github.com/SmartMeshFoundation/Spectrum@v0.0.0-20220621030607-452a266fee1e/cmd/utils/fdlimit_unix.go (about)

     1  // Copyright 2016 The Spectrum Authors
     2  // This file is part of Spectrum.
     3  //
     4  // Spectrum is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // Spectrum is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU General Public License
    15  // along with Spectrum. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  // +build linux darwin netbsd openbsd solaris
    18  
    19  package utils
    20  
    21  import "syscall"
    22  
    23  // raiseFdLimit tries to maximize the file descriptor allowance of this process
    24  // to the maximum hard-limit allowed by the OS.
    25  func raiseFdLimit(max uint64) error {
    26  	// Get the current limit
    27  	var limit syscall.Rlimit
    28  	if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
    29  		return err
    30  	}
    31  	// Try to update the limit to the max allowance
    32  	limit.Cur = limit.Max
    33  	if limit.Cur > max {
    34  		limit.Cur = max
    35  	}
    36  	if err := syscall.Setrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
    37  		return err
    38  	}
    39  	return nil
    40  }
    41  
    42  // getFdLimit retrieves the number of file descriptors allowed to be opened by this
    43  // process.
    44  func getFdLimit() (int, error) {
    45  	var limit syscall.Rlimit
    46  	if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
    47  		return 0, err
    48  	}
    49  	return int(limit.Cur), nil
    50  }
    51  
    52  // getFdMaxLimit retrieves the maximum number of file descriptors this process is
    53  // allowed to request for itself.
    54  func getFdMaxLimit() (int, error) {
    55  	var limit syscall.Rlimit
    56  	if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
    57  		return 0, err
    58  	}
    59  	return int(limit.Max), nil
    60  }