readpassphrase.c revision 91913 
1/*	$OpenBSD: readpassphrase.c,v 1.12 2001/12/15 05:41:00 millert Exp $	*/
2
3/*
4 * Copyright (c) 2000 Todd C. Miller <Todd.Miller@courtesan.com>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. The name of the author may not be used to endorse or promote products
16 *    derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
19 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
20 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
21 * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
22 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
23 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
24 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
25 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
26 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
27 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30#if defined(LIBC_SCCS) && !defined(lint)
31static const char rcsid[] = "$OpenBSD: readpassphrase.c,v 1.12 2001/12/15 05:41:00 millert Exp $";
32#endif /* LIBC_SCCS and not lint */
33#include <sys/cdefs.h>
34__FBSDID("$FreeBSD: head/lib/libc/gen/readpassphrase.c 91913 2002-03-08 21:14:00Z green $");
35
36#include "namespace.h"
37#include <ctype.h>
38#include <errno.h>
39#include <fcntl.h>
40#include <paths.h>
41#include <pwd.h>
42#include <signal.h>
43#include <string.h>
44#include <termios.h>
45#include <unistd.h>
46#include <readpassphrase.h>
47#include "un-namespace.h"
48
49static volatile sig_atomic_t signo;
50
51static void handler(int);
52
53char *
54readpassphrase(const char *prompt, char *buf, size_t bufsiz, int flags)
55{
56	ssize_t nr;
57	int input, output, save_errno;
58	char ch, *p, *end;
59	struct termios term, oterm;
60	struct sigaction sa, saveint, savehup, savequit, saveterm;
61	struct sigaction savetstp, savettin, savettou;
62
63	/* I suppose we could alloc on demand in this case (XXX). */
64	if (bufsiz == 0) {
65		errno = EINVAL;
66		return(NULL);
67	}
68
69restart:
70	/*
71	 * Read and write to /dev/tty if available.  If not, read from
72	 * stdin and write to stderr unless a tty is required.
73	 */
74	if ((input = output = _open(_PATH_TTY, O_RDWR)) == -1) {
75		if (flags & RPP_REQUIRE_TTY) {
76			errno = ENOTTY;
77			return(NULL);
78		}
79		input = STDIN_FILENO;
80		output = STDERR_FILENO;
81	}
82
83	/*
84	 * Catch signals that would otherwise cause the user to end
85	 * up with echo turned off in the shell.  Don't worry about
86	 * things like SIGALRM and SIGPIPE for now.
87	 */
88	sigemptyset(&sa.sa_mask);
89	sa.sa_flags = 0;		/* don't restart system calls */
90	sa.sa_handler = handler;
91	(void)_sigaction(SIGINT, &sa, &saveint);
92	(void)_sigaction(SIGHUP, &sa, &savehup);
93	(void)_sigaction(SIGQUIT, &sa, &savequit);
94	(void)_sigaction(SIGTERM, &sa, &saveterm);
95	(void)_sigaction(SIGTSTP, &sa, &savetstp);
96	(void)_sigaction(SIGTTIN, &sa, &savettin);
97	(void)_sigaction(SIGTTOU, &sa, &savettou);
98
99	/* Turn off echo if possible. */
100	if (tcgetattr(input, &oterm) == 0) {
101		memcpy(&term, &oterm, sizeof(term));
102		if (!(flags & RPP_ECHO_ON))
103			term.c_lflag &= ~(ECHO | ECHONL);
104		if (term.c_cc[VSTATUS] != _POSIX_VDISABLE)
105			term.c_cc[VSTATUS] = _POSIX_VDISABLE;
106		(void)tcsetattr(input, TCSAFLUSH|TCSASOFT, &term);
107	} else {
108		memset(&term, 0, sizeof(term));
109		memset(&oterm, 0, sizeof(oterm));
110	}
111
112	(void)_write(output, prompt, strlen(prompt));
113	end = buf + bufsiz - 1;
114	for (p = buf; (nr = _read(input, &ch, 1)) == 1 && ch != '\n' && ch != '\r';) {
115		if (p < end) {
116			if ((flags & RPP_SEVENBIT))
117				ch &= 0x7f;
118			if (isalpha(ch)) {
119				if ((flags & RPP_FORCELOWER))
120					ch = tolower(ch);
121				if ((flags & RPP_FORCEUPPER))
122					ch = toupper(ch);
123			}
124			*p++ = ch;
125		}
126	}
127	*p = '\0';
128	save_errno = errno;
129	if (!(term.c_lflag & ECHO))
130		(void)_write(output, "\n", 1);
131
132	/* Restore old terminal settings and signals. */
133	if (memcmp(&term, &oterm, sizeof(term)) != 0)
134		(void)tcsetattr(input, TCSANOW|TCSASOFT, &oterm);
135	(void)_sigaction(SIGINT, &saveint, NULL);
136	(void)_sigaction(SIGHUP, &savehup, NULL);
137	(void)_sigaction(SIGQUIT, &savequit, NULL);
138	(void)_sigaction(SIGTERM, &saveterm, NULL);
139	(void)_sigaction(SIGTSTP, &savetstp, NULL);
140	(void)_sigaction(SIGTTIN, &savettin, NULL);
141	(void)_sigaction(SIGTTOU, &savettou, NULL);
142	if (input != STDIN_FILENO)
143		(void)_close(input);
144
145	/*
146	 * If we were interrupted by a signal, resend it to ourselves
147	 * now that we have restored the signal handlers.
148	 */
149	if (signo) {
150		kill(getpid(), signo);
151		switch (signo) {
152		case SIGTSTP:
153		case SIGTTIN:
154		case SIGTTOU:
155			signo = 0;
156			goto restart;
157		}
158	}
159
160	errno = save_errno;
161	return(nr == -1 ? NULL : buf);
162}
163
164#if 0
165char *
166getpass(const char *prompt)
167{
168	static char buf[_PASSWORD_LEN + 1];
169
170	return(readpassphrase(prompt, buf, sizeof(buf), RPP_ECHO_OFF));
171}
172#endif
173
174static void handler(int s)
175{
176
177	signo = s;
178}
179