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      1 /*
      2  * Copyright (C) 2007 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 #define LOG_TAG "NativeHandle"
     18 
     19 #include <errno.h>
     20 #include <stdint.h>
     21 #include <stdlib.h>
     22 #include <string.h>
     23 #include <unistd.h>
     24 
     25 #include <android/log.h>
     26 #include <cutils/native_handle.h>
     27 
     28 static const int kMaxNativeFds = 1024;
     29 static const int kMaxNativeInts = 1024;
     30 
     31 native_handle_t* native_handle_init(char* storage, int numFds, int numInts)
     32 {
     33     if ((uintptr_t) storage % alignof(native_handle_t)) {
     34         return NULL;
     35     }
     36 
     37     native_handle_t* handle = (native_handle_t*) storage;
     38     handle->version = sizeof(native_handle_t);
     39     handle->numFds = numFds;
     40     handle->numInts = numInts;
     41 
     42     return handle;
     43 }
     44 
     45 native_handle_t* native_handle_create(int numFds, int numInts)
     46 {
     47     if (numFds < 0 || numInts < 0 || numFds > kMaxNativeFds || numInts > kMaxNativeInts) {
     48         return NULL;
     49     }
     50 
     51     size_t mallocSize = sizeof(native_handle_t) + (sizeof(int) * (numFds + numInts));
     52     native_handle_t* h = malloc(mallocSize);
     53     if (h) {
     54         h->version = sizeof(native_handle_t);
     55         h->numFds = numFds;
     56         h->numInts = numInts;
     57     }
     58     return h;
     59 }
     60 
     61 native_handle_t* native_handle_clone(const native_handle_t* handle)
     62 {
     63     native_handle_t* clone = native_handle_create(handle->numFds, handle->numInts);
     64     int i;
     65 
     66     for (i = 0; i < handle->numFds; i++) {
     67         clone->data[i] = dup(handle->data[i]);
     68         if (clone->data[i] < 0) {
     69             clone->numFds = i;
     70             native_handle_close(clone);
     71             native_handle_delete(clone);
     72             return NULL;
     73         }
     74     }
     75 
     76     memcpy(&clone->data[handle->numFds], &handle->data[handle->numFds],
     77             sizeof(int) * handle->numInts);
     78 
     79     return clone;
     80 }
     81 
     82 int native_handle_delete(native_handle_t* h)
     83 {
     84     if (h) {
     85         if (h->version != sizeof(native_handle_t))
     86             return -EINVAL;
     87         free(h);
     88     }
     89     return 0;
     90 }
     91 
     92 int native_handle_close(const native_handle_t* h)
     93 {
     94     if (h->version != sizeof(native_handle_t))
     95         return -EINVAL;
     96 
     97     const int numFds = h->numFds;
     98     int i;
     99     for (i=0 ; i<numFds ; i++) {
    100         close(h->data[i]);
    101     }
    102     return 0;
    103 }
    104