github.com/aigarnetwork/aigar@v0.0.0-20191115204914-d59a6eb70f8e/common/fdlimit/fdlimit_unix.go (about)

     1  //  Copyright 2018 The go-ethereum Authors
     2  //  Copyright 2019 The go-aigar Authors
     3  //  This file is part of the go-aigar library.
     4  //
     5  //  The go-aigar library is free software: you can redistribute it and/or modify
     6  //  it under the terms of the GNU Lesser General Public License as published by
     7  //  the Free Software Foundation, either version 3 of the License, or
     8  //  (at your option) any later version.
     9  //
    10  //  The go-aigar library is distributed in the hope that it will be useful,
    11  //  but WITHOUT ANY WARRANTY; without even the implied warranty of
    12  //  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    13  //  GNU Lesser General Public License for more details.
    14  //
    15  //  You should have received a copy of the GNU Lesser General Public License
    16  //  along with the go-aigar library. If not, see <http://www.gnu.org/licenses/>.
    17  
    18  // +build linux netbsd openbsd solaris
    19  
    20  package fdlimit
    21  
    22  import "syscall"
    23  
    24  // Raise tries to maximize the file descriptor allowance of this process
    25  // to the maximum hard-limit allowed by the OS.
    26  // Returns the size it was set to (may differ from the desired 'max')
    27  func Raise(max uint64) (uint64, error) {
    28  	// Get the current limit
    29  	var limit syscall.Rlimit
    30  	if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
    31  		return 0, err
    32  	}
    33  	// Try to update the limit to the max allowance
    34  	limit.Cur = limit.Max
    35  	if limit.Cur > max {
    36  		limit.Cur = max
    37  	}
    38  	if err := syscall.Setrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
    39  		return 0, err
    40  	}
    41  	// MacOS can silently apply further caps, so retrieve the actually set limit
    42  	if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
    43  		return 0, err
    44  	}
    45  	return limit.Cur, nil
    46  }
    47  
    48  // Current retrieves the number of file descriptors allowed to be opened by this
    49  // process.
    50  func Current() (int, error) {
    51  	var limit syscall.Rlimit
    52  	if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
    53  		return 0, err
    54  	}
    55  	return int(limit.Cur), nil
    56  }
    57  
    58  // Maximum retrieves the maximum number of file descriptors this process is
    59  // allowed to request for itself.
    60  func Maximum() (int, error) {
    61  	var limit syscall.Rlimit
    62  	if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
    63  		return 0, err
    64  	}
    65  	return int(limit.Max), nil
    66  }