2 * Empire - A multi-player, client/server Internet based war game.
3 * Copyright (C) 1986-2011, Dave Pare, Jeff Bailey, Thomas Ruschak,
4 * Ken Stevens, Steve McClure, Markus Armbruster
6 * Empire is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, either version 3 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
21 * See files README, COPYING and CREDITS in the root of the source
22 * tree for related information and legal notices. It is expected
23 * that future projects/authors will amend these files as needed.
27 * file.c: Operations on Empire tables (`files' for historical reasons)
29 * Known contributors to this file:
32 * Markus Armbruster, 2005-2011
40 #include <sys/types.h>
50 #include "prototypes.h"
52 static int open_locked(char *, int, mode_t);
53 static int ef_realloc_cache(struct empfile *, int);
54 static int fillcache(struct empfile *, int);
55 static int do_read(struct empfile *, void *, int, int);
56 static int do_write(struct empfile *, void *, int, int);
57 static unsigned get_seqno(struct empfile *, int);
58 static void new_seqno(struct empfile *, void *);
59 static void must_be_fresh(struct empfile *, void *);
60 static void do_blank(struct empfile *, void *, int, int);
61 static int ef_check(int);
63 static unsigned ef_generation;
66 * Open the file-backed table TYPE (EF_SECTOR, ...).
67 * HOW are flags to control operation. Naturally, immutable flags are
69 * If NELT is non-negative, the table must have that many elements.
70 * Return non-zero on success, zero on failure.
71 * You must call ef_close() before the next ef_open().
74 ef_open(int type, int how, int nelt)
77 int oflags, fd, fsiz, nslots;
79 if (ef_check(type) < 0)
81 if (CANT_HAPPEN(how & EFF_IMMUTABLE))
82 how &= ~EFF_IMMUTABLE;
86 if (CANT_HAPPEN(ep->fd >= 0))
89 if (how & EFF_PRIVATE)
92 oflags |= O_CREAT | O_TRUNC;
93 fd = open_locked(ep->file, oflags, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
95 logerror("Can't open %s (%s)", ep->file, strerror(errno));
101 if (fsiz % ep->size) {
102 logerror("Can't open %s (file size not a multiple of record size %d)",
107 ep->fids = fsiz / ep->size;
108 if (nelt >= 0 && nelt != ep->fids) {
109 logerror("Can't open %s (got %d records instead of %d)",
110 ep->file, ep->fids, nelt);
116 if (ep->flags & EFF_STATIC) {
117 /* ep->cache already points to space for ep->csize elements */
119 if (ep->fids > ep->csize) {
120 logerror("Can't open %s (file larger than %d records)",
121 ep->file, ep->csize);
127 if (CANT_HAPPEN(ep->cache))
132 nslots = blksize(fd) / ep->size;
133 if (!ef_realloc_cache(ep, nslots)) {
134 logerror("Can't map %s (%s)", ep->file, strerror(errno));
141 ep->flags = (ep->flags & EFF_IMMUTABLE) | (how & ~EFF_CREATE);
144 /* map file into cache */
145 if ((how & EFF_MEM) && ep->fids) {
146 if (fillcache(ep, 0) != ep->fids) {
147 ep->cids = 0; /* prevent cache flush */
159 open_locked(char *name, int oflags, mode_t mode)
161 int rdlonly = (oflags & O_ACCMODE) == O_RDONLY;
165 fd = _sopen(name, oflags | O_BINARY, rdlonly ? SH_DENYNO : SH_DENYWR,
172 fd = open(name, oflags, mode);
176 lock.l_type = rdlonly ? F_RDLCK : F_WRLCK;
177 lock.l_whence = SEEK_SET;
178 lock.l_start = lock.l_len = 0;
179 if (fcntl(fd, F_SETLK, &lock) == -1) {
188 * Reallocate cache for table EP to hold COUNT slots.
189 * The table must not be allocated statically.
190 * The cache may still be unmapped.
