Re: [2.6.16-rc5-m3 PATCH] inotify: add the monitor for the event source

[Yi Yang <yang.y.yi@gmail.com>]

Arjan van de Ven wrote:
> On Thu, 2006-03-09 at 00:33 +0800, Yi Yang wrote:
>   
>> Current inotify implementation only focus on change of file system, but it doesn't
>>  know who results in this change, this patch adds three fields to struct inotify_event,
>>  tgid, uid and gid, they will save process ID, user ID and user group ID of the process
>>  which leads to change in the file system, such software as anti-virus can make use 
>> of this feature to monitor who is modifying a specific file.
>>     
>
>
> this patch appears to change the ABI! That is bad bad bad.
>   
a change of struct inotify_event can't change ABI, can you describe it 
more clear?
> Also, how can you guarantee that "current" is valid and meaningful at
> the place you use it to get the user id ??
>   
Of course, current process/thread never disappears before fsnotify_* 
returns.
> Also the process ID part is really bogus, after all the process may have
> exited by the time the inotify client gets to it, and the PID may even
> already have been reused.
>
>   
Your concern is correct, but uid and git can give out some hints, I ever 
considered to
save the name of current process, however that needs a bigger and 
length-variable
inotify_event struct, moreover, to get the full path name of current 
process/thread
in kernel will have a big overhead, so I must select a comprise way. In 
fact, the case
 you said is very few.