Changeset 01900b6 in mainline for uspace/app/taskdump/taskdump.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/app/taskdump/taskdump.c (modified) (1 diff)

uspace/app/taskdump/taskdump.c

@@ -126 +126 @@
 static errno_t connect_task(task_id_t task_id)
 {
-        async_sess_t *ksess = async_connect_kbox(task_id);
+        errno_t rc;
+        async_sess_t *ksess = async_connect_kbox(task_id, &rc);
 
         if (!ksess) {
-                if (errno == ENOTSUP) {
+                if (rc == ENOTSUP) {
                         printf("You do not have userspace debugging support "
                             "compiled in the kernel.\n");
                         printf("Compile kernel with 'Support for userspace debuggers' "
                             "(CONFIG_UDEBUG) enabled.\n");
-                        return errno;
+                        return rc;
                 }
 
                 printf("Error connecting\n");
                 printf("async_connect_kbox(%" PRIu64 ") -> %s", task_id, str_error_name(errno));
-                return errno;
-        }
-
-        errno_t rc = udebug_begin(ksess);
+                return rc;
+        }
+
+        rc = udebug_begin(ksess);
         if (rc != EOK) {
                 printf("udebug_begin() -> %s\n", str_error_name(rc));