failtest: use a linked list for history, not an array.

This avoids a silly realloc, but more importantly it gets us closer to
being runtime extensible, as each history element can be a different
size.

ccan/failtest/_info

@@ -61,10 +61,12 @@ int main(int argc, char *argv[])
 		return 1;
 
 	if (strcmp(argv[1], "depends") == 0) {
+		printf("ccan/build_assert\n");
 		printf("ccan/compiler\n");
 		printf("ccan/read_write_all\n");
-		printf("ccan/build_assert\n");
+		printf("ccan/str\n");
 		printf("ccan/time\n");
+		printf("ccan/tlist\n");
 		return 0;
 	}
 

ccan/failtest/failtest.h

@@ -9,6 +9,7 @@
 #include <stdbool.h>
 #include <fcntl.h>
 #include <ccan/compiler/compiler.h>
+#include <ccan/tlist/tlist.h>
 
 /**
  * failtest_init - initialize the failtest module
@@ -124,6 +125,8 @@ struct fcntl_call {
  *	failtest_hook, failtest_exit_check
  */
 struct failtest_call {
+	/* We're in the history list. */
+	struct list_node list;
 	enum failtest_call_type type;
 	/* Where we were called from. */
 	const char *file;
@@ -148,6 +151,9 @@ struct failtest_call {
 	} u;
 };
 
+/* This defines struct tlist_calls. */
+TLIST_TYPE(calls, struct failtest_call);
+
 enum failtest_result {
 	/* Yes try failing this call. */
 	FAIL_OK,
@@ -160,7 +166,6 @@ enum failtest_result {
 /**
  * failtest_hook - whether a certain call should fail or not.
  * @history: the ordered history of all failtest calls.
- * @num: the number of elements in @history (greater than 0)
  *
  * The default value of this hook is failtest_default_hook(), which returns
  * FAIL_OK (ie. yes, fail the call).
@@ -170,25 +175,24 @@ enum failtest_result {
  * call.
  *
  * Example:
- *	static enum failtest_result dont_fail_alloc(struct failtest_call *hist,
- *						    unsigned num)
+ *	static enum failtest_result dont_fail_alloc(struct tlist_calls *history)
  *	{
- *		if (hist[num-1].type == FAILTEST_MALLOC
- *			|| hist[num-1].type == FAILTEST_CALLOC
- *			|| hist[num-1].type == FAILTEST_REALLOC)
+ *		struct failtest_call *call;
+ *		call = tlist_tail(history, struct failtest_call, list);
+ *		if (call->type == FAILTEST_MALLOC
+ *			|| call->type == FAILTEST_CALLOC
+ *			|| call->type == FAILTEST_REALLOC)
  *			return FAIL_DONT_FAIL;
  *		return FAIL_OK;
  *	}
  *	...
  *		failtest_hook = dont_fail_alloc;
  */
-extern enum failtest_result
-(*failtest_hook)(struct failtest_call *history, unsigned num);
+extern enum failtest_result (*failtest_hook)(struct tlist_calls *history);
 
 /**
  * failtest_exit_check - hook for additional checks on a failed child.
  * @history: the ordered history of all failtest calls.
- * @num: the number of elements in @history (greater than 0)
  *
  * Your program might have additional checks to do on failure, such as
  * check that a file is not corrupted, or than an error message has been
@@ -197,16 +201,15 @@ extern enum failtest_result
  * If this returns false, the path to this failure will be printed and the
  * overall test will fail.
  */
-extern bool (*failtest_exit_check)(struct failtest_call *history,
-				   unsigned num);
+extern bool (*failtest_exit_check)(struct tlist_calls *history);
 
 /**
  * failtest_has_failed - determine if a failure has occurred.
  *
- * Sometimes you want to exit immediately if you've experienced a failure.
- * This is useful when you have four separate tests in your test suite,
- * and you don't want to do the next one if you've had a failure in a
- * previous one.
+ * Sometimes you want to exit immediately if you've experienced an
+ * injected failure.  This is useful when you have four separate tests
+ * in your test suite, and you don't want to do the next one if you've
+ * had a failure in a previous one.
  */
 extern bool failtest_has_failed(void);
 

ccan/failtest/test/run-history.c

@@ -102,20 +102,24 @@ int main(void)
 	ok1(call->u.write.fd == write_call.fd);
 	ok1(call->u.write.count == write_call.count);
 
-	ok1(history_num == 7);
+	i = 0;
+	tlist_for_each(&history, call, list)
+		i++;
 
-	for (i = 0; i < history_num; i++)
-		history[i].fail = false;
+	ok1(i == 7);
+
+	tlist_for_each(&history, call, list)
+		call->fail = false;
 
 	path = failpath_string();
-	ok1(strcmp(path, "cmeoprw") == 0);
+	ok1(streq(path, "cmeoprw"));
 	free(path);
 
