* Make the script to start Samba available to the VM stuff in NixOS.

* Use socat's "exec" and "nofork" options to reduce the number of
  processes.  Also, if smbd exits abnormally, exit from the smbd
  restart loop.

svn path=/nixpkgs/trunk/; revision=22279

pkgs/build-support/vm/default.nix

@@ -211,9 +211,11 @@ rec {
 
 
   qemuCommandLinux = ''
-    qemu-system-x86_64 \
+    ${kvm}/bin/qemu-system-x86_64 \
       -nographic -no-reboot \
-      -net nic,model=virtio -chardev socket,id=samba,path=./samba -net user,guestfwd=tcp:10.0.2.4:139-chardev:samba \
+      -net nic,model=virtio \
+      -chardev socket,id=samba,path=./samba \
+      -net user,guestfwd=tcp:10.0.2.4:139-chardev:samba \
       -drive file=$diskImage,if=virtio,boot=on,cache=writeback,werror=report \
       -kernel ${kernel}/bzImage \
       -initrd ${initrd}/initrd \
@@ -222,16 +224,10 @@ rec {
   '';
 
 
-  vmRunCommand = qemuCommand: writeText "vm-run" ''
-    export > saved-env
-
-    PATH=${coreutils}/bin:${kvm}/bin
-
-    diskImage=''${diskImage:-/dev/null}
-
-    eval "$preVM"
-
-    cat > smb.conf <<EOF
+  startSamba =
+    let sambaScript = writeScript "run-smbd" "while ${samba}/sbin/smbd -s $TMPDIR/smb.conf; do true; done"; in
+    ''
+      cat > $TMPDIR/smb.conf <<SMB
       [global]
         private dir = $TMPDIR
         smb ports = 0
@@ -245,7 +241,21 @@ rec {
         path = /
         read only = no
         guest ok = yes
-    EOF
+      SMB
+
+      ${socat}/bin/socat unix-listen:./samba exec:'/bin/sh -c ${sambaScript}',nofork > /dev/null 2>&1 &
+      while [ ! -e ./samba ]; do sleep 0.1; done # ugly
+    '';
+
+
+  vmRunCommand = qemuCommand: writeText "vm-run" ''
+    export > saved-env
+
+    PATH=${coreutils}/bin
+
+    diskImage=''${diskImage:-/dev/null}
+
+    eval "$preVM"
 
     # Write the command to start the VM to a file so that the user can
     # debug inside the VM if the build fails (when Nix is called with
@@ -255,8 +265,7 @@ rec {
     diskImage=$diskImage
     TMPDIR=$TMPDIR
     cd $TMPDIR
-    ${socat}/bin/socat unix-listen:./samba system:'while true; do ${samba}/sbin/smbd -s $TMPDIR/smb.conf; done' > /dev/null 2>&1 &
-    while [ ! -e ./samba ]; do sleep 0.1; done # ugly
+    ${startSamba}
     ${qemuCommand}
     EOF
 
@@ -330,7 +339,7 @@ rec {
 
 
   qemuCommandGeneric = ''
-    qemu-system-x86_64 \
+    ${kvm}/bin/qemu-system-x86_64 \
       -nographic -no-reboot \
       -smb $(pwd) -hda $diskImage \
       $QEMU_OPTS