Our use of PyUnicode_FSConverter was wrong - the result is a PyObject* rather than a char* (where dereferencing then calling free() on that pointer as char* has catastrophic effects). With this patch, I was able to set up a qemu-nbd encrypted server over a Unix socket (using a pending patch on the qemu list), coupled with a python connection to that socket: $ ~/qemu/qemu-nbd -r -k /tmp/nbdsock --object \ tls-creds-psk,id=tls0,endpoint=server,dir=/home/eblake/libnbd/tests \ --tls-creds tls0 -f raw -x / tmpfile $ ./run nbdsh nbd> h.set_tls_psk_file('tests/keys.psk') nbd> h.set_tls(2) nbd> h.set_export_name('/') nbd> h.connect_unix('/tmp/nbdsock') instead of getting a segfault. --- generator/generator | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/generator/generator b/generator/generator index c29460c..fa12232 100755 --- a/generator/generator +++ b/generator/generator @@ -3608,7 +3608,9 @@ let print_python_binding name { args; ret } = | Mutable arg -> pr " PyObject *%s;\n" (List.hd (name_of_arg arg)) | Opaque _ -> () - | Path n -> pr " char *%s = NULL;\n" n + | Path n -> + pr " PyObject *py_%s = NULL;\n" n; + pr " char *%s = NULL;\n" n | SockAddrAndLen (n, _) -> pr " /* XXX Complicated - Python uses a tuple of different\n"; pr " * lengths for the different socket types.\n"; @@ -3699,7 +3701,7 @@ let print_python_binding name { args; ret } = | Int64 n -> pr ", &%s" n | Mutable arg -> pr ", &%s" (List.hd (name_of_arg arg)) | Opaque n -> pr ", &%s_data->data" (find_callback n) - | Path n -> pr ", PyUnicode_FSConverter, &%s" n + | Path n -> pr ", PyUnicode_FSConverter, &py_%s" n | SockAddrAndLen (n, _) -> pr ", &%s" n | String n -> pr ", &%s" n | StringList n -> pr ", &py_%s" n @@ -3750,7 +3752,9 @@ let print_python_binding name { args; ret } = | Mutable _ -> pr " abort (); /* Mutable for normal Python parameters not impl */\n" | Opaque n -> () - | Path _ -> () + | Path n -> + pr " %s = PyBytes_AS_STRING (py_%s);\n" n n; + pr " assert (%s != NULL);\n" n | SockAddrAndLen _ -> pr " abort (); /* XXX SockAddrAndLen not implemented */\n"; | String _ -> () @@ -3860,7 +3864,8 @@ let print_python_binding name { args; ret } = | Int64 _ -> () | Mutable _ -> () | Opaque _ -> () - | Path n -> pr " free (%s);\n" n + | Path n -> + pr " Py_XDECREF (py_%s);\n" n | SockAddrAndLen _ -> () | String n -> () | StringList n -> pr " nbd_internal_py_free_string_list (%s);\n" n -- 2.20.1