-/* $Id: flock.c,v 1.8 2006-06-27 11:56:29 adam Exp $
+/* $Id: flock.c,v 1.13 2006-06-30 15:10:20 adam Exp $
Copyright (C) 1995-2006
Index Data ApS
#include <yaz/xmalloc.h>
#include <yaz/log.h>
+/** whether lock file desciptors are shared within one process' threads */
+#define ZEBRA_FLOCK_SHARE_FD_IN_THREADS 1
+
+/** whether we always lock on the file - even if rd/wr locks should do */
+#define ZEBRA_FLOCK_FILE_LOCK_ALWAYS 1
+
+/** whether we should also use pthreads locking to do "extra" rd/wr locks */
+#define ZEBRA_FLOCK_EXTRA_RDWR_LOCKS 1
+
+/** whether this module should debug */
+#define DEBUG_FLOCK 0
+
/** have this module (mutex) been initialized? */
static int initialized = 0;
/** number of file write locks/read locks */
int no_file_write_lock;
int no_file_read_lock;
+#if ZEBRA_FLOCK_EXTRA_RDWR_LOCKS
Zebra_lock_rdwr rdwr_lock;
+#endif
Zebra_mutex file_mutex;
#endif
/** next in lock list */
ZebraLockHandle zebra_lock_create(const char *dir, const char *name)
{
char *fname = zebra_mk_fname(dir, name);
- struct zebra_lock_info *p;
+ struct zebra_lock_info *p = 0;
ZebraLockHandle h = 0;
assert(initialized);
zebra_mutex_lock(&lock_list_mutex);
+ /* see if we have the same filename in a global list of "lock files" */
+#ifndef WIN32
+#if ZEBRA_FLOCK_SHARE_FD_IN_THREADS
for (p = lock_list; p ; p = p->next)
if (!strcmp(p->fname, fname))
break;
+#endif
+#endif
if (!p)
- {
+ { /* didn't match (or we didn't want it to match! */
p = (struct zebra_lock_info *) xmalloc(sizeof(*p));
p->ref_count = 0;
{
p->fname = fname;
fname = 0; /* fname buffer now owned by p->fname */
- yaz_log(log_level, "zebra_lock_create fd=%d p=%p fname=%s",
- p->fd, p, p->fname);
#ifndef WIN32
+#if ZEBRA_FLOCK_EXTRA_RDWR_LOCKS
zebra_lock_rdwr_init(&p->rdwr_lock);
+#endif
zebra_mutex_init(&p->file_mutex);
p->no_file_write_lock = 0;
p->no_file_read_lock = 0;
}
if (p)
{
+ /* we have lock info so we can make a handle pointing to that */
p->ref_count++;
h = (ZebraLockHandle) xmalloc(sizeof(*h));
h->p = p;
+#ifndef WIN32
h->write_flag = 0;
+#endif
+ yaz_log(log_level, "zebra_lock_create fd=%d p=%p fname=%s",
+ h->p->fd, h, p->fname);
}
zebra_mutex_unlock(&lock_list_mutex);
xfree(fname); /* free it - if it's still there */
yaz_log(log_level, "zebra_lock_destroy fd=%d p=%p fname=%s",
h->p->fd, h, h->p->fname);
zebra_mutex_lock(&lock_list_mutex);
- yaz_log(log_level, "zebra_lock_destroy fd=%d p=%p fname=%s 1",
- h->p->fd, h, h->p->fname);
+ yaz_log(log_level, "zebra_lock_destroy fd=%d p=%p fname=%s refcount=%d",
+ h->p->fd, h, h->p->fname, h->p->ref_count);
assert(h->p->ref_count > 0);
--(h->p->ref_count);
if (h->p->ref_count == 0)
{
+ /* must remove shared info from lock_list */
struct zebra_lock_info **hp = &lock_list;
while (*hp)
{
else
hp = &(*hp)->next;
}
+
+ yaz_log(log_level, "zebra_lock_destroy fd=%d p=%p fname=%s remove",
+ h->p->fd, h, h->p->fname);
+
#ifndef WIN32
+#if ZEBRA_FLOCK_EXTRA_RDWR_LOCKS
zebra_lock_rdwr_destroy(&h->p->rdwr_lock);
+#endif
zebra_mutex_destroy(&h->p->file_mutex);
#endif
if (h->p->fd != -1)
static int unixLock(int fd, int type, int cmd)
{
struct flock area;
+ int r;
area.l_type = type;
area.l_whence = SEEK_SET;
area.l_len = area.l_start = 0L;
