (nread > 0 && buf[nread - 1] == '\n')
81 /* Remove the newline. */
82 buf[nread - 1] = '\0';
83
84 if (tty_changed)
85 {
86 /* Write the newline that was not echoed. */
87 putc('\n', out);
88 /* Restore the original setting. */
89 (void) tcsetattr (fileno (in), TCSAFLUSH|TCSASOFT, &s);
90 }
91
92 if (in != stdin)
93 /* We opened the terminal; now close it. */
94 fclose (in);
95
96 return buf;
97 }
98 #endif
99