-	for (i = 0; i < history_num; i++)
-		history[i].fail = true;
+	tlist_for_each(&history, call, list)
+		call->fail = true;
 
 	path = failpath_string();
-	ok1(strcmp(path, "CMEOPRW") == 0);
+	ok1(streq(path, "CMEOPRW"));
 	free(path);
 
 	return exit_status();

ccan/failtest/test/run-locking.c

@@ -10,8 +10,7 @@
 #define SIZE 8
 
 /* We don't want to fork and fail; we're just testing lock recording. */
-static enum failtest_result dont_fail(struct failtest_call *history,
-				      unsigned num)
+static enum failtest_result dont_fail(struct tlist_calls *history)
 {
 	return FAIL_DONT_FAIL;
 }

ccan/tdb2/test/failtest_helper.c

@@ -26,12 +26,14 @@ bool failmatch(const struct failtest_call *call,
 }
 
 static const struct failtest_call *
-find_repeat(const struct failtest_call *start, const struct failtest_call *end,
+find_repeat(const struct tlist_calls *history,
 	    const struct failtest_call *call)
 {
 	const struct failtest_call *i;
 
-	for (i = start; i < end; i++) {
+	tlist_for_each(history, i, list) {
+		if (i != call)
+			continue;
 		if (failmatch(i, call->file, call->line, call->type))
 			return i;
 	}
@@ -49,32 +51,31 @@ static bool is_unlock(const struct failtest_call *call)
 		&& call->u.fcntl.arg.fl.l_type == F_UNLCK;
 }
 
-bool exit_check_log(struct failtest_call *history, unsigned num)
+bool exit_check_log(struct tlist_calls *history)
 {
-	unsigned int i;
+	const struct failtest_call *i;
 
-	for (i = 0; i < num; i++) {
-		if (!history[i].fail)
+	tlist_for_each(history, i, list) {
+		if (!i->fail)
 			continue;
 		/* Failing the /dev/urandom open doesn't count: we fall back. */
-		if (failmatch(&history[i], URANDOM_OPEN))
+		if (failmatch(i, URANDOM_OPEN))
 			continue;
 
 		/* Similarly with read fail. */
-		if (failmatch(&history[i], URANDOM_READ))
+		if (failmatch(i, URANDOM_READ))
 			continue;
 
 		/* Initial allocation of tdb doesn't log. */
-		if (failmatch(&history[i], INITIAL_TDB_MALLOC))
+		if (failmatch(i, INITIAL_TDB_MALLOC))
 			continue;
 
 		/* We don't block "failures" on non-blocking locks. */
-		if (is_nonblocking_lock(&history[i]))
+		if (is_nonblocking_lock(i))
 			continue;
 
 		if (!tap_log_messages)
-			diag("We didn't log for %u (%s:%u)",
-			     i, history[i].file, history[i].line);
+			diag("We didn't log for %s:%u", i->file, i->line);
 		return tap_log_messages != 0;
 	}
 	return true;
@@ -82,9 +83,11 @@ bool exit_check_log(struct failtest_call *history, unsigned num)
 
 /* Some places we soldier on despite errors: only fail them once. */
 enum failtest_result
-block_repeat_failures(struct failtest_call *history, unsigned num)
+block_repeat_failures(struct tlist_calls *history)
 {
-	const struct failtest_call *i, *last = &history[num-1];
+	const struct failtest_call *i, *last;
+
+	last = tlist_tail(history, struct failtest_call, list);
 
 	if (failtest_suppress)
 		return FAIL_DONT_FAIL;
@@ -92,7 +95,7 @@ block_repeat_failures(struct failtest_call *history, unsigned num)
 	if (failmatch(last, INITIAL_TDB_MALLOC)
 	    || failmatch(last, URANDOM_OPEN)
 	    || failmatch(last, URANDOM_READ)) {
-		if (find_repeat(history, last, last))
+		if (find_repeat(history, last))
 			return FAIL_DONT_FAIL;
 		return FAIL_PROBE;
 	}
@@ -100,21 +103,15 @@ block_repeat_failures(struct failtest_call *history, unsigned num)
 	/* Unlock or non-blocking lock is fail-once. */
 	if (is_unlock(last)) {
 		/* Find a previous unlock at this point? */
-		for (i = find_repeat(history, last, last);
-		     i;
-		     i = find_repeat(history, i, last)) {
-			if (is_unlock(i))
-				return FAIL_DONT_FAIL;
-		}
+		i = find_repeat(history, last);
+		if (i && is_unlock(i))
+			return FAIL_DONT_FAIL;
 		return FAIL_PROBE;
 	} else if (is_nonblocking_lock(last)) {
 		/* Find a previous non-blocking lock at this point? */
-		for (i = find_repeat(history, last, last);
-		     i;
-		     i = find_repeat(history, i, last)) {
-			if (is_nonblocking_lock(i))
-				return FAIL_DONT_FAIL;
-		}
+		i = find_repeat(history, last);
+		if (i && is_nonblocking_lock(i))
+			return FAIL_DONT_FAIL;
 		return FAIL_PROBE;
 	}
 

ccan/tdb2/test/failtest_helper.h

@@ -8,11 +8,10 @@
 #define URANDOM_OPEN		"open.c", 62, FAILTEST_OPEN
 #define URANDOM_READ		"open.c", 42, FAILTEST_READ
 
-bool exit_check_log(struct failtest_call *history, unsigned num);
+bool exit_check_log(struct tlist_calls *history);
 bool failmatch(const struct failtest_call *call,
 	       const char *file, int line, enum failtest_call_type type);
-enum failtest_result
-block_repeat_failures(struct failtest_call *history, unsigned num);
+enum failtest_result block_repeat_failures(struct tlist_calls *history);
 
 /* Set this to suppress failure. */
 extern bool failtest_suppress;