File 0001-python-kdumpfile-add-from_pointer-method-t... of Package libkdumpfile

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File 0001-python-kdumpfile-add-from_pointer-method-to-clone-na.patch of Package libkdumpfile

From 2852532be05e8ad25aa62b2de4bab507d8ce08d4 Mon Sep 17 00:00:00 2001
From: Jeff Mahoney <jeffm@suse.com>
Date: Tue, 6 Sep 2022 11:13:56 -0400
Subject: [PATCH] python/kdumpfile: add from_pointer method to clone native
 context

When using libdumpfile in a project that uses the library directly but
also has Python extensions that need access to it, we want to clone the context
instead of opening a new one so that we share resources and don't need
to open the dump file multiple times.

This is an interface that does allow the developer to shoot themselves
in the foot if an invalid pointer is passed, but this is a common design
pattern.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
---
 python/kdumpfile.c | 90 +++++++++++++++++++++++++++++++++++++---------
 1 file changed, 73 insertions(+), 17 deletions(-)

diff --git a/python/kdumpfile.c b/python/kdumpfile.c
index 7c59175..4854cb6 100644
--- a/python/kdumpfile.c
+++ b/python/kdumpfile.c
@@ -78,12 +78,36 @@ exception_map(kdump_status status)
 	};
 }
 
+static int kdumpfile_init_common(kdumpfile_object *self)
+{
+	kdump_status status;
+	kdump_attr_ref_t rootref;
+
+	status = kdump_attr_ref(self->ctx, NULL, &rootref);
+	if (status != KDUMP_OK) {
+		PyErr_Format(exception_map(status),
+			     "Cannot reference root attribute: %s",
+			     kdump_get_err(self->ctx));
+		return -1;
+	}
+
+	self->attr = attr_dir_new(self, &rootref);
+	if (!self->attr) {
+		kdump_attr_unref(self->ctx, &rootref);
+		return -1;
+	}
+
+	Py_INCREF(addrxlat_API->convert);
+	self->addrxlat_convert = addrxlat_API->convert;
+
+	return 0;
+}
+
 static PyObject *
 kdumpfile_new (PyTypeObject *type, PyObject *args, PyObject *kw)
 {
 	kdumpfile_object *self = NULL;
 	static char *keywords[] = {"file", NULL};
-	kdump_attr_ref_t rootref;
 	kdump_status status;
 	const char *filepath;
 
@@ -115,27 +139,12 @@ kdumpfile_new (PyTypeObject *type, PyObject *args, PyObject *kw)
 		goto fail;
 	}
 
-	status = kdump_attr_ref(self->ctx, NULL, &rootref);
-	if (status != KDUMP_OK) {
-		PyErr_Format(exception_map(status),
-			     "Cannot reference root attribute: %s",
-			     kdump_get_err(self->ctx));
+	if (kdumpfile_init_common(self))
 		goto fail;
-	}
-
-	self->attr = attr_dir_new(self, &rootref);
-	if (!self->attr) {
-		kdump_attr_unref(self->ctx, &rootref);
-		goto fail;
-	}
-
-	Py_INCREF(addrxlat_API->convert);
-	self->addrxlat_convert = addrxlat_API->convert;
 
 	return (PyObject*)self;
 
 fail:
-	Py_XDECREF(self->attr);
 	Py_XDECREF(self);
 	close(self->fd);
 	return NULL;
@@ -156,6 +165,50 @@ kdumpfile_dealloc(PyObject *_self)
 	Py_TYPE(self)->tp_free((PyObject*)self);
 }
 
+PyDoc_STRVAR(kdumpfile_from_pointer__doc__,
+"from_pointer (address) -> kdumpfile\naddress must be valid pointer to kdump_ctx.");
+
+static PyObject *kdumpfile_from_pointer (PyObject *_type, PyObject *args, PyObject *kwargs)
+{
+	PyTypeObject *type = (PyTypeObject *)_type;
+	kdumpfile_object *self = NULL;
+	unsigned long addr = 0;
+	static char *keywords[] = { "address", NULL };
+
+	if (!PyArg_ParseTupleAndKeywords(args, kwargs, "k:from_pointer",
+					 keywords, &addr))
+		return NULL;
+
+	if (addr == 0) {
+		PyErr_SetString(PyExc_ValueError,
+				"Cannot instantiate object with NULL pointer.");
+		return NULL;
+	}
+
+	self = (kdumpfile_object*) type->tp_alloc(type, 0);
+	if (!self)
+		return NULL;
+
+	self->ctx = kdump_clone((kdump_ctx_t *)addr, 0);
+	if (!self->ctx) {
+		PyErr_SetString(PyExc_MemoryError,
+				"Couldn't allocate kdump context");
+		Py_XDECREF(self);
+		goto fail;
+	}
+
+	self->fd = 0;
+	if (kdumpfile_init_common(self))
+		goto fail;
+
+	return (PyObject *)self;
+
+fail:
+	Py_XDECREF(self);
+	return NULL;
+
+}
+
 PyDoc_STRVAR(read__doc__,
 "read (addrtype, address) -> buffer.");
 
@@ -260,6 +313,9 @@ get_addrxlat_sys(PyObject *_self, PyObject *args)
 }
 
 static PyMethodDef kdumpfile_object_methods[] = {
+	{ "from_pointer", (PyCFunction)kdumpfile_from_pointer,
+		METH_VARARGS | METH_KEYWORDS | METH_CLASS,
+		kdumpfile_from_pointer__doc__ },
 	{"read",      (PyCFunction) kdumpfile_read, METH_VARARGS | METH_KEYWORDS,
 		read__doc__},
 	{ "get_addrxlat_ctx", get_addrxlat_ctx, METH_NOARGS,
-- 
2.37.2

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