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Add sequence numbers to game state

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This oopses on output dependency violations, e.g. two threads doing a
read-modify-write without synchronization, or the one thread nesting
several read-modify-writes.  Such bugs are difficult to spot, and tend
to be abusable.  I figure we have quite a few of them.

New struct emptypedstr member seqno.  Make sure all members of unit
empobj_storage share it.  Initialize it in files: main() and
file_sct_init().  Set it in ef_blank() and new ef_set_uid() by calling
new get_seqno().  Use ef_set_uid() when copying objects: swaps(),
doland(), doship(), doplane(), dounit(), delete_old_news().  Step it
in ef_write() by calling new new_seqno().

Factor do_read() out of fillcache() to make it available for
get_seqno().
This commit is contained in:
Markus Armbruster 2008-05-17 22:44:00 +02:00
parent 087c0aae36
commit 536ef0b0a2
20 changed files with 134 additions and 19 deletions
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2
include/file.h
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@ -67,6 +67,7 @@ struct empfile {
struct emptypedstr {
short ef_type;
short uid;
unsigned seqno;
time_t timestamp;
};
@ -189,6 +190,7 @@ extern int ef_close(int);
extern int ef_flush(int);
extern void ef_blank(int, int, void *);
extern int ef_write(int, int, void *);
extern void ef_set_uid(int, void *, int);
extern int ef_extend(int, int);
extern int ef_ensure_space(int, int, int);
extern int ef_truncate(int, int);