www/deno: Add a FreeBSD implementation for rss()

Obtained from:	OpenBSD
Reviewed by:	Val Packett

www/deno/Makefile

@@ -1,6 +1,7 @@
 PORTNAME=	deno
 DISTVERSIONPREFIX=	v
 DISTVERSION=	1.34.3
+PORTREVISION=	1
 CATEGORIES=	www
 
 PATCH_SITES=	https://github.com/denoland/${PORTNAME}/commit/

www/deno/files/patch-runtime_ops_os_mod.rs

@@ -1,12 +1,47 @@
 --- runtime/ops/os/mod.rs.orig	2023-01-13 13:12:37 UTC
 +++ runtime/ops/os/mod.rs
-@@ -399,6 +399,11 @@ fn rss() -> usize {
-   task_info.resident_size as usize
+@@ -427,6 +427,46 @@ fn rss() -> usize {
+   }
  }
  
 +#[cfg(target_os = "freebsd")]
 +fn rss() -> usize {
-+  0
++  // Uses FreeBSD's KERN_PROC_PID sysctl(2)
++  // to retrieve information about the current
++  // process, part of which is the RSS (ki_rssize)
++  let pid = unsafe { libc::getpid() };
++  // SAFETY: libc call (get system page size)
++  let pagesize = unsafe { libc::sysconf(libc::_SC_PAGESIZE) } as usize;
++  // KERN_PROC_PID returns a struct libc::kinfo_proc
++  let mut kinfoproc = std::mem::MaybeUninit::<libc::kinfo_proc>::uninit();
++  let mut size = std::mem::size_of_val(&kinfoproc) as libc::size_t;
++  let mut mib = [
++    libc::CTL_KERN,
++    libc::KERN_PROC,
++    libc::KERN_PROC_PID,
++    pid,
++  ];
++  // SAFETY: libc call, mib has been statically initialized,
++  // kinfoproc is a valid pointer to a libc::kinfo_proc struct
++  let res = unsafe {
++    libc::sysctl(
++      mib.as_mut_ptr(),
++      mib.len() as _,
++      kinfoproc.as_mut_ptr() as *mut libc::c_void,
++      &mut size,
++      std::ptr::null_mut(),
++      0,
++    )
++  };
++
++  if res == 0 {
++    // SAFETY: sysctl returns 0 on success and kinfoproc is initialized
++    // ki_rssize contains size in pages -> multiply with pagesize to
++    // get size in bytes.
++    pagesize * unsafe { (*kinfoproc.as_mut_ptr()).ki_rssize as usize }
++  } else {
++    0
++  } 
 +}
 +
  #[cfg(windows)]