/*
* Empire - A multi-player, client/server Internet based war game.
- * Copyright (C) 1986-2008, Dave Pare, Jeff Bailey, Thomas Ruschak,
- * Ken Stevens, Steve McClure
+ * Copyright (C) 1986-2011, Dave Pare, Jeff Bailey, Thomas Ruschak,
+ * Ken Stevens, Steve McClure, Markus Armbruster
*
- * This program is free software; you can redistribute it and/or modify
+ * Empire is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
+ * the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* ---
*
* ---
*
* file.c: Operations on Empire tables (`files' for historical reasons)
- *
+ *
* Known contributors to this file:
* Dave Pare, 1989
* Steve McClure, 2000
- * Markus Armbruster, 2005-2008
+ * Markus Armbruster, 2005-2011
*/
#include <config.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
+#ifdef _WIN32
+#include <io.h>
+#include <share.h>
+#endif
#include "file.h"
#include "match.h"
#include "misc.h"
#include "nsc.h"
#include "prototypes.h"
+static int open_locked(char *, int, mode_t);
static int ef_realloc_cache(struct empfile *, int);
static int fillcache(struct empfile *, int);
static int do_read(struct empfile *, void *, int, int);
static int do_write(struct empfile *, void *, int, int);
static unsigned get_seqno(struct empfile *, int);
static void new_seqno(struct empfile *, void *);
+static void must_be_fresh(struct empfile *, void *);
static void do_blank(struct empfile *, void *, int, int);
+static int ef_check(int);
+
+static unsigned ef_generation;
/*
* Open the file-backed table TYPE (EF_SECTOR, ...).
ef_open(int type, int how, int nelt)
{
struct empfile *ep;
- struct flock lock;
- int oflags, fd, fsiz, nslots;
+ int oflags, fd, fsiz, fids, nslots;
if (ef_check(type) < 0)
return 0;
/* open file */
ep = &empfile[type];
- if (CANT_HAPPEN(ep->fd >= 0))
+ if (CANT_HAPPEN(!ep->file || ep->base != EF_BAD || ep->fd >= 0))
return 0;
oflags = O_RDWR;
if (how & EFF_PRIVATE)
oflags = O_RDONLY;
if (how & EFF_CREATE)
oflags |= O_CREAT | O_TRUNC;
-#if defined(_WIN32)
- oflags |= O_BINARY;
-#endif
- if ((fd = open(ep->file, oflags, S_IRWUG)) < 0) {
+ fd = open_locked(ep->file, oflags, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
+ if (fd < 0) {
logerror("Can't open %s (%s)", ep->file, strerror(errno));
return 0;
}
- lock.l_type = how & EFF_PRIVATE ? F_RDLCK : F_WRLCK;
- lock.l_whence = SEEK_SET;
- lock.l_start = lock.l_len = 0;
- if (fcntl(fd, F_SETLK, &lock) == -1) {
- logerror("Can't lock %s (%s)", ep->file, strerror(errno));
- close(fd);
- return 0;
- }
-
/* get file size */
fsiz = fsize(fd);
if (fsiz % ep->size) {
close(fd);
return 0;
}
- ep->fids = fsiz / ep->size;
- if (nelt >= 0 && nelt != ep->fids) {
+ fids = fsiz / ep->size;
+ if (nelt >= 0 && nelt != fids) {
logerror("Can't open %s (got %d records instead of %d)",
- ep->file, ep->fids, nelt);
+ ep->file, fids, nelt);
close(fd);
return 0;
}
if (ep->flags & EFF_STATIC) {
/* ep->cache already points to space for ep->csize elements */
if (how & EFF_MEM) {
- if (ep->fids > ep->csize) {
- logerror("Can't open %s: file larger than %d bytes",
- ep->file, ep->fids * ep->size);
+ if (fids > ep->csize) {
+ logerror("Can't open %s (file larger than %d records)",
+ ep->file, ep->csize);
close(fd);
return 0;
}
if (CANT_HAPPEN(ep->cache))
free(ep->cache);
if (how & EFF_MEM)
- nslots = ep->fids;
+ nslots = fids;
else
nslots = blksize(fd) / ep->size;
if (!ef_realloc_cache(ep, nslots)) {
}
ep->baseid = 0;
ep->cids = 0;
+ ep->fids = fids;
ep->flags = (ep->flags & EFF_IMMUTABLE) | (how & ~EFF_CREATE);
ep->fd = fd;
/* map file into cache */
- if ((how & EFF_MEM) && ep->fids) {
- if (fillcache(ep, 0) != ep->fids) {
+ if ((how & EFF_MEM) && fids) {
+ if (fillcache(ep, 0) != fids) {
ep->cids = 0; /* prevent cache flush */
- ep->flags &= EFF_IMMUTABLE; /* maintain invariant */
ef_close(type);
return 0;
}
}
+ if (ep->onresize)
+ ep->onresize(type);
return 1;
}
+static int
+open_locked(char *name, int oflags, mode_t mode)
+{
+ int rdlonly = (oflags & O_ACCMODE) == O_RDONLY;
+ int fd;
+
+#ifdef _WIN32
+ fd = _sopen(name, oflags | O_BINARY, rdlonly ? SH_DENYNO : SH_DENYWR,
+ mode);
+ if (fd < 0)
+ return -1;
+#else /* !_WIN32 */
+ struct flock lock;
+
+ fd = open(name, oflags, mode);
+ if (fd < 0)
+ return -1;
+
+ lock.l_type = rdlonly ? F_RDLCK : F_WRLCK;
+ lock.l_whence = SEEK_SET;
+ lock.l_start = lock.l_len = 0;
+ if (fcntl(fd, F_SETLK, &lock) == -1) {
+ close(fd);
+ return -1;
+ }
+#endif /* !_WIN32 */
+ return fd;
+}
+
/*
* Reallocate cache for table EP to hold COUNT slots.
