https://www.brobwind.com/archives/291
Brillo: 编译运行example-ledflasher程序
我们之前在建立Brillo编译环境的时候（. build/envsetup.sh)， 在lunch的时候，就可以看到ledflasher-userdebug的项目，这个项目是给高通dragonboard使用的sample, 今天试着将这个项目移植到RPi 2B上面。相关的代码和配置文件在product/google/example-ledflasher下面，我们需要用到的文件有sepolicy和src下打面的所有文件。因为这个sample是用来控制LED的，所以我们还需要lights HAL层的代码，可以参考hardware/bsp/qcom/lights下面的代码。具体的操用步骤如下：
- 修改hardware/bsp/qcom/lights下代码，以便生成我们所需要的lights HAL层代码：
修改Android.mk, 将LOCAL_MODULE 改成lights.rpi, 如下所示：
LOCAL_PATH:= $(call my-dir) include $(CLEAR_VARS) LOCAL_SRC_FILES := lights.c LOCAL_MODULE_RELATIVE_PATH := hw LOCAL_SHARED_LIBRARIES := liblog LOCAL_CFLAGS := $(common_flags) -DLOG_TAG="lights" LOCAL_MODULE := lights.rpi LOCAL_MODULE_TAGS := optional include $(BUILD_SHARED_LIBRARY)
出于测试的目的，我并没有在RPi 2B上外接LED, 为了看到效里，暂时先作改lights.c文件，如果LED的状态发生变成，会在logcat中打印log，之后会在硬件上真正实现。相关的代码修改如下：
static int write_int(char const* path, int value)
{
#if 1
ALOGI(" -> write: %s value=0x08%x(%d", path, value, value);
return 0;
#else
FILE *fd;
fd = fopen(path, "w+");
if (fd) {
int bytes = fprintf(fd, "%d", value);
fclose(fd);
return (bytes < 0 ? bytes : 0);
} else {
ALOGE("write_int failed to open %s
", path);
return -errno;
}
#endif
}
最后使用mm编译出lights.rpi.so文件。
- 编译ledflasher与ledservice模块
同样，进入product/google/example-ledflasher/src/ledflasher与product/google/example-ledflasher/src/ledservice文件夹，将这个两模块编译出来。
- 更新ramdisk7.img (selinux配置文件）
修改device/hzak/rpi/BoardConfig.mk，将product/google/example-ledflasher/sepolicy加入编译脚本：
BOARD_SEPOLICY_DIRS +=
product/google/example-ledflasher/sepolicy
最后make编译整个项目，以便生成我们所需的ramdisk文件。
- 更新系统中的其他模块
我们需要将lights.rpi.so, ledflasher和ledservice这几个文件放在特定的目录下。
但是首先将要更新ramdisk7.img：
$ adb push out/target/product/rpi/ramdisk.img /boot/ramdisk7.img
重启系统，这一步很重要，一定要做：
$ adb reboot
最后才去更新lights.rppi.so, ledflasher和ledservice这三个文件：
$ adb remount $ adb sync system
最后重启系统，就可以通过ps命令看到ledflasher服务在运行了。
由于selinux的关系，system文件夹中的文件是有selinux context的，可以通过ls -Z命令查看
ledflasher与ledservice正确的selinux context应该是:
$ adb shell ls -lZ | grep led -rwxr-xr-x 1 root shell u:object_r:ledflasher_exec:s0 67200 2016-01-05 12:14 ledflasher -rwxr-xr-x 1 root shell u:object_r:ledservice_exec:s0 38528 2016-01-05 12:14 ledservice
如果在kernel log出现如下log, 那么说明你没有按照上面的步骤来做，这个service是不会运行的：
01-01 00:00:03.973 0 0 E init : Service ledservice does not have a SELinux domain defined. 01-01 00:00:03.973 0 0 E init : Service ledflasher does not have a SELinux domain defined.
