2 * Empire - A multi-player, client/server Internet based war game.
3 * Copyright (C) 1986-2008, Dave Pare, Jeff Bailey, Thomas Ruschak,
4 * Ken Stevens, Steve McClure
6 * This program 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 2 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, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 * See files README, COPYING and CREDITS in the root of the source
23 * tree for related information and legal notices. It is expected
24 * that future projects/authors will amend these files as needed.
28 * file.c: Operations on Empire tables (`files' for historical reasons)
30 * Known contributors to this file:
33 * Markus Armbruster, 2005-2008
41 #include <sys/types.h>
47 #include "prototypes.h"
49 static int ef_realloc_cache(struct empfile *, int);
50 static int fillcache(struct empfile *, int);
51 static int do_write(struct empfile *, void *, int, int, time_t);
52 static void do_blank(struct empfile *, void *, int, int);
55 * Open the file-backed table TYPE (EF_SECTOR, ...).
56 * HOW are flags to control operation. Naturally, immutable flags are
58 * Return non-zero on success, zero on failure.
59 * You must call ef_close() before the next ef_open().
62 ef_open(int type, int how)
66 int oflags, fd, fsiz, nslots;
68 if (ef_check(type) < 0)
70 if (CANT_HAPPEN(how & EFF_IMMUTABLE))
71 how &= ~EFF_IMMUTABLE;
75 if (CANT_HAPPEN(ep->fd >= 0))
78 if (how & EFF_PRIVATE)
81 oflags |= O_CREAT | O_TRUNC;
85 if ((fd = open(ep->file, oflags, S_IRWUG)) < 0) {
86 logerror("Can't open %s (%s)", ep->file, strerror(errno));
90 lock.l_type = how & EFF_PRIVATE ? F_RDLCK : F_WRLCK;
91 lock.l_whence = SEEK_SET;
92 lock.l_start = lock.l_len = 0;
93 if (fcntl(fd, F_SETLK, &lock) == -1) {
94 logerror("Can't lock %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;
110 if (ep->flags & EFF_STATIC) {
111 /* ep->cache already points to space for ep->csize elements */
113 if (ep->fids > ep->csize) {
114 logerror("Can't open %s: file larger than %d bytes",
115 ep->file, ep->fids * ep->size);
121 if (CANT_HAPPEN(ep->cache))
126 nslots = blksize(fd) / ep->size;
127 if (!ef_realloc_cache(ep, nslots)) {
128 logerror("Can't map %s (%s)", ep->file, strerror(errno));
135 ep->flags = (ep->flags & EFF_IMMUTABLE) | (how & ~EFF_CREATE);
138 /* map file into cache */
139 if ((how & EFF_MEM) && ep->fids) {
140 if (fillcache(ep, 0) != ep->fids) {
141 ep->cids = 0; /* prevent cache flush */
142 ep->flags &= EFF_IMMUTABLE; /* maintain invariant */
152 * Reallocate cache for table EP to hold COUNT slots.
153 * The table must not be allocated statically.
154 * The cache may still be unmapped.
155 * If reallocation succeeds, any pointers obtained from ef_ptr()
157 * If it fails, the cache is unchanged, and errno is set.
158 * Return non-zero on success, zero on failure.
161 ef_realloc_cache(struct empfile *ep, int count)
165 if (CANT_HAPPEN(ep->flags & EFF_STATIC))
167 if (CANT_HAPPEN(count < 0))
171 * Avoid zero slots, because that can lead to null cache, which
172 * would be interpreted as unmapped cache.
176 cache = realloc(ep->cache, count * ep->size);
186 * Close the file-backed table TYPE (EF_SECTOR, ...).
187 * Return non-zero on success, zero on failure.
195 retval = ef_flush(type);
197 ep->flags &= EFF_IMMUTABLE;
198 if (!(ep->flags & EFF_STATIC)) {
202 if (close(ep->fd) < 0) {
203 logerror("Error closing %s (%s)", ep->name, strerror(errno));
211 * Flush table TYPE (EF_SECTOR, ...) to disk.
212 * Does nothing if the table is privately mapped.
213 * Return non-zero on success, zero on failure.
220 if (ef_check(type) < 0)
223 if (ep->flags & EFF_PRIVATE)
224 return 1; /* nothing to do */
225 if (CANT_HAPPEN(ep->fd < 0))
228 * We don't know which cache entries are dirty. ef_write() writes
229 * through, but direct updates through ef_ptr() don't. They are
230 * allowed only with EFF_MEM. Assume the whole cash is dirty
233 if (ep->flags & EFF_MEM) {
234 if (do_write(ep, ep->cache, ep->baseid, ep->cids, time(NULL)) < 0)
242 * Return pointer to element ID in table TYPE if it exists, else NULL.