* The table must not be allocated statically.
}
/*
- * Close the file-backed table TYPE (EF_SECTOR, ...).
+ * Open the table TYPE, which is a view of a base table
+ * The table must not be already open.
+ * Return non-zero on success, zero on failure.
+ * Beware: views work only as long as the base table doesn't change size!
+ * You must close the view before closing its base table.
+ */
+int
+ef_open_view(int type)
+{
+ struct empfile *ep;
+ int base;
+
+ if (ef_check(type) < 0)
+ return 0;
+ ep = &empfile[type];
+ base = ep->base;
+ if (ef_check(base) < 0)
+ return 0;
+ if (CANT_HAPPEN(!(ef_flags(base) & EFF_MEM)
+ || ep->file || ep->size != empfile[base].size
+ || ep->cache || ep->oninit || ep->postread
+ || ep->prewrite || ep->onresize))
+ return -1;
+
+ ep->cache = empfile[base].cache;
+ ep->csize = empfile[base].csize;
+ ep->flags |= EFF_MEM;
+ ep->baseid = empfile[base].baseid;
+ ep->cids = empfile[base].cids;
+ ep->fids = empfile[base].fids;
+ return 0;
+}
+
+/*
+ * Close the open table TYPE (EF_SECTOR, ...).
* Return non-zero on success, zero on failure.
*/
int
ef_close(int type)
{
struct empfile *ep;
- int retval;
+ int retval = 1;
- retval = ef_flush(type);
+ if (ef_check(type) < 0)
+ return 0;
ep = &empfile[type];
- ep->flags &= EFF_IMMUTABLE;
- if (!(ep->flags & EFF_STATIC)) {
- free(ep->cache);
+
+ if (EF_IS_VIEW(type)) {
ep->cache = NULL;
+ ep->csize = 0;
+ } else {
+ if (!ef_flush(type))
+ retval = 0;
+ if (!(ep->flags & EFF_STATIC)) {
+ free(ep->cache);
+ ep->cache = NULL;
+ ep->csize = 0;
+ }
+ if (close(ep->fd) < 0) {
+ logerror("Error closing %s (%s)", ep->file, strerror(errno));
+ retval = 0;
+ }
+ ep->fd = -1;
}
- if (close(ep->fd) < 0) {
- logerror("Error closing %s (%s)", ep->name, strerror(errno));
- retval = 0;
- }
- ep->fd = -1;
+ ep->flags &= EFF_IMMUTABLE;
+ ep->baseid = ep->cids = ep->fids = 0;
+ if (ep->onresize)
+ ep->onresize(type);
return retval;
}
/*
- * Flush table TYPE (EF_SECTOR, ...) to disk.
+ * Flush file-backed table TYPE (EF_SECTOR, ...) to its backing file.
* Do nothing if the table is privately mapped.
* Update timestamps of written elements if table is EFF_TYPED.
* Return non-zero on success, zero on failure.
/*
* Read element ID from table TYPE into buffer INTO.
* FIXME pass buffer size!
+ * INTO is marked fresh with ef_mark_fresh().
* Return non-zero on success, zero on failure.
