How Does Android Binder Work in Intra-Process Calls?
Eddie Ho (何德威)
Hi all,
In the old android-platform mailing list, I saw Dianne Hackborn said Binder works as a local method call in intra-process case.
http://www.mailinglistarchive.com/html/android-...@googlegroups.com/2010-01/msg00305.html
Because Android source code is big, I cannot quickly find the point determining if a Binder call needs go into Binder driver or just works as a local method call.
I know it is handled in Binder library, and I already spent a lot of time trace source code.
Could anyone help tell me where is the point?
Thank you very much. I will very appreciate your help.
Best Regards,
Eddie Ho 何德威
MediaTek Inc.
Tel: +886-3-5670766 ext. 20491
Email: eddi...@mediatek.com
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磊 张
IPC (inter process communication)
Borqs Ltd.
Lei
Date: Wed, 23 Nov 2011 20:10:50 +0300
Subject: Re: How Does Android Binder Work in Intra-Process Calls?
From: alex...@gmail.com
To: android-...@googlegroups.com
frameworks/base/libs/binder
Hi all,
In the old android-platform mailing list, I saw Dianne Hackborn said Binder works as a local method call in intra-process case.
http://www.mailinglistarchive.com/html/android-...@googlegroups.com/2010-01/msg00305.html
Because Android source code is big, I cannot quickly find the point determining if a Binder call needs go into Binder driver or just works as a local method call.
I know it is handled in Binder library, and I already spent a lot of time trace source code.
Could anyone help tell me where is the point?
Thank you very much. I will very appreciate your help.
Best Regards,
Eddie Ho 锟轿碉拷锟斤拷
Eddie Ho (何德威)
Hi all,
After tracing code, I found getService() will return different Binder in inter-process and intra process cases.
Through this difference, intra-process communication does not involve Binder Driver.
Only inter-process communication involves Binder Driver.
Thanks. : )
From: android-...@googlegroups.com [mailto:android-...@googlegroups.com] On Behalf Of 磊 ?
Sent: Thursday, November 24, 2011 9:54 AM
To: android-...@googlegroups.com
Subject: RE: How Does Android Binder Work in Intra-Process Calls?
I think you gotta read the source code of Ibinder in android and android interface definition language(aidl)
IPC (inter process communication)
Borqs Ltd.
Lei
Date: Wed, 23 Nov 2011 20:10:50 +0300
Subject: Re: How Does Android Binder Work in Intra-Process Calls?
From: alex...@gmail.com
To: android-...@googlegroups.com
frameworks/base/libs/binder
by source code in android 2.3.4 it uses symbolic device /dev/binder for ipc between applications
2011/11/23 Eddie Ho (何德威) <eddi...@mediatek.com>
Hi all,
In the old android-platform mailing list, I saw Dianne Hackborn said Binder works as a local method call in intra-process case.
http://www.mailinglistarchive.com/html/android-...@googlegroups.com/2010-01/msg00305.html
Because Android source code is big, I cannot quickly find the point determining if a Binder call needs go into Binder driver or just works as a local method call.
I know it is handled in Binder library, and I already spent a lot of time trace source code.
Could anyone help tell me where is the point?
Thank you very much. I will very appreciate your help.
Best Regards,
Eddie Ho 何德威
Eddie Ho (何德威)
Hi all,
I don't know if my understanding is correct or not. Any feedback is welcome. : )
The following is my study about Binder “intra-process” call:
1. In frameworks/base/libs/binder/IServiceManager.cpp:
getService() will return the result of checkService().
checkService() will call readStrongBinder().
2. In frameworks/base/libs/binder/Parcel.cpp:
readStrongBinder() will call unflatten_binder().
==> if flat->type is BINDER_TYPE_BINDER, return a local pointer, and then the rest communication does not involve Binder Driver.
*out = static_cast<IBinder*>(flat->cookie);
==> if flat->type is BINDER_TYPE_HANDLE, return a proxy, and then the rest communication will involve Binder Driver.
