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

/*
 * Copyright (c) 1988 The Regents of the University of California.
 * All rights reserved.
 *
 * %sccs.include.redist.c%
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)getpass.c   5.10 (Berkeley) %G%";
#endif /* LIBC_SCCS and not lint */

#include <sys/termios.h>
#include <sys/signal.h>

#include <paths.h>
#include <pwd.h>
#include <stdio.h>
#include <unistd.h>

char *
getpass(prompt)
        const char *prompt;
{
        struct termios term;
        register int ch;
        register char *p;
        FILE *fp, *outfp;
        long omask;
        int echo;
        static char buf[_PASSWORD_LEN + 1];

        /*
         * read and write to /dev/tty if possible; else read from
         * stdin and write to stderr.
         */
        if ((outfp = fp = fopen(_PATH_TTY, "w+")) == NULL) {
                outfp = stderr;
                fp = stdin;
        }
        /*
         * note - blocking signals isn't necessarily the
         * right thing, but we leave it for now.
         */
        omask = sigblock(sigmask(SIGINT)|sigmask(SIGTSTP));
        (void)tcgetattr(fileno(fp), &term);
        if (echo = (term.c_lflag & ECHO)) {
                term.c_lflag &= ~ECHO;
                (void)tcsetattr(fileno(fp), TCSAFLUSH|TCSASOFT, &term);
        }
        (void)fputs(prompt, outfp);
        rewind(outfp);                  /* implied flush */
        for (p = buf; (ch = getc(fp)) != EOF && ch != '\n';)
                if (p < buf + _PASSWORD_LEN)
                        *p++ = ch;
        *p = '\0';
        (void)write(fileno(outfp), "\n", 1);
        if (echo) {
                term.c_lflag |= ECHO;
                (void)tcsetattr(fileno(fp), TCSAFLUSH|TCSASOFT, &term);
        }
        (void)sigsetmask(omask);
        if (fp != stdin)
                (void)fclose(fp);
        return(buf);
}