1 /*- 2 * Copyright (c) 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Edward Sze-Tyan Wang. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#)misc.c 8.1 (Berkeley) 6/6/93 33 * $FreeBSD: src/usr.bin/tail/misc.c,v 1.4.8.2 2001/04/18 09:32:08 dwmalone Exp $ 34 */ 35 36 #include <sys/param.h> 37 #include <sys/stat.h> 38 #include <sys/mman.h> 39 #include <errno.h> 40 #include <unistd.h> 41 #include <stdio.h> 42 #include <stdlib.h> 43 #include <string.h> 44 #include <err.h> 45 #include "extern.h" 46 47 void 48 ierr(void) 49 { 50 warn("%s", fname); 51 rval = 1; 52 } 53 54 void 55 oerr(void) 56 { 57 err(1, "stdout"); 58 } 59 60 /* 61 * Print `len' bytes from the file associated with `mip', starting at 62 * absolute file offset `startoff'. May move map window. 63 */ 64 int 65 mapprint(struct mapinfo *mip, off_t startoff, off_t len) 66 { 67 int n; 68 69 while (len > 0) { 70 if (startoff < mip->mapoff || 71 startoff >= (intmax_t)(mip->mapoff + mip->maplen)) { 72 if (maparound(mip, startoff) != 0) 73 return (1); 74 } 75 n = (mip->mapoff + mip->maplen) - startoff; 76 if (n > len) 77 n = len; 78 WR(mip->start + (startoff - mip->mapoff), n); 79 startoff += n; 80 len -= n; 81 } 82 return (0); 83 } 84 85 /* 86 * Move the map window so that it contains the byte at absolute file 87 * offset `offset'. The start of the map window will be TAILMAPLEN 88 * aligned. 89 */ 90 int 91 maparound(struct mapinfo *mip, off_t offset) 92 { 93 94 if (mip->start != NULL && munmap(mip->start, mip->maplen) != 0) 95 return (1); 96 97 mip->mapoff = rounddown2(offset, (off_t)TAILMAPLEN); 98 mip->maplen = TAILMAPLEN; 99 if (mip->maplen > (uintmax_t)(mip->maxoff - mip->mapoff)) 100 mip->maplen = mip->maxoff - mip->mapoff; 101 if (mip->maplen <= 0) 102 abort(); 103 if ((mip->start = mmap(NULL, mip->maplen, PROT_READ, MAP_SHARED, 104 mip->fd, mip->mapoff)) == MAP_FAILED) 105 return (1); 106 107 return (0); 108 } 109