setrlimit always fails

[Brian Inglis]

On 2021-02-12 11:56, Brian Inglis wrote:
> On 2021-02-12 02:12, Corinna Vinschen via Cygwin wrote:
>> On Feb 12 00:26, Brian Inglis wrote:
>>> On 2021-02-11 19:06, Ken Brown via Cygwin wrote:
>>>> On 2/11/2021 10:23 AM, Patrick Chkoreff wrote:
>>>>> I'm trying to use setrlimit to impose limits on various resources such
>>>>> as CPU time and memory.  The call to setrlimit always fails.  I've
>>>>> distilled this into the following example test.c:
>>>>>       if (setrlimit(RLIMIT_CPU,&rlim) < 0)
>>>>> setrlimit: Invalid argument

>>>> Cygwin's setrlimit only supports a few resources, as you can see in the source:
>>>> https://cygwin.com/git/?p=newlib-cygwin.git;a=blob;f=winsup/cygwin/resource.cc;h=97777e9d223466b7635b990d6c9e0bfb9e2e9a46;hb=HEAD#l201 

>>> In that case could I suggest:
>>>     /usr/share/doc/cygwin-doc/html/cygwin-api/compatibility.html#std-susv4
>>>     https://cygwin.com/cygwin-api/compatibility.html#std-susv4
>>> in https://cygwin.com/git/?p=newlib-cygwin.git;a=blob;f=winsup/doc/posix.xml
>>> get/setrlimit entries should be annotated with:

>> https://cygwin.com/acronyms/#PGA

> I'll see what I can do. Does anyone know if <ulink> is supported within 
> <screen>? I seem to remember struggles updating proc(5) in specialnames.xml.
> It appears that code using other than the common POSIX resources need existence 
> checks.
> I am unsure if it is worth adding definitions for any others.
> It may be possible to implement RSS, NPROC, LOCKS, NICE, but
   https://cygwin.com/acronyms/#SHTDI
> 
> Comparing Cygwin and Linux ([uapi/]asm-generic/}:
> 
> #define RLIMIT_CPU		0	/* CPU time in seconds */
> #define RLIMIT_FSIZE		1	/* Maximum filesize */
> #define RLIMIT_DATA		2	/* max data size */
> #define RLIMIT_STACK		3	/* max stack size */
> #define RLIMIT_CORE		4	/* max core file size */
> #ifdef LINUX
> #define RLIMIT_RSS		5	/* max resident set size */
> #define RLIMIT_NPROC		6	/* max number of processes */
> #define RLIMIT_NOFILE		7	/* max number of open files */
   #define RLIMIT_MEMLOCK	8	/* max locked-in-memory address space */
> #define RLIMIT_AS		9	/* address space limit */
> #else
> #define RLIMIT_NOFILE		5	/* max number of open files */
> #define RLIMIT_OFILE		RLIMIT_NOFILE	/* BSD name */
> #define RLIMIT_AS		6	/* address space limit */
> #endif
> #ifdef LINUX
> #define RLIMIT_LOCKS		10	/* maximum file locks held */
> #define RLIMIT_SIGPENDING	11	/* max number of pending signals */
> #define RLIMIT_MSGQUEUE	12	/* maximum bytes in POSIX mqueues */
> #define RLIMIT_NICE		13	/* max nice prio allowed to raise to */
> #define RLIMIT_RTPRIO		14	/* maximum realtime priority */
> #define RLIMIT_RTTIME		15	/* timeout for RT tasks in us */
> #define RLIM_NLIMITS		16
> #else
> #define RLIMIT_NLIMITS	7	/* upper bound of RLIMIT_* defines */
> #endif
> 
> Linux man says:
> 
> "RLIMIT_MEMLOCK and RLIMIT_NPROC derive from BSD and are not specified in 
> POSIX.1; they are present on the BSDs and Linux, but on few other implementations.
> RLIMIT_RSS derives from BSD and is not specified in POSIX.1; it is nevertheless 
> present on most implementations.
> RLIMIT_MSGQUEUE, RLIMIT_NICE, RLIMIT_RTPRIO,  RLIMIT_RTTIME, and 
> RLIMIT_SIGPENDING are Linux-specific."

-- 
Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

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