Change the version reference

Now, if liberasurecode.so exposes a liberasurecode_get_version function,
we'll use that; otherwise, we'll fall back to reporting the version that
PyECLib was built against.

Note that if your liberasurecode.so doesn't support
the liberasurecode_get_verion function, pyeclib will the version at built
as well as older behavior.

Co-Authored-By: Tim Burke <tim.burke@gmail.com>
Change-Id: I54823183cce6775a83e913baf6bb1eeb94aabc13

1 files changed, 26 insertions, 1 deletions

diff --git a/src/c/pyeclib_c/pyeclib_c.c b/src/c/pyeclib_c/pyeclib_c.c
index 8e1a23c..5ba5770 100644
--- a/src/c/pyeclib_c/pyeclib_c.c
+++ b/src/c/pyeclib_c/pyeclib_c.c
@@ -1213,7 +1213,32 @@ pyeclib_c_check_backend_available(PyObject *self, PyObject *args)
 
 static PyObject*
 pyeclib_c_liberasurecode_version(PyObject *self, PyObject *args) {
-    return PyInt_FromLong(LIBERASURECODE_VERSION);
+    void *hLib;
+    char *err;
+    uint32_t (*hGetVersion)(void);
+
+    dlerror();
+    hLib = dlopen("liberasurecode.so", RTLD_LAZY);
+    /* It's important that we clear the last error before calling dysym */
+    err = dlerror();
+    if (err) {
+        /* This should never actually get hit; since we're using various
+           symbols already, liberasurecode.so should *already* be loaded. */
+        return PyInt_FromLong(LIBERASURECODE_VERSION);
+    }
+
+    hGetVersion = dlsym(hLib, "liberasurecode_get_version");
+    err = dlerror();
+    if (err) {
+        /* This is the important bit. Old version, doesn't have get_version
+           support; fall back to old behavior. */
+        dlclose(hLib);
+        return PyInt_FromLong(LIBERASURECODE_VERSION);
+    }
+
+    uint32_t version = (*hGetVersion)();
+    dlclose(hLib);
+    return Py_BuildValue("k", version);
 }
 
 static PyMethodDef PyECLibMethods[] = {