[1404] check the schema version of the SQLite3 data source file

and stop instllation if it's old.  The checker script can also be
used to upgrade the schema via a  non default command line option.

Makefile.am

-SUBDIRS = doc src tests
+SUBDIRS = compatcheck doc src tests
 USE_LCOV=@USE_LCOV@
 LCOV=@LCOV@
 GENHTML=@GENHTML@

compatcheck/Makefile.am

+noinst_SCRIPTS = sqlite3-difftbl-check.py
+
+# We're going to abuse install-data-local for a pre-install check.
+# This is to be considered a short term hack and is expected to be removed
+# in a near future version.
+install-data-local:
+	$(PYTHON) sqlite3-difftbl-check.py \
+	$(localstatedir)/$(PACKAGE)/zone.sqlite3

compatcheck/README

+This directory is a collection of compatibility checker programs.
+They will be run before any other installation attempts on 'make install'
+to see if the installation causes any substantial compatibility problems
+with existing configuratons.  If any checker program finds an issue,
+'make install' will stop at that point.

compatcheck/sqlite3-difftbl-check.py.in

+#!@PYTHON@
+
+# Copyright (C) 2011  Internet Systems Consortium.
+#
+# Permission to use, copy, modify, and distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SYSTEMS CONSORTIUM
+# DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
+# INTERNET SYSTEMS CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
+# INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
+# FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
+# NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
+# WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+import os, sqlite3, sys
+from optparse import OptionParser
+
+usage = 'usage: %prog [options] db_file'
+parser = OptionParser(usage=usage)
+parser.add_option("-u", "--upgrade", action="store_true",
+                  dest="upgrade", default=False,
+                  help="Upgrade the database file [default: %default]")
+(options, args) = parser.parse_args()
+if len(args) == 0:
+    parser.error('missing argument')
+
+db_file = args[0]
+conn = sqlite3.connect(db_file)
+cur = conn.cursor()
+try:
+    # This can be anything that works iff the "diffs" table exists
+    cur.execute('SELECT name FROM diffs DESC LIMIT 1')
+except sqlite3.OperationalError as ex:
+    # If it fails with 'no such table', create a new one or fail with
+    # warning depending on the --upgrade command line option.
+    if str(ex) == 'no such table: diffs':
+        if options.upgrade:
+            cur.execute('CREATE TABLE diffs (id INTEGER PRIMARY KEY, ' +
+                        'zone_id INTEGER NOT NULL, ' +
+                        'version INTEGER NOT NULL, ' +
+                        'operation INTEGER NOT NULL, ' +
+                        'name STRING NOT NULL COLLATE NOCASE, ' +
+                        'rrtype STRING NOT NULL COLLATE NOCASE, ' +
+                        'ttl INTEGER NOT NULL, rdata STRING NOT NULL)')
+        else:
+            sys.stdout.write('Found an older version of SQLite3 DB file: ' +
+                             db_file + '\n' + "Peform '" + os.getcwd() +
+                             "/sqlite3-difftbl-check.py --upgrade " +
+                             db_file + "'\n" +
+                             'before continueing install.\n')
+            sys.exit(1)
+conn.close()

configure.ac

@@ -816,6 +816,7 @@ AM_CONDITIONAL(INSTALL_CONFIGURATIONS, test x$install_configurations = xyes || t
 AC_CONFIG_FILES([Makefile
                  doc/Makefile
                  doc/guide/Makefile
+                 compatcheck/Makefile
                  src/Makefile
                  src/bin/Makefile
                  src/bin/bind10/Makefile
@@ -937,6 +938,7 @@ AC_CONFIG_FILES([Makefile
                  tests/tools/badpacket/tests/Makefile
                ])
 AC_OUTPUT([doc/version.ent
+           compatcheck/sqlite3-difftbl-check.py
            src/bin/cfgmgr/b10-cfgmgr.py
            src/bin/cfgmgr/tests/b10-cfgmgr_test.py
            src/bin/cmdctl/cmdctl.py
@@ -1016,6 +1018,7 @@ AC_OUTPUT([doc/version.ent
            tests/system/ixfr/in-3/setup.sh
            tests/system/ixfr/in-4/setup.sh
           ], [
+           chmod +x compatcheck/sqlite3-difftbl-check.py
            chmod +x src/bin/cmdctl/run_b10-cmdctl.sh
            chmod +x src/bin/xfrin/run_b10-xfrin.sh
            chmod +x src/bin/xfrout/run_b10-xfrout.sh