lib/libc/gen/getpass.c

   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          * note - blocking signals isn't necessarily the
  71          * right thing, but we leave it for now.
  72          */
  73         sigemptyset(&nset);
  74         sigaddset(&nset, SIGINT);
  75         sigaddset(&nset, SIGTSTP);
  76         (void)sigprocmask(SIG_BLOCK, &nset, &oset);
  77
  78         /*
  79          * read and write to /dev/tty if possible; else read from
  80          * stdin and write to stderr.
  81          */
  82         if ((outfp = fp = fopen(_PATH_TTY, "w+")) == NULL) {
  83                 outfp = stderr;
  84                 fp = stdin;
  85         }
  86         (void)tcgetattr(fileno(fp), &term);
  87         if ((echo = (term.c_lflag & ECHO)) != 0) {
  88                 term.c_lflag &= ~ECHO;
  89                 (void)tcsetattr(fileno(fp), TCSAFLUSH|TCSASOFT, &term);
  90         }
  91         if (prompt != NULL)
  92                 (void)fputs(prompt, outfp);
  93         rewind(outfp);                  /* implied flush */
  94         for (p = buf; (ch = getc(fp)) != EOF && ch != '\n';)
  95                 if (p < buf + _PASSWORD_LEN)
  96                         *p++ = ch;
  97         *p = '\0';
  98         (void)write(fileno(outfp), "\n", 1);
  99         if (echo) {
 100                 term.c_lflag |= ECHO;
 101                 (void)tcsetattr(fileno(fp), TCSAFLUSH|TCSASOFT, &term);
 102         }
 103         if (fp != stdin)
 104                 (void)fclose(fp);
 105         (void)sigprocmask(SIG_SETMASK, &oset, NULL);
 106         return(buf);
 107 }