1 files changed, 131 insertions, 0 deletions
diff --git a/source3/locking/locking.c b/source3/locking/locking.c
index 6ff3ab5d12..9ece771266 100644
--- a/source3/locking/locking.c
+++ b/source3/locking/locking.c
@@ -29,6 +29,137 @@ pstring share_del_pending="";
 
 
 /****************************************************************************
+routine to do file locking
+****************************************************************************/
+BOOL fcntl_lock(int fd,int op,uint32 offset,uint32 count,int type)
+{
+#if HAVE_FCNTL_LOCK
+  struct flock lock;
+  int ret;
+
+#if 1
+  uint32 mask = 0xC0000000;
+
+  /* make sure the count is reasonable, we might kill the lockd otherwise */
+  count &= ~mask;
+
+  /* the offset is often strange - remove 2 of its bits if either of
+     the top two bits are set. Shift the top ones by two bits. This
+     still allows OLE2 apps to operate, but should stop lockd from
+     dieing */
+  if ((offset & mask) != 0)
+    offset = (offset & ~mask) | ((offset & mask) >> 2);
+#else
+  unsigned long mask = ((unsigned)1<<31);
+
+  /* interpret negative counts as large numbers */
+  if (count < 0)
+    count &= ~mask;
+
+  /* no negative offsets */
+  offset &= ~mask;
+
+  /* count + offset must be in range */
+  while ((offset < 0 || (offset + count < 0)) && mask)
+    {
+      offset &= ~mask;
+      mask = mask >> 1;
+    }
+#endif
+
+
+  DEBUG(5,("fcntl_lock %d %d %d %d %d\n",fd,op,(int)offset,(int)count,type));
+
+  lock.l_type = type;
+  lock.l_whence = SEEK_SET;
+  lock.l_start = (int)offset;
+  lock.l_len = (int)count;
+  lock.l_pid = 0;
+
+  errno = 0;
+
+  ret = fcntl(fd,op,&lock);
+
+  if (errno != 0)
+    DEBUG(3,("fcntl lock gave errno %d (%s)\n",errno,strerror(errno)));
+
+  /* a lock query */
+  if (op == F_GETLK)
+    {
+      if ((ret != -1) &&
+	  (lock.l_type != F_UNLCK) && 
+	  (lock.l_pid != 0) && 
+	  (lock.l_pid != getpid()))
+	{
+	  DEBUG(3,("fd %d is locked by pid %d\n",fd,lock.l_pid));
+	  return(True);
+	}
+
+      /* it must be not locked or locked by me */
+      return(False);
+    }
+
+  /* a lock set or unset */
+  if (ret == -1)
+    {
+      DEBUG(3,("lock failed at offset %d count %d op %d type %d (%s)\n",
+	       offset,count,op,type,strerror(errno)));
+
+      /* perhaps it doesn't support this sort of locking?? */
+      if (errno == EINVAL)
+	{
+	  DEBUG(3,("locking not supported? returning True\n"));
+	  return(True);
+	}
+
+      return(False);
+    }
+
+  /* everything went OK */
+  DEBUG(5,("Lock call successful\n"));
+
+  return(True);
+#else
+  return(False);
+#endif
+}
+
+/*******************************************************************
+lock a file - returning a open file descriptor or -1 on failure
+The timeout is in seconds. 0 means no timeout
+********************************************************************/
+int file_lock(char *name,int timeout)
+{  
+  int fd = open(name,O_RDWR|O_CREAT,0666);
+  time_t t=0;
+  if (fd < 0) return(-1);
+
+#if HAVE_FCNTL_LOCK
+  if (timeout) t = time(NULL);
+  while (!timeout || (time(NULL)-t < timeout)) {
+    if (fcntl_lock(fd,F_SETLK,0,1,F_WRLCK)) return(fd);    
+    msleep(LOCK_RETRY_TIMEOUT);
+  }
+  return(-1);
+#else
+  return(fd);
+#endif
+}
+
+/*******************************************************************
+unlock a file locked by file_lock
+********************************************************************/
+void file_unlock(int fd)
+{
+  if (fd<0) return;
+#if HAVE_FCNTL_LOCK
+  fcntl_lock(fd,F_SETLK,0,1,F_UNLCK);
+#endif
+  close(fd);
+}
+
+
+/****************************************************************************
   utility function called to see if a file region is locked
 ****************************************************************************/
 BOOL is_locked(int fnum,int cnum,uint32 count,uint32 offset)