*/
int
ef_read(int type, int id, void *into)
{
struct empfile *ep;
- void *from;
+ void *cachep;
if (ef_check(type) < 0)
return 0;
return 0;
if (ep->flags & EFF_MEM) {
- from = ep->cache + id * ep->size;
+ cachep = ep->cache + id * ep->size;
} else {
if (ep->baseid + ep->cids <= id || ep->baseid > id) {
if (fillcache(ep, id) < 1)
return 0;
}
- from = ep->cache + (id - ep->baseid) * ep->size;
+ cachep = ep->cache + (id - ep->baseid) * ep->size;
}
- memcpy(into, from, ep->size);
+ memcpy(into, cachep, ep->size);
+ ef_mark_fresh(type, into);
if (ep->postread)
ep->postread(id, into);
* cache straight to disk.
* Cannot write beyond the end of fully cached table (flags & EFF_MEM).
* Can write at the end of partially cached table.
+ * FROM must be fresh; see ef_make_stale().
* Return non-zero on success, zero on failure.
*/
int
ef_write(int type, int id, void *from)
{
struct empfile *ep;
- char *to;
+ char *cachep;
if (ef_check(type) < 0)
return 0;
ep = &empfile[type];
if (CANT_HAPPEN((ep->flags & (EFF_MEM | EFF_PRIVATE)) == EFF_PRIVATE))
return 0;
- if (ep->prewrite)
- ep->prewrite(id, from);
- if (CANT_HAPPEN((ep->flags & EFF_MEM) ? id >= ep->fids : id > ep->fids))
- return 0; /* not implemented */
new_seqno(ep, from);
+ if (id >= ep->fids) {
+ /* beyond end of file */
+ if (CANT_HAPPEN((ep->flags & EFF_MEM) || id > ep->fids))
+ return 0; /* not implemented */
+ /* write at end of file extends it */
+ ep->fids = id + 1;
+ if (ep->onresize)
+ ep->onresize(type);
+ }
+ if (id >= ep->baseid && id < ep->baseid + ep->cids) {
+ cachep = ep->cache + (id - ep->baseid) * ep->size;
+ if (cachep != from)
+ must_be_fresh(ep, from);
+ } else
+ cachep = NULL;
+ if (ep->prewrite)
+ ep->prewrite(id, cachep, from);
if (ep->fd >= 0) {
if (do_write(ep, from, id, 1) < 0)
return 0;
}
- if (id >= ep->baseid && id < ep->baseid + ep->cids) {
- /* update the cache if necessary */
- to = ep->cache + (id - ep->baseid) * ep->size;
- if (to != from)
- memcpy(to, from, ep->size);
- }
- if (id >= ep->fids) {
- /* write beyond end of file extends it, take note */
- ep->fids = id + 1;
- }
+ if (cachep && cachep != from) /* update the cache if necessary */
+ memcpy(cachep, from, ep->size);
return 1;
}
* Increment sequence number in BUF, which is about to be written to EP.
* Do nothing if table is not EFF_TYPED (it has no sequence number
* then).
+ * Else, BUF's sequence number must match the one in EP's cache. If
+ * it doesn't, we're about to clobber a previous write.
*/
static void
new_seqno(struct empfile *ep, void *buf)
if (!(ep->flags & EFF_TYPED))
return;
old_seqno = get_seqno(ep, elt->uid);
- if (CANT_HAPPEN(old_seqno != elt->seqno))
- old_seqno = MAX(old_seqno, elt->seqno);
+ CANT_HAPPEN(old_seqno != elt->seqno);
elt->seqno = old_seqno + 1;
}
+/*
+ * Make all copies stale.
+ * Only fresh copies may be written back to the cache.
+ * To be called by functions that may yield the processor.
+ * Writing an copy when there has been a yield since it was read is
+ * unsafe, because we could clobber another thread's write then.
+ * Robust code must assume the that any function that may yield does
+ * yield. Marking copies stale there lets us catch unsafe writes.
+ */
+void
+ef_make_stale(void)
+{
+ ef_generation++;
+}
+
+/* Mark copy of an element of table TYPE in BUF fresh. */
+void
+ef_mark_fresh(int type, void *buf)
+{
+ struct empfile *ep;
+
+ if (ef_check(type) < 0)
+ return;
+ ep = &empfile[type];
+ if (!(ep->flags & EFF_TYPED))
+ return;
+ ((struct emptypedstr *)buf)->generation = ef_generation;
+}
+
+static void
+must_be_fresh(struct empfile *ep, void *buf)
+{
+ struct emptypedstr *elt = buf;
+
+ if (!(ep->flags & EFF_TYPED))
+ return;
+ CANT_HAPPEN(elt->generation != (ef_generation & 0xfff));
+}
+
/*
* Extend table TYPE by COUNT elements.
* Any pointers obtained from ef_ptr() become invalid.
