2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1980, 1987, 1992, 1993
5 * The Regents of the University of California. All rights reserved.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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.
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
33 static const char copyright[] =
34 "@(#) Copyright (c) 1980, 1987, 1992, 1993\n\
35 The Regents of the University of California. All rights reserved.\n";
40 static char sccsid[] = "@(#)head.c 8.2 (Berkeley) 5/4/95";
43 #include <sys/cdefs.h>
44 __FBSDID("$FreeBSD$");
46 #include <sys/capsicum.h>
47 #include <sys/types.h>
49 #include <capsicum_helpers.h>
62 #include <libcasper.h>
63 #include <casper/cap_fileargs.h>
66 * head - give the first few lines of a stream or of each of a set of files
68 * Bill Joy UCB August 24, 1977
71 static void head(FILE *, intmax_t);
72 static void head_bytes(FILE *, off_t);
73 static void obsolete(char *[]);
74 static void usage(void) __dead2;
76 static const struct option long_opts[] =
78 {"bytes", required_argument, NULL, 'c'},
79 {"lines", required_argument, NULL, 'n'},
80 {"quiet", no_argument, NULL, 'q'},
81 {"silent", no_argument, NULL, 'q'},
82 {"verbose", no_argument, NULL, 'v'},
83 {NULL, no_argument, NULL, 0}
87 main(int argc, char *argv[])
103 while ((ch = getopt_long(argc, argv, "+n:c:qv", long_opts, NULL)) != -1) {
106 if (expand_number(optarg, &bytecnt) || bytecnt <= 0)
107 errx(1, "illegal byte count -- %s", optarg);
110 if (expand_number(optarg, &linecnt) || linecnt <= 0)
111 errx(1, "illegal line count -- %s", optarg);
130 fa = fileargs_init(argc, argv, O_RDONLY, 0,
131 cap_rights_init(&rights, CAP_READ, CAP_FSTAT, CAP_FCNTL), FA_OPEN);
133 err(1, "unable to init casper");
135 caph_cache_catpages();
136 if (caph_limit_stdio() < 0 || caph_enter_casper() < 0)
137 err(1, "unable to enter capability mode");
139 if (linecnt != -1 && bytecnt != -1)
140 errx(1, "can't combine line and byte counts");
144 for (first = 1; *argv != NULL; ++argv) {
145 if ((fp = fileargs_fopen(fa, *argv, "r")) == NULL) {
150 if (vflag || (qflag == 0 && argc > 1)) {
151 (void)printf("%s==> %s <==\n",
152 first ? "" : "\n", *argv);
158 head_bytes(fp, bytecnt);
161 } else if (bytecnt == -1)
162 head(stdin, linecnt);
164 head_bytes(stdin, bytecnt);
171 head(FILE *fp, intmax_t cnt)
174 size_t error, readlen;
176 while (cnt != 0 && (cp = fgetln(fp, &readlen)) != NULL) {
177 error = fwrite(cp, sizeof(char), readlen, stdout);
178 if (error != readlen)
185 head_bytes(FILE *fp, off_t cnt)
191 if ((uintmax_t)cnt < sizeof(buf))
194 readlen = sizeof(buf);
195 readlen = fread(buf, sizeof(char), readlen, fp);
198 if (fwrite(buf, sizeof(char), readlen, stdout) != readlen)
205 obsolete(char *argv[])
209 while ((ap = *++argv)) {
210 /* Return if "--" or not "-[0-9]*". */
211 if (ap[0] != '-' || ap[1] == '-' || !isdigit(ap[1]))
213 if ((ap = malloc(strlen(*argv) + 2)) == NULL)
217 (void)strcpy(ap + 2, *argv + 1);
226 (void)fprintf(stderr, "usage: head [-n lines | -c bytes] [file ...]\n");