1 /* 2 * Copyright (c) 2016 Maxim Sobolev <sobomax@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 */ 27 28 #include <sys/cdefs.h> 29 __FBSDID("$FreeBSD$"); 30 31 #include <sys/types.h> 32 #include <md5.h> 33 #include <stdlib.h> 34 #include <string.h> 35 #include <unistd.h> 36 37 #if defined(MKUZ_DEBUG) 38 # include <stdio.h> 39 #endif 40 41 #include "mkuz_blockcache.h" 42 43 struct mkuz_blkcache { 44 struct mkuz_blkcache_hit hit; 45 off_t data_offset; 46 unsigned char digest[16]; 47 struct mkuz_blkcache *next; 48 }; 49 50 static struct mkuz_blkcache blkcache; 51 52 struct mkuz_blkcache_hit * 53 mkuz_blkcache_regblock(int fd, uint32_t blkno, off_t offset, ssize_t len, 54 void *data) 55 { 56 struct mkuz_blkcache *bcep; 57 MD5_CTX mcontext; 58 off_t data_offset; 59 unsigned char mdigest[16]; 60 61 data_offset = lseek(fd, 0, SEEK_CUR); 62 if (data_offset < 0) { 63 return (NULL); 64 } 65 MD5Init(&mcontext); 66 MD5Update(&mcontext, data, len); 67 MD5Final(mdigest, &mcontext); 68 if (blkcache.hit.len == 0) { 69 bcep = &blkcache; 70 } else { 71 for (bcep = &blkcache; bcep != NULL; bcep = bcep->next) { 72 if (bcep->hit.len != len) 73 continue; 74 if (memcmp(mdigest, bcep->digest, sizeof(mdigest)) == 0) { 75 break; 76 } 77 } 78 if (bcep != NULL) { 79 #if defined(MKUZ_DEBUG) 80 printf("cache hit %d, %d, %d\n", (int)bcep->hit.offset, (int)data_offset, (int)len); 81 #endif 82 return (&bcep->hit); 83 } 84 bcep = malloc(sizeof(struct mkuz_blkcache)); 85 if (bcep == NULL) 86 return (NULL); 87 memset(bcep, '\0', sizeof(struct mkuz_blkcache)); 88 bcep->next = blkcache.next; 89 blkcache.next = bcep; 90 } 91 memcpy(bcep->digest, mdigest, sizeof(mdigest)); 92 bcep->data_offset = data_offset; 93 bcep->hit.offset = offset; 94 bcep->hit.len = len; 95 bcep->hit.blkno = blkno; 96 return (NULL); 97 } 98