Reload config using idle event

This patch makes it so when you run reload, the actual reloading is
deferred to the next time the event loop becomes idle. This avoids
several use-after-frees and removes the workarounds we have to avoid
them.

When you run reload, we validate the config before creating the idle
event. This is so the reload command will still return an error if there
are validation errors. To allow this, load_main_config has been adjusted
so it doesn't apply the config if validating is true rather than
applying it unconditionally.

This also fixes a memory leak in the reload command where if the config
failed to load, the bar_ids list would not be freed.

1 files changed, 25 insertions, 11 deletions

diff --git a/sway/commands/reload.c b/sway/commands/reload.c
index 36fb9092..9e136d48 100644
--- a/sway/commands/reload.c
+++ b/sway/commands/reload.c
@@ -3,15 +3,12 @@
 #include "sway/commands.h"
 #include "sway/config.h"
 #include "sway/ipc-server.h"
+#include "sway/server.h"
 #include "sway/tree/arrange.h"
 #include "list.h"
+#include "log.h"
 
-struct cmd_results *cmd_reload(int argc, char **argv) {
-        struct cmd_results *error = NULL;
-        if ((error = checkarg(argc, "reload", EXPECTED_EQUAL_TO, 0))) {
-                return error;
-        }
-
+static void do_reload(void *data) {
         // store bar ids to check against new bars for barconfig_update events
         list_t *bar_ids = create_list();
         for (int i = 0; i < config->bars->length; ++i) {
@@ -20,9 +17,12 @@ struct cmd_results *cmd_reload(int argc, char **argv) {
         }
 
         if (!load_main_config(config->current_config_path, true, false)) {
-                return cmd_results_new(CMD_FAILURE, "reload",
-                                "Error(s) reloading config.");
+                wlr_log(WLR_ERROR, "Error(s) reloading config");
+                list_foreach(bar_ids, free);
+                list_free(bar_ids);
+                return;
         }
+
         ipc_event_workspace(NULL, NULL, "reload");
 
         load_swaybars();
@@ -37,12 +37,26 @@ struct cmd_results *cmd_reload(int argc, char **argv) {
                 }
         }
 
-        for (int i = 0; i < bar_ids->length; ++i) {
-                free(bar_ids->items[i]);
-        }
+        list_foreach(bar_ids, free);
         list_free(bar_ids);
 
         arrange_root();
+}
+
+struct cmd_results *cmd_reload(int argc, char **argv) {
+        struct cmd_results *error = NULL;
+        if ((error = checkarg(argc, "reload", EXPECTED_EQUAL_TO, 0))) {
+                return error;
+        }
+
+        if (!load_main_config(config->current_config_path, true, true)) {
+                return cmd_results_new(CMD_FAILURE, "reload",
+                                "Error(s) reloading config.");
+        }
+
+        // The reload command frees a lot of stuff, so to avoid use-after-frees
+        // we schedule the reload to happen using an idle event.
+        wl_event_loop_add_idle(server.wl_event_loop, do_reload, NULL);
 
         return cmd_results_new(CMD_SUCCESS, NULL, NULL);
 }