usr/src/cmd/head/head.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 2004 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 /*
  31  * University Copyright- Copyright (c) 1982, 1986, 1988
  32  * The Regents of the University of California
  33  * All Rights Reserved
  34  *
  35  * University Acknowledgment- Portions of this document are derived from
  36  * software developed by the University of California, Berkeley, and its
  37  * contributors.
  38  */
  39 /*
  40  * Copyright (c) 2014, Joyent, Inc.  All rights reserved.
  41  */
  42
  43
  44 #include <stdio.h>
  45 #include <stdlib.h>
  46 #include <unistd.h>
  47 #include <locale.h>
  48 #include <string.h>
  49 #include <ctype.h>
  50
  51 #define DEF_LINE_COUNT  10
  52
  53 static  void    copyout(off_t, int);
  54 static  void    Usage();
  55 static  FILE    *input;
  56
  57
  58 /*
  59  * head - give the first few lines of a stream or of each of a set of files.
  60  * Optionally shows a specific number of bytes instead.
  61  */
  62 int
  63 main(int argc, char **argv)
  64 {
  65         int     fileCount;
  66         int     around = 0;
  67         int     i;
  68         int     opt;
  69         off_t   linecnt = DEF_LINE_COUNT;
  70         int     isline = 1;
  71         int     error = 0;
  72         int     quiet = 0;
  73
  74         (void) setlocale(LC_ALL, "");
  75 #if !defined(TEXT_DOMAIN)       /* Should be defined by cc -D */
  76 #define TEXT_DOMAIN "SYS_TEST"  /* Use this only if it weren't */
  77 #endif
  78         (void) textdomain(TEXT_DOMAIN);
  79
  80         /* check for non-standard "-line-count" option */
  81         for (i = 1; i < argc; i++) {
  82                 if (strcmp(argv[i], "--") == 0)
  83                         break;
  84
  85                 if ((argv[i][0] == '-') && isdigit(argv[i][1])) {
  86                         if (strlen(&argv[i][1]) !=
  87                             strspn(&argv[i][1], "0123456789")) {
  88                                 (void) fprintf(stderr, gettext(
  89                                     "%s: Badly formed number\n"), argv[0]);
  90                                 Usage();
  91                         }
  92
  93                         linecnt = (off_t)strtoll(&argv[i][1], (char **)NULL,
  94                             10);
  95                         while (i < argc) {
  96                                 argv[i] = argv[i + 1];
  97                                 i++;
  98                         }
  99                         argc--;
 100                 }
 101         }
 102
 103         /* get options */
 104         while ((opt = getopt(argc, argv, "qvn:c:")) != EOF) {
 105                 switch (opt) {
 106                 case 'n':
 107                 case 'c':
 108                         if ((strcmp(optarg, "--") == 0) || (optind > argc)) {
 109                                 (void) fprintf(stderr, gettext(
 110                                     "%s: Missing -%c argument\n"), argv[0],
 111                                     optopt);
 112                                 Usage();
 113                         }
 114                         linecnt = (off_t)strtoll(optarg, (char **)NULL, 10);
 115                         if (linecnt <= 0) {
 116                                 (void) fprintf(stderr, gettext(
 117                                     "%s: Invalid \"-%c %s\" option\n"),
 118                                     argv[0], optopt, optarg);
 119                                 Usage();
 120                         }
 121                         isline = optopt != 'c';
 122                         break;
 123                 case 'q':
 124                         quiet = 1;
 125                         break;
 126                 case 'v':
 127                         quiet = 0;
 128                         break;
 129                 default:
 130                         Usage();
 131                 }
 132         }
 133
 134         fileCount = argc - optind;
 135
 136         do {
 137                 if ((argv[optind] == NULL) && around)
 138                         break;
 139
 140                 if (argv[optind] != NULL) {
 141                         if (input != NULL)
 142                                 (void) fclose(input);
 143                         if ((input = fopen(argv[optind], "r")) == NULL) {
 144                                 perror(argv[optind]);
 145                                 error = 1;
 146                                 optind++;
 147                                 continue;
 148                         }
 149                 } else {
 150                         input = stdin;
 151                 }
 152
 153                 if (quiet == 0) {
 154                         if (around)
 155                                 (void) putchar('\n');
 156
 157                         if (fileCount > 1)
 158                                 (void) printf("==> %s <==\n", argv[optind]);
 159                 }
 160
 161                 if (argv[optind] != NULL)
 162                         optind++;
 163
 164                 copyout(linecnt, isline);
 165                 (void) fflush(stdout);
 166                 around++;
 167
 168         } while (argv[optind] != NULL);
 169
 170         return (error);
 171 }
 172
 173 static void
 174 copyout(off_t cnt, int isline)
 175 {
 176         char lbuf[BUFSIZ];
 177         size_t len;
 178
 179         while (cnt > 0 && fgets(lbuf, sizeof (lbuf), input) != 0) {
 180                 len = strlen(lbuf);
 181                 if (isline) {
 182                         (void) printf("%s", lbuf);
 183                         /*
 184                          * only count as a line if buffer read ends with newline
 185                          */
 186                         if (len > 0) {
 187                                 if (lbuf[len - 1] == '\n') {
 188                                         (void) fflush(stdout);
 189                                         cnt--;
 190                                 }
 191                         }
 192                 } else {
 193                         if (len > cnt) {
 194                                 lbuf[cnt] = '\0';
 195                                 len = cnt;
 196                         }
 197                         (void) printf("%s", lbuf);
 198                         cnt -= len;
 199                         (void) fflush(stdout);
 200                 }
 201         }
 202 }
 203
 204 static void
 205 Usage()
 206 {
 207         (void) printf(gettext("usage: head [-q] [-v] [-n #] [-c #] [-#] "
 208             "[filename...]\n"));
 209         exit(1);
 210 }