*out = proc->getStrongProxyForHandle(flat->handle);
3. Actually, the flat variable is originally generated from Binder Driver, kernel/drivers/staging/android/binder.c:
The following code shows that if the sender and receiver are in the same process, fp->type will be BINDER_TYPE_BINDER,
which leads to the result unflatten_binder() return a local pointer, and then the rest communication never involve Binder Driver.
if (ref->node->proc == target_proc) { <= the case sender and receiver are in the same process.
if (fp->type == BINDER_TYPE_HANDLE)
fp->type = BINDER_TYPE_BINDER; <= In this case, change the Binder type to BINDER_TYPE_BINDER
else
fp->type = BINDER_TYPE_WEAK_BINDER;
fp->binder = ref->node->ptr;
fp->cookie = ref->node->cookie;
binder_inc_node(ref->node, fp->type == BINDER_TYPE_BINDER, 0, NULL);
binder_debug(BINDER_DEBUG_TRANSACTION,
" ref %d desc %d -> node %d u%p\n",
ref->debug_id, ref->desc, ref->node->debug_id,
ref->node->ptr);
} else { <=the case sender and receiver are not in the same process
The conclusion is:
Not every Binder communication involves Binder Driver, and at the stage of getService(), it is determined.
Thank you very much. : )
From: Eddie Ho (何德威)
Sent: Thursday, November 24, 2011 5:37 PM
To: android-...@googlegroups.com
Subject: RE: How Does Android Binder Work in Intra-Process Calls?
Hi all,
After tracing code, I found getService() will return different Binder in inter-process and intra process cases.
Through this difference, intra-process communication does not involve Binder Driver.
Only inter-process communication involves Binder Driver.
Thanks. : )
From: android-...@googlegroups.com [mailto:android-...@googlegroups.com] On Behalf Of 磊
?
Sent: Thursday, November 24, 2011 9:54 AM
To: android-...@googlegroups.com
Subject: RE: How Does Android Binder Work in Intra-Process Calls?
I think you gotta read the source code of Ibinder in android and android interface definition language(aidl)
IPC (inter process communication)
Borqs Ltd.
Lei
Date: Wed, 23 Nov 2011 20:10:50 +0300
Subject: Re: How Does Android Binder Work in Intra-Process Calls?
From: alex...@gmail.com
To: android-...@googlegroups.com
frameworks/base/libs/binder
by source code in android 2.3.4 it uses symbolic device /dev/binder for ipc between applications
2011/11/23 Eddie Ho (何德威) <eddi...@mediatek.com>
Hi all,
In the old android-platform mailing list, I saw Dianne Hackborn said Binder works as a local method call in intra-process case.
http://www.mailinglistarchive.com/html/android-...@googlegroups.com/2010-01/msg00305.html
Because Android source code is big, I cannot quickly find the point determining if a Binder call needs go into Binder driver or just works as a local method call.
I know it is handled in Binder library, and I already spent a lot of time trace source code.
Could anyone help tell me where is the point?
Thank you very much. I will very appreciate your help.
Best Regards,
Eddie Ho 何德威
磊 张
what I meant was that when you are tracing the source code , there are something more you can get.
in the IBinder source code, refer to the java doc , the annotation of the certain class . and then you will hava more
to figure out.
Lei
Subject: RE: How Does Android Binder Work in Intra-Process Calls?
Hi all,
I don't know if my understanding is correct or not. Any feedback is welcome. : )
The following is my study about Binder 锟斤拷intra-process锟斤拷 call:
2011/11/23 Eddie Ho (锟轿碉拷锟斤拷) <eddi...@mediatek.com>
Hi all,
In the old android-platform mailing list, I saw Dianne Hackborn said Binder works as a local method call in intra-process case.
http://www.mailinglistarchive.com/html/android-...@googlegroups.com/2010-01/msg00305.html
Because Android source code is big, I cannot quickly find the point determining if a Binder call needs go into Binder driver or just works as a local method call.
I know it is handled in Binder library, and I already spent a lot of time trace source code.
Could anyone help tell me where is the point?
Thank you very much. I will very appreciate your help.
Best Regards,
Eddie Ho 锟轿碉拷锟斤拷