Changeset 87822ce in mainline for uspace/app/tetris

Timestamp:

2021-03-04T19:14:30Z (5 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.

Location:

uspace/app/tetris

Files:

• scores.c (modified) (2 diffs)
• screen.c (modified) (5 diffs)
• tetris.c (modified) (1 diff)

uspace/app/tetris/scores.c

@@ -126 +126 @@
         cons_event_t ev;
         kbd_event_t *kev;
+        errno_t rc;
 
         clear_screen();
@@ -141 +142 @@
         while (true) {
                 console_flush(console);
-                if (!console_get_event(console, &ev))
+                rc = console_get_event(console, &ev);
+                if (rc != EOK)
                         exit(1);
 

uspace/app/tetris/screen.c

@@ -54 +54 @@
  */
 
+#include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -340 +341 @@
 {
         usec_t timeout = fallrate;
+        errno_t rc;
 
         while (timeout > 0) {
                 cons_event_t event;
 
-                if (!console_get_event_timeout(console, &event, &timeout))
+                rc = console_get_event_timeout(console, &event, &timeout);
+                if (rc == ETIMEOUT)
                         break;
+                if (rc != EOK)
+                        exit(1);
         }
 }
@@ -354 +359 @@
 int tgetchar(void)
 {
+        errno_t rc;
+
         /*
          * Reset timeleft to fallrate whenever it is not positive
@@ -376 +383 @@
                 cons_event_t event;
 
-                if (!console_get_event_timeout(console, &event, &timeleft)) {
+                rc = console_get_event_timeout(console, &event, &timeleft);
+                if (rc == ETIMEOUT) {
                         timeleft = 0;
                         return -1;
                 }
+                if (rc != EOK)
+                        exit(1);
 
                 if (event.type == CEV_KEY && event.ev.key.type == KEY_PRESS)
@@ -394 +404 @@
 {
         char32_t c = 0;
+        errno_t rc;
 
         while (c == 0) {
                 cons_event_t event;
 
-                if (!console_get_event(console, &event))
+                rc = console_get_event(console, &event);
+                if (rc == ETIMEOUT)
                         return -1;
+                if (rc != EOK)
+                        exit(1);
 
                 if (event.type == CEV_KEY && event.ev.key.type == KEY_PRESS)

uspace/app/tetris/tetris.c

@@ -202 +202 @@
         while (true) {
                 int i = getchar();
+                if (i < 0)
+                        return 0;
 
                 switch (i) {