1 /* prompt.c -- prompt routines for vlock,
2 * the VT locking program for linux
4 * This program is copyright (C) 2007 Frank Benkstein, and is free
5 * software which is freely distributable under the terms of the
6 * GNU General Public License version 2, included as the file COPYING in this
7 * distribution. It is NOT public domain software, and any
8 * redistribution not permitted by the GNU General Public License is
9 * expressly forbidden without prior written permission from
13 * The prompt functions (prompt and prompt_echo_off) were
14 * inspired by/copied from openpam's openpam_ttyconv.c:
16 * Copyright (c) 2002-2003 Networks Associates Technology, Inc.
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions
21 * 1. Redistributions of source code must retain the above copyright
22 * notice, this list of conditions and the following disclaimer.
23 * 2. Redistributions in binary form must reproduce the above copyright
24 * notice, this list of conditions and the following disclaimer in the
25 * documentation and/or other materials provided with the distribution.
26 * 3. The name of the author may not be used to endorse or promote
27 * products derived from this software without specific prior written
30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
31 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
32 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
34 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
35 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
36 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
38 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
39 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
49 #include <sys/select.h>
54 #define PROMPT_BUFFER_SIZE 512
56 char *prompt(const char *msg
, const struct timespec
*timeout
) {
57 char buffer
[PROMPT_BUFFER_SIZE
];
61 struct timeval timeout_val
;
62 struct timeval
*timeout_val_p
= NULL
;
66 if (timeout
!= NULL
) {
67 timeout_val
.tv_sec
= timeout
->tv_sec
;
68 timeout_val
.tv_usec
= timeout
->tv_nsec
/ 1000;
69 timeout_val_p
= &timeout_val
;
73 /* Write out the prompt. */
74 (void) fputs(msg
, stderr
); fflush(stderr
);
77 /* Get the current terminal attributes. */
78 (void) tcgetattr(STDIN_FILENO
, &term
);
79 /* Save the lflag value. */
81 /* Enable canonical mode. We're only interested in line buffering. */
82 term
.c_lflag
|= ICANON
;
83 /* Disable terminal signals. */
84 term
.c_lflag
&= ~ISIG
;
85 /* Set the terminal attributes. */
86 (void) tcsetattr(STDIN_FILENO
, TCSAFLUSH
, &term
);
87 /* Discard all unread input characters. */
88 (void) tcflush(STDIN_FILENO
, TCIFLUSH
);
90 /* Initialize file descriptor set. */
92 FD_SET(STDIN_FILENO
, &readfds
);
96 /* Wait until a string was entered. */
97 if (select(STDIN_FILENO
+1, &readfds
, NULL
, NULL
, timeout_val_p
) != 1) {
99 perror("vlock-auth: select() on stdin failed");
101 fprintf(stderr
, "timeout!\n");
107 /* Read the string from stdin. At most buffer length - 1 bytes, to
108 * leave room for the terminating zero byte. */
109 if ((len
= read(STDIN_FILENO
, buffer
, sizeof buffer
- 1)) < 0) {
114 /* Terminate the string. */
117 /* Strip trailing newline characters. */
118 for (len
= strlen(buffer
); len
> 0; --len
) {
119 if (buffer
[len
-1] != '\r' && buffer
[len
-1] != '\n')
123 /* Terminate the string, again. */
126 /* Copy the string. */
127 result
= strdup(buffer
);
129 /* Clear our buffer. */
130 memset(buffer
, 0, sizeof buffer
);
133 /* Restore original terminal attributes. */
134 term
.c_lflag
= lflag
;
135 (void) tcsetattr(STDIN_FILENO
, TCSAFLUSH
, &term
);
140 char *prompt_echo_off(const char *msg
, const struct timespec
*timeout
) {
145 (void) tcgetattr(STDIN_FILENO
, &term
);
146 lflag
= term
.c_lflag
;
147 term
.c_lflag
&= ~ECHO
;
148 (void) tcsetattr(STDIN_FILENO
, TCSAFLUSH
, &term
);
150 result
= prompt(msg
, timeout
);
152 term
.c_lflag
= lflag
;
153 (void) tcsetattr(STDIN_FILENO
, TCSAFLUSH
, &term
);