pln_zap_transient_flags() fixes up planes stuck in the air (commit
7ca4f412, v4.3.12). Since commit 4e9e58bf (v4.3.14), it writes back
the fixed planes. This is wrong for empdump.
empdump should touch data only on successful import. When it fails
because ef_verify() fails, and any planes are found stuck in the air,
the plane file gets rewritten.
Make parameter ef_verify() take parameter may_put to let empdump
suppress the plane write-back. The plane file still get written out
on successful import, along with the other imported game state.
empdump -i now complains about extra rows instead of silently growing
the file to a size the server will reject. Affects tables sector,
nation, realms, game.
Bonus fix: better error message on I/O error or insufficient memory.
New struct empfile member nent replaces ef_open() parameter nelt.
Cleaner, because the expected size is a property of the file, not of
how it's used. Also fixes empdump to check file sizes.
Complication: with EFF_CREATE, ef_open() creates an empty file, to be
extended to the correct size. Callers passed nelt argument -1 along
with EFF_CREATE, to make ef_open() accept the empty file. Can't do
the same for empfile member nent. Instead, make ef_open() not check
the (zero) size then.
Replaces commit 5750107b, v4.3.15.
New struct empfile member base replaces ef_open_view() parameter base.
Cleaner, because the base table is a property of the view, not of how
it's used.
Use it to clean up verify_fail()'s base table access, and for extra
sanity checks in ef_open() and ef_open_view().
ef_open() handles onresize() failing incorrectly. Instead of fixing
that, drop the failure mode. It's not really used: unit_onresize()
fails only when used incorrectly. It isn't. If it ever is, ignoring
the failure is safe.
ef_open() and ef_close() clear EFF_SENTINEL because of that. Broken
since commit 1492845c (v4.3.17) added EFF_SENTINEL. Harmless, as no
file-backed table has a sentinel.
Why upgrade? I'm not a lawyer, but here's my take on the differences
to version 2:
* Software patents: better protection against abuse of patents to
prevent users from exercising the rights under the GPL. I doubt
we'll get hit with a patent suit, but it's a good move just on
general principles.
* License compatibility: compatible with more free licenses, i.e. can
"steal" more free software for use in Empire. I don't expect to steal
much, but it's nice to have the option.
* Definition of "source code": modernization of some details for today's
networked world, to make it easier to distribute the software. Not
really relevant to us now, as we normally distribute full source code.
* Tivoization: this is about putting GPL-licensed software in hardware,
then make the hardware refuse to run modified software. "Neat" trick
to effectively deny its users their rights under the GPL. Abuse was
"pioneered" by TiVo (popular digital video recorders). GPLv3 forbids
it. Unlikely to become a problem for us.
* Internationalization: more careful wording, to harden the license
outside the US. The lawyers tell us it better be done that way.
* License violations: friendlier way to deal with license violations.
This has come out of past experience enforcing the GPL.
* Additional permissions: Probably not relevant to us.
Also include myself in the list of principal authors.
Oops when a stale copy is written back, i.e. the processor was yielded
since the copy was made. Such bugs are difficult to spot. Sequence
numbers catch them when they do actual harm (they also catch different
bugs). Generation numbers catch them even when they don't.
New ef_generation to count generations. Call new ef_make_stale() to
increment it whenever the processor may be yielded.
New struct emptypedstr member generation. To conserve space, make it
a bit-field of twelve bits, i.e. generations are only recorded modulo
2^12. Make sure all members of unit empobj_storage share it. It is
only used in copies; its value on disk and in the cache is
meaningless. Copies with generation other than ef_generation are
stale. Stale copies that are a multiple of 2^12 generations old can't
be detected, but that is sufficiently improbable.
Set generation to ef_generation by calling new ef_mark_fresh() when
making copies in ef_read() and ef_blank(). nav_ship() and
fltp_to_list() make copies without going through ef_read(), and
therefore need to call ef_mark_fresh() as well. Also call it in
obj_changed() to make check_sect_ok() & friends freshen their argument
when it is unchanged.
New must_be_fresh() oopses when its argument is stale. Call it in
ef_write() to catch write back of stale copies.
Store them and ef_type in bit-fields.
Allocate eight bits for ef_type. Values range from 0 to EF_GAME
(currently 16), so this is plenty.
