From: Timo Sirainen <timo.sirainen@open-xchange.com>
Date: Wed, 5 May 2021 09:45:25 +0000 (+0300)
Subject: lib: abort() on unexpected exit()
X-Git-Tag: 2.3.16~160
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f550663b374792e8dbac00c7cce1b2b0b88cddd3;p=thirdparty%2Fdovecot%2Fcore.git

lib: abort() on unexpected exit()

This can especially be useful in catching bugs in Lua script that could
unexpectedly exit.
---

diff --git a/src/lib-master/master-service.c b/src/lib-master/master-service.c
index 703bf44d9b..017a4a2894 100644
--- a/src/lib-master/master-service.c
+++ b/src/lib-master/master-service.c
@@ -661,6 +661,9 @@ void master_service_init_finish(struct master_service *service)
 	i_assert(!service->init_finished);
 	service->init_finished = TRUE;
 
+	/* From now on we'll abort() if exit() is called unexpectedly. */
+	lib_set_clean_exit(FALSE);
+
 	/* set default signal handlers */
 	if ((service->flags & MASTER_SERVICE_FLAG_STANDALONE) == 0)
 		sigint_flags |= LIBSIG_FLAG_RESTART;
diff --git a/src/lib/failures.c b/src/lib/failures.c
index 4a9abd68f7..ab94700296 100644
--- a/src/lib/failures.c
+++ b/src/lib/failures.c
@@ -516,6 +516,7 @@ void i_panic(const char *format, ...)
 	struct failure_context ctx;
 	va_list args;
 
+	lib_set_clean_exit(TRUE);
 	i_zero(&ctx);
 	ctx.type = LOG_TYPE_PANIC;
 
@@ -530,6 +531,7 @@ void i_fatal(const char *format, ...)
 	struct failure_context ctx;
 	va_list args;
 
+	lib_set_clean_exit(TRUE);
 	i_zero(&ctx);
 	ctx.type = LOG_TYPE_FATAL;
 	ctx.exit_status = FATAL_DEFAULT;
@@ -545,6 +547,7 @@ void i_fatal_status(int status, const char *format, ...)
 	struct failure_context ctx;
 	va_list args;
 
+	lib_set_clean_exit(TRUE);
 	i_zero(&ctx);
 	ctx.type = LOG_TYPE_FATAL;
 	ctx.exit_status = status;
diff --git a/src/lib/lib.c b/src/lib/lib.c
index ab08da66e9..bd2da917c1 100644
--- a/src/lib/lib.c
+++ b/src/lib/lib.c
@@ -29,6 +29,7 @@ struct atexit_callback {
 };
 
 static ARRAY(struct atexit_callback) atexit_callbacks = ARRAY_INIT;
+static bool lib_clean_exit;
 
 #undef i_unlink
 int i_unlink(const char *path, const char *source_fname,
@@ -132,6 +133,31 @@ static void lib_open_non_stdio_dev_null(void)
 	fd_close_on_exec(dev_null_fd, TRUE);
 }
 
+void lib_set_clean_exit(bool set)
+{
+	lib_clean_exit = set;
+}
+
+void lib_exit(int status)
+{
+	lib_set_clean_exit(TRUE);
+	exit(status);
+}
+
+static void lib_atexit_handler(void)
+{
+	/* We're already in exit code path. Avoid using any functions that
+	   might cause strange breakage. Especially anything that could call
+	   exit() again could cause infinite looping in some OSes. */
+	if (!lib_clean_exit) {
+		const char *error = "Unexpected exit - converting to abort\n";
+		if (write(STDERR_FILENO, error, strlen(error)) < 0) {
+			/* ignore */
+		}
+		abort();
+	}
+}
+
 void lib_init(void)
 {
 	i_assert(!lib_initialized);
@@ -143,6 +169,13 @@ void lib_init(void)
 	event_filter_init();
 	var_expand_extensions_init();
 
+	/* Default to clean exit. Otherwise there would be too many accidents
+	   with e.g. command line parsing errors that try to return instead
+	   of using lib_exit(). master_service_init_finish() will change this
+	   again to be FALSE. */
+	lib_set_clean_exit(TRUE);
+	atexit(lib_atexit_handler);
+
 	lib_initialized = TRUE;
 }
 
@@ -168,4 +201,6 @@ void lib_deinit(void)
 	failures_deinit();
 	process_title_deinit();
 	random_deinit();
+
+	lib_clean_exit = TRUE;
 }
diff --git a/src/lib/lib.h b/src/lib/lib.h
index e16b4ce48c..9c3ca34ffb 100644
--- a/src/lib/lib.h
+++ b/src/lib/lib.h
@@ -81,7 +81,11 @@ void lib_atexit_priority(lib_atexit_callback_t *callback, int priority);
 /* Manually run the atexit callbacks. lib_deinit() also does this if not
    explicitly called. */
 void lib_atexit_run(void);
-#define lib_exit(status) exit(status)
+/* Unless this or lib_deinit() is called, any unexpected exit() will result
+   in abort(). This can be helpful in catching unexpected exits. */
+void lib_set_clean_exit(bool set);
+/* Same as lib_set_clean_exit(TRUE) followed by exit(status). */
+void lib_exit(int status) ATTR_NORETURN;
 
 void lib_init(void);
 bool lib_is_initialized(void);
diff --git a/src/master/main.c b/src/master/main.c
index a537b3a3cc..4eb126fd1a 100644
--- a/src/master/main.c
+++ b/src/master/main.c
@@ -885,6 +885,7 @@ int main(int argc, char *argv[])
 	pidfile_path =
 		i_strconcat(set->base_dir, "/"MASTER_PID_FILE_NAME, NULL);
 
+	lib_set_clean_exit(TRUE);
 	master_service_init_log(master_service);
 	startup_early_errors_flush();
 	i_get_failure_handlers(&orig_fatal_callback, &orig_error_callback,