Changeset 87822ce in mainline for uspace/lib/c/generic/io/console.c

Timestamp:

2021-03-04T19:14:30Z (4 years ago)

Author:

Jiri Svoboda <jiri@…>

Branches:

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

Children:

d6c4d40

Parents:

760a392

Message:

Avoid infinite loop when console communication is broken

Need to make sure callers of console_get_event_timeout() can distinguish
between timeout and I/O error. Fix all callers of console_get_event()
and console_get_event_timeout() not to enter infinite loop when console
connection is broken. Also avoid setting of errno variable.

File:

• uspace/lib/c/generic/io/console.c (modified) (5 diffs)

uspace/lib/c/generic/io/console.c

@@ -180 +180 @@
 }
 
-bool console_get_event(console_ctrl_t *ctrl, cons_event_t *event)
+/** Get console event.
+ *
+ * @param ctrl Console
+ * @param event Place to store event
+ * @return EOK on success, EIO on failure
+ */
+errno_t console_get_event(console_ctrl_t *ctrl, cons_event_t *event)
 {
         if (ctrl->input_aid == 0) {
@@ -192 +198 @@
                 async_wait_for(aid, &rc);
 
-                if (rc != EOK) {
-                        errno = rc;
-                        return false;
-                }
+                if (rc != EOK)
+                        return EIO;
 
                 rc = console_ev_decode(&result, event);
-                if (rc != EOK) {
-                        errno = rc;
-                        return false;
-                }
+                if (rc != EOK)
+                        return EIO;
         } else {
                 errno_t retval;
@@ -208 +210 @@
                 ctrl->input_aid = 0;
 
-                if (retval != EOK) {
-                        errno = retval;
-                        return false;
-                }
+                if (retval != EOK)
+                        return EIO;
 
                 errno_t rc = console_ev_decode(&ctrl->input_call, event);
-                if (rc != EOK) {
-                        errno = rc;
-                        return false;
-                }
-        }
-
-        return true;
-}
-
-bool console_get_event_timeout(console_ctrl_t *ctrl, cons_event_t *event,
+                if (rc != EOK)
+                        return EIO;
+        }
+
+        return EOK;
+}
+
+/** Get console event with timeout.
+ *
+ * @param ctrl Console
+ * @param event Place to store event
+ * @param timeout Pointer to timeout. This will be updated to reflect
+ *                the remaining time in case of timeout.
+ * @return EOK on success (event received), ETIMEOUT on time out,
+ *         EIO on I/O error (e.g. lost console connection), ENOMEM
+ *         if out of memory
+ */
+errno_t console_get_event_timeout(console_ctrl_t *ctrl, cons_event_t *event,
     usec_t *timeout)
 {
@@ -239 +247 @@
         errno_t rc = async_wait_timeout(ctrl->input_aid, &retval, *timeout);
         if (rc != EOK) {
+                if (rc == ENOMEM)
+                        return ENOMEM;
                 *timeout = 0;
-                errno = rc;
-                return false;
+                return ETIMEOUT;
         }
 
         ctrl->input_aid = 0;
 
-        if (retval != EOK) {
-                errno = retval;
-                return false;
-        }
+        if (retval != EOK)
+                return EIO;
 
         rc = console_ev_decode(&ctrl->input_call, event);
-        if (rc != EOK) {
-                errno = rc;
-                return false;
-        }
+        if (rc != EOK)
+                return EIO;
 
         /* Update timeout */
@@ -262 +267 @@
         *timeout -= NSEC2USEC(ts_sub_diff(&t1, &t0));
 
-        return true;
+        return EOK;
 }