Colin Cross | 28fa5bc | 2012-05-20 13:28:05 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (C) 2010 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #include <stdlib.h> |
| 18 | #include <string.h> |
| 19 | |
| 20 | #include "backed_block.h" |
| 21 | #include "sparse_defs.h" |
| 22 | |
| 23 | struct data_block { |
| 24 | u32 block; |
| 25 | u32 len; |
| 26 | void *data; |
| 27 | const char *filename; |
| 28 | int64_t offset; |
| 29 | struct data_block *next; |
| 30 | u32 fill_val; |
| 31 | u8 fill; |
| 32 | u8 pad1; |
| 33 | u16 pad2; |
| 34 | }; |
| 35 | |
| 36 | static struct data_block *data_blocks = NULL; |
| 37 | static struct data_block *last_used = NULL; |
| 38 | |
| 39 | static void queue_db(struct data_block *new_db) |
| 40 | { |
| 41 | struct data_block *db; |
| 42 | |
| 43 | if (data_blocks == NULL) { |
| 44 | data_blocks = new_db; |
| 45 | return; |
| 46 | } |
| 47 | |
| 48 | if (data_blocks->block > new_db->block) { |
| 49 | new_db->next = data_blocks; |
| 50 | data_blocks = new_db; |
| 51 | return; |
| 52 | } |
| 53 | |
| 54 | /* Optimization: blocks are mostly queued in sequence, so save the |
| 55 | pointer to the last db that was added, and start searching from |
| 56 | there if the next block number is higher */ |
| 57 | if (last_used && new_db->block > last_used->block) |
| 58 | db = last_used; |
| 59 | else |
| 60 | db = data_blocks; |
| 61 | last_used = new_db; |
| 62 | |
| 63 | for (; db->next && db->next->block < new_db->block; db = db->next) |
| 64 | ; |
| 65 | |
| 66 | if (db->next == NULL) { |
| 67 | db->next = new_db; |
| 68 | } else { |
| 69 | new_db->next = db->next; |
| 70 | db->next = new_db; |
| 71 | } |
| 72 | } |
| 73 | |
| 74 | /* Queues a fill block of memory to be written to the specified data blocks */ |
| 75 | void queue_fill_block(unsigned int fill_val, unsigned int len, unsigned int block) |
| 76 | { |
| 77 | struct data_block *db = malloc(sizeof(struct data_block)); |
| 78 | if (db == NULL) { |
| 79 | error_errno("malloc"); |
| 80 | return; |
| 81 | } |
| 82 | |
| 83 | db->block = block; |
| 84 | db->len = len; |
| 85 | db->fill = 1; |
| 86 | db->fill_val = fill_val; |
| 87 | db->data = NULL; |
| 88 | db->filename = NULL; |
| 89 | db->next = NULL; |
| 90 | |
| 91 | queue_db(db); |
| 92 | } |
| 93 | |
| 94 | /* Queues a block of memory to be written to the specified data blocks */ |
| 95 | void queue_data_block(void *data, unsigned int len, unsigned int block) |
| 96 | { |
| 97 | struct data_block *db = malloc(sizeof(struct data_block)); |
| 98 | if (db == NULL) { |
| 99 | error_errno("malloc"); |
| 100 | return; |
| 101 | } |
| 102 | |
| 103 | db->block = block; |
| 104 | db->len = len; |
| 105 | db->data = data; |
| 106 | db->filename = NULL; |
| 107 | db->fill = 0; |
| 108 | db->next = NULL; |
| 109 | |
| 110 | queue_db(db); |
| 111 | } |
| 112 | |
| 113 | /* Queues a chunk of a file on disk to be written to the specified data blocks */ |
| 114 | void queue_data_file(const char *filename, int64_t offset, unsigned int len, |
| 115 | unsigned int block) |
| 116 | { |
| 117 | struct data_block *db = malloc(sizeof(struct data_block)); |
| 118 | if (db == NULL) { |
| 119 | error_errno("malloc"); |
| 120 | return; |
| 121 | } |
| 122 | |
| 123 | db->block = block; |
| 124 | db->len = len; |
| 125 | db->filename = strdup(filename); |
| 126 | db->offset = offset; |
| 127 | db->data = NULL; |
| 128 | db->fill = 0; |
| 129 | db->next = NULL; |
| 130 | |
| 131 | queue_db(db); |
| 132 | } |
| 133 | |
| 134 | /* Iterates over the queued data blocks, calling data_func for each contiguous |
| 135 | data block, and file_func for each contiguous file block */ |
| 136 | void for_each_data_block(data_block_callback_t data_func, |
| 137 | data_block_file_callback_t file_func, |
| 138 | data_block_fill_callback_t fill_func, void *priv, unsigned int block_size) |
| 139 | { |
| 140 | struct data_block *db; |
| 141 | u32 last_block = 0; |
| 142 | |
| 143 | for (db = data_blocks; db; db = db->next) { |
| 144 | if (db->block < last_block) |
| 145 | error("data blocks out of order: %u < %u", db->block, last_block); |
| 146 | last_block = db->block + DIV_ROUND_UP(db->len, block_size) - 1; |
| 147 | |
| 148 | if (db->filename) |
| 149 | file_func(priv, (u64)db->block * block_size, db->filename, db->offset, db->len); |
| 150 | else if (db->fill) |
| 151 | fill_func(priv, (u64)db->block * block_size, db->fill_val, db->len); |
| 152 | else |
| 153 | data_func(priv, (u64)db->block * block_size, db->data, db->len); |
| 154 | } |
| 155 | } |
| 156 | |
| 157 | /* Frees the memory used by the linked list of data blocks */ |
| 158 | void free_data_blocks() |
| 159 | { |
| 160 | if (!data_blocks) return; |
| 161 | struct data_block *db = data_blocks; |
| 162 | while (db) { |
| 163 | struct data_block *next = db->next; |
| 164 | free((void*)db->filename); |
| 165 | |
| 166 | // There used to be a free() of db->data here, but it |
| 167 | // made the function crash since queue_data_block() is |
| 168 | // sometimes passed pointers it can't take ownership of |
| 169 | // (like a pointer into the middle of an allocated |
| 170 | // block). It's not clear what the queue_data_block |
| 171 | // contract is supposed to be, but we'd rather leak |
| 172 | // memory than crash. |
| 173 | |
| 174 | free(db); |
| 175 | db = next; |
| 176 | } |
| 177 | data_blocks = NULL; |
| 178 | last_used = NULL; |
| 179 | } |