From 5ec9ec73c8189023256a6d737600382f9e3d288a Mon Sep 17 00:00:00 2001
From: "Jose M. Guisado" <jguisado@soleta.eu>
Date: Thu, 15 Dec 2022 14:58:22 +0100
Subject: fdisk: add set_PyErr_from_rc

python-libfdisk raises Python exceptions when the libfdisk reports an
error when executing some function. libfdisk returns negative
errno values when reporting some error.

Adds utility function to set PyErr string based on the strerror of
a given errno code. Useful when raising Python exceptions.
---
 context.c   | 20 +++++++++++++++-----
 fdisk.c     | 19 +++++++++++++++++++
 fdisk.h     |  2 ++
 partition.c | 15 ++++++++-------
 4 files changed, 44 insertions(+), 12 deletions(-)

diff --git a/context.c b/context.c
index 326c0c4..07d9304 100644
--- a/context.c
+++ b/context.c
@@ -66,12 +66,19 @@ static int Context_init(ContextObject *self, PyObject *args, PyObject *kwds)
 		return -1;
 	}
 
-	if (device && (rc = fdisk_assign_device(self->cxt, device, readonly)))
+	if (device && (rc = fdisk_assign_device(self->cxt, device, readonly))) {
+		set_PyErr_from_rc(-rc);
 		return -1;
-	if (details && (rc = fdisk_enable_details(self->cxt, details)))
+	}
+	if (details && (rc = fdisk_enable_details(self->cxt, details))) {
+		set_PyErr_from_rc(-rc);
 		return -1;
+	}
 
-	fdisk_get_partitions(self->cxt, &self->tb);
+	if ((fdisk_get_partitions(self->cxt, &self->tb) < 0)) {
+		set_PyErr_from_rc(-rc);
+		return -1;
+	}
 
 	return 0;
 }
@@ -82,6 +89,7 @@ static int Context_init(ContextObject *self, PyObject *args, PyObject *kwds)
 static PyObject *Context_assign_device(ContextObject *self, PyObject *args, PyObject *kwds)
 {
 	char *fname;
+	int rc;
 
 	if (!PyArg_ParseTuple(args, "s", &fname)) {
 		PyErr_SetString(PyExc_TypeError, ARG_ERR);
@@ -94,9 +102,11 @@ static PyObject *Context_assign_device(ContextObject *self, PyObject *args, PyOb
 	fdisk_assign_device(self->cxt, fname, 1);
 
 	self->lb = fdisk_get_label(self->cxt, NULL);
-	fdisk_get_partitions(self->cxt, &self->tb);
+	if ((rc = fdisk_get_partitions(self->cxt, &self->tb) < 0)) {
+		set_PyErr_from_rc(-rc);
+		return NULL;
+	}
 
-	/* XXX: check rc*/
 	Py_INCREF(Py_None);
 	return Py_None;
 }
diff --git a/fdisk.c b/fdisk.c
index d7d3fe4..d78e6e2 100644
--- a/fdisk.c
+++ b/fdisk.c
@@ -14,6 +14,25 @@
 
 #include "fdisk.h"
 
+void *set_PyErr_from_rc(int e)
+{
+	switch (e) {
+	case ENOMEM:
+		PyErr_SetString(PyExc_MemoryError, strerror(e));
+		break;
+	case EINVAL:
+		PyErr_SetString(PyExc_TypeError, strerror(e));
+		break;
+	case ENOSYS:
+		PyErr_SetString(PyExc_NotImplementedError, strerror(e));
+		break;
+	default:
+		PyErr_SetString(PyExc_Exception, strerror(e));
+	}
+
+	return NULL;
+}
+
 PyObject *PyObjectResultStr(const char *s)
 {
 	PyObject *result;
diff --git a/fdisk.h b/fdisk.h
index 39b4c95..3324aad 100644
--- a/fdisk.h
+++ b/fdisk.h
@@ -58,4 +58,6 @@ extern PyObject *PyObjectResultLabel(struct fdisk_label *lb);
 extern PyObject *PyObjectResultPartition(struct fdisk_partition *pa);
 extern PyObject *PyObjectResultPartType(struct fdisk_parttype *t);
 
+extern void *set_PyErr_from_rc(int err);
+
 #endif
diff --git a/partition.c b/partition.c
index 5284869..8685c3f 100644
--- a/partition.c
+++ b/partition.c
@@ -48,7 +48,8 @@ static int Partition_init(PartitionObject *self, PyObject *args, PyObject *kwds)
 	};
 	int partno_follow_default = 0,
 	    start_follow_default = 0,
-	    end_follow_default = 0;
+	    end_follow_default = 0,
+	    rc;
 
 	if (!PyArg_ParseTupleAndKeywords(args,
 					kwds, "|ppp", kwlist,
@@ -60,16 +61,16 @@ static int Partition_init(PartitionObject *self, PyObject *args, PyObject *kwds)
 	}
 
 	self->pa = fdisk_new_partition();
-	if (fdisk_partition_partno_follow_default(self->pa, partno_follow_default) < 0) {
-		PyErr_SetString(PyExc_RuntimeError, "Error setting partno_follow_default");
+	if ((rc = fdisk_partition_partno_follow_default(self->pa, partno_follow_default) < 0)) {
+		set_PyErr_from_rc(-rc);
 		return -1;
 	}
-	if (fdisk_partition_start_follow_default(self->pa, start_follow_default) < 0) {
-		PyErr_SetString(PyExc_RuntimeError, "Error setting start_follow_default");
+	if ((rc = fdisk_partition_start_follow_default(self->pa, start_follow_default) < 0)) {
+		set_PyErr_from_rc(-rc);
 		return -1;
 	}
-	if (fdisk_partition_end_follow_default(self->pa, end_follow_default) < 0) {
-		PyErr_SetString(PyExc_RuntimeError, "Error setting end_follow_default");
+	if ((rc = fdisk_partition_end_follow_default(self->pa, end_follow_default) < 0)) {
+		set_PyErr_from_rc(-rc);
 		return -1;
 	}
 
-- 
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