xref: /dragonfly/sbin/fsck/memzone.c (revision f746689a)
1 /*
2  * Copyright (c) 2006 The DragonFly Project.  All rights reserved.
3  *
4  * This code is derived from software contributed to The DragonFly Project
5  * by Matthew Dillon <dillon@backplane.com>
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  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in
15  *    the documentation and/or other materials provided with the
16  *    distribution.
17  * 3. Neither the name of The DragonFly Project nor the names of its
18  *    contributors may be used to endorse or promote products derived
19  *    from this software without specific, prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  * $DragonFly: src/sbin/fsck/memzone.c,v 1.2 2007/11/25 01:28:23 swildner Exp $
35  */
36 
37 #include <sys/types.h>
38 #include <sys/mman.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <unistd.h>
43 #include "memzone.h"
44 
45 /*
46  * Efficiently allocate memory that will only be freed in bulk
47  */
48 void *
49 mzalloc(struct memzone *zone, int bytes)
50 {
51 	struct memchunk *chunk;
52 	void *ptr;
53 
54 	if ((chunk = zone->curr) != NULL) {
55 		if (bytes > chunk->bytes - zone->index) {
56 			chunk->next = zone->list;
57 			zone->list = chunk;
58 			zone->curr = NULL;
59 			chunk = NULL;
60 		}
61 	}
62 	if (chunk == NULL) {
63 		chunk = malloc(sizeof(*chunk));
64 		if (chunk == NULL)
65 			return(NULL);
66 		bzero(chunk, sizeof(*chunk));
67 		chunk->base = mmap(NULL, MEMZONE_CHUNK, PROT_READ|PROT_WRITE,
68 				   MAP_ANON|MAP_PRIVATE, -1, 0);
69 		if (chunk->base == MAP_FAILED) {
70 			free(chunk);
71 			return(NULL);
72 		}
73 		chunk->bytes = MEMZONE_CHUNK;
74 		zone->curr = chunk;
75 		zone->index = 0;
76 	}
77 	if (bytes > chunk->bytes)
78 		pfatal("allocation to large for mzalloc!");
79 	ptr = chunk->base + zone->index;
80 	zone->index += (bytes + 7) & ~7;
81 	return(ptr);
82 }
83 
84 /*
85  * Free memory in bulk
86  */
87 void *
88 mzpurge(struct memzone *zone)
89 {
90 	struct memchunk *chunk;
91 
92 	if ((chunk = zone->curr) != NULL) {
93 		chunk->next = zone->list;
94 		zone->list = chunk;
95 		zone->curr = NULL;
96 	}
97 	while ((chunk = zone->list) != NULL) {
98 		zone->list = chunk->next;
99 		munmap(chunk->base, chunk->bytes);
100 		free(chunk);
101 	}
102 }
103 
104