62 lines
1.8 KiB
Go
62 lines
1.8 KiB
Go
// Copyright (C) 2015 The Syncthing Authors.
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//
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this file,
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// You can obtain one at https://mozilla.org/MPL/2.0/.
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//go:build !windows
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// +build !windows
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package osutil
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import (
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"runtime"
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"syscall"
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)
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const (
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darwinOpenMax = 10240
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)
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// MaximizeOpenFileLimit tries to set the resource limit RLIMIT_NOFILE (number
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// of open file descriptors) to the max (hard limit), if the current (soft
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// limit) is below the max. Returns the new (though possibly unchanged) limit,
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// or an error if it could not be changed.
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func MaximizeOpenFileLimit() (int, error) {
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// Get the current limit on number of open files.
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var lim syscall.Rlimit
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if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &lim); err != nil {
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return 0, err
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}
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// If we're already at max, there's no need to try to raise the limit.
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if lim.Cur >= lim.Max {
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return int(lim.Cur), nil
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}
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// macOS doesn't like a soft limit greater then OPEN_MAX
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// See also: man setrlimit
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if runtime.GOOS == "darwin" && lim.Max > darwinOpenMax {
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lim.Max = darwinOpenMax
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}
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// Try to increase the limit to the max.
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oldLimit := lim.Cur
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lim.Cur = lim.Max
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if err := syscall.Setrlimit(syscall.RLIMIT_NOFILE, &lim); err != nil {
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return int(oldLimit), err
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}
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// If the set succeeded, perform a new get to see what happened. We might
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// have gotten a value lower than the one in lim.Max, if lim.Max was
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// something that indicated "unlimited" (i.e. intmax).
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if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &lim); err != nil {
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// We don't really know the correct value here since Getrlimit
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// mysteriously failed after working once... Shouldn't ever happen, I
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// think.
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return 0, err
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}
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return int(lim.Cur), nil
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}
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