// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.

//go:build !windows

package startcbinary

import (
	"github.com/vespa-engine/vespa/client/go/trace"
	"golang.org/x/sys/unix"
	"os"
)

type ResourceId int

const (
	RLIMIT_CORE   ResourceId = unix.RLIMIT_AS
	RLIMIT_NOFILE ResourceId = unix.RLIMIT_NOFILE
	RLIMIT_NPROC  ResourceId = unix.RLIMIT_NPROC
	NO_RLIMIT     uint64     = ^uint64(0)
)

func (rid ResourceId) String() string {
	switch rid {
	case RLIMIT_CORE:
		return "core file size"
	case RLIMIT_NOFILE:
		return "open files"
	case RLIMIT_NPROC:
		return "max user processes"
	}
	return "unknown resource id"
}

func setResourceLimit(resource ResourceId, newVal uint64) {
	var current unix.Rlimit
	err := unix.Getrlimit(int(resource), &current)
	if err != nil {
		trace.Warning("Could not get current resource limit:", err)
		return
	}
	wanted := current
	if current.Max < newVal {
		if os.Getuid() == 0 {
			wanted.Max = newVal
		} else {
			newVal = current.Max
		}
	}
	if current.Cur < newVal {
		wanted.Cur = newVal
	}
	err = unix.Setrlimit(int(resource), &wanted)
	if err != nil {
		trace.Trace("Failed setting resource limit:", err)
	} else {
		trace.Trace("Resource limit", resource, "adjusted OK:", wanted.Cur, "/", wanted.Max)
	}
}