Changeset 87822ce in mainline for uspace/app/top/screen.c

Timestamp:

2021-03-04T19:14:30Z (3 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/app/top/screen.c (modified) (4 diffs)

uspace/app/top/screen.c

@@ -534 +534 @@
 /** Get char with timeout
  *
+ * @param sec Timeout in seconds
+ * @param rch Place to store character on success
+ * @return EOK on success, ETIMEOUT on time out, EIO on other error
  */
-int tgetchar(sec_t sec)
-{
+errno_t tgetchar(sec_t sec, int *rch)
+{
+        errno_t rc;
+
         /*
          * Reset timeleft whenever it is not positive.
@@ -548 +553 @@
          * update timeleft so that the next call to tgetchar()
          * will not wait as long. If there is no input,
-         * make timeleft zero and return -1.
+         * make timeleft zero and return ETIMEOUT.
          */
 
@@ -557 +562 @@
 
                 warning_timeleft -= timeleft;
-                if (!console_get_event_timeout(console, &event, &timeleft)) {
+                rc = console_get_event_timeout(console, &event, &timeleft);
+                if (rc == ETIMEOUT) {
                         timeleft = 0;
-                        return -1;
-                }
+                        return ETIMEOUT;
+                }
+
+                if (rc != EOK)
+                        return EIO;
+
                 warning_timeleft += timeleft;
 
@@ -567 +577 @@
         }
 
-        return (int) c;
+        *rch = (int) c;
+        return EOK;
 }