sysroot: Add an API to lock

If a system administrator happens to type `ostree admin upgrade`
multiple times, currently that will lead to a potentially corrupted
system.

I originally attempted to do locking *internally* in `libostree`, but
that didn't work out because currently a number of the commands
perform multi-step operations that all need to be serialized.  All of
the current code in `ostree admin deploy` is an example.

Therefore, allow callers to perform locking, as most of the higher
level logic is presently implemented there.

At some point, we can revisit having internal locking, but it will be
difficult.  A more likely approach would be similar to Java's approach
with concurrency on iterators - a "fail fast" method.

1 files changed, 49 insertions, 0 deletions

diff --git a/tests/test-admin-locking.sh b/tests/test-admin-locking.sh
new file mode 100644
index 00000000..b6cd7bd9
--- /dev/null
+++ b/tests/test-admin-locking.sh
@@ -0,0 +1,49 @@
+#!/bin/bash
+#
+# Copyright (C) 2015 Colin Walters <walters@verbum.org>
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2 of the License, or (at your option) any later version.
+#
+# This library 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
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the
+# Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+# Boston, MA 02111-1307, USA.
+
+set -e
+
+. $(dirname $0)/libtest.sh
+
+echo "1..1"
+
+setup_os_repository "archive-z2" "syslinux"
+
+echo "ok setup"
+
+echo "1..1"
+
+cd ${test_tmpdir}
+${CMD_PREFIX} ostree --repo=sysroot/ostree/repo remote add --set=gpg-verify=false testos $(cat httpd-address)/ostree/testos-repo
+${CMD_PREFIX} ostree --repo=sysroot/ostree/repo pull testos testos/buildmaster/x86_64-runtime
+rev=$(${CMD_PREFIX} ostree --repo=sysroot/ostree/repo rev-parse testos/buildmaster/x86_64-runtime)
+export rev
+echo "rev=${rev}"
+# This initial deployment gets kicked off with some kernel arguments 
+${CMD_PREFIX} ostree admin --sysroot=sysroot deploy --karg=root=LABEL=MOO --karg=quiet --os=testos testos:testos/buildmaster/x86_64-runtime
+assert_has_dir sysroot/boot/ostree/testos-${bootcsum}
+
+count=$(($(getconf _NPROCESSORS_ONLN) * 2))
+seq "${count}" | parallel --no-notice -n0 ${CMD_PREFIX} ostree admin --sysroot=sysroot deploy --retain --os=testos testos:testos/buildmaster/x86_64-runtime
+
+${CMD_PREFIX} ostree admin --sysroot=sysroot status > status.txt
+grep "testos ${rev}" status.txt | wc -l > status-matches.txt
+assert_file_has_content status-matches.txt $((${count} + 1))
+
+echo 'ok deploy locking'