Restrict Windows subprocess handle inheritance - #116
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sheredom
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Aug 14, 2026
| EXPECT_EQ_MSG(wait_timeout, wait_result, | ||
| "subprocess inherited a handle outside its standard streams"); | ||
| #else | ||
| UTEST_SKIP("Windows handle-inheritance test"); |
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Could you not just skip the entire test rather than use an explicit skip on linux/macos?
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* Declare the ProcThreadAttributeList APIs with pointer-width sizes #116 added declarations for InitializeProcThreadAttributeList and UpdateProcThreadAttribute using subprocess_size_t where the SDK has SIZE_T, PSIZE_T and DWORD_PTR. Those are ULONG_PTR, which is unsigned long on Win32 while subprocess_size_t is unsigned int there. Same width, distinct types, so the redeclaration itself is rejected before any call is reached: subprocess.h(461,1): error C2733: 'InitializeProcThreadAttributeList': you cannot overload a function with 'extern "C"' linkage subprocess.h(1157,3): error C2664: cannot convert argument 4 from 'subprocess_size_t *' to 'PSIZE_T' Win64 is unaffected because ULONG_PTR and subprocess_size_t agree there, which is why cmake.yml does not see it — it builds Windows x64 only. Added subprocess_ulongptr_t and used it for those parameters and for attribute_list_size. It sits outside the _MSC_VER < 1920 split, or newer MSVC would keep taking size_t from <inttypes.h> and stay broken. Reproduced with MSVC 19.44 and SDK 10.0.26100 before the change and verified after: -A Win32 goes from four errors to a clean build with both test binaries passing, -A x64 still passes, and Linux glibc is unchanged at 442/442 in both implementations. * Derive the pointer-width type instead of naming __int64 again clang-cl rejects the new typedef under -Weverything: subprocess.h(348,18): error : extension used [-Werror,-Wlanguage-extension-token] The identical typedef a few lines above does not trip it because it sits behind _MSC_VER < 1920, which clang-cl never compiles. Mine does not. On _WIN64 subprocess_size_t is already 64 bits wide and so matches ULONG_PTR, so reusing it avoids naming the extension token at all. Win32 keeps unsigned long, which is what SIZE_T is there. MSVC 19.44 builds and passes on both -A Win32 and -A x64. clang-cl is not installed here, which is why CI found this and the local run did not.
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Summary
STARTUPINFOEXandPROC_THREAD_ATTRIBUTE_HANDLE_LISTsubprocess_createcalls from inheriting each other's temporarily-inheritable pipe handlesThis is the Windows counterpart to the POSIX descriptor inheritance fix in #115, kept as a separate change.
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