cleanup output-background subcommand handling

- fixes a double-free error when access() failed.

- refactor code to make memory managment (alloc/free) more straightforward
   - do not bring the temporary wordexp_t struct around
   - do not postpone errors handling

1 files changed, 28 insertions, 21 deletions

diff --git a/sway/commands/output/background.c b/sway/commands/output/background.c
index 4f422cec..55cbdff0 100644
--- a/sway/commands/output/background.c
+++ b/sway/commands/output/background.c
@@ -69,42 +69,49 @@ struct cmd_results *output_cmd_background(int argc, char **argv) {
                         return cmd_res;
                 }
                 free(src);
-                src = p.we_wordv[0];
+                src = strdup(p.we_wordv[0]);
+                wordfree(&p);
+                if (!src) {
+                        wlr_log(L_ERROR, "Failed to duplicate string");
+                        return cmd_results_new(CMD_FAILURE, "output",
+                                "Unable to allocate resource");
+                }
+
                 if (config->reading && *src != '/') {
+                        // src file is inside configuration dir
+
                         char *conf = strdup(config->current_config);
-                        if (conf) {
-                                char *conf_path = dirname(conf);
-                                src = malloc(strlen(conf_path) + strlen(src) + 2);
-                                if (!src) {
-                                        free(conf);
-                                        wordfree(&p);
-                                        wlr_log(L_ERROR,
-                                                "Unable to allocate resource: Not enough memory");
-                                        return cmd_results_new(CMD_FAILURE, "output",
+                        if(!conf) {
+                                wlr_log(L_ERROR, "Failed to duplicate string");
+                                return cmd_results_new(CMD_FAILURE, "output",
                                                 "Unable to allocate resources");
-                                }
-                                sprintf(src, "%s/%s", conf_path, p.we_wordv[0]);
+                        }
+
+                        char *conf_path = dirname(conf);
+                        char *rel_path = src;
+                        src = malloc(strlen(conf_path) + strlen(src) + 2);
+                        if (!src) {
+                                free(rel_path);
                                 free(conf);
-                        } else {
-                                wlr_log(L_ERROR, "Unable to allocate background source");
+                                wlr_log(L_ERROR, "Unable to allocate memory");
+                                return cmd_results_new(CMD_FAILURE, "output",
+                                                "Unable to allocate resources");
                         }
+
+                        sprintf(src, "%s/%s", conf_path, rel_path);
+                        free(rel_path);
+                        free(conf);
                 }
 
                 if (access(src, F_OK) == -1) {
                         struct cmd_results *cmd_res = cmd_results_new(CMD_FAILURE, "output",
                                 "Unable to access background file '%s': %s", src, strerror(errno));
                         free(src);
-                        wordfree(&p);
                         return cmd_res;
                 }
 
-                output->background = strdup(src);
+                output->background = src;
                 output->background_option = strdup(mode);
-                if (src != p.we_wordv[0]) {
-                        free(src);
-                }
-                wordfree(&p);
-
                 argc -= j + 1; argv += j + 1;
         }