wispr: Add a reference counter mechanism on contexts

Basically, wispr provides a pointer (a wispr/portal context) to third parties
(agent, gweb...) which are answering asynchronously. However, if the technology
related to the service owning such context is disabled: this context is not
valid anymore, leading to a crash when third part answers after such action.

In order to avoid such issue, wispr implement an internal refcount system.

Fixes BMC#25479

diff --git a/src/wispr.c b/src/wispr.c
index 9412f1e..9571fd8 100644 (file)
--- a/src/wispr.c
+++ b/src/wispr.c
@@ -33,6 +33,12 @@
 #define STATUS_URL_IPV4  "http://ipv4.connman.net/online/status.html"
 #define STATUS_URL_IPV6  "http://ipv6.connman.net/online/status.html"
 
+#define wispr_portal_context_ref(_wp_ctxt) \
+       wispr_portal_context_ref_debug(_wp_ctxt, __FILE__, __LINE__, __func__)
+
+#define wispr_portal_context_unref(_wp_ctxt) \
+       wispr_portal_context_unref_debug(_wp_ctxt, __FILE__, __LINE__, __func__)
+
 struct connman_wispr_message {
        gboolean has_error;
        const char *current_element;
@@ -59,6 +65,8 @@ struct wispr_route {
 };
 
 struct connman_wispr_portal_context {
+       int refcount;
+
        struct connman_service *service;
        enum connman_ipconfig_type type;
 
@@ -159,7 +167,8 @@ static void free_connman_wispr_portal_context(struct connman_wispr_portal_contex
        if (wp_context == NULL)
                return;
 
-       connman_service_unref(wp_context->service);
+       if (wp_context->service != NULL)
+               connman_service_unref(wp_context->service);
 
        if (wp_context->token > 0)
                connman_proxy_lookup_cancel(wp_context->token);
@@ -167,11 +176,14 @@ static void free_connman_wispr_portal_context(struct connman_wispr_portal_contex
        if (wp_context->request_id > 0)
                g_web_cancel_request(wp_context->web, wp_context->request_id);
 
-       g_web_unref(wp_context->web);
+       if (wp_context->web != NULL)
+               g_web_unref(wp_context->web);
 
        g_free(wp_context->redirect_url);
 
-       g_web_parser_unref(wp_context->wispr_parser);
+       if (wp_context->wispr_parser != NULL)
+               g_web_parser_unref(wp_context->wispr_parser);
+
        connman_wispr_message_init(&wp_context->wispr_msg);
 
        g_free(wp_context->wispr_username);
@@ -183,6 +195,62 @@ static void free_connman_wispr_portal_context(struct connman_wispr_portal_contex
        g_free(wp_context);
 }
 
+static struct connman_wispr_portal_context *
+wispr_portal_context_ref_debug(struct connman_wispr_portal_context *wp_context,
+                               const char *file, int line, const char *caller)
+{
+       DBG("%p ref %d by %s:%d:%s()", wp_context, wp_context->refcount + 1,
+                                                       file, line, caller);
+
+       __sync_fetch_and_add(&wp_context->refcount, 1);
+
+       return wp_context;
+}
+
+static struct connman_wispr_portal_context *
+wispr_portal_context_unref_debug(struct connman_wispr_portal_context *wp_context,
+                               const char *file, int line, const char *caller)
+{
+       DBG("%p ref %d by %s:%d:%s()", wp_context, wp_context->refcount - 1,
+                                                       file, line, caller);
+
+       if (__sync_fetch_and_sub(&wp_context->refcount, 1) != 1)
+               return wp_context;
+
+       free_connman_wispr_portal_context(wp_context);
+
+       return NULL;
+}
+
+static struct connman_wispr_portal_context *create_wispr_portal_context(void)
+{
+       struct connman_wispr_portal_context *wp_context = NULL;
+
+        wp_context = g_try_new0(struct connman_wispr_portal_context, 1);
+        if (wp_context == NULL)
+               return NULL;
+
+        wp_context->refcount = 1;
+
+        return wp_context;
+}
+
+/**
+ * This function is usued only by free_connman_wispr_portal, context pointer
+ * might still be owned by a third party (gweb, agent dbus call...)
+ * so we don't want service to be referenced in any context when it is not
+ * valid anymore.
+ */
+static void
+reset_service_usage(struct connman_wispr_portal_context *wp_context)
+{
+       if (wp_context->service == NULL)
+               return;
+
+       connman_service_unref(wp_context->service);
+       wp_context->service = NULL;
+}
+
 static void free_connman_wispr_portal(gpointer data)
 {
        struct connman_wispr_portal *wispr_portal = data;
@@ -192,8 +260,15 @@ static void free_connman_wispr_portal(gpointer data)
        if (wispr_portal == NULL)
                return;
 
-       free_connman_wispr_portal_context(wispr_portal->ipv4_context);
-       free_connman_wispr_portal_context(wispr_portal->ipv6_context);
+       if (wispr_portal->ipv4_context != NULL) {
+               reset_service_usage(wispr_portal->ipv4_context);
+               wispr_portal_context_unref(wispr_portal->ipv4_context);
+       }
+
+       if (wispr_portal->ipv6_context != NULL) {
+               reset_service_usage(wispr_portal->ipv6_context);
+               wispr_portal_context_unref(wispr_portal->ipv6_context);
+       }
 
        g_free(wispr_portal);
 }
@@ -487,6 +562,8 @@ static void wispr_portal_request_portal(struct connman_wispr_portal_context *wp_
 
        if (wp_context->request_id == 0)
                wispr_portal_error(wp_context);
+       else
+               wispr_portal_context_ref(wp_context);
 }
 
 static gboolean wispr_input(const guint8 **data, gsize *length,
@@ -528,6 +605,7 @@ static void wispr_portal_browser_reply_cb(struct connman_service *service,
 
