parttype: add parttype class and functions

Parttype is a container for partition types in libfdisk.

In python-libfdisk, the only way to create parttype instances
is using the corresponding label-specific function:

	get_parttype_from_{code,string}

This function wraps libfdisk's label_get_parttype_from_code (lookup DOS
label parttype by hex code) and label_get_parttype_from_string (lookup
GPT parttype by type uuid)

For example, to get the parttype instance of 'EFI System'
partition type of a GPT label, with type uuid
'c12a7328-f81f-11d2-ba4b-00a0c93ec93b':

>>> import fdisk
>>> cxt = fdisk.Context('./disk.bin', readonly=False)
>>> cxt.create_disklabel('gpt')
>>> efitype = cxt.label.get_parttype_from_string("c12a7328-f81f-11d2-ba4b-00a0c93ec93b")
>>> efitype
<libfdisk.PartType object at 0x7f503e4a5270, name=EFI System>

See:

https://cdn.kernel.org/pub/linux/utils/util-linux/v2.34/libfdisk-docs/libfdisk-Partition-types.html
https://cdn.kernel.org/pub/linux/utils/util-linux/v2.34/libfdisk-docs/libfdisk-Label.html#fdisk-label-get-parttype-from-code
https://cdn.kernel.org/pub/linux/utils/util-linux/v2.34/libfdisk-docs/libfdisk-Label.html#fdisk-label-get-parttype-from-string

fdisk.c

@@ -66,6 +66,7 @@ PyInit_fdisk(void)
 	Context_AddModuleObject(m);
 	Label_AddModuleObject(m);
 	Partition_AddModuleObject(m);
+	PartType_AddModuleObject(m);
 
 
 	return m;

fdisk.h

@@ -39,15 +39,23 @@ typedef struct {
 	struct fdisk_partition		*pa;
 } PartitionObject;
 
+typedef struct {
+	PyObject_HEAD
+	struct fdisk_parttype		*type;
+} PartTypeObject;
+
 extern PyTypeObject ContextType;
 extern PyTypeObject PartitionType;
+extern PyTypeObject PartTypeType;
 
 extern void Context_AddModuleObject(PyObject *mod);
 extern void Label_AddModuleObject(PyObject *mod);
 extern void Partition_AddModuleObject(PyObject *mod);
+extern void PartType_AddModuleObject(PyObject *mod);
 
 extern PyObject *PyObjectResultStr(const char *s);
 extern PyObject *PyObjectResultLabel(struct fdisk_label *lb);
 extern PyObject *PyObjectResultPartition(struct fdisk_partition *pa);
+extern PyObject *PyObjectResultPartType(struct fdisk_parttype *t);
 
 #endif

label.c

@@ -60,8 +60,49 @@ static int Label_init(LabelObject *self, PyObject *args, PyObject *kwds)
 	return 0;
 }
 
+#define Label_get_parttype_from_code_HELP "get_parttype_from_code(code)\n\n" \
+	"Search for partition type in label-specific table."
+static PyObject *Label_get_parttype_from_code(LabelObject *self, PyObject *args, PyObject *kwds)
+{
+	struct fdisk_parttype *ptype;
+	unsigned int ptype_code;
 
+	if (!PyArg_ParseTuple(args, "I", &ptype_code)) {
+		PyErr_SetString(PyExc_TypeError, ARG_ERR);
+		return NULL;
+	}
+
+	ptype = fdisk_label_get_parttype_from_code(self->lb, ptype_code);
+	if (!ptype) {
+		PyErr_Format(PyExc_RuntimeError, "No match for parttype with code: %d", ptype_code);
+		return NULL;
+	}
+
+	return PyObjectResultPartType(ptype);
+}
+#define Label_get_parttype_from_string_HELP "get_parttype_from_string(uuid)\n\n" \
+	"Search by string for partition type in label-specific table."
+static PyObject *Label_get_parttype_from_string(LabelObject *self, PyObject *args, PyObject *kwds)
+{
+	struct fdisk_parttype *ptype = NULL;
+	char *str;
+
+	if (!PyArg_ParseTuple(args, "s", &str)) {
+		PyErr_SetString(PyExc_TypeError, ARG_ERR);
+		return NULL;
+	}
+
+	ptype = fdisk_label_get_parttype_from_string(self->lb, str);
+	if (!ptype) {
+		PyErr_Format(PyExc_RuntimeError, "No match for parttype with string: %s", str);
+		return NULL;
+	}
+
+	return PyObjectResultPartType(ptype);
+}
 static PyMethodDef Label_methods[] = {
+	{"get_parttype_from_code",	(PyCFunction)Label_get_parttype_from_code, METH_VARARGS, Label_get_parttype_from_code_HELP},
+	{"get_parttype_from_string",	(PyCFunction)Label_get_parttype_from_string, METH_VARARGS, Label_get_parttype_from_string_HELP},
 	{NULL}
 };
 

