circache: handle the case where the cache dir exists but not the file

src/utils/circache.cpp

@@ -621,21 +621,33 @@ bool CirCache::create(off_t m_maxsize, int flags)
 	LOGERR(("CirCache::create: null data\n"));
 	return false;
     }
+
+    {
 	struct stat st;
 	if (stat(m_dir.c_str(), &st) < 0) {
+	    // Directory does not exist, create it
 	    if (mkdir(m_dir.c_str(), 0777) < 0) {
 		m_d->m_reason << "CirCache::create: mkdir(" << m_dir << 
 		    ") failed" << " errno " << errno;
 		return false;
 	    }
 	} else {
-        if (!(flags & CC_CRTRUNCATE))
+	    // Directory exists but file might still not exist:
+	    // e.g. the user is using a non default directory and
+	    // created it for us.
+	    if (access(m_d->datafn(m_dir).c_str(), 0) >= 0) {
+		// File exists, switch to "open" mode, except if we're told to 
+		// truncate.
+		if (!(flags & CC_CRTRUNCATE)) {
 		    return open(CC_OPWRITE);
 		}
+	    }
+	    // Else fall through to create file
+	}
+    }
 
     if ((m_d->m_fd = ::open(m_d->datafn(m_dir).c_str(), 
-                          O_CREAT | O_RDWR | O_TRUNC, 
+			    O_CREAT | O_RDWR | O_TRUNC, 0666)) < 0) {
-                          0666)) < 0) {
         m_d->m_reason << "CirCache::create: open/creat(" << 
             m_d->datafn(m_dir) << ") failed " << "errno " << errno;
 	return false;