        DBG("");
 
+       wp_context = wispr_portal_context_unref(wp_context);
        if (service == NULL || wp_context == NULL)
                return;
 
@@ -552,8 +630,14 @@ static void wispr_portal_request_wispr_login(struct connman_service *service,
 
        DBG("");
 
+       wp_context = wispr_portal_context_unref(wp_context);
+       if (wp_context == NULL)
+               return;
+
        if (error != NULL && g_strcmp0(error,
                        "net.connman.Agent.Error.LaunchBrowser") == 0) {
+               wispr_portal_context_ref(wp_context);
+
                __connman_agent_request_browser(service,
                                wispr_portal_browser_reply_cb,
                                wp_context->redirect_url, wp_context);
@@ -571,6 +655,8 @@ static void wispr_portal_request_wispr_login(struct connman_service *service,
                                        "application/x-www-form-urlencoded",
                                        wispr_input, wispr_portal_web_result,
                                        wp_context);
+       if (wp_context->request_id != 0)
+               wispr_portal_context_ref(wp_context);
 
        connman_wispr_message_init(&wp_context->wispr_msg);
 }
@@ -608,10 +694,14 @@ static gboolean wispr_manage_message(GWebResult *result,
 
                wp_context->wispr_result = CONNMAN_WISPR_RESULT_LOGIN;
 
+               wispr_portal_context_ref(wp_context);
+
                if (__connman_agent_request_login_input(wp_context->service,
                                        wispr_portal_request_wispr_login,
-                                       wp_context) != -EINPROGRESS)
+                                       wp_context) != -EINPROGRESS) {
+                       wispr_portal_context_unref(wp_context);
                        wispr_portal_error(wp_context);
+               }
 
                break;
        case 120: /* Falling down */
@@ -653,6 +743,10 @@ static gboolean wispr_portal_web_result(GWebResult *result, gpointer user_data)
 
        DBG("");
 
+       wp_context = wispr_portal_context_unref(wp_context);
+       if (wp_context == NULL)
+               return FALSE;
+
        if (wp_context->request_id == 0)
                return FALSE;
 
@@ -660,6 +754,8 @@ static gboolean wispr_portal_web_result(GWebResult *result, gpointer user_data)
                g_web_result_get_chunk(result, &chunk, &length);
 
                if (length > 0) {
+                       wispr_portal_context_ref(wp_context);
+
                        g_web_parser_feed_data(wp_context->wispr_parser,
                                                                chunk, length);
                        return TRUE;
@@ -685,16 +781,21 @@ static gboolean wispr_portal_web_result(GWebResult *result, gpointer user_data)
                if (g_web_result_get_header(result, "X-ConnMan-Status",
                                                                &str) == TRUE)
                        portal_manage_status(result, wp_context);
-               else
+               else {
+                       wispr_portal_context_ref(wp_context);
+
                        __connman_agent_request_browser(wp_context->service,
                                        wispr_portal_browser_reply_cb,
                                        wp_context->redirect_url, wp_context);
+               }
 
                break;
        case 302:
                if (g_web_supports_tls() == FALSE ||
                                g_web_result_get_header(result, "Location",
                                                        &redirect) == FALSE) {
+                       wispr_portal_context_ref(wp_context);
+
                        __connman_agent_request_browser(wp_context->service,
                                        wispr_portal_browser_reply_cb,
                                        wp_context->status_url, wp_context);
@@ -708,6 +809,8 @@ static gboolean wispr_portal_web_result(GWebResult *result, gpointer user_data)
                wp_context->request_id = g_web_request_get(wp_context->web,
                                redirect, wispr_portal_web_result,
                                wispr_route_request, wp_context);
+               if (wp_context->request_id != 0)
+                       wispr_portal_context_ref(wp_context);
 
                goto done;
        case 400:
@@ -734,6 +837,10 @@ static void proxy_callback(const char *proxy, void *user_data)
 
        DBG("proxy %s", proxy);
 
+       wp_context = wispr_portal_context_unref(wp_context);
+       if (wp_context == NULL)
+               return;
+
        wp_context->token = 0;
 
        if (proxy != NULL && g_strcmp0(proxy, "DIRECT") != 0)
@@ -841,12 +948,15 @@ static int wispr_portal_detect(struct connman_wispr_portal_context *wp_context)
                                                wp_context->service,
                                                proxy_callback, wp_context);
 
-               if (wp_context->token == 0)
+               if (wp_context->token == 0) {
                        err = -EINVAL;
+                       goto done;
+               }
        } else {
                g_timeout_add_seconds(0, no_proxy_callback, wp_context);
        }
 
+       wispr_portal_context_ref(wp_context);
 done:
        g_strfreev(nameservers);
 
@@ -890,9 +1000,9 @@ int __connman_wispr_start(struct connman_service *service,
 
        /* If there is already an existing context, we wipe it */
        if (wp_context != NULL)
-               free_connman_wispr_portal_context(wp_context);
+               wispr_portal_context_unref(wp_context);
 
-       wp_context = g_try_new0(struct connman_wispr_portal_context, 1);
+       wp_context = create_wispr_portal_context();
        if (wp_context == NULL)
                return -ENOMEM;