parttype.c

@@ -0,0 +1,86 @@
+/*
+ * (C) 2022 Soleta Consulting S.L. <info@soleta.eu>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Author: Jose M. Guisado <jguisado@soleta.eu>
+ */
+
+#include "fdisk.h"
+
+static PyMemberDef PartType_members[] = {
+	{ NULL }
+};
+
+static void PartType_dealloc(PartTypeObject *self)
+{
+	Py_TYPE(self)->tp_free((PyObject *) self);
+}
+
+static PyMethodDef PartType_methods[] = {
+	{NULL}
+};
+
+static PyObject *PartType_get_name(PartTypeObject *self)
+{
+	return PyObjectResultStr(fdisk_parttype_get_name(self->type));
+}
+static PyObject *PartType_get_code(PartTypeObject *self)
+{
+	return PyLong_FromUnsignedLong(fdisk_parttype_get_code(self->type));
+}
+static PyGetSetDef PartType_getseters[] = {
+	{"name",	(getter)PartType_get_name, NULL, "parttype human readable name", NULL},
+	{"code",	(getter)PartType_get_code, NULL, "parttype DOS code", NULL},
+	{NULL}
+};
+
+static PyObject *PartType_repr(PartTypeObject *self)
+{
+	return PyUnicode_FromFormat("<libfdisk.PartType object at %p, name=%s>",
+			self, fdisk_parttype_get_name(self->type));
+}
+
+PyTypeObject PartTypeType = {
+	PyVarObject_HEAD_INIT(NULL, 0)
+	.tp_name = "libfdisk.PartType",
+	.tp_basicsize = sizeof(PartTypeObject),
+	.tp_dealloc = (destructor)PartType_dealloc,
+	.tp_repr = (reprfunc) PartType_repr,
+	.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
+	/* TODO: .tp_doc = PartType_HELP, */
+	.tp_methods = PartType_methods,
+	.tp_members = PartType_members,
+	.tp_getset = PartType_getseters,
+};
+
+PyObject *PyObjectResultPartType(struct fdisk_parttype *t)
+{
+        PartTypeObject *result;
+
+        if (!t) {
+                PyErr_SetString(PyExc_AssertionError, "lb assert failed");
+                return NULL;
+        }
+
+        result = PyObject_New(PartTypeObject, &PartTypeType);
+        if (!result) {
+                PyErr_SetString(PyExc_MemoryError, "Couldn't allocate PartType object");
+                return NULL;
+        }
+
+        result->type = t;
+        return (PyObject *) result;
+}
+
+void PartType_AddModuleObject(PyObject *mod)
+{
+	if (PyType_Ready(&PartTypeType) < 0)
+		return;
+
+	Py_INCREF(&PartTypeType);
+	PyModule_AddObject(mod, "PartType", (PyObject *)&PartTypeType);
+}

setup.py

@@ -2,7 +2,8 @@ from setuptools import setup, Extension
 
 libfdisk = Extension('fdisk',
                     libraries = ['fdisk'],
-                    sources = ['fdisk.c', 'context.c', 'label.c', 'partition.c'])
+                    sources = ['fdisk.c', 'context.c', 'label.c',
+                               'partition.c', 'parttype.c'])
 
 setup (name = 'libfdisk',
        version = '1.0',