Safety Not Guaranteed: Calling Windows APIs using Unsafe & Syscall
summary
Shows how to call Windows APIs from Go without cgo by using syscall and unsafe, golang.org/x/sys/windows and the make_windows_syscall generator, with concrete examples like CreateJobObject / GetExtendedTcpTable and CredEnumerate. Explains mapping C types to Go, utf16 string conversions, the rule about keeping unsafe-to-uintptr conversions inside the syscall argument list, handling three levels of indirection for pointer arrays, a buffer-resize loop for variable-sized results, and builds working netstat and credential-enumeration tools (repo linked).
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chapters (27)
- 0:00Intro
- 2:06Windows Containers 2016
- 4:16No Syscalls on Windows
- 7:22Pointer Arithmetic
- 8:14Pointer Rules
- 9:04Bad Pointers
- 11:07Finding DLL and Call Signatures
- 14:12Loading a DLL Procedure
- 14:41Calling Windows APIs Mapping C Types
- 16:27Primitive C-Type mappings
- 17:19Mapping Parameters
- 17:37Go string to string
- 19:46Struct Types
- 22:37Inspecting Return Value
- 23:15CreateJobObject
- 23:45Locking memory down during syscall
- 25:18mkwinsyscall - source
- 28:19Memory Management
- 32:24Example: Designing For Unmanged Memory - Free
- 33:46Example: Designing For Unmanged Memory- Iterating
- 35:21Improvement - Copy & Free
- 35:54Example: Copy & Free Design - Cred Enumerate
- 36:48Example: Copy & Free Design - Credential/Attribute
- 37:28Managed Memory: Generic Example
- 39:29Example: GetExtendedTcp Table - Syscall Loop
- 42:43Example: GetExtendedTcp Table - Table to Rows
- 43:52Full Code Available
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