libobs: Check fwrite return value for extra safety

libobs/util/config-file.c

@@ -405,9 +405,15 @@ int config_save(config_t *config)
 	}
 
 #ifdef _WIN32
-	fwrite("\xEF\xBB\xBF", 1, 3, f);
+	if (fwrite("\xEF\xBB\xBF", 3, 1, f) != 1) {
+		fclose(f);
+		return CONFIG_ERROR;
+	}
 #endif
-	fwrite(str.array, 1, str.len, f);
+	if (fwrite(str.array, str.len, 1, f) != 1) {
+		fclose(f);
+		return CONFIG_ERROR;
+	}
 	fclose(f);
 
 	pthread_mutex_unlock(&config->mutex);
@@ -444,6 +450,8 @@ int config_save_safe(config_t *config, const char *temp_ext,
 	config->file = file;
 
 	if (ret != CONFIG_SUCCESS) {
+		blog(LOG_ERROR, "config_save_safe: failed to "
+			"write to %s", temp_file.array);
 		goto cleanup;
 	}
 

libobs/util/platform.c

@@ -262,10 +262,19 @@ bool os_quick_write_utf8_file(const char *path, const char *str, size_t len,
 	if (!f)
 		return false;
 
-	if (marker)
-		fwrite("\xEF\xBB\xBF", 1, 3, f);
-	if (len)
-		fwrite(str, 1, len, f);
+	if (marker) {
+		if (fwrite("\xEF\xBB\xBF", 3, 1, f) != 1) {
+			fclose(f);
+			return false;
+		}
+	}
+
+	if (len) {
+		if (fwrite(str, len, 1, f) != 1) {
+			fclose(f);
+			return false;
+		}
+	}
 	fflush(f);
 	fclose(f);
 
@@ -292,6 +301,8 @@ bool os_quick_write_utf8_file_safe(const char *path, const char *str,
 	dstr_cat(&temp_path, temp_ext);
 
 	if (!os_quick_write_utf8_file(temp_path.array, str, len, marker)) {
+		blog(LOG_ERROR, "os_quick_write_utf8_file_safe: failed to "
+			"write to %s", temp_path.array);
 		goto cleanup;
 	}