Changeset 01900b6 in mainline for uspace/lib/c/generic/async/client.c

Timestamp:

2020-01-21T15:10:26Z (5 years ago)

Author:

Martin Decky <martin@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

51da086

Parents:

f8fb03b

Message:

Use an optional output argument instead of errno to propagate the error

The use of errno is troublesome in all other than top-level library
functions since the value in errno might get overwritten by subsequent
inner calls on the error path (e.g. cleanup, deallocation, etc.). The
optional output argument makes it possible to explicitly ignore the
error code if it is not needed, but still to pass it reliably back to
the original caller.

This change affecs async_connect_me_to(),
async_connect_me_to_blocking(), async_connect_kbox(), service_connect(),
service_connect_blocking() and loader_connect().

File:

• uspace/lib/c/generic/async/client.c (modified) (7 diffs)

uspace/lib/c/generic/async/client.c

@@ -889 +889 @@
  * @param arg2  User defined argument.
  * @param arg3  User defined argument.
+ * @param rc    Placeholder for return code. Unused if NULL.
  *
  * @return New session on success or NULL on error.
@@ -894 +895 @@
  */
 async_sess_t *async_connect_me_to(async_exch_t *exch, iface_t iface,
-    sysarg_t arg2, sysarg_t arg3)
+    sysarg_t arg2, sysarg_t arg3, errno_t *rc)
 {
         if (exch == NULL) {
-                errno = ENOENT;
+                if (rc != NULL)
+                        *rc = ENOENT;
+
                 return NULL;
         }
@@ -903 +906 @@
         async_sess_t *sess = calloc(1, sizeof(async_sess_t));
         if (sess == NULL) {
-                errno = ENOMEM;
+                if (rc != NULL)
+                        *rc = ENOMEM;
+
                 return NULL;
         }
 
         cap_phone_handle_t phone;
-        errno_t rc = async_connect_me_to_internal(exch->phone, iface, arg2,
+        errno_t ret = async_connect_me_to_internal(exch->phone, iface, arg2,
             arg3, 0, &phone);
-        if (rc != EOK) {
-                errno = rc;
+        if (ret != EOK) {
+                if (rc != NULL)
+                        *rc = ret;
+
                 free(sess);
                 return NULL;
@@ -957 +964 @@
  * @param arg2  User defined argument.
  * @param arg3  User defined argument.
+ * @param rc    Placeholder for return code. Unused if NULL.
  *
  * @return New session on success or NULL on error.
@@ -962 +970 @@
  */
 async_sess_t *async_connect_me_to_blocking(async_exch_t *exch, iface_t iface,
-    sysarg_t arg2, sysarg_t arg3)
+    sysarg_t arg2, sysarg_t arg3, errno_t *rc)
 {
         if (exch == NULL) {
-                errno = ENOENT;
+                if (rc != NULL)
+                        *rc = ENOENT;
+
                 return NULL;
         }
@@ -971 +981 @@
         async_sess_t *sess = calloc(1, sizeof(async_sess_t));
         if (sess == NULL) {
-                errno = ENOMEM;
+                if (rc != NULL)
+                        *rc = ENOMEM;
+
                 return NULL;
         }
 
         cap_phone_handle_t phone;
-        errno_t rc = async_connect_me_to_internal(exch->phone, iface, arg2,
+        errno_t ret = async_connect_me_to_internal(exch->phone, iface, arg2,
             arg3, IPC_FLAG_BLOCKING, &phone);
-        if (rc != EOK) {
-                errno = rc;
+        if (ret != EOK) {
+                if (rc != NULL)
+                        *rc = ret;
+
                 free(sess);
                 return NULL;
@@ -999 +1013 @@
 /** Connect to a task specified by id.
  *
- */
-async_sess_t *async_connect_kbox(task_id_t id)
+ * @param id Task to which to connect.
+ * @param rc Placeholder for return code. Unused if NULL.
+ *
+ * @return New session on success or NULL on error.
+ *
+ */
+async_sess_t *async_connect_kbox(task_id_t id, errno_t *rc)
 {
         async_sess_t *sess = calloc(1, sizeof(async_sess_t));
         if (sess == NULL) {
-                errno = ENOMEM;
+                if (rc != NULL)
+                        *rc = ENOMEM;
+
                 return NULL;
         }
 
         cap_phone_handle_t phone;
-        errno_t rc = ipc_connect_kbox(id, &phone);
-        if (rc != EOK) {
-                errno = rc;
+        errno_t ret = ipc_connect_kbox(id, &phone);
+        if (ret != EOK) {
+                if (rc != NULL)
+                        *rc = ret;
+
                 free(sess);
                 return NULL;