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x/sys/windows: FormatMessage can't accept a DLL handle on 64-bit systems #11147

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actgardner opened this issue Jun 10, 2015 · 8 comments
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x/sys/windows: FormatMessage can't accept a DLL handle on 64-bit systems #11147

actgardner opened this issue Jun 10, 2015 · 8 comments

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@actgardner
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@actgardner actgardner commented Jun 10, 2015

  1. What version of Go are you using (go version)?
    go1.3.3 windows/amd64
  2. What operating system and processor architecture are you using?
    Windows x86-64
  3. What did you do?
    Try to call syscall.FormatMessage with a DLL handle.
var flags uint32 = syscall.FORMAT_MESSAGE_ARGUMENT_ARRAY | syscall.FORMAT_MESSAGE_IGNORE_INSERTS | syscall.FORMAT_MESSAGE_FROM_HMODULE
libpdhDll := syscall.MustLoadDLL("pdh.dll")
buffer := make([]uint16, 300)

// Have to cast Handle, which is a uintptr, to a uint32 due to the signature of FormatMessage
syscall.FormatMessage(flags, uint32(libpdhDll.Handle), <some error number>, 0, buffer, nil)
  1. What did you expect to see?
    FormatMessage should accept a syscall.Handle or a uintptr so the cast to uint32 doesn't have to happen.

5.What did you see instead?
FormatMessage returns an error because the truncated pointer doesn't point to a DLL.

@bradfitz
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@bradfitz bradfitz commented Jun 10, 2015

Go 1.3.3 is old and unsupported. Please try with Go 1.4.2 or ideally Go tip and report back.

@actgardner
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@actgardner actgardner commented Jun 10, 2015

The same issue clearly exists in master: https://github.com/golang/sys/blob/master/windows/zsyscall_windows.go#L476

func FormatMessage(flags uint32, msgsrc uint32, msgid uint32, langid uint32, buf []uint16, args *byte) (n uint32, err error) {

edit: To be clear, the issue is just that msgsrc does an insane roundtrip from uintptr to uint32 back to uintptr, which doesn't make sense on 64-bit.

@minux minux changed the title syscall/FormatMessage can't accept a DLL handle on 64-bit systems x/sys/windows: FormatMessage can't accept a DLL handle on 64-bit systems Jun 10, 2015
@minux minux added this to the Unreleased milestone Jun 10, 2015
@minux
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@minux minux commented Jun 10, 2015

The syscall package is frozen, but we can fix the problem in
x/sys/windows sub-repo instead.

@alexbrainman
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@alexbrainman alexbrainman commented Jun 11, 2015

My mistake. I am 386 person.

Any suggestion on what to do about syscall.FormatMessage are welcome. I cannot see what we could do besides documenting the bug.

Alex

@alexbrainman
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@alexbrainman alexbrainman commented Jun 17, 2015

@alanctgardner here https://go-review.googlesource.com/11165 is the change. Will that work for you?

Alex

@actgardner
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@actgardner actgardner commented Jun 17, 2015

Looks good @alexbrainman, thanks for the fix!

@gopherbot
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@gopherbot gopherbot commented Jun 17, 2015

CL https://golang.org/cl/11165 mentions this issue.

@gopherbot
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@gopherbot gopherbot commented Jul 13, 2015

CL https://golang.org/cl/12067 mentions this issue.

gopherbot pushed a commit to golang/sys that referenced this issue Jul 21, 2015
Second FormatMessage parameter lpSource is uintptr not uint32.

Update golang/go#11147.

Change-Id: Icaa67abaed93efdad41564b21f8e511e8f9694b1
Reviewed-on: https://go-review.googlesource.com/11165
Reviewed-by: Yasuhiro MATSUMOTO <mattn.jp@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
@golang golang locked and limited conversation to collaborators Jul 20, 2016
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