where is the code for read system call?

where is the code for read system call?

[Agarwal, Lomesh]

My application reads from socket. I need to change the behavior of read
system call for an experiment. Can someone point me to code?

thanks

Re: where is the code for read system call?

[Karsten Wiese]

Am Samstag, 21. Juli 2007 schrieb Agarwal, Lomesh:
> My application reads from socket. I need to change the behavior of read
> system call for an experiment. Can someone point me to code?

fs/read_write.c: line 356
asmlinkage ssize_t sys_read(unsigned int fd, char __user * buf, size_t count)

RE: where is the code for read system call?

[Agarwal, Lomesh]

For future how do I trace a system call to a function in a kernel?

-----Original Message-----
From: linux-kernel-owner@vger.kernel.org
[mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of Karsten Wiese
Sent: Friday, July 20, 2007 5:09 PM
To: Agarwal, Lomesh
Cc: linux-kernel@vger.kernel.org
Subject: Re: where is the code for read system call?

Am Samstag, 21. Juli 2007 schrieb Agarwal, Lomesh:
> My application reads from socket. I need to change the behavior of
read
> system call for an experiment. Can someone point me to code?

fs/read_write.c: line 356
asmlinkage ssize_t sys_read(unsigned int fd, char __user * buf, size_t
count)
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Re: where is the code for read system call?

[Karsten Wiese]

Am Montag, 23. Juli 2007 schrieb Agarwal, Lomesh:
> For future how do I trace a system call to a function in a kernel?

strace. i.e:
	$ strace ls

Re: where is the code for read system call?

[Randy Dunlap]

On Mon, 23 Jul 2007 18:01:32 +0200 Karsten Wiese wrote:

> Am Montag, 23. Juli 2007 schrieb Agarwal, Lomesh:
> > For future how do I trace a system call to a function in a kernel?
> 
> strace. i.e:
> 	$ strace ls

I thought (maybe I misunderstood) that Lomesh wanted to know
which kernel function (by name) is called for specific syscalls...
and strace will tell the syscall by name, but not the kernel
function names.

If Lomesh wants what I described, then the answer is more like
"see the syscall tables in each $ARCH".

---
~Randy
*** Remember to use Documentation/SubmitChecklist when testing your code ***

Re: where is the code for read system call?

[Folkert van Heusden]

> My application reads from socket. I need to change the behavior of read
> system call for an experiment. Can someone point me to code?

Wouldn't it be easier to create a preload-library-wrapper around glibc?


Folkert van Heusden

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Re: where is the code for read system call?

[Jan Engelhardt]

On Jul 21 2007 07:05, Folkert van Heusden wrote:
>
>> My application reads from socket. I need to change the behavior of read
>> system call for an experiment. Can someone point me to code?
>
>Wouldn't it be easier to create a preload-library-wrapper around glibc?
>
Does not work with statically compiled binaries.
But in an experiment, you are likely to have source and/or dynamically linked
programs.


	Jan
--