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| 1 | +// Copyright 2019 The go-ethereum Authors |
| 2 | +// This file is part of the go-ethereum library. |
| 3 | +// |
| 4 | +// The go-ethereum 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-ethereum 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-ethereum 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 | +} |
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