X-Git-Url: http://git.indexdata.com/?p=idzebra-moved-to-github.git;a=blobdiff_plain;f=util%2Fflock.c;h=317bd19ebee5afb7b241010f8a6743b2fa8f13ee;hp=676b36addfa77ed92e4ba96dc6167ae36d450747;hb=f3f20a205132c39c9434b10086422c6b49b47faf;hpb=95283c5c6fcd51a57d71649d65b4f2196c655a4f

diff --git a/util/flock.c b/util/flock.c
index 676b36a..317bd19 100644
--- a/util/flock.c
+++ b/util/flock.c
@@ -1,8 +1,5 @@
-/* $Id: flock.c,v 1.9 2006-06-27 12:24:14 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) 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
@@ -15,12 +12,15 @@ FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 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>
@@ -43,6 +43,9 @@ Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
 /** 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;
 
@@ -82,12 +85,12 @@ char *zebra_mk_fname(const char *dir, const char *name)
 {
     int dlen = dir ? strlen(dir) : 0;
     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);
         else
@@ -120,15 +123,19 @@ ZebraLockHandle zebra_lock_create(const char *dir, const char *name)
     assert(initialized);
 
     zebra_mutex_lock(&lock_list_mutex);
-#ifndef WIN32 
-    for (p = lock_list; p ; p = p->next)
-        if (!strcmp(p->fname, fname))
-            break;
+    /* 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
         p->fd = open(name, O_BINARY|O_RDONLY);
@@ -140,7 +147,7 @@ ZebraLockHandle zebra_lock_create(const char *dir, const char *name)
         if (p->fd == -1)
         {
             xfree(p);
-            yaz_log(YLOG_WARN | YLOG_ERRNO, 
+            yaz_log(YLOG_WARN | YLOG_ERRNO,
                     "zebra_lock_create fail fname=%s", fname);
             p = 0;
         }
@@ -148,10 +155,10 @@ ZebraLockHandle zebra_lock_create(const char *dir, const char *name)
         {
             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
-            zebra_lock_rdwr_init(&p->rdwr_lock);
+            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;
@@ -162,12 +169,15 @@ ZebraLockHandle zebra_lock_create(const char *dir, const char *name)
     }
     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 */
@@ -182,12 +192,13 @@ void zebra_lock_destroy(ZebraLockHandle 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 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)
         {
@@ -199,8 +210,13 @@ void zebra_lock_destroy(ZebraLockHandle h)
             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
-        zebra_lock_rdwr_destroy(&h->p->rdwr_lock);
+        if (posix_locks)
+            zebra_lock_rdwr_destroy(&h->p->rdwr_lock);
         zebra_mutex_destroy(&h->p->file_mutex);
 #endif
         if (h->p->fd != -1)
@@ -216,103 +232,179 @@ void zebra_lock_destroy(ZebraLockHandle h)
 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 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
     while ((r = _locking(h->p->fd, _LK_LOCK, 1)))
         ;
 #else
+    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);
     }
-    h->p->no_file_write_lock++;
+    else
+    {
+        assert(posix_locks);
+    }
     zebra_mutex_unlock(&h->p->file_mutex);
 
-    zebra_lock_rdwr_wlock(&h->p->rdwr_lock);
     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 r;
-    yaz_log(log_level, "zebra_lock_r fd=%d p=%p fname=%s", 
+    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
     while ((r = _locking(h->p->fd, _LK_LOCK, 1)))
         ;
 #else
+    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);
     }
-    h->p->no_file_read_lock++;
+    else
+    {
+        assert(posix_locks);
+    }
     zebra_mutex_unlock(&h->p->file_mutex);
 
-    zebra_lock_rdwr_rlock(&h->p->rdwr_lock);
     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;
-    yaz_log(log_level, "zebra_unlock fd=%d p=%p fname=%s",
+    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--;
+    {
+        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_write_lock == 0)
     {
+        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
+    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");
         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