AW: Nagios 2.0b4 restart issue

[Andreas Ericsson]

Thibault Genessay wrote:
> Andreas Ericsson wrote:
> 
>> No it's not. Multiple instances has absolutely nothing to do with what 
>> the shell returns when asked to run a program. In this case, it does
>>
>>     result = execve(argv[0], argv, envp);
>>     /* execve() only returns on errors, so hint what went wrong */
>>     exit (-errno);
>>
>> and since ENOENT == 2 this results in a return code of -127 on all 
>> architectures that implement the two-complement bit pattern.
>>
> Andreas, I'm getting away from the initial topic, but I've tryed the 
> following code:
> #include <errno.h>
> int main(int argc, char* argv[])
> {
>  int dontcare = execv(argv[1], argv);
>  printf("Returning -(%d) to the shell\n", errno);
>  exit(-errno);
> }
> Then I called it with something stupid (e.g. ./a.out does-not-exist) and 
> echoed the $?, which happens to be 254. Seems to be something like 
> signed/unsigned issue.


The shell variable $? is always unsigned, but when a program fetches the 
exit status it can choose to use it as signed rather than casting it.


> Anyway this program returns 254 on my x86 box so the 127 value mentioned 
> in this thread might come from somewhere else.
> 

Nopes. (signed)-127 has the exact same bit-pattern as (unsigned)254 for 
an 8 bit wide variable.


> As for Radkon's problem, I remember having had to kill -9 Nagios' 
> processes from time to time when checking/debuging the configuration and 
> NEB and playing too intensively with the [re]start/stop script -- but 
> this did not yield 127 errors.


Nor should it. I expect something else entirely is borked on his system.

-- 
Andreas Ericsson                   andreas.ericsson at op5.se
OP5 AB                             www.op5.se
Tel: +46 8-230225                  Fax: +46 8-230231


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