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getpass.c revision 1.15 
      1 /*	$NetBSD: getpass.c,v 1.15 2003/08/07 16:42:50 agc 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. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #if defined(LIBC_SCCS) && !defined(lint)
     34 #if 0
     35 static char sccsid[] = "@(#)getpass.c	8.1 (Berkeley) 6/4/93";
     36 #else
     37 __RCSID("$NetBSD: getpass.c,v 1.15 2003/08/07 16:42:50 agc Exp $");
     38 #endif
     39 #endif /* LIBC_SCCS and not lint */
     40 
     41 #include "namespace.h"
     42 
     43 #include <assert.h>
     44 #include <paths.h>
     45 #include <pwd.h>
     46 #include <signal.h>
     47 #include <stdio.h>
     48 #include <termios.h>
     49 #include <unistd.h>
     50 
     51 #ifdef __weak_alias
     52 __weak_alias(getpass,_getpass)
     53 #endif
     54 
     55 char *
     56 getpass(prompt)
     57 	const char *prompt;
     58 {
     59 	struct termios term;
     60 	int ch;
     61 	char *p;
     62 	FILE *fp, *outfp;
     63 	int echo;
     64 	static char buf[_PASSWORD_LEN + 1];
     65 	sigset_t oset, nset;
     66 
     67 	_DIAGASSERT(prompt != NULL);
     68 
     69 	/*
     70 	 * read and write to /dev/tty if possible; else read from
     71 	 * stdin and write to stderr.
     72 	 */
     73 	if ((outfp = fp = fopen(_PATH_TTY, "w+")) == NULL) {
     74 		outfp = stderr;
     75 		fp = stdin;
     76 	}
     77 
     78 	/*
     79 	 * note - blocking signals isn't necessarily the
     80 	 * right thing, but we leave it for now.
     81 	 */
     82 	sigemptyset(&nset);
     83 	sigaddset(&nset, SIGINT);
     84 	sigaddset(&nset, SIGTSTP);
     85 	(void)sigprocmask(SIG_BLOCK, &nset, &oset);
     86 
     87 	(void)tcgetattr(fileno(fp), &term);
     88 	if ((echo = (term.c_lflag & ECHO)) != 0) {
     89 		term.c_lflag &= ~ECHO;
     90 		(void)tcsetattr(fileno(fp), TCSAFLUSH|TCSASOFT, &term);
     91 	}
     92 	if (prompt != NULL)
     93 		(void)fputs(prompt, outfp);
     94 	rewind(outfp);			/* implied flush */
     95 	for (p = buf; (ch = getc(fp)) != EOF && ch != '\n';)
     96 		if (p < buf + _PASSWORD_LEN)
     97 			*p++ = ch;
     98 	*p = '\0';
     99 	(void)write(fileno(outfp), "\n", 1);
    100 	if (echo) {
    101 		term.c_lflag |= ECHO;
    102 		(void)tcsetattr(fileno(fp), TCSAFLUSH|TCSASOFT, &term);
    103 	}
    104 	(void)sigprocmask(SIG_SETMASK, &oset, NULL);
    105 	if (fp != stdin)
    106 		(void)fclose(fp);
    107 	return(buf);
    108 }
    109