1 /* $OpenBSD: mmfile.c,v 1.12 2006/09/20 14:29:03 otto 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 42 mmf_t * 43 mmopen(char *fn, char *mode) 44 { 45 mmf_t *mmf; 46 struct stat st; 47 48 /* XXX ignore mode for now */ 49 mode = mode; 50 51 mmf = grep_malloc(sizeof *mmf); 52 if ((mmf->fd = open(fn, O_RDONLY)) == -1) 53 goto ouch1; 54 if (fstat(mmf->fd, &st) == -1) 55 goto ouch2; 56 if (st.st_size > SIZE_T_MAX) /* too big to mmap */ 57 goto ouch2; 58 if (!S_ISREG(st.st_mode)) /* only mmap regular files */ 59 goto ouch2; 60 mmf->len = (size_t)st.st_size; 61 mmf->base = mmap(NULL, mmf->len, PROT_READ, MAP_PRIVATE, mmf->fd, (off_t)0); 62 if (mmf->base == MAP_FAILED) 63 goto ouch2; 64 mmf->ptr = mmf->base; 65 mmf->end = mmf->base + mmf->len; 66 madvise(mmf->base, mmf->len, MADV_SEQUENTIAL); 67 return mmf; 68 69 ouch2: 70 close(mmf->fd); 71 ouch1: 72 free(mmf); 73 return NULL; 74 } 75 76 void 77 mmclose(mmf_t *mmf) 78 { 79 munmap(mmf->base, mmf->len); 80 close(mmf->fd); 81 free(mmf); 82 } 83 84 char * 85 mmfgetln(mmf_t *mmf, size_t *l) 86 { 87 static char *p; 88 89 if (mmf->ptr >= mmf->end) 90 return NULL; 91 for (p = mmf->ptr; mmf->ptr < mmf->end; ++mmf->ptr) 92 if (*mmf->ptr == '\n') 93 break; 94 95 *l = mmf->ptr - p; 96 ++mmf->ptr; 97 return p; 98 } 99