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 * Copyright 2020 Oxide Computer Company
42 */
43
44
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <unistd.h>
48 #include <locale.h>
49 #include <string.h>
50 #include <ctype.h>
51 #include <err.h>
52
53 #define DEF_LINE_COUNT 10
54
55 static void copyout(off_t, int);
56 static void Usage();
57 static FILE *input;
58
59
60 /*
61 * head - give the first few lines of a stream or of each of a set of files.
62 * Optionally shows a specific number of bytes instead.
63 */
64 int
main(int argc,char ** argv)65 main(int argc, char **argv)
66 {
67 int fileCount;
68 int around = 0;
69 int i;
70 int opt;
71 off_t linecnt = DEF_LINE_COUNT;
72 int isline = 1;
73 int error = 0;
74 int quiet = 0;
75 int verbose = 0;
76
77 (void) setlocale(LC_ALL, "");
78 #if !defined(TEXT_DOMAIN) /* Should be defined by cc -D */
79 #define TEXT_DOMAIN "SYS_TEST" /* Use this only if it weren't */
80 #endif
81 (void) textdomain(TEXT_DOMAIN);
82
83 /* check for non-standard "-line-count" option */
84 for (i = 1; i < argc; i++) {
85 if (strcmp(argv[i], "--") == 0)
86 break;
87
88 if ((argv[i][0] == '-') && isdigit(argv[i][1])) {
89 if (strlen(&argv[i][1]) !=
90 strspn(&argv[i][1], "0123456789")) {
91 (void) fprintf(stderr, gettext(
92 "%s: Badly formed number\n"), argv[0]);
93 Usage();
94 }
95
96 linecnt = (off_t)strtoll(&argv[i][1], (char **)NULL,
97 10);
98 while (i < argc) {
99 argv[i] = argv[i + 1];
100 i++;
101 }
102 argc--;
103 }
104 }
105
106 /* get options */
107 while ((opt = getopt(argc, argv, "qvn:c:")) != EOF) {
108 switch (opt) {
109 case 'n':
110 case 'c':
111 if ((strcmp(optarg, "--") == 0) || (optind > argc)) {
112 (void) fprintf(stderr, gettext(
113 "%s: Missing -%c argument\n"), argv[0],
114 optopt);
115 Usage();
116 }
117 linecnt = (off_t)strtoll(optarg, (char **)NULL, 10);
118 if (linecnt <= 0) {
119 (void) fprintf(stderr, gettext(
120 "%s: Invalid \"-%c %s\" option\n"),
121 argv[0], optopt, optarg);
122 Usage();
123 }
124 isline = optopt != 'c';
125 break;
126 case 'q':
127 quiet = 1;
128 verbose = 0;
129 break;
130 case 'v':
131 quiet = 0;
132 verbose = 1;
133 break;
134 default:
135 Usage();
136 }
137 }
138
139 fileCount = argc - optind;
140
141 do {
142 if ((argv[optind] == NULL) && around)
143 break;
144
145 if (argv[optind] != NULL) {
146 if (input != NULL)
147 (void) fclose(input);
148 if ((input = fopen(argv[optind], "r")) == NULL) {
149 perror(argv[optind]);
150 error = 1;
151 optind++;
152 continue;
153 }
154 } else {
155 input = stdin;
156 }
157
158 if (quiet == 0) {
159 if (around)
160 (void) putchar('\n');
161
162 if (fileCount > 1 || verbose != 0) {
163 const char *file = argv[optind];
164 if (file == NULL) {
165 file = "standard input";
166 }
167 (void) printf("==> %s <==\n", file);
168 }
169 }
170
171 if (argv[optind] != NULL)
172 optind++;
173
174 copyout(linecnt, isline);
175 (void) fflush(stdout);
176 around++;
177
178 } while (argv[optind] != NULL);
179
180 return (error);
181 }
182
183 static void
copyout(off_t cnt,int isline)184 copyout(off_t cnt, int isline)
185 {
186 char lbuf[BUFSIZ];
187 size_t len;
188
189 while (cnt > 0) {
190 len = fread(lbuf, sizeof (char), sizeof (lbuf) / sizeof (char),
191 input);
192 if (len == 0) {
193 return;
194 }
195
196 if (isline) {
197 size_t i;
198 for (i = 0; i < len; i++) {
199 if (lbuf[i] == '\n') {
200 cnt--;
201 if (cnt == 0) {
202 i++;
203 break;
204 }
205 }
206 }
207 len = i;
208 } else {
209 if (len > cnt) {
210 len = cnt;
211 }
212 cnt -= len;
213 }
214
215 if (fwrite(lbuf, sizeof (char), len, stdout) != len) {
216 err(EXIT_FAILURE, "failed to write to stdout");
217 }
218 }
219 }
220
221 static void
Usage()222 Usage()
223 {
224 (void) printf(gettext("usage: head [-q] [-v] [-n #] [-c #] [-#] "
225 "[filename...]\n"));
226 exit(1);
227 }
228