1/* $NetBSD: head.c,v 1.22 2010/03/31 21:52:11 joerg Exp $ */ 2 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#include <sys/cdefs.h> 33#ifndef lint 34__COPYRIGHT("@(#) Copyright (c) 1980, 1987, 1992, 1993\ 35 The Regents of the University of California. All rights reserved."); 36#endif /* not lint */ 37 38#ifndef lint 39#if 0 40static char sccsid[] = "@(#)head.c 8.2 (Berkeley) 5/4/95"; 41#else 42__RCSID("$NetBSD: head.c,v 1.22 2010/03/31 21:52:11 joerg Exp $"); 43#endif 44#endif /* not lint */ 45 46#include <sys/types.h> 47 48#include <ctype.h> 49#include <err.h> 50#include <errno.h> 51#include <inttypes.h> 52#include <limits.h> 53#include <locale.h> 54#include <stdio.h> 55#include <stdlib.h> 56#include <string.h> 57#include <unistd.h> 58 59/* 60 * head - give the first few lines of a stream or of each of a set of files 61 * 62 * Bill Joy UCB August 24, 1977 63 */ 64 65static void head(FILE *, intmax_t, intmax_t); 66static void obsolete(char *[]); 67__dead static void usage(void); 68 69 70int 71main(int argc, char *argv[]) 72{ 73 int ch; 74 FILE *fp; 75 int first; 76 uintmax_t linecnt; 77 uintmax_t bytecnt; 78 char *ep; 79 int eval = 0; 80 int qflag = 0; 81 int vflag = 0; 82 83 (void)setlocale(LC_ALL, ""); 84 obsolete(argv); 85 linecnt = 10; 86 bytecnt = 0; 87 while ((ch = getopt(argc, argv, "c:n:qv")) != -1) 88 switch(ch) { 89 case 'c': 90 errno = 0; 91 bytecnt = strtoimax(optarg, &ep, 10); 92 if ((bytecnt == INTMAX_MAX && errno == ERANGE) || 93 *ep || bytecnt <= 0) 94 errx(1, "illegal byte count -- %s", optarg); 95 break; 96 97 case 'n': 98 errno = 0; 99 linecnt = strtoimax(optarg, &ep, 10); 100 if ((linecnt == INTMAX_MAX && errno == ERANGE) || 101 *ep || linecnt <= 0) 102 errx(1, "illegal line count -- %s", optarg); 103 break; 104 105 case 'q': 106 qflag = 1; 107 vflag = 0; 108 break; 109 110 case 'v': 111 qflag = 0; 112 vflag = 1; 113 break; 114 115 case '?': 116 default: 117 usage(); 118 } 119 argc -= optind; 120 argv += optind; 121 122 if (*argv) 123 for (first = 1; *argv; ++argv) { 124 if ((fp = fopen(*argv, "r")) == NULL) { 125 warn("%s", *argv); 126 eval = 1; 127 continue; 128 } 129 if (vflag || (qflag == 0 && argc > 1)) { 130 (void)printf("%s==> %s <==\n", 131 first ? "" : "\n", *argv); 132 first = 0; 133 } 134 head(fp, linecnt, bytecnt); 135 (void)fclose(fp); 136 } 137 else 138 head(stdin, linecnt, bytecnt); 139 exit(eval); 140} 141 142static void 143head(FILE *fp, intmax_t cnt, intmax_t bytecnt) 144{ 145 char buf[65536]; 146 size_t len, rv, rv2; 147 int ch; 148 149 if (bytecnt) { 150 while (bytecnt) { 151 len = sizeof(buf); 152 if (bytecnt > (intmax_t)sizeof(buf)) 153 len = sizeof(buf); 154 else 155 len = bytecnt; 156 rv = fread(buf, 1, len, fp); 157 if (rv == 0) 158 break; /* Distinguish EOF and error? */ 159 rv2 = fwrite(buf, 1, rv, stdout); 160 if (rv2 != rv) { 161 if (feof(stdout)) 162 errx(1, "EOF on stdout"); 163 else 164 err(1, "failure writing to stdout"); 165 } 166 bytecnt -= rv; 167 } 168 } else { 169 while ((ch = getc(fp)) != EOF) { 170 if (putchar(ch) == EOF) 171 err(1, "stdout"); 172 if (ch == '\n' && --cnt == 0) 173 break; 174 } 175 } 176} 177 178static void 179obsolete(char *argv[]) 180{ 181 char *ap; 182 183 while ((ap = *++argv)) { 184 /* Return if "--" or not "-[0-9]*". */ 185 if (ap[0] != '-' || ap[1] == '-' || 186 !isdigit((unsigned char)ap[1])) 187 return; 188 if ((ap = malloc(strlen(*argv) + 2)) == NULL) 189 err(1, NULL); 190 ap[0] = '-'; 191 ap[1] = 'n'; 192 (void)strcpy(ap + 2, *argv + 1); 193 *argv = ap; 194 } 195} 196 197static void 198usage(void) 199{ 200 201 (void)fprintf(stderr, "usage: %s [-n lines] [file ...]\n", 202 getprogname()); 203 exit(1); 204} 205