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 #include <sys/capsicum.h> 45 #include <sys/types.h> 46 47 #include <capsicum_helpers.h> 48 #include <ctype.h> 49 #include <err.h> 50 #include <errno.h> 51 #include <getopt.h> 52 #include <inttypes.h> 53 #include <stdio.h> 54 #include <stdlib.h> 55 #include <string.h> 56 #include <unistd.h> 57 58 #include <libutil.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 *, intmax_t); 70 static void head_bytes(FILE *, off_t); 71 static void obsolete(char *[]); 72 static void usage(void) __dead2; 73 74 static const struct option long_opts[] = 75 { 76 {"bytes", required_argument, NULL, 'c'}, 77 {"lines", required_argument, NULL, 'n'}, 78 {"quiet", no_argument, NULL, 'q'}, 79 {"silent", no_argument, NULL, 'q'}, 80 {"verbose", no_argument, NULL, 'v'}, 81 {NULL, no_argument, NULL, 0} 82 }; 83 84 int 85 main(int argc, char *argv[]) 86 { 87 FILE *fp; 88 off_t bytecnt; 89 intmax_t linecnt; 90 int ch, first, eval; 91 fileargs_t *fa; 92 cap_rights_t rights; 93 int qflag = 0; 94 int vflag = 0; 95 96 linecnt = -1; 97 eval = 0; 98 bytecnt = -1; 99 100 obsolete(argv); 101 while ((ch = getopt_long(argc, argv, "+n:c:qv", long_opts, NULL)) != -1) { 102 switch(ch) { 103 case 'c': 104 if (expand_number(optarg, &bytecnt) || bytecnt <= 0) 105 errx(1, "illegal byte count -- %s", optarg); 106 break; 107 case 'n': 108 if (expand_number(optarg, &linecnt) || linecnt <= 0) 109 errx(1, "illegal line count -- %s", optarg); 110 break; 111 case 'q': 112 qflag = 1; 113 vflag = 0; 114 break; 115 case 'v': 116 qflag = 0; 117 vflag = 1; 118 break; 119 case '?': 120 default: 121 usage(); 122 /* NOTREACHED */ 123 } 124 } 125 argc -= optind; 126 argv += optind; 127 128 fa = fileargs_init(argc, argv, O_RDONLY, 0, 129 cap_rights_init(&rights, CAP_READ, CAP_FSTAT, CAP_FCNTL), FA_OPEN); 130 if (fa == NULL) 131 err(1, "unable to init casper"); 132 133 caph_cache_catpages(); 134 if (caph_limit_stdio() < 0 || caph_enter_casper() < 0) 135 err(1, "unable to enter capability mode"); 136 137 if (linecnt != -1 && bytecnt != -1) 138 errx(1, "can't combine line and byte counts"); 139 if (linecnt == -1) 140 linecnt = 10; 141 if (*argv != NULL) { 142 for (first = 1; *argv != NULL; ++argv) { 143 if ((fp = fileargs_fopen(fa, *argv, "r")) == NULL) { 144 warn("%s", *argv); 145 eval = 1; 146 continue; 147 } 148 if (vflag || (qflag == 0 && argc > 1)) { 149 (void)printf("%s==> %s <==\n", 150 first ? "" : "\n", *argv); 151 first = 0; 152 } 153 if (bytecnt == -1) 154 head(fp, linecnt); 155 else 156 head_bytes(fp, bytecnt); 157 (void)fclose(fp); 158 } 159 } else if (bytecnt == -1) 160 head(stdin, linecnt); 161 else 162 head_bytes(stdin, bytecnt); 163 164 fileargs_free(fa); 165 exit(eval); 166 } 167 168 static void 169 head(FILE *fp, intmax_t cnt) 170 { 171 char *cp; 172 size_t error, readlen; 173 174 while (cnt != 0 && (cp = fgetln(fp, &readlen)) != NULL) { 175 error = fwrite(cp, sizeof(char), readlen, stdout); 176 if (error != readlen) 177 err(1, "stdout"); 178 cnt--; 179 } 180 } 181 182 static void 183 head_bytes(FILE *fp, off_t cnt) 184 { 185 char buf[4096]; 186 size_t readlen; 187 188 while (cnt) { 189 if ((uintmax_t)cnt < sizeof(buf)) 190 readlen = cnt; 191 else 192 readlen = sizeof(buf); 193 readlen = fread(buf, sizeof(char), readlen, fp); 194 if (readlen == 0) 195 break; 196 if (fwrite(buf, sizeof(char), readlen, stdout) != readlen) 197 err(1, "stdout"); 198 cnt -= readlen; 199 } 200 } 201 202 static void 203 obsolete(char *argv[]) 204 { 205 char *ap; 206 207 while ((ap = *++argv)) { 208 /* Return if "--" or not "-[0-9]*". */ 209 if (ap[0] != '-' || ap[1] == '-' || !isdigit(ap[1])) 210 return; 211 if ((ap = malloc(strlen(*argv) + 2)) == NULL) 212 err(1, NULL); 213 ap[0] = '-'; 214 ap[1] = 'n'; 215 (void)strcpy(ap + 2, *argv + 1); 216 *argv = ap; 217 } 218 } 219 220 static void 221 usage(void) 222 { 223 224 (void)fprintf(stderr, "usage: head [-n lines | -c bytes] [file ...]\n"); 225 exit(1); 226 } 227