tdb2: enforce TDB_CONVERT

If the caller actually specifies TDB_CONVERT, fail if the TDB does not
need conversion.  It's unusual for the user to specify TDB_CONVERT
(it's auto-detected) but better to be strict.

ccan/tdb2/open.c

@@ -532,6 +532,12 @@ struct tdb_context *tdb_open(const char *name, int tdb_flags,
 					   name, (long long)hdr.version);
 			goto fail;
 		}
+	} else if (tdb->flags & TDB_CONVERT) {
+		ecode = tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
+				   "tdb_open:"
+				   " %s does not need TDB_CONVERT",
+				   name);
+		goto fail;
 	}
 
 	tdb_convert(tdb, &hdr, sizeof(hdr));

ccan/tdb2/test/logging.c

@@ -5,6 +5,7 @@
 
 unsigned tap_log_messages;
 const char *log_prefix = "";
+char *log_last = NULL;
 bool suppress_logging;
 
 union tdb_attribute tap_log_attr = {
@@ -20,6 +21,9 @@ void tap_log_fn(struct tdb_context *tdb,
 		return;
 
 	diag("tdb log level %u: %s%s", level, log_prefix, message);
+	if (log_last)
+		free(log_last);
+	log_last = strdup(message);
 	tap_log_messages++;
 }
 

ccan/tdb2/test/logging.h

@@ -8,6 +8,7 @@ extern bool suppress_logging;
 extern const char *log_prefix;
 extern unsigned tap_log_messages;
 extern union tdb_attribute tap_log_attr;
+extern char *log_last;
 
 void tap_log_fn(struct tdb_context *tdb,
 		enum tdb_log_level level,

ccan/tdb2/test/run-35-convert.c

@@ -0,0 +1,61 @@
+#include <ccan/tdb2/private.h>
+#include <ccan/failtest/failtest_override.h>
+#include <ccan/tdb2/tdb.c>
+#include <ccan/tdb2/open.c>
+#include <ccan/tdb2/free.c>
+#include <ccan/tdb2/lock.c>
+#include <ccan/tdb2/io.c>
+#include <ccan/tdb2/hash.c>
+#include <ccan/tdb2/transaction.c>
+#include <ccan/tdb2/check.c>
+#include <ccan/tap/tap.h>
+#include <ccan/failtest/failtest.h>
+#include "logging.h"
+#include "failtest_helper.h"
+
+int main(int argc, char *argv[])
+{
+	unsigned int i, messages = 0;
+	struct tdb_context *tdb;
+	int flags[] = { TDB_DEFAULT, TDB_NOMMAP,
+			TDB_CONVERT, TDB_NOMMAP|TDB_CONVERT };
+
+	failtest_init(argc, argv);
+	failtest_hook = block_repeat_failures;
+	failtest_exit_check = exit_check_log;
+	plan_tests(sizeof(flags) / sizeof(flags[0]) * 4);
+	for (i = 0; i < sizeof(flags) / sizeof(flags[0]); i++) {
+		tdb = tdb_open("run-35-convert.tdb", flags[i],
+			       O_RDWR|O_CREAT|O_TRUNC, 0600, &tap_log_attr);
+		if (!ok1(tdb))
+			failtest_exit(exit_status());
+
+		tdb_close(tdb);
+		/* If we say TDB_CONVERT, it must be converted */
+		tdb = tdb_open("run-35-convert.tdb",
+			       flags[i]|TDB_CONVERT,
+			       O_RDWR, 0600, &tap_log_attr);
+		if (flags[i] & TDB_CONVERT) {
+			if (!tdb)
+				failtest_exit(exit_status());
+			ok1(tdb_get_flags(tdb) & TDB_CONVERT);
+			tdb_close(tdb);
+		} else {
+			if (!ok1(!tdb && errno == EIO))
+				failtest_exit(exit_status());
+			ok1(tap_log_messages == ++messages);
+			if (!ok1(log_last && strstr(log_last, "TDB_CONVERT")))
+				failtest_exit(exit_status());
+		}
+
+		/* If don't say TDB_CONVERT, it *may* be converted */
+		tdb = tdb_open("run-35-convert.tdb",
+			       flags[i] & ~TDB_CONVERT,
+			       O_RDWR, 0600, &tap_log_attr);
+		if (!tdb)
+			failtest_exit(exit_status());
+		ok1(tdb_get_flags(tdb) == flags[i]);
+		tdb_close(tdb);
+	}
+	failtest_exit(exit_status());
+}