191 * If reallocation succeeds, any pointers obtained from ef_ptr()
193 * If it fails, the cache is unchanged, and errno is set.
194 * Return non-zero on success, zero on failure.
197 ef_realloc_cache(struct empfile *ep, int count)
201 if (CANT_HAPPEN(ep->flags & EFF_STATIC))
203 if (CANT_HAPPEN(count < 0))
207 * Avoid zero slots, because that can lead to null cache, which
208 * would be interpreted as unmapped cache.
212 cache = realloc(ep->cache, count * ep->size);
222 * Open the table TYPE as view of table BASE.
223 * Return non-zero on success, zero on failure.
224 * Beware: views work only as long as BASE doesn't change size!
225 * You must call ef_close(TYPE) before closing BASE.
228 ef_open_view(int type, int base)
232 if (CANT_HAPPEN(!EF_IS_VIEW(type)))
235 if (CANT_HAPPEN(!(ef_flags(base) & EFF_MEM)))
238 ep->cache = empfile[base].cache;
239 ep->csize = empfile[base].csize;
240 ep->flags |= EFF_MEM;
241 ep->baseid = empfile[base].baseid;
242 ep->cids = empfile[base].cids;
243 ep->fids = empfile[base].fids;
248 * Close the open table TYPE (EF_SECTOR, ...).
249 * Return non-zero on success, zero on failure.
257 if (ef_check(type) < 0)
261 if (EF_IS_VIEW(type))
266 if (!(ep->flags & EFF_STATIC)) {
270 if (close(ep->fd) < 0) {
271 logerror("Error closing %s (%s)", ep->file, strerror(errno));
276 ep->flags &= EFF_IMMUTABLE;
277 ep->baseid = ep->cids = ep->fids = 0;
284 * Flush file-backed table TYPE (EF_SECTOR, ...) to its backing file.
285 * Do nothing if the table is privately mapped.
286 * Update timestamps of written elements if table is EFF_TYPED.
287 * Return non-zero on success, zero on failure.
294 if (ef_check(type) < 0)
297 if (ep->flags & EFF_PRIVATE)
298 return 1; /* nothing to do */
299 if (CANT_HAPPEN(ep->fd < 0))
302 * We don't know which cache entries are dirty. ef_write() writes
303 * through, but direct updates through ef_ptr() don't. They are
304 * allowed only with EFF_MEM. Assume the whole cash is dirty
307 if (ep->flags & EFF_MEM) {
308 if (do_write(ep, ep->cache, ep->baseid, ep->cids) < 0)
316 * Return pointer to element ID in table TYPE if it exists, else NULL.
317 * The table must be fully cached, i.e. flags & EFF_MEM.
318 * The caller is responsible for flushing changes he makes.
321 ef_ptr(int type, int id)
325 if (ef_check(type) < 0)
328 if (CANT_HAPPEN(!(ep->flags & EFF_MEM) || !ep->cache))
330 if (id < 0 || id >= ep->fids)
332 return ep->cache + ep->size * id;
336 * Read element ID from table TYPE into buffer INTO.
337 * FIXME pass buffer size!
338 * INTO is marked fresh with ef_mark_fresh().
339 * Return non-zero on success, zero on failure.
342 ef_read(int type, int id, void *into)
347 if (ef_check(type) < 0)
350 if (CANT_HAPPEN(!ep->cache))
352 if (id < 0 || id >= ep->fids)
355 if (ep->flags & EFF_MEM) {
356 cachep = ep->cache + id * ep->size;
358 if (ep->baseid + ep->cids <= id || ep->baseid > id) {
359 if (fillcache(ep, id) < 1)
362 cachep = ep->cache + (id - ep->baseid) * ep->size;
364 memcpy(into, cachep, ep->size);
365 ef_mark_fresh(type, into);
368 ep->postread(id, into);
373 * Fill cache of file-backed EP with elements starting at ID.
374 * If any were read, return their number.
375 * Else return -1 and leave the cache unchanged.
