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, fids, nslots;
79 if (ef_check(type) < 0)
81 if (CANT_HAPPEN(how & EFF_IMMUTABLE))
82 how &= ~EFF_IMMUTABLE;
86 if (CANT_HAPPEN(!ep->file || ep->base != EF_BAD || 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 fids = fsiz / ep->size;
108 if (nelt >= 0 && nelt != fids) {
109 logerror("Can't open %s (got %d records instead of %d)",
110 ep->file, fids, nelt);
116 if (ep->flags & EFF_STATIC) {
117 /* ep->cache already points to space for ep->csize elements */
119 if (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));
142 ep->flags = (ep->flags & EFF_IMMUTABLE) | (how & ~EFF_CREATE);
145 /* map file into cache */
146 if ((how & EFF_MEM) && fids) {
147 if (fillcache(ep, 0) != fids) {
148 ep->cids = 0; /* prevent cache flush */
160 open_locked(char *name, int oflags, mode_t mode)
162 int rdlonly = (oflags & O_ACCMODE) == O_RDONLY;
166 fd = _sopen(name, oflags | O_BINARY, rdlonly ? SH_DENYNO : SH_DENYWR,
173 fd = open(name, oflags, mode);
177 lock.l_type = rdlonly ? F_RDLCK : F_WRLCK;
178 lock.l_whence = SEEK_SET;
179 lock.l_start = lock.l_len = 0;
180 if (fcntl(fd, F_SETLK, &lock) == -1) {
189 * Reallocate cache for table EP to hold COUNT slots.
190 * The table must not be allocated statically.
191 * The cache may still be unmapped.
192 * If reallocation succeeds, any pointers obtained from ef_ptr()
194 * If it fails, the cache is unchanged, and errno is set.
195 * Return non-zero on success, zero on failure.
198 ef_realloc_cache(struct empfile *ep, int count)
202 if (CANT_HAPPEN(ep->flags & EFF_STATIC))
204 if (CANT_HAPPEN(count < 0))
208 * Avoid zero slots, because that can lead to null cache, which
209 * would be interpreted as unmapped cache.
213 cache = realloc(ep->cache, count * ep->size);
223 * Open the table TYPE, which is a view of a base table
224 * The table must not be already open.
225 * Return non-zero on success, zero on failure.
226 * Beware: views work only as long as the base table doesn't change size!
227 * You must close the view before closing its base table.
230 ef_open_view(int type)
235 if (ef_check(type) < 0)
239 if (ef_check(base) < 0)
241 if (CANT_HAPPEN(!(ef_flags(base) & EFF_MEM)
242 || ep->file || ep->size != empfile[base].size
243 || ep->cache || ep->oninit || ep->postread
244 || ep->prewrite || ep->onresize))
247 ep->cache = empfile[base].cache;
248 ep->csize = empfile[base].csize;
249 ep->flags |= EFF_MEM;
250 ep->baseid = empfile[base].baseid;
251 ep->cids = empfile[base].cids;
252 ep->fids = empfile[base].fids;
257 * Close the open table TYPE (EF_SECTOR, ...).
258 * Return non-zero on success, zero on failure.
266 if (ef_check(type) < 0)
270 if (EF_IS_VIEW(type)) {
276 if (!(ep->flags & EFF_STATIC)) {
281 if (close(ep->fd) < 0) {
282 logerror("Error closing %s (%s)", ep->file, strerror(errno));
287 ep->flags &= EFF_IMMUTABLE;
288 ep->baseid = ep->cids = ep->fids = 0;
295 * Flush file-backed table TYPE (EF_SECTOR, ...) to its backing file.
296 * Do nothing if the table is privately mapped.
297 * Update timestamps of written elements if table is EFF_TYPED.
298 * Return non-zero on success, zero on failure.
305 if (ef_check(type) < 0)
308 if (ep->flags & EFF_PRIVATE)
309 return 1; /* nothing to do */
310 if (CANT_HAPPEN(ep->fd < 0))
313 * We don't know which cache entries are dirty. ef_write() writes
314 * through, but direct updates through ef_ptr() don't. They are
315 * allowed only with EFF_MEM. Assume the whole cash is dirty
318 if (ep->flags & EFF_MEM) {
319 if (do_write(ep, ep->cache, ep->baseid, ep->cids) < 0)
327 * Return pointer to element ID in table TYPE if it exists, else NULL.
