Android native进程间通信实例-binder结合共享内存
- 2019 年 10 月 3 日
- 筆記
???android?????????????????????????????kerneldriversstagingandroidashmem.c???????????android?????????????????????
??1.
???linux???????????????????32????????????????????4G??????????????????????????
?????????????????????????????binder?socket?????android??????????????????????????????????????1001???????addr?????“hello world”???1009???????addr???“hello world”???????????addr???“hello china”??????????????????????????????????????????????????
???????binder???????????????????????????
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??2.
???????????????
????????????????????????????????????adb shell??????????a??????????b????a???????????b???????????????????????????????????
?????????????
????a?1. ???????????????????????fd?2. ?????????3. ??????????????????4. ?fd??binder???????????
????b?1. ??binder???fd?2. ?fd?????????3. ???????????????????
?????linux?????????????fd??????
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??3.
??3.1
??????????????????android.mk????????????????a????mysharememory_a?????
??
#include <fcntl.h> #include <stdio.h> #include <string.h> #include <linux/ashmem.h> #include <sys/mman.h> #include <sys/ioctl.h> #include <stddef.h> #include <linux/ipc.h> #include <linux/shm.h> #include <binder/IServiceManager.h> #include <binder/IPCThreadState.h> #include <binder/Parcel.h> #include <binder/IInterface.h> #define DEVASHMEM "/dev/ashmem" #define SHNAME "hellomemory" #define MAXBUFSIZE 1024 #define TRANSFDCODE 1000 #define WRITEDATACODE 1001 using namespace android; int main(int argc, char *argv[]) { int fd = open(DEVASHMEM, O_RDWR); if(fd < 0) { return -1; } int ret = ioctl(fd, ASHMEM_SET_NAME, SHNAME); if(ret < 0){ close(fd); return -1; } char *get_sh_addr_write = NULL; ret = ioctl(fd, ASHMEM_SET_SIZE, MAXBUFSIZE); if(ret < 0){ close(fd); return -1; } get_sh_addr_write = (char*)mmap(NULL, MAXBUFSIZE , PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); if(NULL == get_sh_addr_write) { return -1; } sp<IServiceManager> sm = defaultServiceManager(); sp<IBinder> binder = sm->checkService(String16("mybindertag")); Parcel data, reply; data.writeDupFileDescriptor(fd); binder->transact(TRANSFDCODE, data, &reply); char input_data[MAXBUFSIZE] = {0}; while(1) { printf("read share memory buf is %sn", get_sh_addr_write); printf("please input data to buf :"); scanf("%s", input_data); getchar(); strcpy(get_sh_addr_write,input_data); binder->transact(WRITEDATACODE, data, &reply); } return ret; }
??3.2
??mysharememory_b?????
??
#include <fcntl.h> #include <stdio.h> #include <string.h> #include <linux/ashmem.h> #include <sys/mman.h> #include <sys/ioctl.h> #include <stddef.h> #include <linux/ipc.h> #include <linux/shm.h> #include <binder/IServiceManager.h> #include <binder/IPCThreadState.h> #include <binder/Parcel.h> #include <binder/IInterface.h> #define DEVASHMEM "/dev/ashmem" #define SHNAME "hellomemory" #define MAXBUFSIZE 1024 #define TRANSFDCODE 1000 #define WRITEDATACODE 1001 using namespace android; int g_sh_fd = 0; class MyBinderService : public BBinder{ status_t onTransact(uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags) { int ret; char *get_sh_addr_read = NULL; int get_sh_size; printf("songsong!! **** onTransact ***** code = %d n",code); switch(code) { case TRANSFDCODE: g_sh_fd = data.readFileDescriptor(); break; case WRITEDATACODE: get_sh_size = ioctl(g_sh_fd, ASHMEM_GET_SIZE,NULL); if(get_sh_size > 0) { get_sh_addr_read = (char*)mmap(NULL, get_sh_size, PROT_READ | PROT_WRITE, MAP_SHARED, g_sh_fd, 0); } else { printf("mmap failed %dn", get_sh_size); return -1; } printf("what is in the share memory: %sn", get_sh_addr_read); break; default: break; } return NO_ERROR; } }; int main(int argc, char *argv[]) { defaultServiceManager()->addService(String16("mybindertag"), new MyBinderService()); sp<ProcessState> proc(ProcessState::self()); ProcessState::self()->startThreadPool(); IPCThreadState::self()->joinThreadPool(); return 0; }
??3.3
????????????????mysharememory_b?????
??
int ret; ret = munmap((void*)get_sh_addr_read, get_sh_size); if(ret == -1) { return -1; } ret = close(g_sh_fd); if(ret == -1) { return -1; }
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??3.4
???????
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??4. ?????????????????????????????????????????????????????????
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