378 fillcache(struct empfile *ep, int id)
382 if (CANT_HAPPEN(!ep->cache))
385 ret = do_read(ep, ep->cache, id, MIN(ep->csize, ep->fids - id));
395 do_read(struct empfile *ep, void *buf, int id, int count)
400 if (CANT_HAPPEN(ep->fd < 0 || id < 0 || count < 0))
403 if (lseek(ep->fd, id * ep->size, SEEK_SET) == (off_t)-1) {
404 logerror("Error seeking %s to elt %d (%s)",
405 ep->file, id, strerror(errno));
410 n = count * ep->size;
412 ret = read(ep->fd, p, n);
414 if (errno != EINTR) {
415 logerror("Error reading %s elt %d (%s)",
417 id + (int)((p - (char *)buf) / ep->size),
421 } else if (ret == 0) {
422 logerror("Unexpected EOF reading %s elt %d",
423 ep->file, id + (int)((p - (char *)buf) / ep->size));
431 return (p - (char *)buf) / ep->size;
435 * Write COUNT elements starting at ID from BUF to file-backed EP.
436 * Update the timestamp if the table is EFF_TYPED.
437 * Don't actually write if table is privately mapped.
438 * Return 0 on success, -1 on error (file may be corrupt then).
441 do_write(struct empfile *ep, void *buf, int id, int count)
445 struct emptypedstr *elt;
448 if (CANT_HAPPEN(ep->fd < 0 || id < 0 || count < 0))
451 if (ep->flags & EFF_TYPED) {
452 now = ep->flags & EFF_NOTIME ? (time_t)-1 : time(NULL);
453 for (i = 0; i < count; i++) {
455 * TODO Oopses here could be due to bad data corruption.
456 * Fail instead of attempting to recover?
458 elt = (struct emptypedstr *)((char *)buf + i * ep->size);
459 if (CANT_HAPPEN(elt->ef_type != ep->uid))
460 elt->ef_type = ep->uid;
461 if (CANT_HAPPEN(elt->uid != id + i))
463 if (now != (time_t)-1)
464 elt->timestamp = now;
468 if (ep->flags & EFF_PRIVATE)
471 if (lseek(ep->fd, id * ep->size, SEEK_SET) == (off_t)-1) {
472 logerror("Error seeking %s to elt %d (%s)",
473 ep->file, id, strerror(errno));
478 n = count * ep->size;
480 ret = write(ep->fd, p, n);
482 if (errno != EINTR) {
483 logerror("Error writing %s elt %d (%s)",
485 id + (int)((p - (char *)buf) / ep->size),
499 * Write element ID into table TYPE from buffer FROM.
500 * FIXME pass buffer size!
501 * Update timestamp in FROM if table is EFF_TYPED.
502 * If table is file-backed and not privately mapped, write through
503 * cache straight to disk.
504 * Cannot write beyond the end of fully cached table (flags & EFF_MEM).
505 * Can write at the end of partially cached table.
506 * FROM must be fresh; see ef_make_stale().
507 * Return non-zero on success, zero on failure.
510 ef_write(int type, int id, void *from)
515 if (ef_check(type) < 0)
518 if (CANT_HAPPEN((ep->flags & (EFF_MEM | EFF_PRIVATE)) == EFF_PRIVATE))
520 if (CANT_HAPPEN((ep->flags & EFF_MEM) ? id >= ep->fids : id > ep->fids))
521 return 0; /* not implemented */
523 if (id >= ep->fids) {
524 /* write beyond end of file extends it, take note */
529 if (id >= ep->baseid && id < ep->baseid + ep->cids) {
530 cachep = ep->cache + (id - ep->baseid) * ep->size;
532 must_be_fresh(ep, from);
536 ep->prewrite(id, cachep, from);
538 if (do_write(ep, from, id, 1) < 0)
541 if (cachep && cachep != from) /* update the cache if necessary */
542 memcpy(cachep, from, ep->size);
548 * BUF is an element of table TYPE.
