From b0423a260ccea427da5e6da85e5fd5df837e6ae7 Mon Sep 17 00:00:00 2001
From: Dominik Gschwind <dominik.gschwind99@gmail.com>
Date: Wed, 10 Aug 2022 16:27:14 +0200
Subject: [PATCH 1/2] Copy files instead of hard-linking on Windows

Fixes an issue on Windows where when source and build directory are on different drives hard-linking
to files or directory fails as it doesn't work across filesystem boundaries. Note that symlinking is also
not possible because it requires administrator privileges on Windows.

The solution copies the files using the built-in cmake `configure_file(src dest COPYONLY)` command.
As this command only operates on files, if a directory is specified the files will be globbed recursively
and through symlinks.

Signed-off-by: Dominik Gschwind <dominik.gschwind99@gmail.com>
---
 CMakeLists.txt                          | 35 +++++++++++--------------
 ChangeLog.d/fix_hard_link_across_drives |  3 +++
 2 files changed, 18 insertions(+), 20 deletions(-)
 create mode 100644 ChangeLog.d/fix_hard_link_across_drives

diff --git a/CMakeLists.txt b/CMakeLists.txt
index e18f607be..755ac271e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -137,35 +137,30 @@ endif()
 
 # Create a symbolic link from ${base_name} in the binary directory
 # to the corresponding path in the source directory.
+# Note: Copies the file(s) on Windows.
 function(link_to_source base_name)
-    # Get OS dependent path to use in `execute_process`
-    if (CMAKE_HOST_WIN32)
-        #mklink is an internal command of cmd.exe it can only work with \
-        string(REPLACE "/" "\\" link "${CMAKE_CURRENT_BINARY_DIR}/${base_name}")
-        string(REPLACE "/" "\\" target "${CMAKE_CURRENT_SOURCE_DIR}/${base_name}")
-    else()
-        set(link "${CMAKE_CURRENT_BINARY_DIR}/${base_name}")
-        set(target "${CMAKE_CURRENT_SOURCE_DIR}/${base_name}")
-    endif()
+    set(link "${CMAKE_CURRENT_BINARY_DIR}/${base_name}")
+    set(target "${CMAKE_CURRENT_SOURCE_DIR}/${base_name}")
 
     if (NOT EXISTS ${link})
         if (CMAKE_HOST_UNIX)
-            set(command ln -s ${target} ${link})
+            execute_process(COMMAND ln -s ${target} ${link}
+                RESULT_VARIABLE result
+                ERROR_VARIABLE output)
+
+            if (NOT ${result} EQUAL 0)
+                message(FATAL_ERROR "Could not create symbolic link for: ${target} --> ${output}")
+            endif()
         else()
             if (IS_DIRECTORY ${target})
-                set(command cmd.exe /c mklink /j ${link} ${target})
+                file(GLOB_RECURSE files FOLLOW_SYMLINKS LIST_DIRECTORIES false RELATIVE ${target} "${target}/*")
+                foreach(file IN LISTS files)
+                    configure_file("${target}/${file}" "${link}/${file}" COPYONLY)
+                endforeach(file)
             else()
-                set(command cmd.exe /c mklink /h ${link} ${target})
+                configure_file(${target} ${link} COPYONLY)
             endif()
         endif()
-
-        execute_process(COMMAND ${command}
-            RESULT_VARIABLE result
-            ERROR_VARIABLE output)
-
-        if (NOT ${result} EQUAL 0)
-            message(FATAL_ERROR "Could not create symbolic link for: ${target} --> ${output}")
-        endif()
     endif()
 endfunction(link_to_source)
 
diff --git a/ChangeLog.d/fix_hard_link_across_drives b/ChangeLog.d/fix_hard_link_across_drives
new file mode 100644
index 000000000..0c55c3038
--- /dev/null
+++ b/ChangeLog.d/fix_hard_link_across_drives
@@ -0,0 +1,3 @@
+Bugfix
+   * Fix a build issue on Windows where the source and build directory could not be on
+     different drives (#5751).

From 29cf15dfbcd1091fd44bcc12ebd659866ac5de91 Mon Sep 17 00:00:00 2001
From: David Horstmann <david.horstmann@arm.com>
Date: Thu, 8 Dec 2022 12:12:37 +0100
Subject: [PATCH 2/2] Improve CMake backward compatibility

Use code with clear behavior in CMake 2.8.12 (which we try to support in
Mbed TLS 2.28, although that's mostly for the sake of RHEL, not Windows).
The code in the previous commit relied on features introduced in CMake 3.x,
although it worked as desired by accident because `LIST_DIRECTORIES false`
was effectively ignored and `configure_file` on a directory had no
harmful effect.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
Signed-off-by: David Horstmann <david.horstmann@arm.com>
---
 CMakeLists.txt | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 755ac271e..72cc737c6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -153,9 +153,11 @@ function(link_to_source base_name)
             endif()
         else()
             if (IS_DIRECTORY ${target})
-                file(GLOB_RECURSE files FOLLOW_SYMLINKS LIST_DIRECTORIES false RELATIVE ${target} "${target}/*")
+                file(GLOB_RECURSE files FOLLOW_SYMLINKS RELATIVE ${target} "${target}/*")
                 foreach(file IN LISTS files)
-                    configure_file("${target}/${file}" "${link}/${file}" COPYONLY)
+                    if(NOT IS_DIRECTORY "${target}/${file}")
+                        configure_file("${target}/${file}" "${link}/${file}" COPYONLY)
+                    endif()
                 endforeach(file)
             else()
                 configure_file(${target} ${link} COPYONLY)