lib: Initialize libvirt and libxml2 once when the library loads.

examples/copy_over.c

@@ -21,7 +21,6 @@
 #include <pthread.h>
 
 #include <guestfs.h>
-#include <libvirt/libvirt.h>
 
 struct threaddata {
   const char *src;
@@ -66,9 +65,6 @@ main (int argc, char *argv[])
   struct timeval start_t, end_t;
   int64_t ms;
 
-  /* This is required when using libvirt from multiple threads. */
-  virInitialize ();
-
   if (argc != 5) {
     usage ();
     exit (EXIT_FAILURE);

src/guestfs.c

@@ -61,6 +61,15 @@
 #include <arpa/inet.h>
 #include <netinet/in.h>
 
+#ifdef HAVE_LIBVIRT
+#include <libvirt/libvirt.h>
+#endif
+
+#ifdef HAVE_LIBXML2
+#include <libxml/parser.h>
+#include <libxml/xmlversion.h>
+#endif
+
 #include "c-ctype.h"
 #include "glthread/lock.h"
 #include "hash.h"
@@ -80,6 +89,33 @@ gl_lock_define_initialized (static, handles_lock);
 static guestfs_h *handles = NULL;
 static int atexit_handler_set = 0;
 
+gl_lock_define_initialized (static, init_lock);
+
+/* No initialization is required by libguestfs, but libvirt and
+ * libxml2 require initialization if they might be called from
+ * multiple threads.  Hence this constructor function which is called
+ * when libguestfs is first loaded.
+ */
+static void init_libguestfs (void) __attribute__((constructor));
+
+static void
+init_libguestfs (void)
+{
+#if defined(HAVE_LIBVIRT) || defined(HAVE_LIBXML2)
+  gl_lock_lock (init_lock);
+#endif
+#ifdef HAVE_LIBVIRT
+  virInitialize ();
+#endif
+#ifdef HAVE_LIBXML2
+  xmlInitParser ();
+  LIBXML_TEST_VERSION;
+#endif
+#if defined(HAVE_LIBVIRT) || defined(HAVE_LIBXML2)
+  gl_lock_unlock (init_lock);
+#endif
+}
+
 guestfs_h *
 guestfs_create (void)
 {

src/libvirtdomain.c

@@ -44,17 +44,6 @@
 
 #if defined(HAVE_LIBVIRT) && defined(HAVE_LIBXML2)
 
-static void init_libxml2 (void) __attribute__((constructor));
-
-static void
-init_libxml2 (void)
-{
-  /* I am told that you don't really need to call virInitialize ... */
-
-  xmlInitParser ();
-  LIBXML_TEST_VERSION;
-}
-
 static void
 ignore_errors (void *ignore, virErrorPtr ignore2)
 {