-/* $Id: flock.c,v 1.1 2006-03-23 09:15:25 adam Exp $
- Copyright (C) 1995-2005
- 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>
#endif
#include <idzebra/flock.h>
+#include <zebra-lock.h>
#include <yaz/xmalloc.h>
+#include <yaz/log.h>
+
+/** 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;
+
+/** our list of file locked files */
+static struct zebra_lock_info *lock_list = 0;
+
+/** the internal handle, with a pointer to each lock file info */
+struct zebra_lock_handle {
+#ifndef WIN32
+ /** so we can call zebra_lock_rdwr_wunlock or zebra_lock_lock_runlock */
+ int write_flag;
+#endif
+ struct zebra_lock_info *p;
+};
struct zebra_lock_info {
+ /** file descriptor */
int fd;
+ /** full path (xmalloc'ed) */
+ char *fname;
+ /** reference counter: number of zebra_lock_handles pointing to us */
+ int ref_count;
+#ifndef WIN32
+ /** number of file write locks/read locks */
+ int no_file_write_lock;
+ int no_file_read_lock;
+ Zebra_lock_rdwr rdwr_lock;
+ Zebra_mutex file_mutex;
+#endif
+ /** next in lock list */
+ struct zebra_lock_info *next;
};
-char *zebra_mk_fname (const char *dir, const char *name)
+static int log_level = 0;
+
+char *zebra_mk_fname(const char *dir, const char *name)
{
int dlen = dir ? strlen(dir) : 0;
- char *fname = xmalloc (dlen + strlen(name) + 3);
-
+ char *fname = xmalloc(dlen + strlen(name) + 3);
+
#ifdef WIN32
if (dlen)
{
int last_one = dir[dlen-1];
-
- if (!strchr ("/\\:", last_one))
- sprintf (fname, "%s\\%s", dir, name);
+
+ if (!strchr("/\\:", last_one))
+ sprintf(fname, "%s\\%s", dir, name);
else
- sprintf (fname, "%s%s", dir, name);
+ sprintf(fname, "%s%s", dir, name);
}
else
- sprintf (fname, "%s", name);
+ sprintf(fname, "%s", name);
#else
if (dlen)
{
int last_one = dir[dlen-1];
- if (!strchr ("/", last_one))
- sprintf (fname, "%s/%s", dir, name);
+ if (!strchr("/", last_one))
+ sprintf(fname, "%s/%s", dir, name);
else
- sprintf (fname, "%s%s", dir, name);
+ sprintf(fname, "%s%s", dir, name);
}
else
- sprintf (fname, "%s", name);
+ sprintf(fname, "%s", name);
#endif
return fname;
}
-ZebraLockHandle zebra_lock_create (const char *dir, const char *name)
+ZebraLockHandle zebra_lock_create(const char *dir, const char *name)
{
char *fname = zebra_mk_fname(dir, name);
- ZebraLockHandle h = (ZebraLockHandle) xmalloc (sizeof(*h));
+ struct zebra_lock_info *p = 0;
+ ZebraLockHandle h = 0;
+
+ assert(initialized);
- h->fd = -1;
+ zebra_mutex_lock(&lock_list_mutex);
+ /* see if we have the same filename in a global list of "lock files" */
+#ifndef WIN32
+ 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 = (struct zebra_lock_info *) xmalloc(sizeof(*p));
+
+ p->ref_count = 0;
#ifdef WIN32
- h->fd = open (name, O_BINARY|O_RDONLY);
- if (h->fd == -1)
- h->fd = open (fname, (O_BINARY|O_CREAT|O_RDWR), 0666);
+ p->fd = open(name, O_BINARY|O_RDONLY);
+ if (p->fd == -1)
+ p->fd = open(fname, (O_BINARY|O_CREAT|O_RDWR), 0666);
#else
- h->fd= open (fname, (O_BINARY|O_CREAT|O_RDWR), 0666);
+ p->fd = open(fname, (O_BINARY|O_CREAT|O_RDWR), 0666);
+#endif
+ if (p->fd == -1)
+ {
+ xfree(p);
+ yaz_log(YLOG_WARN | YLOG_ERRNO,
+ "zebra_lock_create fail fname=%s", fname);
+ p = 0;
+ }
+ else
+ {
