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      1 /* libs/diskconfig/write_lst.c
      2  *
      3  * Copyright 2008, The Android Open Source Project
      4  *
      5  * Licensed under the Apache License, Version 2.0 (the "License");
      6  * you may not use this file except in compliance with the License.
      7  * You may obtain a copy of the License at
      8  *
      9  *     http://www.apache.org/licenses/LICENSE-2.0
     10  *
     11  * Unless required by applicable law or agreed to in writing, software
     12  * distributed under the License is distributed on an "AS IS" BASIS,
     13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     14  * See the License for the specific language governing permissions and
     15  * limitations under the License.
     16  */
     17 
     18 #define LOG_TAG "write_lst"
     19 #include <sys/types.h>
     20 #include <stdint.h>
     21 #include <stdio.h>
     22 #include <stdlib.h>
     23 #include <unistd.h>
     24 
     25 #include <cutils/log.h>
     26 
     27 #include <diskconfig/diskconfig.h>
     28 
     29 struct write_list *
     30 alloc_wl(uint32_t data_len)
     31 {
     32     struct write_list *item;
     33 
     34     if (!(item = malloc(sizeof(struct write_list) + data_len))) {
     35         ALOGE("Unable to allocate memory.");
     36         return NULL;
     37     }
     38 
     39     item->len = data_len;
     40     return item;
     41 }
     42 
     43 void
     44 free_wl(struct write_list *item)
     45 {
     46     if (item)
     47         free(item);
     48 }
     49 
     50 struct write_list *
     51 wlist_add(struct write_list **lst, struct write_list *item)
     52 {
     53     item->next = (*lst);
     54     *lst = item;
     55     return item;
     56 }
     57 
     58 void
     59 wlist_free(struct write_list *lst)
     60 {
     61     struct write_list *temp_wr;
     62     while (lst) {
     63         temp_wr = lst->next;
     64         free_wl(lst);
     65         lst = temp_wr;
     66     }
     67 }
     68 
     69 int
     70 wlist_commit(int fd, struct write_list *lst, int test)
     71 {
     72     for(; lst; lst = lst->next) {
     73         if (lseek64(fd, lst->offset, SEEK_SET) != (loff_t)lst->offset) {
     74             ALOGE("Cannot seek to the specified position (%lld).", (long long)lst->offset);
     75             goto fail;
     76         }
     77 
     78         if (!test) {
     79             if (write(fd, lst->data, lst->len) != (int)lst->len) {
     80                 ALOGE("Failed writing %u bytes at position %lld.", lst->len,
     81                      (long long)lst->offset);
     82                 goto fail;
     83             }
     84         } else
     85             ALOGI("Would write %d bytes @ offset %lld.", lst->len, (long long)lst->offset);
     86     }
     87 
     88     return 0;
     89 
     90 fail:
     91     return -1;
     92 }
     93