Allocate twelve bits for sequence numbers. Sequence number mismatches
are now missed when the numbers are equal modulo 2^12. Still
sufficiently improbable.
Common machines store the bit-fields in a 32 bit word. There are
twelve bits left in that word for future use. Total savings 16 bits,
which is exactly what the previous commit spent on wider uids on
common machines.
Before, they were stored as short. Wider uids use more space, but the
next commit will recover it by narrowing other members.
The use of short has always limited the number of ships, planes, land
units and nukes to SHRT_MAX (commonly 32768). Only the most extreme
games ever came close.
Commit 49780e2c (v4.3.12) added struct sctstr member sct_uid to make
struct empobj member uid work for sectors. This made the limit apply
to sectors as well. We've had games with more than 32768 sectors.
Really belongs there, because it manipulates empfile[].
New ef_open_view() to replace ef_init_view(). Make ef_close() cope
with views, and remove ef_fina_view(). Make ef_extend() and
ef_truncate() oops on views.
Xundump had special hackery to maintain configuration tables'
sentinels: xubody() and getobj() added a sentinel element when
initializing or growing a table, which xubody() stripped off again
before returning. The latter was an unclean hack.
Replace this by building knowledge of sentinels into struct empfile:
new flag EFF_SENTINEL, set for the appropriate members of empfile[],
obeyed by ef_extend() and ef_truncate().
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().
Commit f33b96b1 (v4.3.12) made files again set timestamps. That was
intentionally suppressed in commit 990eb46b (v4.3.10), because it
facilitates attacks against the PRNG. Commit 8f98e53a (v4.3.0) had
added it as a feature.
Fix by making files's main() pass new flag EFF_NOTIME to ef_open().
Implement the flag in do_write().
Certain tables have a fixed size depending on configuration: EF_SECTOR
has WORLD_SZ() elements, EF_NATION, EF_MAP and EF_BMAP have MAXNOC
elements, and EF_REALM has MAXNOC * MAXNOR elements. Bad things
happen if the files backing them are shorter.
Pass expected size to ef_open(), and make it fail when the actual size
differs.
Make sure all members of unit empobj_storage share it.
Add matching timestamp member to struct comstr, struct empobj, struct
gamestr, struct lonstr, struct natstr, struct nwsstr, struct trdstr,
struct trtstr. The timestamp isn't yet set for these. To be fixed.
Move the timestamp member to the right place in struct lndstr, struct
loststr, struct realmstr, struct nukstr, struct plnstr, struct sctstr,
struct shpstr.
Where ordinary selectors specify a value stored in some object,
virtual selectors specify a function to call to compute a value
associated with some object.
Use them to replace the special case xdump ver by new table
EF_VERSION.
Move configkeys[] to lib/common because nsc_init() needs it to
initialize empfile[EF_VERSION].cadef.
New struct emptypedstr to avoid depending on empobj.h there.
Remove now superfluous manual initializations elsewhere.
This doesn't fix any missing initializations.
Read-only was a bit of a misnomer: you could write to the table by
obtaining a pointer into it from ef_ptr(), you just couldn't write to
the backing file.
Semantic changes:
* ef_flush() is now allowed when the table is file-backed or privately
mapped. Before, it had to be file-backed. Flushing a privately
mapped table does nothing, just like flushing a read-only table did.
* ef_write() is now allowed when the table is file-backed or fully
cached. Before, it had to be file-backed and not read-only.
Writing to a privately mapped file-backed table doesn't write to the
file.
* ef_extend() is not implemented for privately mapped tables, just
like it wasn't implemented for read-only tables.
Split ef_init() into two functions: empfile_init() for initialization,
and empfile_fixup() to fix it up for configuration. Put them next to
empfile[]. Move the call to empfile_init() from behind emp_config()
to before it.
(gamestr, EF_GAME, game_ca): New.
(empfile): Declare the table.
(ef_open_srv, ef_close_srv): Open and close it.
(main): Create it.
(empobj_storage): New member game.
(EF_DYNMAX): New.
(EF_IS_GAME_STATE): Use it.
other. Ensure headers in include/ can be included in any order
(except for econfig-spec.h, which is special). New header types.h to
help avoid inclusion cycles. Sort include directives. Remove some
superflous includes.
