Ken Brown via Cygwin wrote on 2/11/21 9:06 PM: > 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
Thank you to all who replied. Shortly after I sent the email, I did some more searching and did find some posts to that effect, including one that said setrlimit was originally added as a stub to support porting OpenSSH. Also thank you for the pointer to the source code. The reason I'm asking about setrlimit is that I'm porting the code for my functional programming language "Fexl" from Linux to Windows under Cygwin. (https://fexl.com) In that language I have embedded functions limit_time, limit_stack, and limit_memory which call setrlimit. Those functions can be used to set sensible limits before running potentially dangerous code. It's safe enough to allow running a program entered by a stranger in a text area on a web site -- even a program which deliberately tries to use an unbounded amount of memory. I don't know if native Windows provides enough to flesh out setrlimit with the equivalent behavior on Linux, even for my very limited usage (RLIMIT_CPU, RLIMIT_STACK, RLIMIT_AS). Therefore the only way for me to do safe limits in Fexl would be to actually count evaluation steps in my evaluation loop, and memory usage in my allocation wrapper, and halt the program if it exceeds any user-imposed limits. So I would have to check evaluation steps here: https://github.com/chkoreff/Fexl/blob/956bdf85ff5046ebfa7fe582584fedc6881152db/src/value.c#L137 And check memory usage here: https://github.com/chkoreff/Fexl/blob/956bdf85ff5046ebfa7fe582584fedc6881152db/src/memory.c#L28 It's either that or deprecate my usage of setrlimit altogether, making it impossible to protect against runaway execution of potentially dangerous unvetted code. I will say that my first attempt at compiling the Linux code under Cygwin went very well. The only compiler error was in some code that calls strptime. To fix that, I had to use some macros in a sequence like this: #ifdef __CYGWIN__ /* Ensure that strptime is accessible. */ #define _XOPEN_SOURCE #endif #include <stdint.h> ... #ifndef __CYGWIN__ /* Ensure that strptime is accessible. */ #define __USE_XOPEN #endif #include <time.h> That seems to be the simplest I can make that. Thank you to all the Cygwin developers who made this porting effort possible! -- Patrick -- Problem reports: https://cygwin.com/problems.html FAQ: https://cygwin.com/faq/ Documentation: https://cygwin.com/docs.html Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple
