1 /* $OpenBSD: mmfile.c,v 1.14 2011/07/17 12:17:10 aschrijver 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 *
mmopen(const char * fn,const char * mode)45 mmopen(const char *fn, const char *mode)
46 {
47 mmf_t *mmf;
48 struct stat st;
49
50 #ifndef __minix
51 /* XXX ignore mode for now */
52 mode = mode;
53 #endif /* !__minix */
54
55 mmf = grep_malloc(sizeof *mmf);
56 if ((mmf->fd = open(fn, O_RDONLY)) == -1)
57 goto ouch1;
58 if (fstat(mmf->fd, &st) == -1)
59 goto ouch2;
60 if (st.st_size > SIZE_T_MAX) /* too big to mmap */
61 goto ouch2;
62 if (!S_ISREG(st.st_mode)) /* only mmap regular files */
63 goto ouch2;
64 mmf->len = (size_t)st.st_size;
65 mmf->base = mmap(NULL, mmf->len, PROT_READ, MAP_PRIVATE, mmf->fd, (off_t)0);
66 if (mmf->base == MAP_FAILED)
67 goto ouch2;
68 mmf->ptr = mmf->base;
69 mmf->end = mmf->base + mmf->len;
70 #ifndef __minix
71 madvise(mmf->base, mmf->len, MADV_SEQUENTIAL);
72 #endif /* !__minix */
73 return mmf;
74
75 ouch2:
76 close(mmf->fd);
77 ouch1:
78 free(mmf);
79 return NULL;
80 }
81
82 void
mmclose(mmf_t * mmf)83 mmclose(mmf_t *mmf)
84 {
85 munmap(mmf->base, mmf->len);
86 close(mmf->fd);
87 free(mmf);
88 }
89
90 char *
mmfgetln(mmf_t * mmf,size_t * l)91 mmfgetln(mmf_t *mmf, size_t *l)
92 {
93 static char *p;
94
95 if (mmf->ptr >= mmf->end)
96 return NULL;
97 for (p = mmf->ptr; mmf->ptr < mmf->end; ++mmf->ptr)
98 if (*mmf->ptr == '\n')
99 break;
100
101 *l = mmf->ptr - p;
102 ++mmf->ptr;
103 return p;
104 }
105
106 #endif
107