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getpass.c revision 1.10 
      1 /*	$NetBSD: getpass.c,v 1.10 1997/07/13 19:13:01 christos Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1988, 1993
      5  *	The Regents of the University of California.  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. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 #if defined(LIBC_SCCS) && !defined(lint)
     38 #if 0
     39 static char sccsid[] = "@(#)getpass.c	8.1 (Berkeley) 6/4/93";
     40 #else
     41 __RCSID("$NetBSD: getpass.c,v 1.10 1997/07/13 19:13:01 christos Exp $");
     42 #endif
     43 #endif /* LIBC_SCCS and not lint */
     44 
     45 #include <termios.h>
     46 #include <signal.h>
     47 
     48 #include <paths.h>
     49 #include <pwd.h>
     50 #include <stdio.h>
     51 #include <unistd.h>
     52 
     53 char *
     54 getpass(prompt)
     55 	const char *prompt;
     56 {
     57 	struct termios term;
     58 	register int ch;
     59 	register char *p;
     60 	FILE *fp, *outfp;
     61 	int echo;
     62 	static char buf[_PASSWORD_LEN + 1];
     63 	sigset_t oset, nset;
     64 
     65 	/*
     66 	 * read and write to /dev/tty if possible; else read from
     67 	 * stdin and write to stderr.
     68 	 */
     69 	if ((outfp = fp = fopen(_PATH_TTY, "w+")) == NULL) {
     70 		outfp = stderr;
     71 		fp = stdin;
     72 	}
     73 
     74 	/*
     75 	 * note - blocking signals isn't necessarily the
     76 	 * right thing, but we leave it for now.
     77 	 */
     78 	sigemptyset(&nset);
     79 	sigaddset(&nset, SIGINT);
     80 	sigaddset(&nset, SIGTSTP);
     81 	(void)sigprocmask(SIG_BLOCK, &nset, &oset);
     82 
     83 	(void)tcgetattr(fileno(fp), &term);
     84 	if ((echo = (term.c_lflag & ECHO)) != 0) {
     85 		term.c_lflag &= ~ECHO;
     86 		(void)tcsetattr(fileno(fp), TCSAFLUSH|TCSASOFT, &term);
     87 	}
     88 	(void)fputs(prompt, outfp);
     89 	rewind(outfp);			/* implied flush */
     90 	for (p = buf; (ch = getc(fp)) != EOF && ch != '\n';)
     91 		if (p < buf + _PASSWORD_LEN)
     92 			*p++ = ch;
     93 	*p = '\0';
     94 	(void)write(fileno(outfp), "\n", 1);
     95 	if (echo) {
     96 		term.c_lflag |= ECHO;
     97 		(void)tcsetattr(fileno(fp), TCSAFLUSH|TCSASOFT, &term);
     98 	}
     99 	(void)sigprocmask(SIG_SETMASK, &oset, NULL);
    100 	if (fp != stdin)
    101 		(void)fclose(fp);
    102 	return(buf);
    103 }
    104