328 * The table must be fully cached, i.e. flags & EFF_MEM.
329 * The caller is responsible for flushing changes he makes.
332 ef_ptr(int type, int id)
336 if (ef_check(type) < 0)
339 if (CANT_HAPPEN(!(ep->flags & EFF_MEM) || !ep->cache))
341 if (id < 0 || id >= ep->fids)
343 return ep->cache + ep->size * id;
347 * Read element ID from table TYPE into buffer INTO.
348 * FIXME pass buffer size!
349 * INTO is marked fresh with ef_mark_fresh().
350 * Return non-zero on success, zero on failure.
353 ef_read(int type, int id, void *into)
358 if (ef_check(type) < 0)
361 if (CANT_HAPPEN(!ep->cache))
363 if (id < 0 || id >= ep->fids)
366 if (ep->flags & EFF_MEM) {
367 cachep = ep->cache + id * ep->size;
369 if (ep->baseid + ep->cids <= id || ep->baseid > id) {
370 if (fillcache(ep, id) < 1)
373 cachep = ep->cache + (id - ep->baseid) * ep->size;
375 memcpy(into, cachep, ep->size);
376 ef_mark_fresh(type, into);
379 ep->postread(id, into);
384 * Fill cache of file-backed EP with elements starting at ID.
385 * If any were read, return their number.
386 * Else return -1 and leave the cache unchanged.
389 fillcache(struct empfile *ep, int id)
393 if (CANT_HAPPEN(!ep->cache))
396 ret = do_read(ep, ep->cache, id, MIN(ep->csize, ep->fids - id));
406 do_read(struct empfile *ep, void *buf, int id, int count)
411 if (CANT_HAPPEN(ep->fd < 0 || id < 0 || count < 0))
414 if (lseek(ep->fd, id * ep->size, SEEK_SET) == (off_t)-1) {
415 logerror("Error seeking %s to elt %d (%s)",
416 ep->file, id, strerror(errno));
421 n = count * ep->size;
423 ret = read(ep->fd, p, n);
425 if (errno != EINTR) {
426 logerror("Error reading %s elt %d (%s)",
428 id + (int)((p - (char *)buf) / ep->size),
432 } else if (ret == 0) {
433 logerror("Unexpected EOF reading %s elt %d",
434 ep->file, id + (int)((p - (char *)buf) / ep->size));
442 return (p - (char *)buf) / ep->size;
446 * Write COUNT elements starting at ID from BUF to file-backed EP.
447 * Update the timestamp if the table is EFF_TYPED.
448 * Don't actually write if table is privately mapped.
449 * Return 0 on success, -1 on error (file may be corrupt then).
452 do_write(struct empfile *ep, void *buf, int id, int count)
456 struct emptypedstr *elt;
459 if (CANT_HAPPEN(ep->fd < 0 || id < 0 || count < 0))
462 if (ep->flags & EFF_TYPED) {
463 now = ep->flags & EFF_NOTIME ? (time_t)-1 : time(NULL);
464 for (i = 0; i < count; i++) {
466 * TODO Oopses here could be due to bad data corruption.
467 * Fail instead of attempting to recover?
469 elt = (struct emptypedstr *)((char *)buf + i * ep->size);
470 if (CANT_HAPPEN(elt->ef_type != ep->uid))
471 elt->ef_type = ep->uid;
472 if (CANT_HAPPEN(elt->uid != id + i))
474 if (now != (time_t)-1)
475 elt->timestamp = now;
479 if (ep->flags & EFF_PRIVATE)
482 if (lseek(ep->fd, id * ep->size, SEEK_SET) == (off_t)-1) {
483 logerror("Error seeking %s to elt %d (%s)",
484 ep->file, id, strerror(errno));
489 n = count * ep->size;
491 ret = write(ep->fd, p, n);
493 if (errno != EINTR) {
494 logerror("Error writing %s elt %d (%s)",
496 id + (int)((p - (char *)buf) / ep->size),
510 * Write element ID into table TYPE from buffer FROM.
511 * FIXME pass buffer size!
512 * Update timestamp in FROM if table is EFF_TYPED.
513 * If table is file-backed and not privately mapped, write through
514 * cache straight to disk.
515 * Cannot write beyond the end of fully cached table (flags & EFF_MEM).
516 * Can write at the end of partially cached table.
517 * FROM must be fresh; see ef_make_stale().
