2.Binder系统_C程序示例_编写程序 & 平台测试

1>. Binder系统 之 C语言 代码编写

• 按照上一章的分析：参考btest.c，编写test_client.c / test_server.c

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2>. 编译代码

1<. 包含所有的头文件

cp /work/android-5.0.2/system/core/include/private/android_filesystem_config.h ./include/private/cp /work/android-5.0.2/system/core/include/private/android_filesystem_capability.h ./include/private/cp /work/android-5.0.2/bionic/libc/kernel/uapi/linux/binder.h ./include/linux/

2<. 修改 service_manager.c :

1<. 减少头文件  fatal error: selinux/android.h: No such file or directory  -- #include <selinux/avc.h>-- #include <selinux/android.h>2<. 添加头文件   error: expected '=', ',', ';', 'asm' or '__attribute__' before 'binder_size_t'  ++ #include <liunx/types.h>  error: expected '=', ',', ';', 'asm' or '__attribute__' before 'check_mac_perms'  ++ #include <stdbool.h>3<. 修改打印语句宏  #if 14<. 删除代码    1<.         union selinux_callback cb;        cb.func_audit = audit_callback;        selinux_set_callback(SELINUX_CB_AUDIT, cb);        cb.func_log = selinux_log_callback;        selinux_set_callback(SELINUX_CB_LOG, cb);    2<.     static int audit_callback(void *data, security_class_t cls, char *buf, size_t len)    {        snprintf(buf, len, "service=%s", !data ? "NULL" : (char *)data);        return 0;    }    3<. undefined reference to `selinux_status_updated'    if (sehandle && selinux_status_updated() > 0) {        struct selabel_handle *tmp_sehandle = selinux_android_service_context_handle();        if (tmp_sehandle) {            selabel_close(sehandle);            sehandle = tmp_sehandle;        }    }    4<.     undefined reference to `selinux_android_service_context_handle'    undefined reference to `selabel_close'    undefined reference to `is_selinux_enabled'    undefined reference to `getcon'    selinux_enabled = is_selinux_enabled();    sehandle = selinux_android_service_context_handle();    if (selinux_enabled > 0) {        if (sehandle == NULL) {            ALOGE("SELinux: Failed to acquire sehandle. Aborting.\n");            abort();        }        if (getcon(&service_manager_context) != 0) {            ALOGE("SELinux: Failed to acquire service_manager context. Aborting.\n");            abort();        }    }3<. 修改Makefile  %.o : %.c    arm-linux-gcc -c -I include -DBINDER_IPC_32BIT=1 -o $@ $<

3<. 修改 binder.c

 2<. 添加头文件  error: incompatible implicit declaration of built-in function 'memset'  ++ #include <string.h>  error: expected '=', ',', ';', 'asm' or '__attribute__' before 'binder_size_t'  ++ #include <liunx/types.h>  error: expected '=', ',', ';', 'asm' or '__attribute__' before 'check_mac_perms'  ++ #include <stdbool.h> 4<. 删除代码  1<. fatal error: cutils/log.h: No such file or directory    #define LOG_TAG "Binder"    #include <cutils/log.h> 5<. 添加代码   undefined reference to `ALOGE'   #if TRACE 1   #define ALOGI(x...) fprintf(stderr, "binder: " x)   #define ALOGE(x...) fprintf(stderr, "binder: " x)

4<. 修改 test_client.c

2<. 添加头文件  error: expected '=', ',', ';', 'asm' or '__attribute__' before 'binder_size_t'  ++ #include <liunx/types.h>  error: expected '=', ',', ';', 'asm' or '__attribute__' before 'check_mac_perms'  ++ #include <stdbool.h>  expected specifier-qualifier-list before '__u32'6<. 修改代码warning: 'return' with a value, in function returning voidreturn;

5<. 修改 test_server.c

2<. 添加头文件  error: expected '=', ',', ';', 'asm' or '__attribute__' before 'binder_size_t'  ++ #include <liunx/types.h>  error: expected '=', ',', ';', 'asm' or '__attribute__' before 'check_mac_perms'  ++ #include <stdbool.h>

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3<. 测试代码

1<. 运行环境: 非 Android 系统, 例如 QT

2<. 上机测试:

