[PATCH] shell: monitor child client disconnects

[Arnaud Vrac]

From: Arnaud Vrac <avrac at freebox.fr>

A crash could happen when killing weston, since the wayland client of
the shell child process could be destroyed twice: once when the wayland
client disconnects (before sigchld is caught), and then again when
destroying the shell.
---
 src/shell.c        | 21 ++++++++++++++++++++-
 src/text-backend.c | 21 ++++++++++++++++++++-
 2 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/src/shell.c b/src/shell.c
index fe332e1..a1a3ea7 100644
--- a/src/shell.c
+++ b/src/shell.c
@@ -116,6 +116,7 @@ struct desktop_shell {
 		struct weston_process process;
 		struct wl_client *client;
 		struct wl_resource *desktop_shell;
+		struct wl_listener client_destroy_listener;
 
 		unsigned deathcount;
 		uint32_t deathstamp;
@@ -3949,6 +3950,16 @@ desktop_shell_sigchld(struct weston_process *process, int status)
 }
 
 static void
+desktop_shell_handle_disconnect(struct wl_listener *listener, void *data)
+{
+	struct desktop_shell *shell =
+		container_of(listener, struct desktop_shell,
+			     child.client_destroy_listener);
+
+	shell->child.client = NULL;
+}
+
+static void
 launch_desktop_shell_process(void *data)
 {
 	struct desktop_shell *shell = data;
@@ -3959,8 +3970,16 @@ launch_desktop_shell_process(void *data)
 						 shell_exe,
 						 desktop_shell_sigchld);
 
-	if (!shell->child.client)
+	if (!shell->child.client) {
 		weston_log("not able to start %s\n", shell_exe);
+		return;
+	}
+
+	shell->child.client_destroy_listener.notify =
+		desktop_shell_handle_disconnect;
+
+	wl_client_add_destroy_listener(shell->child.client,
+				       &shell->child.client_destroy_listener);
 }
 
 static void
diff --git a/src/text-backend.c b/src/text-backend.c
index 107ccd6..79544b2 100644
--- a/src/text-backend.c
+++ b/src/text-backend.c
@@ -95,6 +95,7 @@ struct text_backend {
 		struct wl_resource *binding;
 		struct weston_process process;
 		struct wl_client *client;
+		struct wl_listener client_destroy_listener;
 
 		unsigned deathcount;
 		uint32_t deathstamp;
@@ -865,6 +866,16 @@ handle_input_method_sigchld(struct weston_process *process, int status)
 }
 
 static void
+handle_input_method_disconnect(struct wl_listener *listener, void *data)
+{
+	struct text_backend *text_backend =
+		container_of(listener, struct text_backend,
+			     input_method.client_destroy_listener);
+
+	text_backend->input_method.client = NULL;
+}
+
+static void
 launch_input_method(struct text_backend *text_backend)
 {
 	if (text_backend->input_method.binding)
@@ -881,8 +892,16 @@ launch_input_method(struct text_backend *text_backend)
 								 text_backend->input_method.path,
 								 handle_input_method_sigchld);
 
-	if (!text_backend->input_method.client)
+	if (!text_backend->input_method.client) {
 		weston_log("not able to start %s\n", text_backend->input_method.path);
+		return;
+	}
+
+	text_backend->input_method.client_destroy_listener.notify =
+		handle_input_method_disconnect;
+
+	wl_client_add_destroy_listener(text_backend->input_method.client,
+				       &text_backend->input_method.client_destroy_listener);
 }
 
 static void
-- 
1.8.3.2