1/*	$OpenBSD: mmfile.c,v 1.19 2019/01/27 14:43:09 deraadt 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/mman.h>
30#include <sys/stat.h>
31
32#include <err.h>
33#include <fcntl.h>
34#include <stdlib.h>
35#include <unistd.h>
36
37#include "grep.h"
38
39#ifndef SMALL
40
41#define MAX_MAP_LEN 1048576
42
43mmf_t *
44mmopen(int fd, struct stat *st)
45{
46	mmf_t *mmf;
47
48	mmf = grep_malloc(sizeof *mmf);
49	if (st->st_size > SIZE_MAX) /* too big to mmap */
50		goto ouch;
51	mmf->len = (size_t)st->st_size;
52	mmf->fd = fd;
53	mmf->base = mmap(NULL, mmf->len, PROT_READ, MAP_PRIVATE, mmf->fd, (off_t)0);
54	if (mmf->base == MAP_FAILED)
55		goto ouch;
56	mmf->ptr = mmf->base;
57	mmf->end = mmf->base + mmf->len;
58	madvise(mmf->base, mmf->len, MADV_SEQUENTIAL);
59	return mmf;
60
61ouch:
62	free(mmf);
63	return NULL;
64}
65
66void
67mmclose(mmf_t *mmf)
68{
69	munmap(mmf->base, mmf->len);
70	close(mmf->fd);
71	free(mmf);
72}
73
74char *
75mmfgetln(mmf_t *mmf, size_t *l)
76{
77	static char *p;
78
79	if (mmf->ptr >= mmf->end)
80		return NULL;
81	for (p = mmf->ptr; mmf->ptr < mmf->end; ++mmf->ptr)
82		if (*mmf->ptr == '\n')
83		    break;
84
85	*l = mmf->ptr - p;
86	++mmf->ptr;
87	return p;
88}
89
90#endif
91