path: root/common/fdlimit/fdlimit_unix.go

// Copyright 2016 The go-ethereum Authors
// This file is part of go-ethereum.
//
// go-ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// go-ethereum 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.

// +build linux darwin 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.
func Raise(max uint64) error {
    // Get the current limit
    var limit syscall.Rlimit
    if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
        return 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 err
    }
    return 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
}