{
struct empfile *ep;
char *p;
- int i, id;
+ int need_sentinel, i, id;
- if (ef_check(type) < 0)
+ if (ef_check(type) < 0 || CANT_HAPPEN(EF_IS_VIEW(type)))
return 0;
ep = &empfile[type];
if (CANT_HAPPEN(count < 0))
id = ep->fids;
if (ep->flags & EFF_MEM) {
- if (id + count > ep->csize) {
+ need_sentinel = (ep->flags & EFF_SENTINEL) != 0;
+ if (id + count + need_sentinel > ep->csize) {
if (ep->flags & EFF_STATIC) {
logerror("Can't extend %s beyond %d elements",
- ep->file, ep->csize);
+ ep->name, ep->csize - need_sentinel);
return 0;
}
- if (!ef_realloc_cache(ep, id + count)) {
+ if (!ef_realloc_cache(ep, id + count + need_sentinel)) {
logerror("Can't extend %s to %d elements (%s)",
- ep->file, id + count, strerror(errno));
+ ep->name, id + count, strerror(errno));
return 0;
}
}
if (do_write(ep, p, id, count) < 0)
return 0;
}
- ep->cids += count;
+ if (need_sentinel)
+ memset(ep->cache + (id + count) * ep->size, 0, ep->size);
+ ep->cids = id + count;
} else {
/* need a buffer, steal last cache slot */
if (ep->cids == ep->csize)
return 0;
}
}
- ep->fids += count;
+ ep->fids = id + count;
+ if (ep->onresize)
+ ep->onresize(type);
return 1;
}
/*
- * Initialize element ID for EP in BUF.
+ * Initialize element ID for table TYPE in BUF.
* FIXME pass buffer size!
+ * BUF is marked fresh with ef_mark_fresh().
*/
void
ef_blank(int type, int id, void *buf)
elt = buf;
elt->seqno = get_seqno(ep, elt->uid);
}
+ ef_mark_fresh(type, buf);
}
/*
struct emptypedstr *elt;
memset(buf, 0, count * ep->size);
- if (ep->flags & EFF_TYPED) {
- for (i = 0; i < count; i++) {
- elt = (struct emptypedstr *)((char *)buf + i * ep->size);
+ for (i = 0; i < count; i++) {
+ elt = (struct emptypedstr *)((char *)buf + i * ep->size);
+ if (ep->flags & EFF_TYPED) {
elt->ef_type = ep->uid;
elt->uid = id + i;
}
+ if (ep->oninit)
+ ep->oninit(elt);
}
}
ef_truncate(int type, int count)
{
struct empfile *ep;
+ int need_sentinel;
- if (ef_check(type) < 0)
+ if (ef_check(type) < 0 || CANT_HAPPEN(EF_IS_VIEW(type)))
return 0;
ep = &empfile[type];
if (CANT_HAPPEN(count < 0 || count > ep->fids))
ep->fids = count;
if (ep->flags & EFF_MEM) {
+ need_sentinel = (ep->flags & EFF_SENTINEL) != 0;
if (!(ep->flags & EFF_STATIC)) {
- if (!ef_realloc_cache(ep, count)) {
- logerror("Can't shrink cache after truncate");
+ if (!ef_realloc_cache(ep, count + need_sentinel)) {
+ logerror("Can't shrink %s cache after truncate (%s)",
+ ep->name, strerror(errno));
/* continue with unshrunk cache */
}
}
+ if (need_sentinel)
+ memset(ep->cache + count * ep->size, 0, ep->size);
ep->cids = count;
} else {
if (ep->baseid >= count)
ep->cids = count - ep->baseid;
}
+ if (ep->onresize)
+ ep->onresize(type);
return 1;
}
struct castr *
ef_cadef(int type)
{
+ if (ef_check(type) < 0)
+ return NULL;
return empfile[type].cadef;
}
int
ef_nelem(int type)
{
+ if (ef_check(type) < 0)
+ return 0;
return empfile[type].fids;
}
int
ef_flags(int type)
{
+ if (ef_check(type) < 0)
+ return 0;
return empfile[type].flags;
}
time_t
ef_mtime(int type)
{
+ if (ef_check(type) < 0)
+ return 0;
if (empfile[type].fd <= 0)
return 0;
return fdate(empfile[type].fd);
return empfile[type].name;
}
-int
+static int
ef_check(int type)
{
if (CANT_HAPPEN((unsigned)type >= EF_MAX))
}
/*
- * Ensure file-backed table contains ID.
+ * Ensure table contains element ID.
* If necessary, extend it in steps of COUNT elements.
* Return non-zero on success, zero on failure.
*/
projects / empserver / blobdiff