service命令使用笔记

一、简介

# service --help
Usage: service [-h|-?]
       service list
       service check SERVICE
       service call SERVICE CODE [i32 N | i64 N | f N | d N | s16 STR | null | fd f | nfd n | afd f ] ...
Options:
   i32: Write the 32-bit integer N into the send parcel.
   i64: Write the 64-bit integer N into the send parcel.
   f:   Write the 32-bit single-precision number N into the send parcel.
   d:   Write the 64-bit double-precision number N into the send parcel.
   s16: Write the UTF-16 string STR into the send parcel.
  null: Write a null binder into the send parcel.
    fd: Write a file descriptor for the file f to the send parcel.
   nfd: Write file descriptor n to the send parcel.
   afd: Write an ashmem file descriptor for a region containing the data from file f to the send parcel.

此命令会自动写接口进去，使用时不需要再手动写接口了（由于其会自动写接口，服务端实现时也要有读接口的动作）。

二、实验

1. 调用服务函数

service call boostservice 7 s16 com.samsung.perf.IBoostManager s16 /proc/ed_task s16 "w 1125" //失败，不应该写接口
service call boostservice 7 s16 /proc/ed_task s16 "w 1125"  //成功

等效代理端使用第7个函数(函数序号从1开始)：

virtual void TestwriteProcNode(String16& path, String16& val)
{
    Parcel data, reply;
    data.writeInterfaceToken(IBoostManager::getInterfaceDescriptor());
    data.writeString16(path);
    data.writeString16(val);
    remote()->transact(IBinder::FIRST_CALL_TRANSACTION + 6,, data, &reply);
    reply.readExceptionCode();
}