github.com/aigarnetwork/aigar@v0.0.0-20191115204914-d59a6eb70f8e/common/fdlimit/fdlimit_darwin.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  package fdlimit
    19  
    20  import "syscall"
    21  
    22  // hardlimit is the number of file descriptors allowed at max by the kernel.
    23  const hardlimit = 10240
    24  
    25  // Raise tries to maximize the file descriptor allowance of this process
    26  // to the maximum hard-limit allowed by the OS.
    27  // Returns the size it was set to (may differ from the desired 'max')
    28  func Raise(max uint64) (uint64, error) {
    29  	// Get the current limit
    30  	var limit syscall.Rlimit
    31  	if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
    32  		return 0, err
    33  	}
    34  	// Try to update the limit to the max allowance
    35  	limit.Cur = limit.Max
    36  	if limit.Cur > max {
    37  		limit.Cur = max
    38  	}
    39  	if err := syscall.Setrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
    40  		return 0, err
    41  	}
    42  	// MacOS can silently apply further caps, so retrieve the actually set limit
    43  	if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
    44  		return 0, err
    45  	}
    46  	return limit.Cur, nil
    47  }
    48  
    49  // Current retrieves the number of file descriptors allowed to be opened by this
    50  // process.
    51  func Current() (int, error) {
    52  	var limit syscall.Rlimit
    53  	if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
    54  		return 0, err
    55  	}
    56  	return int(limit.Cur), nil
    57  }
    58  
    59  // Maximum retrieves the maximum number of file descriptors this process is
    60  // allowed to request for itself.
    61  func Maximum() (int, error) {
    62  	// Retrieve the maximum allowed by dynamic OS limits
    63  	var limit syscall.Rlimit
    64  	if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
    65  		return 0, err
    66  	}
    67  	// Cap it to OPEN_MAX (10240) because macos is a special snowflake
    68  	if limit.Max > hardlimit {
    69  		limit.Max = hardlimit
    70  	}
    71  	return int(limit.Max), nil
    72  }