-/* $Id: flock.c,v 1.13 2006-06-30 15:10:20 adam Exp $
- Copyright (C) 1995-2006
- Index Data ApS
-
-This file is part of the Zebra server.
+/* This file is part of the Zebra server.
+ Copyright (C) 1994-2011 Index Data
Zebra 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
for more details.
You should have received a copy of the GNU General Public License
-along with Zebra; see the file LICENSE.zebra. If not, write to the
-Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
-02111-1307, USA.
+along with this program; if not, write to the Free Software
+Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+
*/
+#if HAVE_CONFIG_H
+#include <config.h>
+#endif
#include <stdio.h>
#include <assert.h>
#include <string.h>
#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;
+/** whether fcntl locks are shared for all threads in a process (POSIX) */
+static int posix_locks = 1;
+
/** mutex for lock_list below */
Zebra_mutex lock_list_mutex;
/** 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 */
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
+ if (posix_locks)
+ {
+ for (p = lock_list; p ; p = p->next)
+ if (!strcmp(p->fname, fname))
+ break;
+ }
#endif
if (!p)
{ /* didn't match (or we didn't want it to match! */
p->fname = fname;
fname = 0; /* fname buffer now owned by p->fname */
#ifndef WIN32
-#if ZEBRA_FLOCK_EXTRA_RDWR_LOCKS
- zebra_lock_rdwr_init(&p->rdwr_lock);
-#endif
+ if (posix_locks)
+ zebra_lock_rdwr_init(&p->rdwr_lock);
+
zebra_mutex_init(&p->file_mutex);
p->no_file_write_lock = 0;
p->no_file_read_lock = 0;
h->p->fd, h, h->p->fname);
#ifndef WIN32
-#if ZEBRA_FLOCK_EXTRA_RDWR_LOCKS
- zebra_lock_rdwr_destroy(&h->p->rdwr_lock);
-#endif
+ if (posix_locks)
+ zebra_lock_rdwr_destroy(&h->p->rdwr_lock);
zebra_mutex_destroy(&h->p->file_mutex);
#endif
if (h->p->fd != -1)
int zebra_lock_w(ZebraLockHandle h)
{
- int r;
- int do_lock = ZEBRA_FLOCK_FILE_LOCK_ALWAYS;
+ int r = 0;
+ int do_lock = 0;
yaz_log(log_level, "zebra_lock_w fd=%d p=%p fname=%s begin",
h->p->fd, h, h->p->fname);
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
+ if (posix_locks)
+ zebra_lock_rdwr_wlock(&h->p->rdwr_lock);
zebra_mutex_lock(&h->p->file_mutex);
if (h->p->no_file_write_lock == 0)
/* if there is already a read lock.. upgrade to write lock */
r = unixLock(h->p->fd, F_WRLCK, F_SETLKW);
}
+ else
+ {
+ assert(posix_locks);
+ }
zebra_mutex_unlock(&h->p->file_mutex);
h->write_flag = 1;
+#endif
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;
+ int r = 0;
+ int do_lock = 0;
- yaz_log(log_level, "zebra_lock_r fd=%d p=%p fname=%s",
+ yaz_log(log_level, "zebra_lock_r 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_rlock(&h->p->rdwr_lock);
-#endif
+ if (posix_locks)
+ zebra_lock_rdwr_rlock(&h->p->rdwr_lock);
zebra_mutex_lock(&h->p->file_mutex);
if (h->p->no_file_read_lock == 0 && h->p->no_file_write_lock == 0)
/* only read lock if no write locks already */
r = unixLock(h->p->fd, F_RDLCK, F_SETLKW);
}
+ else
+ {
+ assert(posix_locks);
+ }
zebra_mutex_unlock(&h->p->file_mutex);
h->write_flag = 0;
#endif
+ yaz_log(log_level, "zebra_lock_r fd=%d p=%p fname=%s end",
+ h->p->fd, h, h->p->fname);
return r;
}
int zebra_unlock(ZebraLockHandle h)
{
int r = 0;
- 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
#else
zebra_mutex_lock(&h->p->file_mutex);
if (h->write_flag)
- h->p->no_file_write_lock--;
+ {
+ if (h->p->no_file_write_lock > 0)
+ 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_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);
+ else
+ {
+ r = 0;
+ assert(posix_locks);
+ }
+
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);
+ if (posix_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;
}
+/** \brief see if the fcntl locking is not POSIX
+ *
+ * The default posix_locks=1 is assumed.. This function sets posix_locks
+ * to zero if linuxthreads is in use.
+ */
+static int check_for_linuxthreads(void)
+{
+#if __linux
+#ifdef _CS_GNU_LIBPTHREAD_VERSION
+ char conf_buf[512];
+ size_t r = confstr(_CS_GNU_LIBPTHREAD_VERSION, conf_buf, sizeof(conf_buf));
+ if (r == 0)
+ {
+ yaz_log(YLOG_WARN|YLOG_ERRNO, "confstr failed");
+ return -1;
+ }
+ if (strncmp(conf_buf, "linuxthreads", 12) == 0)
+ posix_locks = 0; /* Using linuxthreads.. */
+#else
+ posix_locks = 0; /* Old GLIBC on Linux. Assume linuxthreads */
+#endif
+#endif
+ return 0;
+}
+
void zebra_flock_init()
{
if (!initialized)
{
- log_level = yaz_log_module_level("flock");
-#if DEBUG_FLOCK
- log_level = YLOG_LOG|YLOG_FLUSH;
-#endif
initialized = 1;
+ log_level = yaz_log_module_level("flock");
+ yaz_log(log_level, "zebra_flock_init");
+ check_for_linuxthreads();
zebra_mutex_init(&lock_list_mutex);
+ yaz_log(log_level, "posix_locks: %d", posix_locks);
}
- yaz_log(log_level, "zebra_flock_init");
}
/*
* Local variables:
* c-basic-offset: 4
+ * c-file-style: "Stroustrup"
* indent-tabs-mode: nil
* End:
* vim: shiftwidth=4 tabstop=8 expandtab
projects / idzebra-moved-to-github.git / blobdiff