setrlimit

/*
 *  call-seq:
 *     Process.setrlimit(resource, cur_limit, max_limit)        => nil
 *     Process.setrlimit(resource, cur_limit)                   => nil
 *
 *  Sets the resource limit of the process.
 *  _cur_limit_ means current (soft) limit and
 *  _max_limit_ means maximum (hard) limit.
 *
 *  If _max_limit_ is not given, _cur_limit_ is used.
 *
 *  _resource_ indicates the kind of resource to limit.
 *  The list of resources are OS dependent.
 *  Ruby may support following resources.
 *
 *  [Process::RLIMIT_CORE] core size (bytes) (SUSv3)
 *  [Process::RLIMIT_CPU] CPU time (seconds) (SUSv3)
 *  [Process::RLIMIT_DATA] data segment (bytes) (SUSv3)
 *  [Process::RLIMIT_FSIZE] file size (bytes) (SUSv3)
 *  [Process::RLIMIT_NOFILE] file descriptors (number) (SUSv3)
 *  [Process::RLIMIT_STACK] stack size (bytes) (SUSv3)
 *  [Process::RLIMIT_AS] total available memory (bytes) (SUSv3, NetBSD, FreeBSD, OpenBSD but 4.4BSD-Lite)
 *  [Process::RLIMIT_MEMLOCK] total size for mlock(2) (bytes) (4.4BSD, GNU/Linux)
 *  [Process::RLIMIT_NPROC] number of processes for the user (number) (4.4BSD, GNU/Linux)
 *  [Process::RLIMIT_RSS] resident memory size (bytes) (4.2BSD, GNU/Linux)
 *  [Process::RLIMIT_SBSIZE] all socket buffers (bytes) (NetBSD, FreeBSD)
 *
 *  Other <code>Process::RLIMIT_???</code> constants may be defined.
 *
 *  _cur_limit_ and _max_limit_ may be <code>Process::RLIM_INFINITY</code>,
 *  which means that the resource is not limited.
 *  They may be <code>Process::RLIM_SAVED_MAX</code> or
 *  <code>Process::RLIM_SAVED_CUR</code> too.
 *  See system setrlimit(2) manual for details.
 *
 */

static VALUE
proc_setrlimit(int argc, VALUE *argv, VALUE obj)
{
#if defined(HAVE_SETRLIMIT) && defined(NUM2RLIM)
    VALUE resource, rlim_cur, rlim_max;
    struct rlimit rlim;

    rb_secure(2);

    rb_scan_args(argc, argv, "21", &resource, &rlim_cur, &rlim_max);
    if (rlim_max == Qnil)
        rlim_max = rlim_cur;

    rlim.rlim_cur = NUM2RLIM(rlim_cur);
    rlim.rlim_max = NUM2RLIM(rlim_max);

    if (setrlimit(NUM2INT(resource), &rlim) < 0) {
        rb_sys_fail("setrlimit");
    }
    return Qnil;
#else
    rb_notimplement();
#endif
}