+ p->fname = fname;
+ fname = 0; /* fname buffer now owned by p->fname */
+#ifndef WIN32
+ 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;
#endif
- if (h->fd == -1)
+ p->next = lock_list;
+ lock_list = p;
+ }
+ }
+ if (p)
{
- xfree (h);
- h = 0;
+ /* 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);
}
- xfree (fname);
+ zebra_mutex_unlock(&lock_list_mutex);
+ xfree(fname); /* free it - if it's still there */
+
return h;
}
-void zebra_lock_destroy (ZebraLockHandle h)
+void zebra_lock_destroy(ZebraLockHandle h)
{
if (!h)
return;
- if (h->fd != -1)
- close (h->fd);
- xfree (h);
+ 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 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)
+ {
+ if (*hp == h->p)
+ {
+ *hp = h->p->next;
+ break;
+ }
+ 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 (posix_locks)
+ zebra_lock_rdwr_destroy(&h->p->rdwr_lock);
+ zebra_mutex_destroy(&h->p->file_mutex);
+#endif
+ if (h->p->fd != -1)
+ close(h->p->fd);
+ xfree(h->p->fname);
+ xfree(h->p);
+ }
+ xfree(h);
+ zebra_mutex_unlock(&lock_list_mutex);
}
#ifndef WIN32
-static int unixLock (int fd, int type, int cmd)
+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 zebra_lock_w(ZebraLockHandle h)
{
+ 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);
+
#ifdef WIN32
- return _locking (h->fd, _LK_LOCK, 1);
+ while ((r = _locking(h->p->fd, _LK_LOCK, 1)))
+ ;
#else
- return unixLock (h->fd, F_WRLCK, F_SETLKW);
+ 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)
+ 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);
+ }
+ 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);
+
+ return r;
}
-int zebra_lock_r (ZebraLockHandle h)
+int zebra_lock_r(ZebraLockHandle h)
{
+ int r = 0;
+ int do_lock = 0;
+
+ yaz_log(log_level, "zebra_lock_r fd=%d p=%p fname=%s begin",
+ h->p->fd, h, h->p->fname);
#ifdef WIN32
- return _locking (h->fd, _LK_LOCK, 1);
+ while ((r = _locking(h->p->fd, _LK_LOCK, 1)))
+ ;
#else
- return unixLock (h->fd, F_RDLCK, F_SETLKW);
+ 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)
+ 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);
+ }
+ 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 zebra_unlock(ZebraLockHandle h)
{
+ int r = 0;
+ yaz_log(log_level, "zebra_unlock fd=%d p=%p fname=%s begin",
+ h->p->fd, h, h->p->fname);
#ifdef WIN32
- return _locking (h->fd, _LK_UNLCK, 1);
+ r = _locking(h->p->fd, _LK_UNLCK, 1);
+#else
+ zebra_mutex_lock(&h->p->file_mutex);
+ if (h->write_flag)
+ {
+ if (h->p->no_file_write_lock > 0)
+ h->p->no_file_write_lock--;
+ }
+ else
+ {
+ 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)
+ r = unixLock(h->p->fd, F_UNLCK, F_SETLKW);
+ else
+ {
+ r = 0;
+ assert(posix_locks);
+ }
+
+ zebra_mutex_unlock(&h->p->file_mutex);
+
+ 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);
+ 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
- return unixLock (h->fd, F_UNLCK, F_SETLKW);
+ posix_locks = 0; /* Old GLIBC on Linux. Assume linuxthreads */
#endif
+#endif
+ return 0;
+}
+
+void zebra_flock_init()
+{
+ if (!initialized)
+ {
+ 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);
+ }
}
+/*
+ * 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