mozglue/android/Ashmem.cpp

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this
   3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 #include <cstring>
   6 #include <dlfcn.h>
   7 #include <fcntl.h>
   8 #include <linux/ashmem.h>
   9 #include <stdio.h>
  10 #include <sys/stat.h>
  11 #include <sys/types.h>
  12 #include <sys/ioctl.h>
  13 #include <unistd.h>
  14
  15 #include "Ashmem.h"
  16
  17 namespace mozilla {
  18 namespace android {
  19
  20 static void* libhandle() {
  21   static void* handle = dlopen("libandroid.so", RTLD_LAZY | RTLD_LOCAL);
  22   return handle;
  23 }
  24
  25 int ashmem_create(const char* name, size_t size) {
  26   static auto fCreate =
  27       (int (*)(const char*, size_t))dlsym(libhandle(), "ASharedMemory_create");
  28
  29   if (fCreate) {
  30     return fCreate(name, size);
  31   }
  32
  33   int fd = open("/" ASHMEM_NAME_DEF, O_RDWR);
  34   if (fd < 0) {
  35     return fd;
  36   }
  37
  38   if (name) {
  39     char str[ASHMEM_NAME_LEN];
  40     strlcpy(str, name, sizeof(str));
  41     ioctl(fd, ASHMEM_SET_NAME, str);
  42   }
  43
  44   if (ioctl(fd, ASHMEM_SET_SIZE, size) != 0) {
  45     close(fd);
  46     return -1;
  47   }
  48
  49   return fd;
  50 }
  51
  52 size_t ashmem_getSize(int fd) {
  53   static auto fGetSize =
  54       (size_t(*)(int))dlsym(libhandle(), "ASharedMemory_getSize");
  55   if (fGetSize) {
  56     return fGetSize(fd);
  57   }
  58
  59   return (size_t)ioctl(fd, ASHMEM_GET_SIZE, nullptr);
  60 }
  61
  62 int ashmem_setProt(int fd, int prot) {
  63   static auto fSetProt =
  64       (int (*)(int, int))dlsym(libhandle(), "ASharedMemory_setProt");
  65   if (fSetProt) {
  66     return fSetProt(fd, prot);
  67   }
  68
  69   return ioctl(fd, ASHMEM_SET_PROT_MASK, prot);
  70 }
  71
  72 }  // namespace android
  73 }  // namespace mozilla