而你看到的selinux context可能是这样的：
$ adb shell ls -lZ | grep led -rwxr-xr-x 1 root shell u:object_r:system_file:s0 67200 2016-01-05 12:14 ledflasher -rwxr-xr-x 1 root shell u:object_r:system_file:s0 38528 2016-01-05 12:14 ledservice
从/privet/v3/commandDefs中可以看到，已经有led相关的字段了。接下来就要了解怎么去查询，更新LED的状态了。
NOTE: 关于authorization token的获取，请参考之前的文章。
$ curl -H "Authorization: Privet 4oqc8UPPmgY8z+N7vjZTs4sSBcp/4CRVtQD38GIW5RozOjE6MTQ1MTE5NzM2OQ==" -k http://10.0.0.18/privet/v3/commandDefs
{
"commands": {
"_ledflasher": {
"_animate": {
"minimalRole": "user",
"parameters": {
"_duration": {
"maximum": 100.0,
"minimum": 0.1,
"type": "number"
},
"_type": {
"enum": [ "none", "marquee_left", "marquee_right", "blink" ],
"type": "string"
}
}
},
"_set": {
"minimalRole": "user",
"parameters": {
"_led": {
"maximum": 4,
"minimum": 1,
"type": "integer"
},
"_on": {
"type": "boolean"
}
}
},
"_toggle": {
"minimalRole": "user",
"parameters": {
"_led": {
"maximum": 4,
"minimum": 1,
"type": "integer"
}
}
}
},
"_metrics": {
"_disableAnalyticsReporting": {
"minimalRole": "manager"
},
"_enableAnalyticsReporting": {
"minimalRole": "manager"
}
},
"base": {
"updateBaseConfiguration": {
"minimalRole": "manager",
"parameters": {
"localAnonymousAccessMaxRole": {
"enum": [ "none", "viewer", "user" ],
"type": "string"
},
"localDiscoveryEnabled": {
"type": "boolean"
},
"localPairingEnabled": {
"type": "boolean"
}
}
},
"updateDeviceInfo": {
"minimalRole": "manager",
"parameters": {
"description": {
"type": "string"
},
"location": {
"type": "string"
},
"name": {
"type": "string"
}
}
}
}
},
"fingerprint": "3"
}
再看看/privet/v3/traits和/privet/v3/components:
$ curl -H "Authorization: Privet 4oqc8UPPmgY8z+N7vjZTs4sSBcp/4CRVtQD38GIW5RozOjE6MTQ1MTE5NzM2OQ==" -k https://10.0.0.18/privet/v3/traits
{
"fingerprint": "3",
"traits": {
"_ledflasher": {
"commands": {
"_animate": {
"minimalRole": "user",
"parameters": {
"_duration": {
"maximum": 100.0,
"minimum": 0.1,
"type": "number"
},
"_type": {
"enum": [ "none", "marquee_left", "marquee_right", "blink" ],
"type": "string"
}
}
},
"_set": {
"minimalRole": "user",
"parameters": {
"_led": {
"maximum": 4,
"minimum": 1,
"type": "integer"
},
"_on": {
"type": "boolean"
}
}
},
"_toggle": {
"minimalRole": "user",
"parameters": {
"_led": {
"maximum": 4,
"minimum": 1,
"type": "integer"
}
}
}
},
"states": {
"_leds": {
"items": {
"type": "boolean"
},
"type": "array"
},
"_status": {
"enum": {
"enum": [ "idle", "animating" ],
"type": "string"
}
}
}
},
"_metrics": {
"commands": {
"_disableAnalyticsReporting": {
"minimalRole": "manager"
},
"_enableAnalyticsReporting": {
"minimalRole": "manager"
}
},
"state": {
"_AnalyticsReportingState": {
"enum": [ "enabled", "disabled" ],
"type": "string"
}
}
},
"base": {
"commands": {
"updateBaseConfiguration": {
"minimalRole": "manager",
"parameters": {
"localAnonymousAccessMaxRole": {
"enum": [ "none", "viewer", "user" ],
"type": "string"
},
"localDiscoveryEnabled": {
"type": "boolean"
},
"localPairingEnabled": {
"type": "boolean"
}
}
},
"updateDeviceInfo": {
"minimalRole": "manager",
"parameters": {
"description": {
"type": "string"
},
"location": {
"type": "string"
},
"name": {
"type": "string"
}
}
}
},
"state": {
"firmwareVersion": "string",
"localAnonymousAccessMaxRole": [ "none", "viewer", "user" ],
"localDiscoveryEnabled": "boolean",
"localPairingEnabled": "boolean"
}
}
}
}
$ curl -H "Authorization: Privet 4oqc8UPPmgY8z+N7vjZTs4sSBcp/4CRVtQD38GIW5RozOjE6MTQ1MTE5NzM2OQ==" -k https://10.0.0.18/privet/v3/components
{
"components": {
"ledflasher": {
"state": {
"_ledflasher": {
"_leds": [ false, false, false, false ],
"_status": "idle"
}
},
"traits": [ "_ledflasher" ]
},
"metrics": {
"state": {
"_metrics": {
"_AnalyticsReportingState": "disabled"
}
},
"traits": [ "_metrics" ]
},
"weave": {
"state": {
"base": {
"firmwareVersion": "0.0.0.1451996914",
"localAnonymousAccessMaxRole": "viewer",
"localDiscoveryEnabled": true,
"localPairingEnabled": true
}
},
"traits": [ "base" ]
}
},
"fingerprint": "5"
}