软件层:1<. 重新编写内核让它支持NFS, 更新板上内核    make menuconfig        <*>   NFS client support                                                        | |        [*]     NFS client support for NFS version 3                                    | |        [*]       NFS client support for the NFSv3 ACL protocol extension               | |        [*]     NFS client support for NFS version 4                                    | |        [*]       NFS client support for NFSv4.1 (EXPERIMENTAL)     make zImage, 并使用新的zImage启动单板2<. mount nfs , 运行 server_manager, test_client, test_server   pint <server:ip>   mount -t nfs -o nolock <server:ip>:/<share-dir> /mnt    eg : mount -t nfs -o nolock 192.168.1.111:/home/book/student /mnt硬件层: 1<. 修改启动文件 FriendlyARM.ini    OS = Linux    #OS = Android    #USB-Mode = yes2<. 再次修改启动文件 FriendlyARM.ini    OS = Linux    #OS = Android    USB-Mode = yes

3<. 测试程序:

./server_manager &./test_server &./test_client hello   or  ./test_client hello luo[杀死程序]:killall <pid_name>

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示例代码:

1<. Makefile

APPS = service_manager test_client test_serverall : $(APPS)service_manager : service_manager.o binder.o    arm-linux-gcc -o $@ $^test_client : test_client.o binder.o    arm-linux-gcc -o $@ $^test_server : test_server.o binder.o    arm-linux-gcc -o $@ $^ %.o : %.c    arm-linux-gcc -c -I include -DBINDER_IPC_32BIT=1 -o $@ $<clean:    rm $(APPS) -f; rm -f *.o

2<. test_client.c

/* Copyright 2008 The Android Open Source Project */#include <stdio.h>#include <stdlib.h>#include <errno.h>#include <linux/types.h>#include <stdbool.h>#include <private/android_filesystem_config.h>#include "binder.h"#include "test_server.h"uint32_t svcmgr_lookup(struct binder_state *bs, uint32_t target, const char *name){    uint32_t handle;    unsigned iodata[512/4];    struct binder_io msg, reply;    bio_init(&msg, iodata, sizeof(iodata), 4);    bio_put_uint32(&msg, 0);  // strict mode header    bio_put_string16_x(&msg, SVC_MGR_NAME);    bio_put_string16_x(&msg, name);    if (binder_call(bs, &msg, &reply, target, SVC_MGR_CHECK_SERVICE))        return 0;    handle = bio_get_ref(&reply);    if (handle)        binder_acquire(bs, handle);    binder_done(bs, &msg, &reply);    return handle;}int svcmgr_publish(struct binder_state *bs, uint32_t target, const char *name, void *ptr){    int status;    unsigned iodata[512/4];    struct binder_io msg, reply;    bio_init(&msg, iodata, sizeof(iodata), 4);    bio_put_uint32(&msg, 0);  // strict mode header    bio_put_string16_x(&msg, SVC_MGR_NAME);    bio_put_string16_x(&msg, name);    bio_put_obj(&msg, ptr);    if (binder_call(bs, &msg, &reply, target, SVC_MGR_ADD_SERVICE))        return -1;    status = bio_get_uint32(&reply);    binder_done(bs, &msg, &reply);    return status;}struct binder_state *g_tBs;uint32_t g_uiHandle;void sayhello(void){    /* 构造一个 binder_io     */    unsigned iodata[512 / 4];    struct binder_io msg, reply;    bio_init(&msg, iodata, sizeof(iodata), 4);    bio_put_uint32(&msg, 0);       /* strict mode header */    /* 调用binder_call */    if (binder_call(g_tBs, &msg, &reply, g_uiHandle, HELLO_SVR_CMD_SAYHELLO)) {        return ;    }    /* 从reply取出返回值 */    /* 无：因为被调用的sayhello没有返回值 */    /* 调用binder_done表示完成 */    binder_done(g_tBs, &msg, &reply);}int sayhello_to(char *name){    int iRet = 0;    /* 构造一个 binder_io     */    unsigned iodata[512 / 4];    struct binder_io msg, reply;    bio_init(&msg, iodata, sizeof(iodata), 4);    bio_put_uint32(&msg, 0);       /* strict mode header */    /* 放入参数 */    bio_put_string16(&msg, (uint16_t *)name);    /* 调用binder_call */    if (binder_call(g_tBs, &msg, &reply, g_uiHandle, HELLO_SVR_CMD_SAYHELLO_TO)) {        return 0;    }    /* 从reply取出返回值 */    iRet = bio_get_uint32(&reply);    /* 调用binder_done表示完成 */    binder_done(g_tBs, &msg, &reply);    return iRet;}/* test_client: * ./test_client helloc * ./test_client helloc <xxx>; */int main(int argc, char **argv){    int fd;    int iRet;    struct binder_state *bs;    uint32_t svcmgr = BINDER_SERVICE_MANAGER;    uint32_t handle;    bs = binder_open(128*1024);    if (!bs) {        fprintf(stderr, "failed to open binder driver\n");        return -1;    }    /* 获得服务 */    handle = svcmgr_lookup(bs, svcmgr, "hello");    if (handle) {        fprintf(stderr, "svcmgr_lookup get hello server error! \n");        return -1;    }    g_tBs = bs;    g_uiHandle = handle;    /* 发送数据给服务器 */    if (argc == 2) {        sayhello();    } else if (argc == 3) {        iRet = sayhello_to(argv[2]);        fprintf(stderr, "get ret of sayhelloc_to = %d \n", iRet);    }    binder_release(bs, handle);    return 0;}

