1 /* $OpenBSD: mmfile.c,v 1.6 2003/06/24 18:43:11 tedu Exp $ */ 2 3 /*- 4 * Copyright (c) 1999 James Howard and Dag-Erling Co�dan Sm�rgrav 5 * 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 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/param.h> 30 #include <sys/mman.h> 31 #include <sys/stat.h> 32 33 #include <err.h> 34 #include <fcntl.h> 35 #include <stdlib.h> 36 #include <unistd.h> 37 38 #include "grep.h" 39 40 #define MAX_MAP_LEN 1048576 41 #define BLOCKSIZE 32768 42 43 mmf_t * 44 mmopen(char *fn, char *mode) 45 { 46 mmf_t *mmf; 47 struct stat st; 48 49 /* XXX ignore mode for now */ 50 mode = mode; 51 52 mmf = grep_malloc(sizeof *mmf); 53 if ((mmf->fd = open(fn, O_RDONLY)) == -1) 54 goto ouch1; 55 if (fstat(mmf->fd, &st) == -1) 56 goto ouch2; 57 if (st.st_size > SIZE_T_MAX) /* too big to mmap */ 58 goto ouch2; 59 if ((st.st_mode & S_IFREG) == 0) /* only mmap regular files */ 60 goto ouch2; 61 mmf->len = (size_t)st.st_size; 62 mmf->base = mmap(NULL, mmf->len, PROT_READ, MAP_PRIVATE, mmf->fd, (off_t)0); 63 if (mmf->base == NULL) 64 goto ouch2; 65 mmf->ptr = mmf->base; 66 mmf->end = mmf->base + mmf->len; 67 madvise(mmf->base, mmf->len, MADV_SEQUENTIAL); 68 return mmf; 69 70 ouch2: 71 close(mmf->fd); 72 ouch1: 73 free(mmf); 74 return NULL; 75 } 76 77 void 78 mmclose(mmf_t *mmf) 79 { 80 munmap(mmf->base, mmf->len); 81 close(mmf->fd); 82 free(mmf); 83 } 84 85 char * 86 mmfgetln(mmf_t *mmf, size_t *l) 87 { 88 static char *p; 89 90 if (mmf->ptr >= mmf->end) 91 return NULL; 92 if ((lflag || qflag) && !boleol) { 93 /* Find starting point to search. */ 94 if (mmf->ptr == mmf->base) 95 p = mmf->ptr; 96 else 97 p = mmf->ptr - maxPatternLen; 98 /* Move the start pointer ahead for next iteration */ 99 if (mmf->end - mmf->ptr > BLOCKSIZE) 100 mmf->ptr += BLOCKSIZE; 101 else 102 mmf->ptr = mmf->end; 103 } else { 104 for (p = mmf->ptr; mmf->ptr < mmf->end; ++mmf->ptr) 105 if (*mmf->ptr == '\n') 106 break; 107 } 108 109 *l = mmf->ptr - p; 110 ++mmf->ptr; 111 return p; 112 } 113 114 long 115 mmtell(mmf_t *mmf) 116 { 117 return mmf->ptr - mmf->base; 118 } 119 120 void 121 mmrewind(mmf_t *mmf) 122 { 123 mmf->ptr = mmf->base; 124 } 125