1 /* $OpenBSD: mmfile.c,v 1.15 2014/11/08 22:13:47 brad 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 #ifndef SMALL 41 42 #define MAX_MAP_LEN 1048576 43 44 mmf_t * 45 mmopen(char *fn, char *mode) 46 { 47 mmf_t *mmf; 48 struct stat st; 49 50 if (*mode != 'r') 51 return NULL; 52 53 mmf = grep_malloc(sizeof *mmf); 54 if ((mmf->fd = open(fn, O_RDONLY)) == -1) 55 goto ouch1; 56 if (fstat(mmf->fd, &st) == -1) 57 goto ouch2; 58 if (st.st_size > SIZE_T_MAX) /* too big to mmap */ 59 goto ouch2; 60 if (!S_ISREG(st.st_mode)) /* only mmap regular files */ 61 goto ouch2; 62 mmf->len = (size_t)st.st_size; 63 mmf->base = mmap(NULL, mmf->len, PROT_READ, MAP_PRIVATE, mmf->fd, (off_t)0); 64 if (mmf->base == MAP_FAILED) 65 goto ouch2; 66 mmf->ptr = mmf->base; 67 mmf->end = mmf->base + mmf->len; 68 madvise(mmf->base, mmf->len, MADV_SEQUENTIAL); 69 return mmf; 70 71 ouch2: 72 close(mmf->fd); 73 ouch1: 74 free(mmf); 75 return NULL; 76 } 77 78 void 79 mmclose(mmf_t *mmf) 80 { 81 munmap(mmf->base, mmf->len); 82 close(mmf->fd); 83 free(mmf); 84 } 85 86 char * 87 mmfgetln(mmf_t *mmf, size_t *l) 88 { 89 static char *p; 90 91 if (mmf->ptr >= mmf->end) 92 return NULL; 93 for (p = mmf->ptr; mmf->ptr < mmf->end; ++mmf->ptr) 94 if (*mmf->ptr == '\n') 95 break; 96 97 *l = mmf->ptr - p; 98 ++mmf->ptr; 99 return p; 100 } 101 102 #endif 103