From: Timo Sirainen <timo.sirainen@open-xchange.com>
Date: Mon, 1 Mar 2021 10:56:21 +0000 (+0200)
Subject: lib: test-ioloop - Make sure recreating 0-timeout in callback works
X-Git-Tag: 2.3.15~134
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d92eb240cdcbebf5e09dab46641a54c030bd06b8;p=thirdparty%2Fdovecot%2Fcore.git

lib: test-ioloop - Make sure recreating 0-timeout in callback works
---

diff --git a/src/lib/ioloop.c b/src/lib/ioloop.c
index f3be87480d..43251cd3f6 100644
--- a/src/lib/ioloop.c
+++ b/src/lib/ioloop.c
@@ -288,7 +288,9 @@ struct timeout *timeout_add_to(struct ioloop *ioloop, unsigned int msecs,
 		/* start this timeout in the next run cycle */
 		array_push_back(&timeout->ioloop->timeouts_new, &timeout);
 	} else {
-		/* trigger zero timeouts as soon as possible */
+		/* Trigger zero timeouts as soon as possible. When ioloop is
+		   running, refresh the timestamp to prevent infinite loops
+		   in case a timeout callback keeps recreating the 0-timeout. */
 		timeout_update_next(timeout, timeout->ioloop->running ?
 			    NULL : &ioloop_timeval);
 		priorityq_add(timeout->ioloop->timeouts, &timeout->item);
diff --git a/src/lib/test-ioloop.c b/src/lib/test-ioloop.c
index 57fdacd3e5..91f38e0ea2 100644
--- a/src/lib/test-ioloop.c
+++ b/src/lib/test-ioloop.c
@@ -168,6 +168,56 @@ static void test_ioloop_zero_timeout(void)
 	test_end();
 }
 
+struct zero_timeout_recreate_ctx {
+	struct timeout *to;
+	unsigned int counter;
+};
+
+static void
+zero_timeout_recreate_callback(struct zero_timeout_recreate_ctx *ctx)
+{
+	timeout_remove(&ctx->to);
+	ctx->to = timeout_add_short(0, zero_timeout_recreate_callback, ctx);
+	ctx->counter++;
+}
+
+static void test_ioloop_zero_timeout_recreate(void)
+{
+	struct ioloop *ioloop;
+	struct io *io;
+	struct zero_timeout_recreate_ctx ctx = { .counter = 0 };
+	int fd[2];
+
+	test_begin("ioloop zero timeout recreate");
+
+	if (pipe(fd) < 0)
+		i_fatal("pipe() failed: %m");
+	switch (fork()) {
+	case (pid_t)-1:
+		i_fatal("fork() failed: %m");
+	case 0:
+		sleep(1);
+		char c = 0;
+		if (write(fd[1], &c, 1) < 0)
+			i_fatal("write(pipe) failed: %m");
+		test_exit(0);
+	default:
+		break;
+	}
+
+	ioloop = io_loop_create();
+	ctx.to = timeout_add_short(0, zero_timeout_recreate_callback, &ctx);
+	io = io_add(fd[0], IO_READ, io_loop_stop, ioloop);
+
+	io_loop_run(ioloop);
+	test_assert_ucmp(ctx.counter, >, 1000);
+
+	timeout_remove(&ctx.to);
+	io_remove(&io);
+	io_loop_destroy(&ioloop);
+	test_end();
+}
+
 static void io_callback(void *context ATTR_UNUSED)
 {
 }
@@ -241,6 +291,7 @@ void test_ioloop(void)
 {
 	test_ioloop_timeout();
 	test_ioloop_zero_timeout();
+	test_ioloop_zero_timeout_recreate();
 	test_ioloop_find_fd_conditions();
 	test_ioloop_pending_io();
 	test_ioloop_fd();