72 lines
2.4 KiB
Go
72 lines
2.4 KiB
Go
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// Copyright 2019 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package fdlimit
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import "syscall"
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// hardlimit is the number of file descriptors allowed at max by the kernel.
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const hardlimit = 10240
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// Raise tries to maximize the file descriptor allowance of this process
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// to the maximum hard-limit allowed by the OS.
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// Returns the size it was set to (may differ from the desired 'max')
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func Raise(max uint64) (uint64, error) {
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// Get the current limit
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var limit syscall.Rlimit
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if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
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return 0, err
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}
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// Try to update the limit to the max allowance
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limit.Cur = limit.Max
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if limit.Cur > max {
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limit.Cur = max
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}
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if err := syscall.Setrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
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return 0, err
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}
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// MacOS can silently apply further caps, so retrieve the actually set limit
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if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
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return 0, err
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}
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return limit.Cur, nil
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}
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// Current retrieves the number of file descriptors allowed to be opened by this
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// process.
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func Current() (int, error) {
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var limit syscall.Rlimit
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if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
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return 0, err
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}
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return int(limit.Cur), nil
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}
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// Maximum retrieves the maximum number of file descriptors this process is
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// allowed to request for itself.
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func Maximum() (int, error) {
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// Retrieve the maximum allowed by dynamic OS limits
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var limit syscall.Rlimit
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if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
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return 0, err
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}
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// Cap it to OPEN_MAX (10240) because macos is a special snowflake
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if limit.Max > hardlimit {
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limit.Max = hardlimit
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}
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return int(limit.Max), nil
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}
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