Previously errors caused a RuntimeException to be raised. This commit defines a custom exception (libnbdmod.Error) which has two parameters, the required error string, and the optional errno (which may be 0 if unavailable). For example: $ ./run nbdsh -c 'h.pread(0, 0)' Traceback (most recent call last): File "/usr/lib64/python3.7/runpy.py", line 193, in _run_module_as_main "__main__", mod_spec) File "/usr/lib64/python3.7/runpy.py", line 85, in _run_code exec(code, run_globals) File "/home/rjones/d/libnbd/python/nbd.py", line 1133, in <module> nbdsh.shell() File "/home/rjones/d/libnbd/python/nbdsh.py", line 62, in shell exec (c) File "<string>", line 1, in <module> File "/home/rjones/d/libnbd/python/nbd.py", line 453, in pread return libnbdmod.pread (self._o, count, offset, flags) libnbdmod.Error: ('nbd_pread: invalid state: START: the handle must be connected and finished handshaking with the server: Transport endpoint is not connected', 107) --- generator/generator | 31 ++++++++++++++++++++++++++++++- python/t/610-exception.py | 34 ++++++++++++++++++++++++++++++++++ 2 files changed, 64 insertions(+), 1 deletion(-) diff --git a/generator/generator b/generator/generator index 157a9cb..11ab8b8 100755 --- a/generator/generator +++ b/generator/generator @@ -3337,6 +3337,19 @@ get_handle (PyObject *obj) return (struct nbd_handle *) PyCapsule_GetPointer(obj, \"nbd_handle\"); } +/* nbd.Error exception. */ +extern PyObject *nbd_internal_py_Error; + +static inline void +raise_exception () +{ + PyObject *args = PyTuple_New (2); + + PyTuple_SetItem (args, 0, PyUnicode_FromString (nbd_get_error ())); + PyTuple_SetItem (args, 1, PyLong_FromLong (nbd_get_errno ())); + PyErr_SetObject (nbd_internal_py_Error, args); +} + "; List.iter ( @@ -3390,6 +3403,9 @@ static struct PyModuleDef moduledef = { NULL, /* m_free */ }; +/* nbd.Error exception. */ +PyObject *nbd_internal_py_Error; + extern PyMODINIT_FUNC PyInit_libnbdmod (void); PyMODINIT_FUNC @@ -3401,6 +3417,19 @@ PyInit_libnbdmod (void) if (mod == NULL) return NULL; + nbd_internal_py_Error = PyErr_NewExceptionWithDoc ( + \"libnbdmod.Error\", + \"Exception thrown when the underlying libnbd call fails. This\\n\" + \"exception carries a two element tuple. The first element is a\\n\" + \"printable string containing the error message. The second\\n\" + \"element is the optional errno (which may be 0 in some cases\\n\" + \"if the error does not correspond to a system call failure).\\n\", + NULL, NULL + ); + if (nbd_internal_py_Error == NULL) + return NULL; + PyModule_AddObject (mod, \"Error\", nbd_internal_py_Error); + return mod; } " @@ -3796,7 +3825,7 @@ let print_python_binding name { args; ret } = | RBool | RErr | RFd | RInt | RInt64 -> pr " if (ret == -1) {\n"; | RConstString | RString -> pr " if (ret == NULL) {\n"; ); - pr " PyErr_SetString (PyExc_RuntimeError, nbd_get_error ());\n"; + pr " raise_exception ();\n"; pr " py_ret = NULL;\n"; pr " goto out;\n"; pr " }\n"; diff --git a/python/t/610-exception.py b/python/t/610-exception.py new file mode 100644 index 0000000..f27b57d --- /dev/null +++ b/python/t/610-exception.py @@ -0,0 +1,34 @@ +# libnbd Python bindings +# Copyright (C) 2010-2019 Red Hat Inc. +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program; if not, write to the Free Software +# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + +import nbd +import libnbdmod + +h = nbd.NBD () + +try: + # This will always throw an exception because the handle is not + # connected. + h.pread (0, 0) +except libnbdmod.Error as ex: + str = ex.args[0] + errno = ex.args[1] + print ("str = %s\nerr = %d\n" % (str, errno)) + exit (0) + +# If we reach here then we didn't catch the exception above. +exit (1) -- 2.22.0