Make Windows QEMU Guest Agent Support UTF-8

make-windows-qemu-guest-agent-support-utf-8.md

0. References

   a. QEMU Guest Agent for Windows Build Environment

   b. GB2312, BIG5, UTF8, Unicode之间的互换

   c. WideCharToMultiByte function

1. Build Enviroment (Please refer to 0.a)

   a. Build a vm with minimal installation of latest stable Fedora (Thrity 30).

   b. Install Ruby.

   sudo yum install ruby

   c. Install Docker.

   cd /tmp/
   curl -fsSL https://get.docker.com -o get-docker.sh
   sudo sh get-docker.sh 
   sudo systemctl enable docker.service
   sudo gpasswd -a <username> docker
   sudo systemctl start docker.service
   

   d. Install rebuild.

   sudo yum install ruby-devel
   sudo dnf groupinstall development-tools rpm-development-tools c-development
   gem install rake
   gem install rbld
   

   e. Setting up the environment.

   rbld create --base fedora qemu-ga-win
   rbld modify qemu-ga-win:initial
   <In the docker>
   sudo dnf update -y
   sudo dnf install -y git glib2-devel libfdt-devel pixman-devel zlib-devel \
   python gcc findutils make msitools \
   mingw*-glib2 mingw*-pixman* mingw*-gmp mingw*-SDL2 mingw*-pkg-config \
   mingw*-glib2-static mingw*-zlib-static \
   mingw*-winpthreads-static mingw*-pcre-static \
   flex bison
   <Ctrl-D to exit>
   rbld commit qemu-ga-win:initial --tag <tagname>
   rbld rm qemu-ga-win:initial
   

2. Modify the source code of qemu-ga (Please refer 0.b and 0.c)

   a. Into the build docker and download the source code of qemu.

   rbld run qemu-ga-win:<tagname>
   git clone https://github.com/qemu/qemu.git
   cd qemu
   curl -o VSS_SDK_7.2_setup.exe https://download.microsoft.com/download/9/4/c/94c588cf-8176-4bdb-9d55-2597c76043c6/setup.exe
   scripts/extract-vsssdk-headers  VSS_SDK_7.2_setup.exe
   

   b. Modify qemu/qga/commands-win32.c static char *guest_wctomb_dup(WCHAR *wstr)

   static char *guest_wctomb_dup(WCHAR *wstr)
   {
       char *str = NULL;
       size_t i;
   
       i = WideCharToMultiByte(CP_UTF8, 0, wstr, -1, NULL, 0, NULL, NULL);
       //i = wcslen(wstr) + 1;
       str = g_malloc(i+1);
       //WideCharToMultiByte(CP_ACP, WC_COMPOSITECHECK,
       //                    wstr, -1, str, i, NULL, NULL);
   
       WideCharToMultiByte(CP_UTF8, 0, wstr, -1, str, i, NULL, NULL);
       return str;
   }

   (Use WideCharToMultiByte() twice.)

   c. Build qemu-ga and send to the target windows vms.

   ./configure --disable-docs --target-list=x86_64-softmmu --cross-prefix=x86_64-w64-mingw32- --static --enable-guest-agent-msi --with-vss-sdk
   make qemu-ga
   <this is the 64-bits build, send the built msi file to the target windows vms> 
   make clean
   ./configure --disable-docs --target-list=x86_64-softmmu --cross-prefix=i686-w64-mingw32- --static --enable-guest-agent-msi --with-vss-sdk
   make qemu-ga
   <this is the 32-bits build, send the built msi file to the target windows vms> 
   
   

3. The download url of binary and modified source code

4. If you can not install the msi file, and it didn't work for uninstalling the previus version, you can install back original version, extract and copy them into your qemu-ga folder (need to stop qemu-ga windows service), mind the file name for this build (qemu-ga and qemu_ga).