xref: /original-bsd/lib/libc/gen/getpass.c (revision 81f57ac7)
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 are permitted
6  * provided that the above copyright notice and this paragraph are
7  * duplicated in all such forms and that any documentation,
8  * advertising materials, and other materials related to such
9  * distribution and use acknowledge that the software was developed
10  * by the University of California, Berkeley.  The name of the
11  * University may not be used to endorse or promote products derived
12  * from this software without specific prior written permission.
13  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
14  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
15  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
16  */
17 
18 #if defined(LIBC_SCCS) && !defined(lint)
19 static char sccsid[] = "@(#)getpass.c	5.3 (Berkeley) 09/22/88";
20 #endif /* LIBC_SCCS and not lint */
21 
22 #include <sys/ioctl.h>
23 #include <sys/signal.h>
24 #include <stdio.h>
25 
26 char *
27 getpass(prompt)
28 	char *prompt;
29 {
30 	struct sgttyb ttyb;
31 	register int ch;
32 	register char *p;
33 	FILE *fp, *outfp;
34 	long omask;
35 	int svflagval;
36 #define	PASSWD_LEN	8
37 	static char buf[PASSWD_LEN + 1];
38 
39 	/*
40 	 * read and write to /dev/tty if possible; else read from
41 	 * stdin and write to stderr.
42 	 */
43 	if ((outfp = fp = fopen("/dev/tty", "w+")) == NULL) {
44 		outfp = stderr;
45 		fp = stdin;
46 	}
47 
48 	(void)ioctl(fileno(fp), TIOCGETP, &ttyb);
49 	svflagval = ttyb.sg_flags;
50 	ttyb.sg_flags &= ~ECHO;
51 	omask = sigblock(sigmask(SIGINT));
52 	(void)ioctl(fileno(fp), TIOCSETP, &ttyb);
53 
54 	fputs(prompt, outfp);
55 	rewind(outfp);			/* implied flush */
56 	for (p = buf; (ch = getc(fp)) != EOF && ch != '\n';)
57 		if (p < buf + PASSWD_LEN)
58 			*p++ = ch;
59 	*p = '\0';
60 	(void)write(fileno(outfp), "\n", 1);
61 
62 	ttyb.sg_flags = svflagval;
63 	(void)ioctl(fileno(fp), TIOCSETP, &ttyb);
64 	(void)sigsetmask(omask);
65 	if (fp != stdin)
66 		(void)fclose(fp);
67 	return(buf);
68 }
69