518 * Return non-zero on success, zero on failure.
521 ef_write(int type, int id, void *from)
526 if (ef_check(type) < 0)
529 if (CANT_HAPPEN((ep->flags & (EFF_MEM | EFF_PRIVATE)) == EFF_PRIVATE))
532 if (id >= ep->fids) {
533 /* beyond end of file */
534 if (CANT_HAPPEN((ep->flags & EFF_MEM) || id > ep->fids))
535 return 0; /* not implemented */
536 /* write at end of file extends it */
541 if (id >= ep->baseid && id < ep->baseid + ep->cids) {
542 cachep = ep->cache + (id - ep->baseid) * ep->size;
544 must_be_fresh(ep, from);
548 ep->prewrite(id, cachep, from);
550 if (do_write(ep, from, id, 1) < 0)
553 if (cachep && cachep != from) /* update the cache if necessary */
554 memcpy(cachep, from, ep->size);
560 * BUF is an element of table TYPE.
561 * ID is its new element ID.
562 * If table is EFF_TYPED, change id and sequence number stored in BUF.
566 ef_set_uid(int type, void *buf, int uid)
568 struct emptypedstr *elt;
571 if (ef_check(type) < 0)
574 if (!(ep->flags & EFF_TYPED))
580 elt->seqno = get_seqno(ep, uid);
584 * Return sequence number of element ID in table EP.
585 * Return zero if table is not EFF_TYPED (it has no sequence number
589 get_seqno(struct empfile *ep, int id)
591 struct emptypedstr *elt;
593 if (!(ep->flags & EFF_TYPED))
595 if (id < 0 || id >= ep->fids)
597 if (id >= ep->baseid && id < ep->baseid + ep->cids)
598 elt = (void *)(ep->cache + (id - ep->baseid) * ep->size);
600 /* need a buffer, steal last cache slot */
601 if (ep->cids == ep->csize)
603 elt = (void *)(ep->cache + ep->cids * ep->size);
604 if (do_read(ep, elt, id, 1) < 0)
605 return 0; /* deep trouble */
611 * Increment sequence number in BUF, which is about to be written to EP.
612 * Do nothing if table is not EFF_TYPED (it has no sequence number
614 * Else, BUF's sequence number must match the one in EP's cache. If
615 * it doesn't, we're about to clobber a previous write.
618 new_seqno(struct empfile *ep, void *buf)
620 struct emptypedstr *elt = buf;
623 if (!(ep->flags & EFF_TYPED))
625 old_seqno = get_seqno(ep, elt->uid);
626 CANT_HAPPEN(old_seqno != elt->seqno);
627 elt->seqno = old_seqno + 1;
631 * Make all copies stale.
632 * Only fresh copies may be written back to the cache.
633 * To be called by functions that may yield the processor.
634 * Writing an copy when there has been a yield since it was read is
635 * unsafe, because we could clobber another thread's write then.
636 * Robust code must assume the that any function that may yield does
637 * yield. Marking copies stale there lets us catch unsafe writes.
645 /* Mark copy of an element of table TYPE in BUF fresh. */
647 ef_mark_fresh(int type, void *buf)
651 if (ef_check(type) < 0)
654 if (!(ep->flags & EFF_TYPED))
656 ((struct emptypedstr *)buf)->generation = ef_generation;
660 must_be_fresh(struct empfile *ep, void *buf)
662 struct emptypedstr *elt = buf;
664 if (!(ep->flags & EFF_TYPED))
666 CANT_HAPPEN(elt->generation != (ef_generation & 0xfff));
670 * Extend table TYPE by COUNT elements.
671 * Any pointers obtained from ef_ptr() become invalid.
672 * Return non-zero on success, zero on failure.