243 * The table must be fully cached, i.e. flags & EFF_MEM.
244 * The caller is responsible for flushing changes he makes.
247 ef_ptr(int type, int id)
251 if (ef_check(type) < 0)
254 if (CANT_HAPPEN(!(ep->flags & EFF_MEM) || !ep->cache))
256 if (id < 0 || id >= ep->fids)
258 return ep->cache + ep->size * id;
262 * Read element ID from table TYPE into buffer INTO.
263 * FIXME pass buffer size!
264 * Return non-zero on success, zero on failure.
267 ef_read(int type, int id, void *into)
272 if (ef_check(type) < 0)
275 if (CANT_HAPPEN(!ep->cache))
277 if (id < 0 || id >= ep->fids)
280 if (ep->flags & EFF_MEM) {
281 from = ep->cache + id * ep->size;
283 if (ep->baseid + ep->cids <= id || ep->baseid > id) {
284 if (fillcache(ep, id) < 1)
287 from = ep->cache + (id - ep->baseid) * ep->size;
289 memcpy(into, from, ep->size);
292 ep->postread(id, into);
297 * Fill cache of file-backed EP with elements starting at ID.
298 * If any were read, return their number.
299 * Else return -1 and leave the cache unchanged.
302 fillcache(struct empfile *ep, int id)
307 if (CANT_HAPPEN(ep->fd < 0 || !ep->cache))
310 if (lseek(ep->fd, id * ep->size, SEEK_SET) == (off_t)-1) {
311 logerror("Error seeking %s to elt %d (%s)",
312 ep->file, id, strerror(errno));
317 n = MIN(ep->csize, ep->fids - id) * ep->size;
319 ret = read(ep->fd, p, n);
321 if (errno != EINTR) {
322 logerror("Error reading %s elt %d (%s)",
324 id + (int)((p - ep->cache) / ep->size),
328 } else if (ret == 0) {
329 logerror("Unexpected EOF reading %s elt %d",
330 ep->file, id + (int)((p - ep->cache) / ep->size));
339 return -1; /* nothing read, old cache still ok */
342 ep->cids = (p - ep->cache) / ep->size;
347 * Write COUNT elements starting at ID from BUF to file-backed EP.
348 * Set the timestamp to NOW if the table has those.
349 * Return 0 on success, -1 on error (file may be corrupt then).
352 do_write(struct empfile *ep, void *buf, int id, int count, time_t now)
356 struct emptypedstr *elt;
358 if (CANT_HAPPEN(ep->fd < 0 || (ep->flags & EFF_PRIVATE)
359 || id < 0 || count < 0))
362 if (ep->flags & EFF_TYPED) {
363 for (i = 0; i < count; i++) {
365 * TODO Oopses here could be due to bad data corruption.
366 * Fail instead of attempting to recover?
368 elt = (struct emptypedstr *)((char *)buf + i * ep->size);
369 if (CANT_HAPPEN(elt->ef_type != ep->uid))
370 elt->ef_type = ep->uid;
371 if (CANT_HAPPEN(elt->uid != id + i))
373 elt->timestamp = now;
377 if (lseek(ep->fd, id * ep->size, SEEK_SET) == (off_t)-1) {
378 logerror("Error seeking %s to elt %d (%s)",
379 ep->file, id, strerror(errno));
384 n = count * ep->size;
386 ret = write(ep->fd, p, n);
388 if (errno != EINTR) {
389 logerror("Error writing %s elt %d (%s)",
391 id + (int)((p - (char *)buf) / ep->size),
405 * Write element ID into table TYPE from buffer FROM.
406 * FIXME pass buffer size!
407 * If table is file-backed and not privately mapped, write through
408 * cache straight to disk.
409 * Cannot write beyond the end of fully cached table (flags & EFF_MEM).
410 * Can write at the end of partially cached table.
411 * Return non-zero on success, zero on failure.
414 ef_write(int type, int id, void *from)
419 if (ef_check(type) < 0)
422 if (CANT_HAPPEN((ep->flags & (EFF_MEM | EFF_PRIVATE)) == EFF_PRIVATE))
425 ep->prewrite(id, from);
426 if (CANT_HAPPEN((ep->flags & EFF_MEM) ? id >= ep->fids : id > ep->fids))
427 return 0; /* not implemented */
428 if (!(ep->flags & EFF_PRIVATE)) {
429 if (do_write(ep, from, id, 1, time(NULL)) < 0)
432 if (id >= ep->baseid && id < ep->baseid + ep->cids) {
433 /* update the cache if necessary */
434 to = ep->cache + (id - ep->baseid) * ep->size;
436 memcpy(to, from, ep->size);
438 if (id >= ep->fids) {
439 /* write beyond end of file extends it, take note */
446 * Extend table TYPE by COUNT elements.
