如何查找android emulator内核的精确版本

android api22, arm images

root@generic:/ # cat /proc/version
Linux version 3.4.67-01422-gd3ffcc7-dirty (digit@tyrion.par.corp.google.com) (gcc version 4.8 (GCC) ) #1 PREEMPT Tue Sep 16 19:34:06 CEST 2014

内核版本3.4.67，下载goldfish代码：

git clone git://mirrors.ustc.edu.cn/aosp/kernel/goldfish.git

$ git branch -a
* (no branch)
master
remotes/origin/HEAD -> origin/master
remotes/origin/android-3.10
remotes/origin/android-3.18
remotes/origin/android-3.4
remotes/origin/android-goldfish-2.6.29
remotes/origin/android-goldfish-3.10
remotes/origin/android-goldfish-3.10-l-mr1-dev
remotes/origin/android-goldfish-3.10-m-dev
remotes/origin/android-goldfish-3.18-dev
remotes/origin/android-goldfish-3.4
remotes/origin/android-goldfish-3.4-l-mr1-dev
remotes/origin/android-goldfish-4.4-dev
remotes/origin/linux-goldfish-3.0-wip
remotes/origin/master

git checkout remotes/origin/android-goldfish-3.4

但是，预编译好的kernel-qemu到底对应了哪个commit id呢？

看版本号，发现g后面的就是commit id，d3ffcc7

然后git checkout d3ffcc7就可以了

android api22， x86 images

root@generic_x86:/ # cat /proc/version
Linux version 3.4.67+ (digit@tyrion.par.corp.google.com) (gcc version 4.8 (GCC) ) #3 PREEMPT Tue Sep 16 19:46:22 CEST 2014

没有goldfish commit id信息，怎么玩呢？

1、求取预编译的kernel-qemu的md5sum为6c5f6f4359c7b94b637ef266387c5ff9

2、cd android-5.1.0_r1/prebuilts/qemu-kernel/

3、求取x86/kernel-qemu的md5sum，对比是否相同

4、相同，那么看commit msg，里面有说明对应的goldfish commit id是多少

5、不同，git reset --hard <上一次的prebuilts commit id>，回到第3步

最后，得到的commit msg是：

commit 2cd41c75898f6eb19619e4d03fd39e08821a1e38
Author: David 'Digit' Turner <digit@google.com>
Date:   Wed Sep 17 00:14:04 2014 +0200

Upgrade qemu kernels to support multinetwork.

This patch updates the binaries of emulator-specific kernels to
the following revisions (https://android.googlesource.com/kernel/goldfish):

android-goldfish-3.4:   ea97df6 goldfish: Enable multinetwork kernel featu
android-goldfish-3.10:  64a0393 goldfish: Enable multinetwork kernel featu

The main goals is to get multinetwork working, which is required to
properly emulate Android L and beyond. This also includes other patches,
including compatibility-related patches for the ARM64 kernel that make
ARMv7 binaries run properly under it.

BUG=17516983

Change-Id: I2f1c352b72ca6b254dbcb9732dee3c014867ae99

goldfish commit id是ea97df6

PS：如果用md5sum的方式，得到的arm的goldfish commit id也是ea97df6