[ostree] upgrade: Add --override-commit=CHECKSUM option

[Matthew Barnes <mbarnes src gnome org>]

commit 2210a79bfa10f4a29113ee78f33300cea254715b
Author: Matthew Barnes <mbarnes redhat com>
Date:   Tue Oct 6 11:33:18 2015 -0400

    upgrade: Add --override-commit=CHECKSUM option
    
    Adds an entry to the origin file to force the OstreeSysrootUpgrader to
    pull and deploy the given checksum.
    
      [origin]
      override-commit=CHECKSUM
    
    If the option is not given, any such entry is explicitly removed from
    the origin file to ensure we upgrade to the latest available commit.

 doc/ostree-admin-upgrade.xml          |    8 ++++++++
 src/ostree/ot-admin-builtin-upgrade.c |   32 ++++++++++++++++++++++++++++++++
 tests/admin-test.sh                   |   15 +++++++++++++++
 3 files changed, 55 insertions(+), 0 deletions(-)
---
diff --git a/doc/ostree-admin-upgrade.xml b/doc/ostree-admin-upgrade.xml
index 37e3e5d..ddd33dc 100644
--- a/doc/ostree-admin-upgrade.xml
+++ b/doc/ostree-admin-upgrade.xml
@@ -88,6 +88,14 @@ Boston, MA 02111-1307, USA.
                     Permit deployment of chronologically older trees.
                 </para></listitem>
             </varlistentry>
+
+            <varlistentry>
+                <term><option>--override-commit</option>="CHECKSUM"</term>
+
+                <listitem><para>
+                    Deploy CHECKSUM instead of the latest tree.
+                </para></listitem>
+            </varlistentry>
         </variablelist>
     </refsect1>
 
diff --git a/src/ostree/ot-admin-builtin-upgrade.c b/src/ostree/ot-admin-builtin-upgrade.c
index 006914a..90d0ce9 100644
--- a/src/ostree/ot-admin-builtin-upgrade.c
+++ b/src/ostree/ot-admin-builtin-upgrade.c
@@ -35,11 +35,13 @@
 static gboolean opt_reboot;
 static gboolean opt_allow_downgrade;
 static char *opt_osname;
+static char *opt_override_commit;
 
 static GOptionEntry options[] = {
   { "os", 0, 0, G_OPTION_ARG_STRING, &opt_osname, "Use a different operating system root than the current 
one", "OSNAME" },
   { "reboot", 'r', 0, G_OPTION_ARG_NONE, &opt_reboot, "Reboot after a successful upgrade", NULL },
   { "allow-downgrade", 0, 0, G_OPTION_ARG_NONE, &opt_allow_downgrade, "Permit deployment of chronologically 
older trees", NULL },
+  { "override-commit", 0, 0, G_OPTION_ARG_STRING, &opt_override_commit, "Deploy CHECKSUM instead of the 
latest tree", "CHECKSUM" },
   { NULL }
 };
 
@@ -52,6 +54,7 @@ ot_admin_builtin_upgrade (int argc, char **argv, GCancellable *cancellable, GErr
   glnx_unref_object OstreeSysrootUpgrader *upgrader = NULL;
   g_autoptr(GFile) deployment_path = NULL;
   g_autoptr(GFile) deployment_origin_path = NULL;
+  g_autoptr(GKeyFile) origin = NULL;
   GSConsole *console = NULL;
   gboolean in_status_line = FALSE;
   glnx_unref_object OstreeAsyncProgress *progress = NULL;
@@ -73,6 +76,35 @@ ot_admin_builtin_upgrade (int argc, char **argv, GCancellable *cancellable, GErr
   if (!upgrader)
     goto out;
 
+  origin = ostree_sysroot_upgrader_dup_origin (upgrader);
+  if (origin != NULL)
+    {
+      gboolean origin_changed = FALSE;
+
+      if (opt_override_commit != NULL)
+        {
+          /* Override the commit to pull and deploy. */
+          g_key_file_set_string (origin, "origin",
+                                 "override-commit",
+                                 opt_override_commit);
+          origin_changed = TRUE;
+        }
+      else
+        {
+          /* Strip any override-commit from the origin file so
+           * we always upgrade to the latest available commit. */
+          origin_changed = g_key_file_remove_key (origin, "origin",
+                                                  "override-commit", NULL);
+        }
+
+      if (origin_changed)
+        {
+          /* XXX GCancellable parameter is not used. */
+          if (!ostree_sysroot_upgrader_set_origin (upgrader, origin, NULL, error))
+            goto out;
+        }
+    }
+
   console = gs_console_get ();
   if (console)
     {
diff --git a/tests/admin-test.sh b/tests/admin-test.sh
index ca1ac2c..edbf665 100755
--- a/tests/admin-test.sh
+++ b/tests/admin-test.sh
@@ -203,3 +203,18 @@ assert_file_has_content sysroot/boot/loader/entries/ostree-testos-0.conf 'consol
 validate_bootloader
 
 echo "ok upgrade with multiple kernel args"
+
+# Test upgrade with and without --override-commit
+# See https://github.com/GNOME/ostree/pull/147
+${CMD_PREFIX} ostree pull --repo=sysroot/ostree/repo --commit-metadata-only --depth=-1 
testos:testos/buildmaster/x86_64-runtime
+head_rev=$(${CMD_PREFIX} ostree rev-parse --repo=sysroot/ostree/repo testos/buildmaster/x86_64-runtime)
+prev_rev=$(${CMD_PREFIX} ostree rev-parse --repo=sysroot/ostree/repo testos/buildmaster/x86_64-runtime^^^^)
+assert_not_streq ${head_rev} ${prev_rev}
+${CMD_PREFIX} ostree admin upgrade --os=testos --override-commit=${prev_rev} --allow-downgrade
+curr_rev=$(${CMD_PREFIX} ostree rev-parse --repo=sysroot/ostree/repo testos/buildmaster/x86_64-runtime)
+assert_streq ${curr_rev} ${prev_rev}
+${CMD_PREFIX} ostree admin upgrade --os=testos
+curr_rev=$(${CMD_PREFIX} ostree rev-parse --repo=sysroot/ostree/repo testos/buildmaster/x86_64-runtime)
+assert_streq ${curr_rev} ${head_rev}
+
+echo "ok upgrade with and without override-commit"