1 /* 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1980, 1987, 1992, 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 #ifndef lint 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"; 36 #endif /* not lint */ 37 38 #ifndef lint 39 #if 0 40 static char sccsid[] = "@(#)head.c 8.2 (Berkeley) 5/4/95"; 41 #endif 42 #endif /* not lint */ 43 #include <sys/cdefs.h> 44 __FBSDID("$FreeBSD$"); 45 46 #include <sys/capsicum.h> 47 #include <sys/types.h> 48 49 #include <capsicum_helpers.h> 50 #include <ctype.h> 51 #include <err.h> 52 #include <errno.h> 53 #include <getopt.h> 54 #include <inttypes.h> 55 #include <stdio.h> 56 #include <stdlib.h> 57 #include <string.h> 58 #include <unistd.h> 59 60 #include <libcasper.h> 61 #include <casper/cap_fileargs.h> 62 63 /* 64 * head - give the first few lines of a stream or of each of a set of files 65 * 66 * Bill Joy UCB August 24, 1977 67 */ 68 69 static void head(FILE *, int); 70 static void head_bytes(FILE *, off_t); 71 static void obsolete(char *[]); 72 static void usage(void); 73 74 static const struct option long_opts[] = 75 { 76 {"bytes", required_argument, NULL, 'c'}, 77 {"lines", required_argument, NULL, 'n'}, 78 {NULL, no_argument, NULL, 0} 79 }; 80 81 int 82 main(int argc, char *argv[]) 83 { 84 FILE *fp; 85 char *ep; 86 off_t bytecnt; 87 int ch, first, linecnt, eval; 88 fileargs_t *fa; 89 cap_rights_t rights; 90 91 linecnt = -1; 92 eval = 0; 93 bytecnt = -1; 94 95 obsolete(argv); 96 while ((ch = getopt_long(argc, argv, "+n:c:", long_opts, NULL)) != -1) { 97 switch(ch) { 98 case 'c': 99 bytecnt = strtoimax(optarg, &ep, 10); 100 if (*ep || bytecnt <= 0) 101 errx(1, "illegal byte count -- %s", optarg); 102 break; 103 case 'n': 104 linecnt = strtol(optarg, &ep, 10); 105 if (*ep || linecnt <= 0) 106 errx(1, "illegal line count -- %s", optarg); 107 break; 108 case '?': 109 default: 110 usage(); 111 /* NOTREACHED */ 112 } 113 } 114 argc -= optind; 115 argv += optind; 116 117 fa = fileargs_init(argc, argv, O_RDONLY, 0, 118 cap_rights_init(&rights, CAP_READ, CAP_FSTAT, CAP_FCNTL), FA_OPEN); 119 if (fa == NULL) 120 err(1, "unable to init casper"); 121 122 caph_cache_catpages(); 123 if (caph_limit_stdio() < 0 || caph_enter_casper() < 0) 124 err(1, "unable to enter capability mode"); 125 126 if (linecnt != -1 && bytecnt != -1) 127 errx(1, "can't combine line and byte counts"); 128 if (linecnt == -1) 129 linecnt = 10; 130 if (*argv != NULL) { 131 for (first = 1; *argv != NULL; ++argv) { 132 if ((fp = fileargs_fopen(fa, *argv, "r")) == NULL) { 133 warn("%s", *argv); 134 eval = 1; 135 continue; 136 } 137 if (argc > 1) { 138 (void)printf("%s==> %s <==\n", 139 first ? "" : "\n", *argv); 140 first = 0; 141 } 142 if (bytecnt == -1) 143 head(fp, linecnt); 144 else 145 head_bytes(fp, bytecnt); 146 (void)fclose(fp); 147 } 148 } else if (bytecnt == -1) 149 head(stdin, linecnt); 150 else 151 head_bytes(stdin, bytecnt); 152 153 fileargs_free(fa); 154 exit(eval); 155 } 156 157 static void 158 head(FILE *fp, int cnt) 159 { 160 char *cp; 161 size_t error, readlen; 162 163 while (cnt != 0 && (cp = fgetln(fp, &readlen)) != NULL) { 164 error = fwrite(cp, sizeof(char), readlen, stdout); 165 if (error != readlen) 166 err(1, "stdout"); 167 cnt--; 168 } 169 } 170 171 static void 172 head_bytes(FILE *fp, off_t cnt) 173 { 174 char buf[4096]; 175 size_t readlen; 176 177 while (cnt) { 178 if ((uintmax_t)cnt < sizeof(buf)) 179 readlen = cnt; 180 else 181 readlen = sizeof(buf); 182 readlen = fread(buf, sizeof(char), readlen, fp); 183 if (readlen == 0) 184 break; 185 if (fwrite(buf, sizeof(char), readlen, stdout) != readlen) 186 err(1, "stdout"); 187 cnt -= readlen; 188 } 189 } 190 191 static void 192 obsolete(char *argv[]) 193 { 194 char *ap; 195 196 while ((ap = *++argv)) { 197 /* Return if "--" or not "-[0-9]*". */ 198 if (ap[0] != '-' || ap[1] == '-' || !isdigit(ap[1])) 199 return; 200 if ((ap = malloc(strlen(*argv) + 2)) == NULL) 201 err(1, NULL); 202 ap[0] = '-'; 203 ap[1] = 'n'; 204 (void)strcpy(ap + 2, *argv + 1); 205 *argv = ap; 206 } 207 } 208 209 static void 210 usage(void) 211 { 212 213 (void)fprintf(stderr, "usage: head [-n lines | -c bytes] [file ...]\n"); 214 exit(1); 215 } 216