3<. test_server.c

/* Copyright 2008 The Android Open Source Project */#include <stdio.h>#include <stdlib.h>#include <errno.h>#include <linux/types.h>#include <stdbool.h>#include <private/android_filesystem_config.h>#include "binder.h"#include "test_server.h"uint32_t svcmgr_lookup(struct binder_state *bs, uint32_t target, const char *name){    uint32_t handle;    unsigned iodata[512/4];    struct binder_io msg, reply;    bio_init(&msg, iodata, sizeof(iodata), 4);    bio_put_uint32(&msg, 0);  // strict mode header    bio_put_string16_x(&msg, SVC_MGR_NAME);    bio_put_string16_x(&msg, name);    if (binder_call(bs, &msg, &reply, target, SVC_MGR_CHECK_SERVICE))        return 0;    handle = bio_get_ref(&reply);    if (handle)        binder_acquire(bs, handle);    binder_done(bs, &msg, &reply);    return handle;}int svcmgr_publish(struct binder_state *bs, uint32_t target, const char *name, void *ptr){    int status;    unsigned iodata[512/4];    struct binder_io msg, reply;    bio_init(&msg, iodata, sizeof(iodata), 4);    bio_put_uint32(&msg, 0);  // strict mode header    bio_put_string16_x(&msg, SVC_MGR_NAME);    bio_put_string16_x(&msg, name);    bio_put_obj(&msg, ptr);    if (binder_call(bs, &msg, &reply, target, SVC_MGR_ADD_SERVICE))        return -1;    status = bio_get_uint32(&reply);    binder_done(bs, &msg, &reply);    return status;}void say_hello(void) {    static int cnt = 0;    fprintf(stderr, "say hello to %s : %d\n", cnt++);}int say_hello_to(char *name){    static int cnt = 0;    fprintf(stderr, "say hello to %s : %d\n", name, cnt);    return cnt;}int hello_service_handler(struct binder_state *bs,                   struct binder_transaction_data *txn,                   struct binder_io *msg,                   struct binder_io *reply){    /*  根据txn->code知道要调用那个函数     *  如果需要参数，可以从msg取出     *  如果要返回结果，可以把结果放入reply     */    /* sayhello     * sayhello_to     */    uint16_t *s;    size_t len;    char name[512];    int i;    uint32_t strict_policy;    strict_policy = bio_get_uint32(msg);    switch (txn->code) {        case HELLO_SVR_CMD_SAYHELLO: {            say_hello();        }break;        case HELLO_SVR_CMD_SAYHELLO_TO: {            /* 从 msg 取出字符串 */            s = bio_get_string16(msg, &len);            if (s == NULL) {                return -1;            }            for (i = 0; i < len; ++i) {                name[i] = s[i];            }            name[i] = '\0';            /* 处理 */            i = say_hello_to(name);            /* 把结果放入 reply */            bio_put_uint32(reply, i);        }break;        defalut: {            ALOGE("unknown code %d \n", txn->code);        }break;    }}int main(int argc, char **argv){    int iFd;    int iRet;    struct binder_state *bs;    uint32_t svcmgr = BINDER_SERVICE_MANAGER;    uint32_t handle;    bs = binder_open(128*1024);    if (!bs) {        fprintf(stderr, "failed to open binder driver\n");        return -1;    }    /* 添加服务 */    iRet = svcmgr_publish(bs, svcmgr, "hello", (void *)123);    if (!iRet) {        fprintf(stderr, "svcmgr_publish : hello service error! \n");        return -1;    }    iRet = svcmgr_publish(bs, svcmgr, "goodbye", (void *)123);    if (!iRet) {        fprintf(stderr, "svcmgr_publish : goodbye service error! \n");    }#if 0    while (1) {        /* 读数据 */        /* 解析数据，并且处理 */        /* 回复 */    }#endif    /* 可以替换上面的 while (1)循环          */    binder_loop(bs, hello_service_handler);    return 0;}