如何通过fd找到打开文件的路径及名称

如何通过fd找到打开文件的路径及名称

[Helight.Xu]

在用户程序中打开文件进行编辑，那在内核中如何能通过open后的fd
来找到相应打开文件的路径及其名字呢？

-- 
---------------------------------
Zhenwen Xu - Open and Free
Home Page:	http://zhwen.org

Re: 如何通过fd找到打开文件的路径及名称

[Xiaotian Feng]

in fs/open.c
   sys_open
             | --> do_sys_open
                          |--->  fd_install

Then fd is installed into file_fdtable

in fs/file_table.c
     fget_light/fget
            |----> fcheck_files

Then kernel get files from fd.

2009/11/20 Helight.Xu <helight.xu@gmail.com>:
> 在用户程序中打开文件进行编辑，那在内核中如何能通过open后的fd
> 来找到相应打开文件的路径及其名字呢？
>
> --
> ---------------------------------
> Zhenwen Xu - Open and Free
> Home Page:      http://zhwen.org
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
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> Please read the FAQ at  http://www.tux.org/lkml/
>

Re: 如何通过fd找到打开文件的路径及名称

[Helight.Xu]

Xiaotian Feng wrote:
> in fs/open.c
>    sys_open
>              | --> do_sys_open
>                           |--->  fd_install
>
> Then fd is installed into file_fdtable
>
> in fs/file_table.c
>      fget_light/fget
>             |----> fcheck_files
>
> Then kernel get files from fd.
>   
struct file is easy to get : current->files->fd_array[fd]

but I didn't find the file name!
> 2009/11/20 Helight.Xu <helight.xu@gmail.com>:
>   
>> 在用户程序中打开文件进行编辑，那在内核中如何能通过open后的fd
>> 来找到相应打开文件的路径及其名字呢？
>>
>> --
>> ---------------------------------
>> Zhenwen Xu - Open and Free
>> Home Page:      http://zhwen.org
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>> Please read the FAQ at  http://www.tux.org/lkml/
>>
>>     
>
>   


-- 
---------------------------------
Zhenwen Xu - Open and Free
Home Page:	http://zhwen.org

Re: 如何通过fd找到打开文件的路径及名称

[Américo Wang]

On Fri, Nov 20, 2009 at 02:33:48PM +0800, Helight.Xu wrote:
> 在用户程序中打开文件进行编辑，那在内核中如何能通过open后的fd
> 来找到相应打开文件的路径及其名字呢？
>

问题是你为什么要在内核中做呢？在用户空间完全可以完成：

 % readlink /proc/<PID>/fd/X


-- 
Live like a child, think like the god.
 

Re: 如何通过fd找到打开文件的路径及名称

[Helight.Xu]

Américo Wang wrote:
> On Fri, Nov 20, 2009 at 02:33:48PM +0800, Helight.Xu wrote:
>   
>> 在用户程序中打开文件进行编辑，那在内核中如何能通过open后的fd
>> 来找到相应打开文件的路径及其名字呢？
>>
>>     
>
> 问题是你为什么要在内核中做呢？在用户空间完全可以完成：
>
>  % readlink /proc/<PID>/fd/X
>   
我是想在内核中实现一些功能，所以现在内核中找到文件的路径及其名称，现在只 
能找到文件名，还在找路径。。。
>
>   


-- 
---------------------------------
Zhenwen Xu - Open and Free
Home Page:	http://zhwen.org

Re: 如何通过fd找到打开文件的路径及名称

[Américo Wang]

On Mon, Nov 23, 2009 at 09:02:33AM +0800, Helight.Xu wrote:
> Américo Wang wrote:
>> On Fri, Nov 20, 2009 at 02:33:48PM +0800, Helight.Xu wrote:
>>   
>>> 在用户程序中打开文件进行编辑，那在内核中如何能通过open后的fd
>>> 来找到相应打开文件的路径及其名字呢？
>>>
>>>     
>>
>> 问题是你为什么要在内核中做呢？在用户空间完全可以完成：
>>
>>  % readlink /proc/<PID>/fd/X
>>   
> 我是想在内核中实现一些功能，所以现在内核中找到文件的路径及其名称，


能在用户层完成的就不要跑到内核里去做，完全没必要。

而且，你在处理这个问题时还要考虑pipe和socket这些特殊的文件，
它们对应的fd可是没有file的。

> 现在只  
> 能找到文件名，还在找路径。。。

你可以看看proc文件中对fd/X的处理，或许能帮上忙。


-- 
Live like a child, think like the god.
 

Re: 如何通过fd找到打开文件的路径及名称

[Américo Wang]

On Mon, Nov 23, 2009 at 04:05:55PM +0100, Jiri Kosina wrote:

<snip>

>Come on guys, you keep CCing LKML with this :)
>

Wow, I missed the "lkml" label on this email in my inbox... :-/

I thought it was from linux-kernel@zh-kernel.org since $subject
is in Chinese.

I guess Helight wanted to send to zh-kernel.org, right?

-- 
Live like a child, think like the god.
 

non-english on list (was Re: ????????????fd????????????????????????????????????)

[Pavel Machek]

On Mon 2009-11-23 09:02:33, Helight.Xu wrote:
> Am??rico Wang wrote:
>> On Fri, Nov 20, 2009 at 02:33:48PM +0800, Helight.Xu wrote:
>>   
>>> ???????????????????????????????????????????????????????????????????????????open??????fd
>>> ??????????????????????????????????????????????????????
>>>
>>>     
>>
>> ?????????????????????????????????????????????????????????????????????????????????
>>
>>  % readlink /proc/<PID>/fd/X
>>   
 
> ???????????????????????????????????????????????????????????????????????????????????????????????????????????? 
> ?????????????????????????????????????????????
>>
>>   

Could we keep the list english-only?

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: non-english on list (was Re: ????????????fd????????????????????????????????????)

[David Newall]

Pavel Machek wrote:
> Could we keep the list english-only?

I thought that was the rule, but then concluded that there was probably 
good reason for using Chinese--perhaps insufficient skill in 
English--and why shouldn't people be allowed to post in a language they 
understand? Certainly less people can answer in other languages, but as 
we've seen, it's more than zero, and I gather a satisfactory result was 
achieved. If you don't understand the language just skip the thread and 
move on.

Re: non-english on list

[Américo Wang]

On Wed, Nov 25, 2009 at 12:40:05AM +1030, David Newall wrote:
> Pavel Machek wrote:
>> Could we keep the list english-only?
>
> I thought that was the rule, but then concluded that there was probably  
> good reason for using Chinese--perhaps insufficient skill in  
> English--and why shouldn't people be allowed to post in a language they  
> understand? Certainly less people can answer in other languages, but as  
> we've seen, it's more than zero, and I gather a satisfactory result was  
> achieved. If you don't understand the language just skip the thread and  
> move on.

Hi, sorry about this.

It was proved to be a mistake, I checked this with Helight, he wanted
to send to a Chinese lkml.

Don't worry, none of us has problems to write English emails. ;)

Thanks for your care.


-- 
Live like a child, think like the god.