libxl: un-constify return value of libxl_basename

The string returned is malloc'ed but marked as "const".

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

tools/libxl/libxl.h

@@ -477,6 +477,16 @@ typedef struct libxl__ctx libxl_ctx;
 #define LIBXL_HAVE_NONCONST_EVENT_OCCURS_EVENT_ARG 1
 #endif
 
+/*
+ * LIBXL_HAVE_CONST_LIBXL_BASENAME_RETURN_VALUE
+ *
+ * The return value of libxl_basename is malloc'ed but the erroneously
+ * marked as "const" in releases before 4.5.
+ */
+#if defined(LIBXL_API_VERSION) && LIBXL_API_VERSION < 0x040500
+#define LIBXL_HAVE_CONST_LIBXL_BASENAME_RETURN_VALUE 1
+#endif
+
 /*
  * LIBXL_HAVE_PHYSINFO_OUTSTANDING_PAGES
  *

tools/libxl/libxl_utils.c

@@ -19,7 +19,10 @@
 
 #include "libxl_internal.h"
 
-const char *libxl_basename(const char *name)
+#ifdef LIBXL_HAVE_CONST_LIBXL_BASENAME_RETURN_VALUE
+const
+#endif
+char *libxl_basename(const char *name)
 {
     const char *filename;
     if (name == NULL)

tools/libxl/libxl_utils.h

@@ -18,7 +18,11 @@
 
 #include "libxl.h"
 
-const char *libxl_basename(const char *name); /* returns string from strdup */
+#ifdef LIBXL_HAVE_CONST_LIBXL_BASENAME_RETURN_VALUE
+const
+#endif
+char *libxl_basename(const char *name); /* returns string from strdup */
+
 unsigned long libxl_get_required_shadow_memory(unsigned long maxmem_kb, unsigned int smp_cpus);
 int libxl_name_to_domid(libxl_ctx *ctx, const char *name, uint32_t *domid);
 int libxl_domain_qualifier_to_domid(libxl_ctx *ctx, const char *name, uint32_t *domid);