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getpass.c revision 1.4 
      1 /*
      2  * Copyright (c) 1988 The Regents of the University of California.
      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. All advertising materials mentioning features or use of this software
     14  *    must display the following acknowledgement:
     15  *	This product includes software developed by the University of
     16  *	California, Berkeley and its contributors.
     17  * 4. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  */
     33 
     34 #if defined(LIBC_SCCS) && !defined(lint)
     35 /*static char *sccsid = "from: @(#)getpass.c	5.9 (Berkeley) 5/6/91";*/
     36 static char *rcsid = "$Id: getpass.c,v 1.4 1994/01/04 18:27:08 jtc Exp $";
     37 #endif /* LIBC_SCCS and not lint */
     38 
     39 #include <sys/termios.h>
     40 #include <sys/signal.h>
     41 #include <stdio.h>
     42 #include <unistd.h>
     43 #include <pwd.h>
     44 #include <paths.h>
     45 
     46 char *
     47 getpass(prompt)
     48 	const char *prompt;
     49 {
     50 	struct termios term;
     51 	register int ch;
     52 	register char *p;
     53 	FILE *fp, *outfp;
     54 	long omask;
     55 	int echo;
     56 	static char buf[_PASSWORD_LEN + 1];
     57 
     58 	/*
     59 	 * read and write to /dev/tty if possible; else read from
     60 	 * stdin and write to stderr.
     61 	 */
     62 	if ((outfp = fp = fopen(_PATH_TTY, "w+")) == NULL) {
     63 		outfp = stderr;
     64 		fp = stdin;
     65 	}
     66 	/*
     67 	 * note - blocking signals isn't necessarily the
     68 	 * right thing, but we leave it for now.
     69 	 */
     70 	omask = sigblock(sigmask(SIGINT)|sigmask(SIGTSTP));
     71 	(void)tcgetattr(fileno(fp), &term);
     72 	if (echo = (term.c_lflag & ECHO)) {
     73 		term.c_lflag &= ~ECHO;
     74 		(void)tcsetattr(fileno(fp), TCSAFLUSH|TCSASOFT, &term);
     75 	}
     76 	(void)fputs(prompt, outfp);
     77 	rewind(outfp);			/* implied flush */
     78 	for (p = buf; (ch = getc(fp)) != EOF && ch != '\n';)
     79 		if (p < buf + _PASSWORD_LEN)
     80 			*p++ = ch;
     81 	*p = '\0';
     82 	(void)write(fileno(outfp), "\n", 1);
     83 	if (echo) {
     84 		term.c_lflag |= ECHO;
     85 		tcsetattr(fileno(fp), TCSAFLUSH|TCSASOFT, &term);
     86 	}
     87 	(void)sigsetmask(omask);
     88 	if (fp != stdin)
     89 		(void)fclose(fp);
     90 	return(buf);
     91 }
     92