- return fcntl(fd, cmd, &area);
+
+ yaz_log(log_level, "fcntl begin type=%d fd=%d", type, fd);
+ r = fcntl(fd, cmd, &area);
+ if (r == -1)
+ yaz_log(YLOG_WARN|YLOG_ERRNO, "fcntl FAIL type=%d fd=%d", type, fd);
+ else
+ yaz_log(log_level, "fcntl type=%d OK fd=%d", type, fd);
+
+ return r;
}
#endif
int zebra_lock_w(ZebraLockHandle h)
{
int r;
- yaz_log(log_level, "zebra_lock_w fd=%d p=%p fname=%s",
+ int do_lock = ZEBRA_FLOCK_FILE_LOCK_ALWAYS;
+ yaz_log(log_level, "zebra_lock_w fd=%d p=%p fname=%s begin",
h->p->fd, h, h->p->fname);
-
+
#ifdef WIN32
while ((r = _locking(h->p->fd, _LK_LOCK, 1)))
;
#else
+#if ZEBRA_FLOCK_EXTRA_RDWR_LOCKS
+ zebra_lock_rdwr_wlock(&h->p->rdwr_lock);
+#endif
+
zebra_mutex_lock(&h->p->file_mutex);
if (h->p->no_file_write_lock == 0)
+ do_lock = 1;
+ h->p->no_file_write_lock++;
+ if (do_lock)
{
/* if there is already a read lock.. upgrade to write lock */
r = unixLock(h->p->fd, F_WRLCK, F_SETLKW);
}
- h->p->no_file_write_lock++;
zebra_mutex_unlock(&h->p->file_mutex);
- zebra_lock_rdwr_wlock(&h->p->rdwr_lock);
-#endif
h->write_flag = 1;
+ yaz_log(log_level, "zebra_lock_w fd=%d p=%p fname=%s end",
+ h->p->fd, h, h->p->fname);
+#endif
+
return r;
}
int zebra_lock_r(ZebraLockHandle h)
{
int r;
+ int do_lock = ZEBRA_FLOCK_FILE_LOCK_ALWAYS;
+
yaz_log(log_level, "zebra_lock_r fd=%d p=%p fname=%s",
h->p->fd, h, h->p->fname);
#ifdef WIN32
while ((r = _locking(h->p->fd, _LK_LOCK, 1)))
;
#else
+#if ZEBRA_FLOCK_EXTRA_RDWR_LOCKS
+ zebra_lock_rdwr_rlock(&h->p->rdwr_lock);
+#endif
+
zebra_mutex_lock(&h->p->file_mutex);
if (h->p->no_file_read_lock == 0 && h->p->no_file_write_lock == 0)
+ do_lock = 1;
+ h->p->no_file_read_lock++;
+ if (do_lock)
{
/* only read lock if no write locks already */
r = unixLock(h->p->fd, F_RDLCK, F_SETLKW);
}
- h->p->no_file_read_lock++;
zebra_mutex_unlock(&h->p->file_mutex);
-
- zebra_lock_rdwr_rlock(&h->p->rdwr_lock);
+
h->write_flag = 0;
#endif
return r;
int zebra_unlock(ZebraLockHandle h)
{
int r = 0;
- yaz_log(log_level, "zebra_unlock fd=%d p=%p fname=%s",
+ int do_unlock = ZEBRA_FLOCK_FILE_LOCK_ALWAYS;
+ yaz_log(log_level, "zebra_unlock fd=%d p=%p fname=%s begin",
h->p->fd, h, h->p->fname);
#ifdef WIN32
r = _locking(h->p->fd, _LK_UNLCK, 1);
#else
- if (h->write_flag)
- zebra_lock_rdwr_wunlock(&h->p->rdwr_lock);
- else
- zebra_lock_rdwr_runlock(&h->p->rdwr_lock);
-
zebra_mutex_lock(&h->p->file_mutex);
if (h->write_flag)
h->p->no_file_write_lock--;
else
h->p->no_file_read_lock--;
if (h->p->no_file_read_lock == 0 && h->p->no_file_write_lock == 0)
- {
+ do_unlock = 1;
+ if (do_unlock)
r = unixLock(h->p->fd, F_UNLCK, F_SETLKW);
- }
zebra_mutex_unlock(&h->p->file_mutex);
+
+#if ZEBRA_FLOCK_EXTRA_RDWR_LOCKS
+ if (h->write_flag)
+ zebra_lock_rdwr_wunlock(&h->p->rdwr_lock);
+ else
+ zebra_lock_rdwr_runlock(&h->p->rdwr_lock);
+#endif
+
+ yaz_log(log_level, "zebra_unlock fd=%d p=%p fname=%s end",
+ h->p->fd, h, h->p->fname);
#endif
return r;
}
if (!initialized)
{
log_level = yaz_log_module_level("flock");
+#if DEBUG_FLOCK
+ log_level = YLOG_LOG|YLOG_FLUSH;
+#endif
initialized = 1;
zebra_mutex_init(&lock_list_mutex);
}
+ yaz_log(log_level, "zebra_flock_init");
}
/*
projects / idzebra-moved-to-github.git / blobdiff