675 ef_extend(int type, int count)
679 int need_sentinel, i, id;
681 if (ef_check(type) < 0 || CANT_HAPPEN(EF_IS_VIEW(type)))
684 if (CANT_HAPPEN(count < 0))
688 if (ep->flags & EFF_MEM) {
689 need_sentinel = (ep->flags & EFF_SENTINEL) != 0;
690 if (id + count + need_sentinel > ep->csize) {
691 if (ep->flags & EFF_STATIC) {
692 logerror("Can't extend %s beyond %d elements",
693 ep->name, ep->csize - need_sentinel);
696 if (!ef_realloc_cache(ep, id + count + need_sentinel)) {
697 logerror("Can't extend %s to %d elements (%s)",
698 ep->name, id + count, strerror(errno));
702 p = ep->cache + id * ep->size;
703 do_blank(ep, p, id, count);
705 if (do_write(ep, p, id, count) < 0)
709 memset(ep->cache + (id + count) * ep->size, 0, ep->size);
710 ep->cids = id + count;
712 /* need a buffer, steal last cache slot */
713 if (ep->cids == ep->csize)
715 p = ep->cache + ep->cids * ep->size;
716 for (i = 0; i < count; i++) {
717 do_blank(ep, p, id + i, 1);
718 if (do_write(ep, p, id + i, 1) < 0)
722 ep->fids = id + count;
729 * Initialize element ID for table TYPE in BUF.
730 * FIXME pass buffer size!
731 * BUF is marked fresh with ef_mark_fresh().
734 ef_blank(int type, int id, void *buf)
737 struct emptypedstr *elt;
739 if (ef_check(type) < 0)
742 do_blank(ep, buf, id, 1);
743 if (ep->flags & EFF_TYPED) {
745 elt->seqno = get_seqno(ep, elt->uid);
747 ef_mark_fresh(type, buf);
751 * Initialize COUNT elements of EP in BUF, starting with element ID.
754 do_blank(struct empfile *ep, void *buf, int id, int count)
757 struct emptypedstr *elt;
759 memset(buf, 0, count * ep->size);
760 for (i = 0; i < count; i++) {
761 elt = (struct emptypedstr *)((char *)buf + i * ep->size);
762 if (ep->flags & EFF_TYPED) {
763 elt->ef_type = ep->uid;
772 * Truncate table TYPE to COUNT elements.
773 * Any pointers obtained from ef_ptr() become invalid.
774 * Return non-zero on success, zero on failure.
777 ef_truncate(int type, int count)
782 if (ef_check(type) < 0 || CANT_HAPPEN(EF_IS_VIEW(type)))
785 if (CANT_HAPPEN(count < 0 || count > ep->fids))
788 if (ep->fd >= 0 && !(ep->flags & EFF_PRIVATE)) {
789 if (ftruncate(ep->fd, count * ep->size) < 0) {
790 logerror("Can't truncate %s to %d elements (%s)",
791 ep->file, count, strerror(errno));
797 if (ep->flags & EFF_MEM) {
798 need_sentinel = (ep->flags & EFF_SENTINEL) != 0;
799 if (!(ep->flags & EFF_STATIC)) {
800 if (!ef_realloc_cache(ep, count + need_sentinel)) {
801 logerror("Can't shrink %s cache after truncate (%s)",
802 ep->name, strerror(errno));
803 /* continue with unshrunk cache */
807 memset(ep->cache + count * ep->size, 0, ep->size);
810 if (ep->baseid >= count)
812 else if (ep->cids > count - ep->baseid)
813 ep->cids = count - ep->baseid;
824 if (ef_check(type) < 0)
826 return empfile[type].cadef;
832 if (ef_check(type) < 0)
834 return empfile[type].fids;
840 if (ef_check(type) < 0)
842 return empfile[type].flags;
848 if (ef_check(type) < 0)
850 if (empfile[type].fd <= 0)
852 return fdate(empfile[type].fd);
856 * Search for a table matching NAME, return its table type.
857 * Return M_NOTFOUND if there are no matches, M_NOTUNIQUE if there are
861 ef_byname(char *name)
863 return stmtch(name, empfile, offsetof(struct empfile, name),
868 * Search CHOICES[] for a table type matching NAME, return it.
869 * Return M_NOTFOUND if there are no matches, M_NOTUNIQUE if there are
871 * CHOICES[] must be terminated with a negative value.
874 ef_byname_from(char *name, int choices[])
880 for (p = choices; *p >= 0; p++) {
881 if (ef_check(*p) < 0)
883 switch (mineq(name, empfile[*p].name)) {
901 if (ef_check(type) < 0)
902 return "bad ef_type";
903 return empfile[type].name;
909 if (CANT_HAPPEN((unsigned)type >= EF_MAX))
915 * Ensure table contains element ID.
916 * If necessary, extend it in steps of COUNT elements.
917 * Return non-zero on success, zero on failure.
920 ef_ensure_space(int type, int id, int count)
922 if (ef_check(type) < 0)
926 while (id >= empfile[type].fids) {
927 if (!ef_extend(type, count))