// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
// +build linux netbsd openbsd solaris
package fdlimit
import "syscall"
// Raise tries to maximize the file descriptor allowance of this process
// to the maximum hard-limit allowed by the OS.
// Returns the size it was set to (may differ from the desired 'max')
func Raise(max uint64) (uint64, error) {
// Get the current limit
var limit syscall.Rlimit
if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
return 0, err
}
// Try to update the limit to the max allowance
limit.Cur = limit.Max
if limit.Cur > max {
limit.Cur = max
}
if err := syscall.Setrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
return 0, err
}
// MacOS can silently apply further caps, so retrieve the actually set limit
if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
return 0, err
}
return limit.Cur, nil
}
// Current retrieves the number of file descriptors allowed to be opened by this
// process.
func Current() (int, error) {
var limit syscall.Rlimit
if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
return 0, err
}
return int(limit.Cur), nil
}
// Maximum retrieves the maximum number of file descriptors this process is
// allowed to request for itself.
func Maximum() (int, error) {
var limit syscall.Rlimit
if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
return 0, err
}
return int(limit.Max), nil
}
