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. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)misc.c 8.1 (Berkeley) 6/6/93 37 * $FreeBSD: src/usr.bin/tail/misc.c,v 1.4.8.2 2001/04/18 09:32:08 dwmalone Exp $ 38 * $DragonFly: src/usr.bin/tail/misc.c,v 1.2 2003/06/17 04:29:32 dillon Exp $ 39 */ 40 41 #include <sys/types.h> 42 #include <sys/stat.h> 43 #include <sys/mman.h> 44 #include <errno.h> 45 #include <unistd.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <err.h> 50 #include "extern.h" 51 52 void 53 ierr() 54 { 55 warn("%s", fname); 56 rval = 1; 57 } 58 59 void 60 oerr() 61 { 62 err(1, "stdout"); 63 } 64 65 /* 66 * Print `len' bytes from the file associated with `mip', starting at 67 * absolute file offset `startoff'. May move map window. 68 */ 69 int 70 mapprint(mip, startoff, len) 71 struct mapinfo *mip; 72 off_t startoff, len; 73 { 74 int n; 75 76 while (len > 0) { 77 if (startoff < mip->mapoff || startoff >= mip->mapoff + 78 mip->maplen) { 79 if (maparound(mip, startoff) != 0) 80 return (1); 81 } 82 n = (mip->mapoff + mip->maplen) - startoff; 83 if (n > len) 84 n = len; 85 WR(mip->start + (startoff - mip->mapoff), n); 86 startoff += n; 87 len -= n; 88 } 89 return (0); 90 } 91 92 /* 93 * Move the map window so that it contains the byte at absolute file 94 * offset `offset'. The start of the map window will be TAILMAPLEN 95 * aligned. 96 */ 97 int 98 maparound(mip, offset) 99 struct mapinfo *mip; 100 off_t offset; 101 { 102 103 if (mip->start != NULL && munmap(mip->start, mip->maplen) != 0) 104 return (1); 105 106 mip->mapoff = offset & ~((off_t)TAILMAPLEN - 1); 107 mip->maplen = TAILMAPLEN; 108 if (mip->maplen > mip->maxoff - mip->mapoff) 109 mip->maplen = mip->maxoff - mip->mapoff; 110 if (mip->maplen <= 0) 111 abort(); 112 if ((mip->start = mmap(NULL, mip->maplen, PROT_READ, MAP_SHARED, 113 mip->fd, mip->mapoff)) == MAP_FAILED) 114 return (1); 115 116 return (0); 117 } 118