sbin/fsck/memzone.c

   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