549 * ID is its new element ID.
550 * If table is EFF_TYPED, change id and sequence number stored in BUF.
554 ef_set_uid(int type, void *buf, int uid)
556 struct emptypedstr *elt;
559 if (ef_check(type) < 0)
562 if (!(ep->flags & EFF_TYPED))
568 elt->seqno = get_seqno(ep, uid);
572 * Return sequence number of element ID in table EP.
573 * Return zero if table is not EFF_TYPED (it has no sequence number
577 get_seqno(struct empfile *ep, int id)
579 struct emptypedstr *elt;
581 if (!(ep->flags & EFF_TYPED))
583 if (id < 0 || id >= ep->fids)
585 if (id >= ep->baseid && id < ep->baseid + ep->cids)
586 elt = (void *)(ep->cache + (id - ep->baseid) * ep->size);
588 /* need a buffer, steal last cache slot */
589 if (ep->cids == ep->csize)
591 elt = (void *)(ep->cache + ep->cids * ep->size);
592 if (do_read(ep, elt, id, 1) < 0)
593 return 0; /* deep trouble */
599 * Increment sequence number in BUF, which is about to be written to EP.
600 * Do nothing if table is not EFF_TYPED (it has no sequence number
602 * Else, BUF's sequence number must match the one in EP's cache. If
603 * it doesn't, we're about to clobber a previous write.
606 new_seqno(struct empfile *ep, void *buf)
608 struct emptypedstr *elt = buf;
611 if (!(ep->flags & EFF_TYPED))
613 old_seqno = get_seqno(ep, elt->uid);
614 CANT_HAPPEN(old_seqno != elt->seqno);
615 elt->seqno = old_seqno + 1;
619 * Make all copies stale.
620 * Only fresh copies may be written back to the cache.
621 * To be called by functions that may yield the processor.
622 * Writing an copy when there has been a yield since it was read is
623 * unsafe, because we could clobber another thread's write then.
624 * Robust code must assume the that any function that may yield does
625 * yield. Marking copies stale there lets us catch unsafe writes.
633 /* Mark copy of an element of table TYPE in BUF fresh. */
635 ef_mark_fresh(int type, void *buf)
639 if (ef_check(type) < 0)
642 if (!(ep->flags & EFF_TYPED))
644 ((struct emptypedstr *)buf)->generation = ef_generation;
648 must_be_fresh(struct empfile *ep, void *buf)
650 struct emptypedstr *elt = buf;
652 if (!(ep->flags & EFF_TYPED))
654 CANT_HAPPEN(elt->generation != (ef_generation & 0xfff));
658 * Extend table TYPE by COUNT elements.
659 * Any pointers obtained from ef_ptr() become invalid.
660 * Return non-zero on success, zero on failure.
663 ef_extend(int type, int count)
667 int need_sentinel, i, id;
669 if (ef_check(type) < 0 || CANT_HAPPEN(EF_IS_VIEW(type)))
672 if (CANT_HAPPEN(count < 0))
676 if (ep->flags & EFF_MEM) {
677 need_sentinel = (ep->flags & EFF_SENTINEL) != 0;
678 if (id + count + need_sentinel > ep->csize) {
679 if (ep->flags & EFF_STATIC) {
680 logerror("Can't extend %s beyond %d elements",
681 ep->name, ep->csize - need_sentinel);
684 if (!ef_realloc_cache(ep, id + count + need_sentinel)) {
685 logerror("Can't extend %s to %d elements (%s)",
686 ep->name, id + count, strerror(errno));
690 p = ep->cache + id * ep->size;
691 do_blank(ep, p, id, count);
693 if (do_write(ep, p, id, count) < 0)
697 memset(ep->cache + (id + count) * ep->size, 0, ep->size);
698 ep->cids = id + count;
700 /* need a buffer, steal last cache slot */
701 if (ep->cids == ep->csize)
703 p = ep->cache + ep->cids * ep->size;
704 for (i = 0; i < count; i++) {
705 do_blank(ep, p, id + i, 1);
706 if (do_write(ep, p, id + i, 1) < 0)
710 ep->fids = id + count;
717 * Initialize element ID for table TYPE in BUF.
