diff options
| -rw-r--r-- | engines/parallaction/commands.cpp | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/engines/parallaction/commands.cpp b/engines/parallaction/commands.cpp index fada14c94e..44910b35aa 100644 --- a/engines/parallaction/commands.cpp +++ b/engines/parallaction/commands.cpp @@ -295,11 +295,19 @@ void runCommands(Command *list, Zone *z) { break; case CMD_ON: // on - u->_zone->_flags &= ~kFlagsRemove; - u->_zone->_flags |= kFlagsActive; - if ((u->_zone->_type & 0xFFFF) == kZoneGet) { - addJob(&jobDisplayDroppedItem, u->_zone, kPriority17 ); - } + // WORKAROUND: the original DOS-based engine didn't check u->_zone before dereferencing + // the pointer to get structure members, thus leading to crashes in systems with memory + // protection. + // As a side note, the overwritten address is the 5th entry in the DOS interrupt table + // (print screen handler): this suggests that a system would hang when the print screen + // key is pressed after playing Nippon Safes, provided that this code path is taken. + if (u->_zone != NULL) { + u->_zone->_flags &= ~kFlagsRemove; + u->_zone->_flags |= kFlagsActive; + if ((u->_zone->_type & 0xFFFF) == kZoneGet) { + addJob(&jobDisplayDroppedItem, u->_zone, kPriority17 ); + } + } break; case CMD_OFF: // off |