Capture QEMU serial port output

.gitignore

@@ -1,3 +1,4 @@
 .rscons*
 /x86_64-elf-gcc/
 /build/
+/qemu/

Rsconscript

@@ -187,15 +187,22 @@ hello_env = env "hello", use: %w[ldc2 x86_64-w64-mingw32-gcc] do |env|
 end
 
 task "run", desc: "Run HOS in QEMU" do
-  Dir.mktmpdir do |tmpdir|
-    img = hello_env.expand("^/HOS.img")
-    FileUtils.cp(img, tmpdir)
-    ovmf = "OVMF.fd"
-    if File.exist?("/usr/share/edk2/x64/OVMF.fd")
-      ovmf = "/usr/share/edk2/x64/OVMF.fd"
-    end
-    sh %W[qemu-system-x86_64 -cpu max -bios #{ovmf} -drive file=#{tmpdir}/HOS.img,format=raw -device qemu-xhci -device usb-tablet]
+  FileUtils.rm_rf("qemu")
+  FileUtils.mkdir_p("qemu")
+  img = hello_env.expand("^/HOS.img")
+  FileUtils.cp(img, "qemu")
+  ovmf = "OVMF.fd"
+  if File.exist?("/usr/share/edk2/x64/OVMF.fd")
+    ovmf = "/usr/share/edk2/x64/OVMF.fd"
   end
+  sh %W[
+    qemu-system-x86_64
+    -cpu max
+    -serial file:qemu/serial.out
+    -bios #{ovmf}
+    -drive file=qemu/HOS.img,format=raw
+    -device qemu-xhci
+    -device usb-tablet]
 end
 
 # See README.md for how to set up VirtualBox for HOS.