readpassphrase.c revision 86669 
1/*
2 * Copyright (c) 2000 Todd C. Miller <Todd.Miller@courtesan.com>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. The name of the author may not be used to endorse or promote products
14 *    derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
17 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
18 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
19 * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
20 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#if defined(LIBC_SCCS) && !defined(lint)
29static const char rcsid[] = "$OpenBSD: readpassphrase.c,v 1.7 2001/08/07 19:34:11 millert Exp $";
30#endif /* LIBC_SCCS and not lint */
31#include <sys/cdefs.h>
32__FBSDID("$FreeBSD: head/lib/libc/gen/readpassphrase.c 86669 2001-11-20 15:15:42Z green $");
33
34#include <ctype.h>
35#include <errno.h>
36#include <fcntl.h>
37#include <paths.h>
38#include <pwd.h>
39#include <signal.h>
40#include <string.h>
41#include <termios.h>
42#include <unistd.h>
43#include <readpassphrase.h>
44
45char *
46readpassphrase(prompt, buf, bufsiz, flags)
47	const char *prompt;
48	char *buf;
49	size_t bufsiz;
50	int flags;
51{
52	struct termios term, oterm;
53	char ch, *p, *end;
54	int input, output;
55	sigset_t oset, nset;
56
57	/* I suppose we could alloc on demand in this case (XXX). */
58	if (bufsiz == 0) {
59		errno = EINVAL;
60		return(NULL);
61	}
62
63	/*
64	 * Read and write to /dev/tty if available.  If not, read from
65	 * stdin and write to stderr unless a tty is required.
66	 */
67	if ((input = output = open(_PATH_TTY, O_RDWR)) == -1) {
68		if (flags & RPP_REQUIRE_TTY) {
69			errno = ENOTTY;
70			return(NULL);
71		}
72		input = STDIN_FILENO;
73		output = STDERR_FILENO;
74	}
75
76	/*
77	 * We block SIGINT and SIGTSTP so the terminal is not left
78	 * in an inconsistent state (ie: no echo).  It would probably
79	 * be better to simply catch these though.
80	 */
81	sigemptyset(&nset);
82	sigaddset(&nset, SIGINT);
83	sigaddset(&nset, SIGTSTP);
84	(void)sigprocmask(SIG_BLOCK, &nset, &oset);
85
86	/* Turn off echo if possible. */
87	if (tcgetattr(input, &oterm) == 0) {
88		memcpy(&term, &oterm, sizeof(term));
89		if (!(flags & RPP_ECHO_ON) && (term.c_lflag & ECHO))
90			term.c_lflag &= ~ECHO;
91		if (term.c_cc[VSTATUS] != _POSIX_VDISABLE)
92			term.c_cc[VSTATUS] = _POSIX_VDISABLE;
93		(void)tcsetattr(input, TCSAFLUSH|TCSASOFT, &term);
94	} else {
95		memset(&term, 0, sizeof(term));
96		memset(&oterm, 0, sizeof(oterm));
97	}
98
99	(void)write(output, prompt, strlen(prompt));
100	end = buf + bufsiz - 1;
101	for (p = buf; read(input, &ch, 1) == 1 && ch != '\n' && ch != '\r';) {
102		if (p < end) {
103			if ((flags & RPP_SEVENBIT))
104				ch &= 0x7f;
105			if (isalpha(ch)) {
106				if ((flags & RPP_FORCELOWER))
107					ch = tolower(ch);
108				if ((flags & RPP_FORCEUPPER))
109					ch = toupper(ch);
110			}
111			*p++ = ch;
112		}
113	}
114	*p = '\0';
115	if (!(term.c_lflag & ECHO))
116		(void)write(output, "\n", 1);
117
118	/* Restore old terminal settings and signal mask. */
119	if (memcmp(&term, &oterm, sizeof(term)) != 0)
120		(void)tcsetattr(input, TCSAFLUSH|TCSASOFT, &oterm);
121	(void)sigprocmask(SIG_SETMASK, &oset, NULL);
122	if (input != STDIN_FILENO)
123		(void)close(input);
124	return(buf);
125}
126
127char *
128getpass(prompt)
129        const char *prompt;
130{
131	static char buf[_PASSWORD_LEN + 1];
132
133	return(readpassphrase(prompt, buf, sizeof(buf), RPP_ECHO_OFF));
134}
135