From ec601d947f0a3e56b7f6af9acb2a9bdde603ea86 Mon Sep 17 00:00:00 2001
From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Tue, 5 Nov 2019 17:54:11 +0100
Subject: [PATCH] installer: use locale-independent way to create Cygwin
 symlinks

Since https://github.com/git-for-windows/build-extra/pull/255, we create
the `/dev/{fd,stdin,stdout,stderr}` symlinks in the installer
explicitly, without relying on Git Bash's initial `post-install`
scripts.

However, the method chosen to create those (Cygwin-style) symlinks seems
to work only in US locales.

Let's jump through another hoop and make sure that it works also in
non-US locales.

The approach implemented in this patch was inspired by
https://stackoverflow.com/questions/38617829/writing-binary-file-in-inno-setup

This fixes https://github.com/git-for-windows/git/issues/2388

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 installer/install.iss | 34 ++++++++++++++++++++++++++++++----
 1 file changed, 30 insertions(+), 4 deletions(-)

diff --git a/installer/install.iss b/installer/install.iss
index e86df630ff..b68bf7bb7d 100644
--- a/installer/install.iss
+++ b/installer/install.iss
@@ -2368,10 +2368,25 @@ function GetFileAttributes(Path:PAnsiChar):DWORD;
 function SetFileAttributes(Path:PAnsiChar;dwFileAttributes:DWORD):BOOL;
 external 'SetFileAttributesA@kernel32.dll stdcall';
 
+function CryptStringToBinary(sz:string;cch:LongWord;flags:LongWord;binary:string;var size:LongWord;skip:LongWord;flagsused:LongWord):Integer;
+external 'CryptStringToBinaryW@crypt32.dll stdcall';
+
+const
+  CRYPT_STRING_HEX = $04;
+  HEX_CHARS = '0123456789abcdef';
+
+function CharToHex(C:Integer):string;
+begin
+    Result:=HEX_CHARS[((C div 16) and 15)+1]+HEX_CHARS[(C and 15)+1];
+end;
+
 function CreateCygwinSymlink(SymlinkPath,TargetPath:String):Boolean;
 var
     Attribute:DWord;
     i:Integer;
+    Hex,Buffer:string;
+    Stream:TStream;
+    Size:LongWord;
 begin
     Result:=True;
 
@@ -2379,13 +2394,24 @@ begin
     for i:=Length(TargetPath) downto 1 do
         TargetPath:=Copy(TargetPath,1,i)+#0+Copy(TargetPath,i+1,Length(TargetPath)-i);
 
-    // insert `!<symlink>\xff\xfe` prefix, and append `\0\0`
-    TargetPath:='!<symlink>'+#255+#254+TargetPath+#0+#0;
+    Hex:='213c73796d6c696e6b3efffe'; // "!<symlink>\xff\xfe"
+    for i:=1 to Length(TargetPath) do
+        Hex:=Hex+CharToHex(Ord(TargetPath[i])); // append wide characters as hex
+    Hex:=Hex+'0000'; // append a wide NUL
 
     // write the file
-    if not SaveStringToFile(SymlinkPath,TargetPath,False) then begin
-        LogError('Could not write "'+SymlinkPath+'"');
+    Stream:=TFileStream.Create(SymlinkPath,fmCreate);
+    try
+        Size:=Length(Hex) div 2;
+        SetLength(Buffer,Size);
+        if (CryptStringToBinary(Hex,Length(Hex),CRYPT_STRING_HEX,Buffer,Size,0,0)=0) or (Size<>Length(Hex) div 2) then
+            RaiseException('could not decode hex '+Hex);
+        Stream.WriteBuffer(Buffer,Size);
+    except
+        LogError('Could not write "'+SymlinkPath+'" '+GetExceptionMessage());
         Result:=False;
+    finally
+        Stream.Free
     end;
 
     // Set system bit (required for Cygwin to interpret this as a symlink)