// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

/// darwin_fd_limit exists to work around an issue where launchctl on Mac OS X
/// defaults the rlimit maxfiles to 256/unlimited. The default soft limit of 256
/// ends up being far too low for our multithreaded scheduler testing, depending
/// on the number of cores available.
///
#[cfg(any(target_os = "macos", target_os = "ios"))]
#[allow(non_camel_case_types)]
pub fn raise_fd_limit() {
	use libc;
	use std::cmp;
	use std::io;
	use std::mem::size_of_val;
	use std::ptr::null_mut;

	unsafe {
		static CTL_KERN: libc::c_int = 1;
		static KERN_MAXFILESPERPROC: libc::c_int = 29;

		// The strategy here is to fetch the current resource limits, read the
		// kern.maxfilesperproc sysctl value, and bump the soft resource limit for
		// maxfiles up to the sysctl value.

		// Fetch the kern.maxfilesperproc value
		let mut mib: [libc::c_int; 2] = [CTL_KERN, KERN_MAXFILESPERPROC];
		let mut maxfiles: libc::c_int = 0;
		let mut size: libc::size_t = size_of_val(&maxfiles) as libc::size_t;
		if libc::sysctl(&mut mib[0], 2, &mut maxfiles as *mut _ as *mut _, &mut size,
				  null_mut(), 0) != 0 {
			let err = io::Error::last_os_error();
			panic!("raise_fd_limit: error calling sysctl: {}", err);
		}

		// Fetch the current resource limits
		let mut rlim = libc::rlimit{rlim_cur: 0, rlim_max: 0};
		if libc::getrlimit(libc::RLIMIT_NOFILE, &mut rlim) != 0 {
			let err = io::Error::last_os_error();
			panic!("raise_fd_limit: error calling getrlimit: {}", err);
		}

		// Bump the soft limit to the smaller of kern.maxfilesperproc and the hard
		// limit
		rlim.rlim_cur = cmp::min(maxfiles as libc::rlim_t, rlim.rlim_max);

		// Set our newly-increased resource limit
		if libc::setrlimit(libc::RLIMIT_NOFILE, &rlim) != 0 {
			let err = io::Error::last_os_error();
			panic!("raise_fd_limit: error calling setrlimit: {}", err);
		}
	}
}

#[cfg(any(target_os = "linux"))]
#[allow(non_camel_case_types)]
pub fn raise_fd_limit() {
	use libc;
	use std::io;

	unsafe {
		// Fetch the current resource limits
		let mut rlim = libc::rlimit{rlim_cur: 0, rlim_max: 0};
		if libc::getrlimit(libc::RLIMIT_NOFILE, &mut rlim) != 0 {
			let err = io::Error::last_os_error();
			panic!("raise_fd_limit: error calling getrlimit: {}", err);
		}

		// Set soft limit to hard imit
		rlim.rlim_cur = rlim.rlim_max;

		// Set our newly-increased resource limit
		if libc::setrlimit(libc::RLIMIT_NOFILE, &rlim) != 0 {
			let err = io::Error::last_os_error();
			panic!("raise_fd_limit: error calling setrlimit: {}", err);
		}
	}
}

#[cfg(not(any(target_os = "macos", target_os = "ios", target_os = "linux")))]
pub fn raise_fd_limit() {}
