GeezerVison

🏁 Script executed:

cd crates/vm/src/stdlib && wc -l msvcrt.rs

Repository: RustPython/RustPython

Length of output: 78

🏁 Script executed:

cd crates/vm/src/stdlib && sed -n '30,45p' msvcrt.rs

Repository: RustPython/RustPython

Length of output: 535

🏁 Script executed:

cd crates/vm/src/stdlib && sed -n '120,140p' msvcrt.rs

Repository: RustPython/RustPython

Length of output: 595

🌐 Web query:

Windows CRT _locking function signature nbytes parameter type int long

💡 Result:

In the Microsoft C Runtime (CRT), _locking has this signature:

int _locking(int fd, int mode, long nbytes);

So the nbytes parameter type is long (signed long), not int. [1]

Source: Microsoft Learn _locking documentation. [1]

[1] (learn.microsoft.com)

Citations:

• 1: https://learn.microsoft.com/en-us/previous-versions/8054ew2f%28v%3Dvs.140%29?utm_source=openai

🌐 Web query:

_locking vs _locking64 Windows C runtime function difference

💡 Result:

• _locking is the (documented) MSVC C runtime function that locks/unlocks a byte range starting at the current file pointer for nbytes bytes, where nbytes is a 32-bit long:
  int _locking(int fd, int mode, long nbytes); This means the length you can request in a single call is limited by 32-bit long range (and long stays 32-bit even on 64-bit Windows). [1]

• _locking64 is not a standard/documented MSVC CRT API (at least not in the classic msvcrt.dll export surface): msvcrt.dll exports _locking but does not list an _locking64 export. [2] A separate MSVCRT export-definition listing likewise shows _locking but not _locking64. [3]

What to use instead (for “64-bit”/large-range locks): use the Win32 file-locking APIs (LockFile / LockFileEx), which support 64-bit ranges via low/high parts. [4]

Sources:
[1] Microsoft Learn: _locking signature/behavior https://learn.microsoft.com/en-us/previous-versions/8054ew2f(v=vs.140)
[2] msvcrt.dll exported functions list (shows _locking, no _locking64) https://strontic.github.io/xcyclopedia/library/msvcrt.dll-6297CA08C873060692FF97074895FA95.html
[3] MSVCRT export .def listing (shows _locking, no _locking64) https://www-user.tu-chemnitz.de/~heha/viewzip.php/hs/msvcrt-light.zip/src/msvcrt.winxp-x64.def?as=DEF
[4] Microsoft Learn: byte-range locking overview (LockFile / LockFileEx) https://learn.microsoft.com/en-us/windows/win32/fileio/locking-and-unlocking-byte-ranges-in-files

🌐 Web query:

CPython _winapi CreateFile security_attributes template_file implementation

💡 Result:

In CPython, _winapi.CreateFile is a very thin wrapper over the Win32 CreateFile API:

• Signature in Modules/_winapi.c (shown here from CPython v3.9.7) is:

  _winapi.CreateFile(file_name, desired_access, share_mode,
                    security_attributes, creation_disposition,
                    flags_and_attributes, template_file) -> HANDLE
  

  and the implementation just calls CreateFile(file_name, ..., security_attributes, ..., template_file) (wrapped in Py_BEGIN_ALLOW_THREADS) and raises OSError on INVALID_HANDLE_VALUE. (chromium.googlesource.com)

• security_attributes is declared as LPSECURITY_ATTRIBUTES, but Argument Clinic defines LPSECURITY_ATTRIBUTES as a raw pointer-sized integer (“k” on 32-bit, “K” on 64-bit) (i.e., an address), not a Python object representing a SECURITY_ATTRIBUTES struct. (chromium.googlesource.com)
  Practically: pass 0 to mean NULL (no security attrs / non-inheritable handle by default), or pass an integer address to a valid SECURITY_ATTRIBUTES struct you created elsewhere in native code.

• template_file is a HANDLE (also passed straight through). Pass 0/NULL for “no template file”. (chromium.googlesource.com)

For the Win32 meaning of these two parameters:

• lpSecurityAttributes can be NULL; it controls the optional security descriptor and whether the returned handle is inheritable. (learn.microsoft.com)
• hTemplateFile can be NULL; it supplies attributes/extended attributes for a newly created file and is ignored when opening an existing file. (learn.microsoft.com)

Citations:

• 1: https://chromium.googlesource.com/external/github.com/python/cpython/%2B/refs/tags/v3.9.7/Modules/_winapi.c
• 2: https://chromium.googlesource.com/external/github.com/python/cpython/%2B/refs/tags/v3.9.7/Modules/_winapi.c
• 3: https://chromium.googlesource.com/external/github.com/python/cpython/%2B/refs/tags/v3.9.7/Modules/_winapi.c
• 4: https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilea?utm_source=openai
• 5: https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilea?utm_source=openai

🌐 Web query:

Windows API CreateFileW security_attributes template_file parameter significance

💡 Result:

lpSecurityAttributes (4th parameter)

Controls (a) the new object’s security and (b) whether the returned handle is inheritable:

• Points to a SECURITY_ATTRIBUTES containing:
  • lpSecurityDescriptor: security descriptor used only when a new file/object is created; ignored when opening an existing file, but…
  • bInheritHandle: still controls whether the returned handle can be inherited by child processes. (learn.microsoft.com)
• If lpSecurityAttributes == NULL:
  • the handle is not inheritable
  • a newly created file gets a default security descriptor (ACLs typically inherited from the parent directory). (learn.microsoft.com)

hTemplateFile (7th parameter)

Provides attributes/extended attributes to copy when creating a new file:

• A handle to an existing template file (must be open with GENERIC_READ) whose file attributes and extended attributes are applied to the new file. (learn.microsoft.com)
• Ignored when opening an existing file. (learn.microsoft.com)
• When creating, if a template is supplied, its extended attributes are copied and can override FILE_ATTRIBUTE_* choices you passed in dwFlagsAndAttributes. (learn.microsoft.com)

Citations:

• 1: https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilew?utm_source=openai
• 2: https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilew?utm_source=openai
• 3: https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilew?utm_source=openai
• 4: https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilew?utm_source=openai
• 5: https://learn.microsoft.com/en-us/windows/win32/fileio/creating-and-opening-files?utm_source=openai

🏁 Script executed:

# Check if there are any tests or other code in the repository that might use CreateFile with these parameters
fd -t f "\.rs$" | xargs rg -l "CreateFile" | head -20

Repository: RustPython/RustPython

Length of output: 147

🏁 Script executed:

# Check if there are any test files or usage examples for CreateFile
rg -t rs "CreateFile" crates/vm/src --context 5

# Also check if there are tests specifically for this function
fd -t f "test.*\.rs|.*_test\.rs" | xargs rg -l "CreateFile" 2>/dev/null || echo "No test files found with CreateFile"

Repository: RustPython/RustPython

Length of output: 144

🏁 Script executed:

# Check the implementation context to understand how other similar parameters are handled
cat -n crates/vm/src/stdlib/winapi.rs | head -200

Repository: RustPython/RustPython

Length of output: 8794

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