Add support for hotplugging (adding disks) to the libvirt attach-method.

When libvirt is used, we can allow disks to be hotplugged.
guestfs_add_drive can be called after launch to hot-add a disk.

When a disk is hot-added, we first ask libvirt to add the disk to the
appliance, then we make an internal call into the appliance to get it
to wait for the disk to appear (ie. udev_settle ()).

Hot-added disks are tracked in the g->drives array.

This also adds a test.

2 files changed, 92 insertions, 0 deletions

diff --git a/tests/hotplug/Makefile.am b/tests/hotplug/Makefile.am
new file mode 100644
index 00000000..6644930a
--- /dev/null
+++ b/tests/hotplug/Makefile.am
@@ -0,0 +1,26 @@
+# libguestfs
+# Copyright (C) 2012 Red Hat Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+include $(top_srcdir)/subdir-rules.mk
+
+TESTS = \
+	test-hot-add.pl
+
+TESTS_ENVIRONMENT = $(top_builddir)/run --test
+
+EXTRA_DIST = \
+	$(TESTS)
diff --git a/tests/hotplug/test-hot-add.pl b/tests/hotplug/test-hot-add.pl
new file mode 100755
index 00000000..b1322e88
--- /dev/null
+++ b/tests/hotplug/test-hot-add.pl
@@ -0,0 +1,66 @@
+#!/usr/bin/perl
+# Copyright (C) 2012 Red Hat Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+# Test hot-adding disks.
+
+use strict;
+use warnings;
+
+use Sys::Guestfs;
+
+my $g = Sys::Guestfs->new ();
+
+# Skip the test if the default attach-method isn't libvirt, since only
+# the libvirt backend supports hotplugging.
+my $attach_method = $g->get_attach_method ();
+unless ($attach_method eq "libvirt" || $attach_method =~ /^libvirt:/) {
+    print "$0: test skipped because attach-method ($attach_method) is not libvirt\n";
+    exit 77
+}
+
+# We don't need to add disks before launch.
+$g->launch ();
+
+# Create some temporary disks.
+open FILE, ">test1.img" or die "test1.img: $!";
+truncate FILE, 512 * 1024 * 1024 or die "test1.img: truncate: $!";
+close FILE;
+
+open FILE, ">test2.img" or die "test2.img: $!";
+truncate FILE, 512 * 1024 * 1024 or die "test2.img: truncate: $!";
+close FILE;
+
+die unless system ("qemu-img create -f qcow2 test3.img 1G") == 0;
+
+# Hot-add them.  Labels are required.
+$g->add_drive ("test1.img", label => "a"); # autodetect format
+$g->add_drive ("test2.img", label => "b", format => "raw", readonly => 1);
+$g->add_drive ("test3.img", label => "c", format => "qcow2");
+
+# Check we can use the disks immediately.
+$g->part_disk ("/dev/disk/guestfs/a", "mbr");
+$g->mkfs ("ext2", "/dev/disk/guestfs/c");
+$g->mkfs ("ext2", "/dev/disk/guestfs/a1");
+
+$g->shutdown ();
+$g->close ();
+
+unlink "test1.img";
+unlink "test2.img";
+unlink "test3.img";
+
+exit 0