447 * Any pointers obtained from ef_ptr() become invalid.
448 * Return non-zero on success, zero on failure.
451 ef_extend(int type, int count)
456 time_t now = time(NULL);
458 if (ef_check(type) < 0)
461 if (CANT_HAPPEN(count < 0))
465 if (ep->flags & EFF_MEM) {
466 if (id + count > ep->csize) {
467 if (ep->flags & EFF_STATIC) {
468 logerror("Can't extend %s beyond %d elements",
469 ep->file, ep->csize);
472 if (!ef_realloc_cache(ep, id + count)) {
473 logerror("Can't extend %s to %d elements (%s)",
474 ep->file, id + count, strerror(errno));
478 p = ep->cache + id * ep->size;
479 do_blank(ep, p, id, count);
480 if (ep->fd >= 0 && !(ep->flags & EFF_PRIVATE)) {
481 if (do_write(ep, p, id, count, now) < 0)
486 /* need a buffer, steal last cache slot */
487 if (ep->cids == ep->csize)
489 p = ep->cache + ep->cids * ep->size;
490 for (i = 0; i < count; i++) {
491 do_blank(ep, p, id + i, 1);
492 if (do_write(ep, p, id + i, 1, now) < 0)
501 * Initialize element ID for EP in BUF.
502 * FIXME pass buffer size!
505 ef_blank(int type, int id, void *buf)
507 if (ef_check(type) < 0)
509 do_blank(&empfile[type], buf, id, 1);
513 * Initialize COUNT elements of EP in BUF, starting with element ID.
516 do_blank(struct empfile *ep, void *buf, int id, int count)
519 struct emptypedstr *elt;
521 memset(buf, 0, count * ep->size);
522 if (ep->flags & EFF_TYPED) {
523 for (i = 0; i < count; i++) {
524 elt = (struct emptypedstr *)((char *)buf + i * ep->size);
525 elt->ef_type = ep->uid;
532 * Truncate table TYPE to COUNT elements.
533 * Any pointers obtained from ef_ptr() become invalid.
534 * Return non-zero on success, zero on failure.
537 ef_truncate(int type, int count)
541 if (ef_check(type) < 0)
544 if (CANT_HAPPEN(count < 0 || count > ep->fids))
547 if (ep->fd >= 0 && !(ep->flags & EFF_PRIVATE)) {
548 if (ftruncate(ep->fd, count * ep->size) < 0) {
549 logerror("Can't truncate %s to %d elements (%s)",
550 ep->file, count, strerror(errno));
556 if (ep->flags & EFF_MEM) {
557 if (!(ep->flags & EFF_STATIC)) {
558 if (!ef_realloc_cache(ep, count)) {
559 logerror("Can't shrink cache after truncate");
560 /* continue with unshrunk cache */
565 if (ep->baseid >= count)
567 else if (ep->cids > count - ep->baseid)
568 ep->cids = count - ep->baseid;
577 return empfile[type].cadef;
583 return empfile[type].fids;
589 return empfile[type].flags;
595 if (empfile[type].fd <= 0)
597 return fdate(empfile[type].fd);
601 * Search for a table matching NAME, return its table type.
602 * Return M_NOTFOUND if there are no matches, M_NOTUNIQUE if there are
606 ef_byname(char *name)
608 return stmtch(name, empfile, offsetof(struct empfile, name),
613 * Search CHOICES[] for a table type matching NAME, return it.
614 * Return M_NOTFOUND if there are no matches, M_NOTUNIQUE if there are
616 * CHOICES[] must be terminated with a negative value.
619 ef_byname_from(char *name, int choices[])
625 for (p = choices; *p >= 0; p++) {
626 if (ef_check(*p) < 0)
628 switch (mineq(name, empfile[*p].name)) {
646 if (ef_check(type) < 0)
647 return "bad ef_type";
648 return empfile[type].name;
654 if (CANT_HAPPEN((unsigned)type >= EF_MAX))
660 * Ensure file-backed table contains ID.
661 * If necessary, extend it in steps of COUNT elements.
662 * Return non-zero on success, zero on failure.
665 ef_ensure_space(int type, int id, int count)
667 if (ef_check(type) < 0)
671 while (id >= empfile[type].fids) {
672 if (!ef_extend(type, count))