fix(esp_linenoise): close eventfd associated with an instance when deleting it

Add a Kconfig option to let the user select the maximum number of instance
that are possible to be created simultaneously.

Update the behavioral tests to test this new feature.

Author: SoucheSouche

esp_linenoise/Kconfig

@@ -0,0 +1,15 @@
+menu "esp_linenoise configuration"
+    config ESP_LINENOISE_MAX_INSTANCE_NB
+        int "Maximum number of esp_linenoise instances that can be created simultaneously"
+        range 1 32
+        default 5
+        help
+            Specifies the maximum number of esp_linenoise instances that can be created simultaneously.
+            This limitation applies only when esp_linenoise_abort is used, and the following note is
+            relevant in that context.
+
+            A dynamic memory allocation is performed when the first esp_linenoise instance is created and is
+            freed once the last instance is deleted. The allocated memory size is proportional to the value
+            set in this configuration. Therefore, it is recommended to keep this value as low as possible
+            to reduce memory consumption while ensuring the application’s functional requirements are met.
+endmenu

esp_linenoise/idf_component.yml

@@ -1,4 +1,4 @@
-version: "1.0.1"
+version: "1.0.2"
 description: "ESP Linenoise - Line editing C library"
 url: https://github.com/espressif/idf-extra-components/tree/master/esp_linenoise
 license: Apache-2.0

esp_linenoise/src/esp_linenoise_internals.c

@@ -92,7 +92,9 @@ esp_err_t esp_linenoise_set_event_fd(esp_linenoise_instance_t *instance)
 
     /* Tell linenoise what file descriptor to add to the read file descriptor set,
      * that will be used to signal a read termination */
-    esp_vfs_eventfd_config_t eventfd_config = ESP_VFS_EVENTD_CONFIG_DEFAULT();
+    esp_vfs_eventfd_config_t eventfd_config = {
+        .max_fds = CONFIG_ESP_LINENOISE_MAX_INSTANCE_NB
+    };
     esp_err_t ret = esp_vfs_eventfd_register(&eventfd_config);
     int new_eventfd = -1;
     if (ret != ESP_ERR_INVALID_ARG) {
@@ -102,6 +104,12 @@ esp_err_t esp_linenoise_set_event_fd(esp_linenoise_instance_t *instance)
         return ESP_FAIL;
     }
 
+    /* make sure the FD returned is not -1, which would indicate that eventfd
+     * has reached the maximum number of FDs it can create */
+    if (new_eventfd == -1) {
+        return ESP_FAIL;
+    }
+
     state->mux = xSemaphoreCreateMutex();
     if (state->mux == NULL) {
         close(new_eventfd);
@@ -136,6 +144,9 @@ esp_err_t esp_linenoise_remove_event_fd(esp_linenoise_instance_t *instance)
     eventfd_pair_t *prev = NULL;
     SLIST_FOREACH(cur, &s_eventfd_pairs, next_pair) {
         if (cur->in_fd == config->in_fd) {
+            /* close the eventfd */
+            close(cur->eventfd);
+
             if (prev == NULL) {
                 /* remove head */
                 SLIST_REMOVE_HEAD(&s_eventfd_pairs, next_pair);
@@ -161,6 +172,13 @@ esp_err_t esp_linenoise_remove_event_fd(esp_linenoise_instance_t *instance)
     /* free the mutex */
     vSemaphoreDelete(state->mux);
 
+    /* if the list is empty, it means the last instance of esp_linenoise
+     * running is being deleted. Unregister eventfd to free the heap memory
+     * allocated when calling esp_vfs_eventfd_register */
+    if (SLIST_EMPTY(&s_eventfd_pairs)) {
+        return esp_vfs_eventfd_unregister();
+    }
+
     return ESP_OK;
 }