sway/output: Improve logging of swaybg execvp failure and more checks

This doesn't catch the error if a background changing command is
executed via swaymsg, but improves logging.
The additional checks at least propagate if e.g. forking failed.

(cherry picked from commit c8676fad54bb0f4152947a6781626872bfa6ad64)

2 files changed, 10 insertions, 4 deletions

diff --git a/sway/commands/output.c b/sway/commands/output.c
index df32c673..462dffd2 100644
--- a/sway/commands/output.c
+++ b/sway/commands/output.c
@@ -111,7 +111,10 @@ struct cmd_results *cmd_output(int argc, char **argv) {
         if (!config->reloading && !config->validating) {
                 apply_output_config_to_outputs(output);
                 if (background) {
-                        spawn_swaybg();
+                        if (!spawn_swaybg()) {
+                                return cmd_results_new(CMD_FAILURE,
+                                        "Failed to apply background configuration");
+                        }
                 }
         }
 
diff --git a/sway/config/output.c b/sway/config/output.c
index 3316085a..3c1822d8 100644
--- a/sway/config/output.c
+++ b/sway/config/output.c
@@ -825,7 +825,9 @@ static bool _spawn_swaybg(char **command) {
                         setenv("WAYLAND_SOCKET", wayland_socket_str, true);
 
                         execvp(command[0], command);
-                        sway_log_errno(SWAY_ERROR, "execvp failed");
+                        sway_log_errno(SWAY_ERROR, "failed to execute '%s' "
+                                "(background configuration probably not applied)",
+                                command[0]);
                         _exit(EXIT_FAILURE);
                 }
                 _exit(EXIT_SUCCESS);
@@ -835,12 +837,13 @@ static bool _spawn_swaybg(char **command) {
                 sway_log_errno(SWAY_ERROR, "close failed");
                 return false;
         }
-        if (waitpid(pid, NULL, 0) < 0) {
+        int fork_status = 0;
+        if (waitpid(pid, &fork_status, 0) < 0) {
                 sway_log_errno(SWAY_ERROR, "waitpid failed");
                 return false;
         }
 
-        return true;
+        return WIFEXITED(fork_status) && WEXITSTATUS(fork_status) == EXIT_SUCCESS;
 }
 
 bool spawn_swaybg(void) {