chen08209
db6f5d9036
Changelog: Rebuilt the core, provider, and application layers Changelog-Type: feat
75 lines
1.4 KiB
Go
75 lines
1.4 KiB
Go
//go:build android && cgo
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package platform
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import (
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"sync/atomic"
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"syscall"
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"time"
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"github.com/metacubex/mihomo/log"
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)
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const fdPressureWindow = 10 * time.Millisecond
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var nullFd = -1
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var maxFdCount int
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var (
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lastProbeAt atomic.Int64
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lastProbeBlocked atomic.Bool
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)
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func init() {
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// This runs while the shared library is being loaded, so a panic here takes
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// the application down before it has a chance to report anything. The probe
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// is a safety valve against fd exhaustion rather than something correctness
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// depends on, so a failure to arm it degrades to never blocking.
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fd, err := syscall.Open("/dev/null", syscall.O_WRONLY, 0644)
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if err != nil {
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log.Errorln("[APP] fd pressure probe disabled: %v", err)
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return
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}
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nullFd = fd
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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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maxFdCount = 1024
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} else {
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maxFdCount = int(limit.Cur)
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}
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maxFdCount = maxFdCount / 4 * 3
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}
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func ShouldBlockConnection() bool {
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if nullFd < 0 {
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return false
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}
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now := time.Now().UnixNano()
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if !lastProbeBlocked.Load() {
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if last := lastProbeAt.Load(); last != 0 && now-last < int64(fdPressureWindow) {
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return false
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}
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}
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blocked := probeFdPressure()
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lastProbeBlocked.Store(blocked)
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lastProbeAt.Store(now)
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return blocked
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}
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func probeFdPressure() bool {
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fd, err := syscall.Dup(nullFd)
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if err != nil {
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return true
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}
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_ = syscall.Close(fd)
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return fd > maxFdCount
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}
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