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 <libutil.h> 61 62 #include <libcasper.h> 63 #include <casper/cap_fileargs.h> 64 65 /* 66 * head - give the first few lines of a stream or of each of a set of files 67 * 68 * Bill Joy UCB August 24, 1977 69 */ 70 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); 75 76 static const struct option long_opts[] = 77 { 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} 84 }; 85 86 int 87 main(int argc, char *argv[]) 88 { 89 FILE *fp; 90 off_t bytecnt; 91 intmax_t linecnt; 92 int ch, first, eval; 93 fileargs_t *fa; 94 cap_rights_t rights; 95 int qflag = 0; 96 int vflag = 0; 97 98 linecnt = -1; 99 eval = 0; 100 bytecnt = -1; 101 102 obsolete(argv); 103 while ((ch = getopt_long(argc, argv, "+n:c:qv", long_opts, NULL)) != -1) { 104 switch(ch) { 105 case 'c': 106 if (expand_number(optarg, &bytecnt) || bytecnt <= 0) 107 errx(1, "illegal byte count -- %s", optarg); 108 break; 109 case 'n': 110 if (expand_number(optarg, &linecnt) || linecnt <= 0) 111 errx(1, "illegal line count -- %s", optarg); 112 break; 113 case 'q': 114 qflag = 1; 115 vflag = 0; 116 break; 117 case 'v': 118 qflag = 0; 119 vflag = 1; 120 break; 121 case '?': 122 default: 123 usage(); 124 /* NOTREACHED */ 125 } 126 } 127 argc -= optind; 128 argv += optind; 129 130 fa = fileargs_init(argc, argv, O_RDONLY, 0, 131 cap_rights_init(&rights, CAP_READ, CAP_FSTAT, CAP_FCNTL), FA_OPEN); 132 if (fa == NULL) 133 err(1, "unable to init casper"); 134 135 caph_cache_catpages(); 136 if (caph_limit_stdio() < 0 || caph_enter_casper() < 0) 137 err(1, "unable to enter capability mode"); 138 139 if (linecnt != -1 && bytecnt != -1) 140 errx(1, "can't combine line and byte counts"); 141 if (linecnt == -1) 142 linecnt = 10; 143 if (*argv != NULL) { 144 for (first = 1; *argv != NULL; ++argv) { 145 if ((fp = fileargs_fopen(fa, *argv, "r")) == NULL) { 146 warn("%s", *argv); 147 eval = 1; 148 continue; 149 } 150 if (vflag || (qflag == 0 && argc > 1)) { 151 (void)printf("%s==> %s <==\n", 152 first ? "" : "\n", *argv); 153 first = 0; 154 } 155 if (bytecnt == -1) 156 head(fp, linecnt); 157 else 158 head_bytes(fp, bytecnt); 159 (void)fclose(fp); 160 } 161 } else if (bytecnt == -1) 162 head(stdin, linecnt); 163 else 164 head_bytes(stdin, bytecnt); 165 166 fileargs_free(fa); 167 exit(eval); 168 } 169 170 static void 171 head(FILE *fp, intmax_t cnt) 172 { 173 char *cp; 174 size_t error, readlen; 175 176 while (cnt != 0 && (cp = fgetln(fp, &readlen)) != NULL) { 177 error = fwrite(cp, sizeof(char), readlen, stdout); 178 if (error != readlen) 179 err(1, "stdout"); 180 cnt--; 181 } 182 } 183 184 static void 185 head_bytes(FILE *fp, off_t cnt) 186 { 187 char buf[4096]; 188 size_t readlen; 189 190 while (cnt) { 191 if ((uintmax_t)cnt < sizeof(buf)) 192 readlen = cnt; 193 else 194 readlen = sizeof(buf); 195 readlen = fread(buf, sizeof(char), readlen, fp); 196 if (readlen == 0) 197 break; 198 if (fwrite(buf, sizeof(char), readlen, stdout) != readlen) 199 err(1, "stdout"); 200 cnt -= readlen; 201 } 202 } 203 204 static void 205 obsolete(char *argv[]) 206 { 207 char *ap; 208 209 while ((ap = *++argv)) { 210 /* Return if "--" or not "-[0-9]*". */ 211 if (ap[0] != '-' || ap[1] == '-' || !isdigit(ap[1])) 212 return; 213 if ((ap = malloc(strlen(*argv) + 2)) == NULL) 214 err(1, NULL); 215 ap[0] = '-'; 216 ap[1] = 'n'; 217 (void)strcpy(ap + 2, *argv + 1); 218 *argv = ap; 219 } 220 } 221 222 static void 223 usage(void) 224 { 225 226 (void)fprintf(stderr, "usage: head [-n lines | -c bytes] [file ...]\n"); 227 exit(1); 228 } 229