AuroraMiddleware/winpty
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Add a test for what seems to be an obscure Windows XP bug.

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* The read end of a pipe is translated to NULL by the special
   bInheritHandles=FALSE, no-STARTF_USESTDHANDLES inheritance mode.  The
   write end of the pipe works fine.

 * Passing bInheritHandles=TRUE with an inheritable pipe handle fixes it.
   Adding STARTF_USESTDHANDLES to this also works.
This commit is contained in:
Ryan Prichard 2015-10-24 03:10:36 -05:00
parent 51e84a50d4
commit 9b4155eccc
2 changed files with 57 additions and 5 deletions
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47
misc/buffer-tests/HandleTests_Common.cc
View File

@ -397,18 +397,19 @@ static void Test_CreateProcess_SpecialInherit() {
// Base case: a non-inheritable pipe is still inherited.
Worker p;
auto pipe = newPipe(p, false);
auto rh = std::get<0>(pipe).setStdin();
auto wh = std::get<1>(pipe).setStdout().setStderr();
auto wh = std::get<1>(pipe).setStdin().setStdout().setStderr();
auto c = p.child({ false });
CHECK(ntHandlePointer(c.getStdin()) == ntHandlePointer(rh));
CHECK(ntHandlePointer(c.getStdin()) == ntHandlePointer(wh));
CHECK(ntHandlePointer(c.getStdout()) == ntHandlePointer(wh));
CHECK(ntHandlePointer(c.getStderr()) == ntHandlePointer(wh));
// CreateProcess makes separate handles for stdout/stderr.
// CreateProcess makes separate handles for stdin/stdout/stderr.
CHECK(c.getStdin().value() != c.getStdout().value());
CHECK(c.getStdout().value() != c.getStderr().value());
CHECK(c.getStdin().value() != c.getStderr().value());
// Calling FreeConsole in the child does not free the duplicated
// handles.
c.detach();
CHECK(ntHandlePointer(c.getStdin()) == ntHandlePointer(rh));
CHECK(ntHandlePointer(c.getStdin()) == ntHandlePointer(wh));
CHECK(ntHandlePointer(c.getStdout()) == ntHandlePointer(wh));
CHECK(ntHandlePointer(c.getStderr()) == ntHandlePointer(wh));
}
@ -472,6 +473,42 @@ static void Test_CreateProcess_SpecialInherit() {
CHECK(handleInts(stdHandles(c)) ==
(std::vector<uint64_t> { 0x0FFFFFFFull, 0, 3 }));
}
{
// Windows XP bug: special inheritance doesn't work with the read end
// of a pipe, even if it's inheritable. It works with the write end.
auto check = [](Worker &proc, Handle correct, bool expectBroken) {
CHECK((proc.getStdin().value() == nullptr) == expectBroken);
CHECK((proc.getStdout().value() == nullptr) == expectBroken);
CHECK((proc.getStderr().value() == nullptr) == expectBroken);
if (!expectBroken) {
CHECK(ntHandlePointer(proc.getStdin()) == ntHandlePointer(correct));
CHECK(ntHandlePointer(proc.getStdout()) == ntHandlePointer(correct));
CHECK(ntHandlePointer(proc.getStderr()) == ntHandlePointer(correct));
}
};
Worker p;
auto pipe = newPipe(p, false);
auto rh = std::get<0>(pipe).setStdin().setStdout().setStderr();
auto c1 = p.child({ false });
check(c1, rh, !isAtLeastVista());
// Marking the handle itself inheritable makes no difference.
rh.setInheritable(true);
auto c2 = p.child({ false });
check(c2, rh, !isAtLeastVista());
// If we enter bInheritHandles=TRUE mode, it works.
auto c3 = p.child({ true });
check(c3, rh, false);
// Using STARTF_USESTDHANDLES works too.
Handle::invent(nullptr, p).setStdin().setStdout().setStderr();
auto c4 = p.child({ true, 0, { rh, rh, rh }});
check(c4, rh, false);
}
}

15
misc/console-handles.md
View File

@ -345,6 +345,21 @@ Here's what's evident from examining the OS behavior:
`GetConsoleWindow` and `IsWindowVisible` calls. `GetConsoleWindow` returns
`NULL` starting with Windows 7.
### Windows XP pipe read handle inheritance anomaly
On Windows XP, `CreateProcess` fails to propagate a handle in this situation:
- `bInheritHandles` is `FALSE`.
- `STARTF_USESTDHANDLES` is not specified in `STARTUPINFO.dwFlags`.
- One of the `STDIN/STDOUT/STDERR` handles is set to the read end of an
anonymous pipe.
In this situation, Windows XP will set the child process's standard handle to
`NULL`. The write end of the pipe works fine. Passing a `bInheritHandles`
of `TRUE` (and an inheritable pipe handle) works fine. Using
`STARTF_USESTDHANDLES` also works. See `Test_CreateProcess_SpecialInherit`
in `misc/buffer-tests` for a test case.
### Windows Vista BSOD
It is easy to cause a BSOD on Vista and Server 2008 by (1) closing all handles