usr/src/cmd/line/line.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
  28 /*        All Rights Reserved   */
  29
  30 #pragma ident   "%Z%%M% %I%     %E% SMI"
  31
  32 /*
  33  *      This program reads a single line from the standard input
  34  *      and writes it on the standard output. It is probably most useful
  35  *      in conjunction with the shell.
  36  */
  37
  38 #include <limits.h>
  39 #include <unistd.h>
  40
  41 #define LSIZE   LINE_MAX                /* POSIX.2 */
  42
  43 static char     readc(void);
  44
  45 static int EOF;
  46 static char nl = '\n';
  47
  48 /*ARGSUSED*/
  49 int
  50 main(int argc, char **argv)
  51 {
  52         char c;
  53         char line[LSIZE];
  54         char *linep, *linend;
  55
  56         EOF = 0;
  57         linep = line;
  58         linend = line + LSIZE;
  59
  60         while ((c = readc()) != nl) {
  61                 if (linep == linend) {
  62                         (void) write(1, line, LSIZE);
  63                         linep = line;
  64                 }
  65                 *linep++ = c;
  66         }
  67
  68         /* LINTED  E_PTRDIFF_T_OVERFLOW */
  69         (void) write(1, line, linep-line);
  70         (void) write(1, &nl, 1);
  71         if (EOF == 1)
  72                 return (1);
  73         return (0);
  74 }
  75
  76 static char
  77 readc(void)
  78 {
  79         char c;
  80
  81         if (read(0, &c, 1) != 1) {
  82                 EOF = 1;
  83                 return (nl);
  84         }
  85         else
  86                 return (c);
  87 }