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 37 #ifndef lint 38 #if 0 39 static char sccsid[] = "@(#)misc.c 8.1 (Berkeley) 6/6/93"; 40 #endif 41 static const char rcsid[] = 42 "$FreeBSD: src/usr.bin/tail/misc.c,v 1.4.8.2 2001/04/18 09:32:08 dwmalone Exp $"; 43 #endif /* not lint */ 44 45 #include <sys/types.h> 46 #include <sys/stat.h> 47 #include <sys/mman.h> 48 #include <errno.h> 49 #include <unistd.h> 50 #include <stdio.h> 51 #include <stdlib.h> 52 #include <string.h> 53 #include <err.h> 54 #include "extern.h" 55 56 void 57 ierr() 58 { 59 warn("%s", fname); 60 rval = 1; 61 } 62 63 void 64 oerr() 65 { 66 err(1, "stdout"); 67 } 68 69 /* 70 * Print `len' bytes from the file associated with `mip', starting at 71 * absolute file offset `startoff'. May move map window. 72 */ 73 int 74 mapprint(mip, startoff, len) 75 struct mapinfo *mip; 76 off_t startoff, len; 77 { 78 int n; 79 80 while (len > 0) { 81 if (startoff < mip->mapoff || startoff >= mip->mapoff + 82 mip->maplen) { 83 if (maparound(mip, startoff) != 0) 84 return (1); 85 } 86 n = (mip->mapoff + mip->maplen) - startoff; 87 if (n > len) 88 n = len; 89 WR(mip->start + (startoff - mip->mapoff), n); 90 startoff += n; 91 len -= n; 92 } 93 return (0); 94 } 95 96 /* 97 * Move the map window so that it contains the byte at absolute file 98 * offset `offset'. The start of the map window will be TAILMAPLEN 99 * aligned. 100 */ 101 int 102 maparound(mip, offset) 103 struct mapinfo *mip; 104 off_t offset; 105 { 106 107 if (mip->start != NULL && munmap(mip->start, mip->maplen) != 0) 108 return (1); 109 110 mip->mapoff = offset & ~((off_t)TAILMAPLEN - 1); 111 mip->maplen = TAILMAPLEN; 112 if (mip->maplen > mip->maxoff - mip->mapoff) 113 mip->maplen = mip->maxoff - mip->mapoff; 114 if (mip->maplen <= 0) 115 abort(); 116 if ((mip->start = mmap(NULL, mip->maplen, PROT_READ, MAP_SHARED, 117 mip->fd, mip->mapoff)) == MAP_FAILED) 118 return (1); 119 120 return (0); 121 } 122