718 * FIXME pass buffer size!
719 * BUF is marked fresh with ef_mark_fresh().
722 ef_blank(int type, int id, void *buf)
725 struct emptypedstr *elt;
727 if (ef_check(type) < 0)
730 do_blank(ep, buf, id, 1);
731 if (ep->flags & EFF_TYPED) {
733 elt->seqno = get_seqno(ep, elt->uid);
735 ef_mark_fresh(type, buf);
739 * Initialize COUNT elements of EP in BUF, starting with element ID.
742 do_blank(struct empfile *ep, void *buf, int id, int count)
745 struct emptypedstr *elt;
747 memset(buf, 0, count * ep->size);
748 for (i = 0; i < count; i++) {
749 elt = (struct emptypedstr *)((char *)buf + i * ep->size);
750 if (ep->flags & EFF_TYPED) {
751 elt->ef_type = ep->uid;
760 * Truncate table TYPE to COUNT elements.
761 * Any pointers obtained from ef_ptr() become invalid.
762 * Return non-zero on success, zero on failure.
765 ef_truncate(int type, int count)
770 if (ef_check(type) < 0 || CANT_HAPPEN(EF_IS_VIEW(type)))
773 if (CANT_HAPPEN(count < 0 || count > ep->fids))
776 if (ep->fd >= 0 && !(ep->flags & EFF_PRIVATE)) {
777 if (ftruncate(ep->fd, count * ep->size) < 0) {
778 logerror("Can't truncate %s to %d elements (%s)",
779 ep->file, count, strerror(errno));
785 if (ep->flags & EFF_MEM) {
786 need_sentinel = (ep->flags & EFF_SENTINEL) != 0;
787 if (!(ep->flags & EFF_STATIC)) {
788 if (!ef_realloc_cache(ep, count + need_sentinel)) {
789 logerror("Can't shrink %s cache after truncate (%s)",
790 ep->name, strerror(errno));
791 /* continue with unshrunk cache */
795 memset(ep->cache + count * ep->size, 0, ep->size);
798 if (ep->baseid >= count)
800 else if (ep->cids > count - ep->baseid)
801 ep->cids = count - ep->baseid;
812 if (ef_check(type) < 0)
814 return empfile[type].cadef;
820 if (ef_check(type) < 0)
822 return empfile[type].fids;
828 if (ef_check(type) < 0)
830 return empfile[type].flags;
836 if (ef_check(type) < 0)
838 if (empfile[type].fd <= 0)
840 return fdate(empfile[type].fd);
844 * Search for a table matching NAME, return its table type.
845 * Return M_NOTFOUND if there are no matches, M_NOTUNIQUE if there are
849 ef_byname(char *name)
851 return stmtch(name, empfile, offsetof(struct empfile, name),
856 * Search CHOICES[] for a table type matching NAME, return it.
857 * Return M_NOTFOUND if there are no matches, M_NOTUNIQUE if there are
859 * CHOICES[] must be terminated with a negative value.
862 ef_byname_from(char *name, int choices[])
868 for (p = choices; *p >= 0; p++) {
869 if (ef_check(*p) < 0)
871 switch (mineq(name, empfile[*p].name)) {
889 if (ef_check(type) < 0)
890 return "bad ef_type";
891 return empfile[type].name;
897 if (CANT_HAPPEN((unsigned)type >= EF_MAX))
903 * Ensure table contains element ID.
904 * If necessary, extend it in steps of COUNT elements.
905 * Return non-zero on success, zero on failure.
908 ef_ensure_space(int type, int id, int count)
910 if (ef_check(type) < 0)
914 while (id >= empfile[type].fids) {
915 if (!ef_extend(type, count))