From b9a1d67637cfae6206fffce78fc2e40780ef4fb5 Mon Sep 17 00:00:00 2001
From: LemonBoy <thatlemon@gmail.com>
Date: Fri, 6 Mar 2020 00:02:45 +0100
Subject: [PATCH] std: Nicer way to access the PEB

Use the NtCurrentTeb API instead of using some inline asm, this is much
nicer and also more portable.

Closes #4645
---
 lib/std/os/windows.zig       | 17 +----------------
 lib/std/os/windows/bits.zig  | 13 +++++++++++++
 lib/std/os/windows/ntdll.zig |  1 +
 3 files changed, 15 insertions(+), 16 deletions(-)

diff --git a/lib/std/os/windows.zig b/lib/std/os/windows.zig
index b8e14a220dbba57e0d4cef4352528cee4fe75b96..14e7b2b04cbfe2f8f534f5df737ef6734c86b25b 100644
--- a/lib/std/os/windows.zig
+++ b/lib/std/os/windows.zig
@@ -1084,22 +1084,7 @@ pub fn SetFileTime(
 }
 
 pub fn peb() *PEB {
-    switch (builtin.arch) {
-        .i386 => {
-            return asm (
-                \\ mov %%fs:0x18, %[ptr]
-                \\ mov %%ds:0x30(%[ptr]), %[ptr]
-                : [ptr] "=r" (-> *PEB)
-            );
-        },
-        .x86_64 => {
-            return asm (
-                \\ mov %%gs:0x60, %[ptr]
-                : [ptr] "=r" (-> *PEB)
-            );
-        },
-        else => @compileError("unsupported architecture"),
-    }
+    return ntdll.NtCurrentTeb().ProcessEnvironmentBlock;
 }
 
 /// A file time is a 64-bit value that represents the number of 100-nanosecond
diff --git a/lib/std/os/windows/bits.zig b/lib/std/os/windows/bits.zig
index f9ba6cf40e0e694c8eadf975ffcb410c54c8b703..41466234ed00c5e1c6966118b15d167bf8c540ea 100644
--- a/lib/std/os/windows/bits.zig
+++ b/lib/std/os/windows/bits.zig
@@ -1154,6 +1154,19 @@ const RTL_BITMAP = @OpaqueType();
 pub const PRTL_BITMAP = *RTL_BITMAP;
 const KAFFINITY = usize;
 
+pub const TEB = extern struct {
+    Reserved1: [12]PVOID,
+    ProcessEnvironmentBlock: *PEB,
+    Reserved2: [399]PVOID,
+    Reserved3: [1952]u8,
+    TlsSlots: [64]PVOID,
+    Reserved4: [8]u8,
+    Reserved5: [26]PVOID,
+    ReservedForOle: PVOID,
+    Reserved6: [4]PVOID,
+    TlsExpansionSlots: PVOID,
+};
+
 /// Process Environment Block
 /// Microsoft documentation of this is incomplete, the fields here are taken from various resources including:
 ///  - https://github.com/wine-mirror/wine/blob/1aff1e6a370ee8c0213a0fd4b220d121da8527aa/include/winternl.h#L269
diff --git a/lib/std/os/windows/ntdll.zig b/lib/std/os/windows/ntdll.zig
index 49e60803bc74138173acb09820d962e9c03e4b4a..76a11a19c1418c9f4d82c249e810acff0048dfc2 100644
--- a/lib/std/os/windows/ntdll.zig
+++ b/lib/std/os/windows/ntdll.zig
@@ -16,6 +16,7 @@ pub extern "NtDll" fn NtQueryInformationFile(
     Length: ULONG,
     FileInformationClass: FILE_INFORMATION_CLASS,
 ) callconv(.Stdcall) NTSTATUS;
+pub extern "NtDll" fn NtCurrentTeb() callconv(.Stdcall) *TEB;
 
 pub extern "NtDll" fn NtQueryAttributesFile(
     ObjectAttributes: *OBJECT_ATTRIBUTES,
-- 
2.54.0