usr/src/lib/libc/gen/getpass.c

/*
 * Copyright (c) 1988 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)getpass.c   5.3 (Berkeley) %G%";
#endif /* LIBC_SCCS and not lint */

#include <sys/ioctl.h>
#include <sys/signal.h>
#include <stdio.h>

char *
getpass(prompt)
        char *prompt;
{
        struct sgttyb ttyb;
        register int ch;
        register char *p;
        FILE *fp, *outfp;
        long omask;
        int svflagval;
#define PASSWD_LEN      8
        static char buf[PASSWD_LEN + 1];

        /*
         * read and write to /dev/tty if possible; else read from
         * stdin and write to stderr.
         */
        if ((outfp = fp = fopen("/dev/tty", "w+")) == NULL) {
                outfp = stderr;
                fp = stdin;
        }

        (void)ioctl(fileno(fp), TIOCGETP, &ttyb);
        svflagval = ttyb.sg_flags;
        ttyb.sg_flags &= ~ECHO;
        omask = sigblock(sigmask(SIGINT));
        (void)ioctl(fileno(fp), TIOCSETP, &ttyb);

        fputs(prompt, outfp);
        rewind(outfp);                  /* implied flush */
        for (p = buf; (ch = getc(fp)) != EOF && ch != '\n';)
                if (p < buf + PASSWD_LEN)
                        *p++ = ch;
        *p = '\0';
        (void)write(fileno(outfp), "\n", 1);

        ttyb.sg_flags = svflagval;
        (void)ioctl(fileno(fp), TIOCSETP, &ttyb);
        (void)sigsetmask(omask);
        if (fp != stdin)
                (void)fclose(fp);
        return(buf);
}