github.com/core-coin/go-core/v2@v2.1.9/common/fdlimit/fdlimit_darwin.go (about)

     1  // Copyright 2016 by the Authors
     2  // This file is part of the go-core library.
     3  //
     4  // The go-core library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser 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  // The go-core library 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 Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-core library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package fdlimit
    18  
    19  import "syscall"
    20  
    21  // hardlimit is the number of file descriptors allowed at max by the kernel.
    22  const hardlimit = 10240
    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  	// Retrieve the maximum allowed by dynamic OS limits
    62  	var limit syscall.Rlimit
    63  	if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
    64  		return 0, err
    65  	}
    66  	// Cap it to OPEN_MAX (10240) because macos is a special snowflake
    67  	if limit.Max > hardlimit {
    68  		limit.Max = hardlimit
    69  	}
    70  	return int(limit.Max), nil
    71  }