[ILUG] [TOTD] find error corresponding to number

[Bryan O'Donoghue]

Stephen Shirley wrote:
> Bryan O'Donoghue wrote:
> 
>> Stephen Shirley wrote:
>>
>>> Also, as a nit pick, you should not be using the kernel headers, but 
>>> rather the headers of the kernel your glibc was compiled against, 
>>> which should be under /usr/include/{bits,asm,asm-generic,linux}
>>>
>>
>> Why would that be now?
>>
>> If the Kernel sets the signal state for a process, with a particular 
>> number and for argument's sake the signal number had changed from 
>> kernel version x, to kernel version y, you'd want to be aware of the 
>> current meaning of the signal number, ergo you'd want to check the 
>> meaning of the signal number in the *currently* running kernel, as 
>> opposed to the kernel, you libc may or may not have been compiled 
>> against?
>>
> 
> http://linuxmafia.com/faq/Kernel/usr-src-linux-symlink.html
> 
> Short version: the kernel can take care of backwards compatibility

Which violates the given postulate, that the signal number has changed from 
version (x) to version (y).

If the kernel structures took care of backwards compatability like that, 
there'd be no problem in having another kernel in /usr/src/linux then the one 
you compiled your libc against.

So if Andrew Morton in a fit of "I'm going to sort some stuff out" randomly 
changed the number the kernel set a task's sig state to, such that sigterm and 
sigkill were now mapped in the opposite direction, a script that was grepping 
the *old* symlinked /usr/src/linux + *libc, wouldn't adequately trap that 
signal number and map it back to the correct SIGTERM, SIGINT and those would 
appear to be reversed... if you catch my drift.

I don't really think it's the same thing as the "Don't have your current kernel 
source in /usr/src/linux, cause it foobars *libc" problem... but, I guess I 
could be wrong.

-- 
Bryan O'Donoghue
Embedded Software Engineer

Europlex Technologies Ltd
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