From b570a4147dae9efd28b48cec5b0500f599a2a99e Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Thu, 21 Nov 2019 16:16:56 +0100 Subject: [PATCH] [release-branch.go1.13] runtime: do not use PowerRegisterSuspendResumeNotification on systems with "program time" timer Systems where PowerRegisterSuspendResumeNotification returns ERROR_ FILE_NOT_FOUND are also systems where nanotime() is on "program time" rather than "real time". The chain for this is: powrprof.dll!PowerRegisterSuspendResumeNotification -> umpdc.dll!PdcPortOpen -> ntdll.dll!ZwAlpcConnectPort("\\PdcPort") -> syscall -> ntoskrnl.exe!AlpcpConnectPort Opening \\.\PdcPort fails with STATUS_OBJECT_NAME_NOT_FOUND when pdc.sys hasn't been initialized. Pdc.sys also provides the various hooks for sleep resumption events, which means if it's not loaded, then our "real time" timer is actually on "program time". Finally STATUS_OBJECT_NAME_ NOT_FOUND is passed through RtlNtStatusToDosError, which returns ERROR_ FILE_NOT_FOUND. Therefore, in the case where the function returns ERROR_ FILE_NOT_FOUND, we don't mind, since the timer we're using will correspond fine with the lack of sleep resumption notifications. This applies, for example, to Docker users. Updates #35447 Updates #35482 Fixes #35746 Change-Id: I9e1ce5bbc54b9da55ff7a3918b5da28112647eee Reviewed-on: https://go-review.googlesource.com/c/go/+/211280 Run-TryBot: Jason A. Donenfeld TryBot-Result: Gobot Gobot Reviewed-by: Austin Clements Reviewed-by: Jason A. Donenfeld --- src/runtime/os_windows.go | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) diff --git a/src/runtime/os_windows.go b/src/runtime/os_windows.go index 1cd0932eae..6897933e30 100644 --- a/src/runtime/os_windows.go +++ b/src/runtime/os_windows.go @@ -262,7 +262,10 @@ func loadOptionalSyscalls() { } func monitorSuspendResume() { - const _DEVICE_NOTIFY_CALLBACK = 2 + const ( + _DEVICE_NOTIFY_CALLBACK = 2 + _ERROR_FILE_NOT_FOUND = 2 + ) type _DEVICE_NOTIFY_SUBSCRIBE_PARAMETERS struct { callback uintptr context uintptr @@ -288,10 +291,20 @@ func monitorSuspendResume() { callback: compileCallback(*efaceOf(&fn), true), } handle := uintptr(0) - if stdcall3(powerRegisterSuspendResumeNotification, _DEVICE_NOTIFY_CALLBACK, - uintptr(unsafe.Pointer(¶ms)), - uintptr(unsafe.Pointer(&handle))) != 0 { - throw("PowerRegisterSuspendResumeNotification failure") + ret := stdcall3(powerRegisterSuspendResumeNotification, _DEVICE_NOTIFY_CALLBACK, + uintptr(unsafe.Pointer(¶ms)), uintptr(unsafe.Pointer(&handle))) + // This function doesn't use GetLastError(), so we use the return value directly. + switch ret { + case 0: + return // Successful, nothing more to do. + case _ERROR_FILE_NOT_FOUND: + // Systems without access to the suspend/resume notifier + // also have their clock on "program time", and therefore + // don't want or need this anyway. + return + default: + println("runtime: PowerRegisterSuspendResumeNotification failed with errno=", ret) + throw("runtime: PowerRegisterSuspendResumeNotification failure") } } -- 2.48.1