[PATCH 0/4] Introduce Python bindings for libfdt

[PATCH 0/4] Introduce Python bindings for libfdt

[Simon Glass]

At present libfdt consists of only a C implementation. Many scripts are
written using Python so it useful to have Python bindings for libfdt.
Apparently this has never been attempted before, or if so I cannot find a
reference.

This series starts the process of adding this support, with just a
bare-bones set of methods, to attract initial comments.


Simon Glass (4):
  Add an initial Python library for libfdt
  Add tests for pylibfdt
  Mention pylibfdt in the documentation
  RFC: Build pylibfdt as part of the normal build process

 Makefile                   |  16 +++-
 README                     |   6 ++
 pylibfdt/.gitignore        |   3 +
 pylibfdt/Makefile.pylibfdt |  21 ++++++
 pylibfdt/libfdt.swig       | 157 +++++++++++++++++++++++++++++++++++++++
 pylibfdt/setup.py          |  34 +++++++++
 tests/pylibfdt_tests.py    | 179 +++++++++++++++++++++++++++++++++++++++++++++
 tests/run_tests.sh         |  19 ++++-
 8 files changed, 433 insertions(+), 2 deletions(-)
 create mode 100644 pylibfdt/.gitignore
 create mode 100644 pylibfdt/Makefile.pylibfdt
 create mode 100644 pylibfdt/libfdt.swig
 create mode 100644 pylibfdt/setup.py
 create mode 100644 tests/pylibfdt_tests.py

-- 
2.8.0.rc3.226.g39d4020

[PATCH 1/4] Add an initial Python library for libfdt

[Simon Glass]

Add Python bindings for a bare-bones set of libfdt functions. These allow
navigating the tree and reading node names and properties.

Signed-off-by: Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
---

 pylibfdt/.gitignore        |   3 +
 pylibfdt/Makefile.pylibfdt |  21 ++++++
 pylibfdt/libfdt.swig       | 157 +++++++++++++++++++++++++++++++++++++++++++++
 pylibfdt/setup.py          |  34 ++++++++++
 4 files changed, 215 insertions(+)
 create mode 100644 pylibfdt/.gitignore
 create mode 100644 pylibfdt/Makefile.pylibfdt
 create mode 100644 pylibfdt/libfdt.swig
 create mode 100644 pylibfdt/setup.py

diff --git a/pylibfdt/.gitignore b/pylibfdt/.gitignore
new file mode 100644
index 0000000..5e8c5e3
--- /dev/null
+++ b/pylibfdt/.gitignore
@@ -0,0 +1,3 @@
+libfdt.py
+libfdt.pyc
+libfdt_wrap.c
diff --git a/pylibfdt/Makefile.pylibfdt b/pylibfdt/Makefile.pylibfdt
new file mode 100644
index 0000000..fbdbca5
--- /dev/null
+++ b/pylibfdt/Makefile.pylibfdt
@@ -0,0 +1,21 @@
+# Makefile.pylibfdt
+#
+# This is not a complete Makefile of itself.  Instead, it is designed to
+# be easily embeddable into other systems of Makefiles.
+#
+
+PYLIBFDT_srcs = $(addprefix $(LIBFDT_srcdir)/,$(LIBFDT_SRCS))
+WRAP = $(PYLIBFDT_objdir)/libfdt_wrap.c
+PYMODULE = $(PYLIBFDT_objdir)/_libfdt.so
+
+$(PYMODULE): $(PYLIBFDT_srcs) $(WRAP)
+	@$(VECHO) PYMOD $@
+	python $(PYLIBFDT_objdir)/setup.py "$(CPPFLAGS)" $^
+	mv _libfdt.so $(PYMODULE)
+
+$(WRAP): $(PYLIBFDT_srcdir)/libfdt.swig
+	@$(VECHO) SWIG $@
+	swig -python -o $@ $<
+
+PYLIBFDT_cleanfiles = libfdt_wrap.c libfdt.py libfdt.pyc
+PYLIBFDT_CLEANFILES = $(addprefix $(PYLIBFDT_objdir)/,$(PYLIBFDT_cleanfiles))
diff --git a/pylibfdt/libfdt.swig b/pylibfdt/libfdt.swig
new file mode 100644
index 0000000..91887da
--- /dev/null
+++ b/pylibfdt/libfdt.swig
@@ -0,0 +1,157 @@
+/*
+ * pylibfdt - Flat Device Tree manipulation in Python
+ * Copyright (C) 2016 Google, Inc.
+ * Written by Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
+ *
+ * libfdt is dual licensed: you can use it either under the terms of
+ * the GPL, or the BSD license, at your option.
+ *
+ *  a) This library 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 library 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 library; if not, write to the Free
+ *     Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
+ *     MA 02110-1301 USA
+ *
+ * Alternatively,
+ *
+ *  b) Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *     1. Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *     2. Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ *     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ *     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ *     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ *     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ *     CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ *     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ *     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ *     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ *     OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+%module libfdt
+
+%{
+#define SWIG_FILE_WITH_INIT
+#include "libfdt.h"
+%}
+
+%pythoncode %{
+
+def Raise(errnum):
+    raise ValueError('Error %s' % fdt_strerror(errnum))
+
+def Name(fdt, offset):
+    name, len = fdt_get_name(fdt, offset)
+    return name
+
+def String(fdt, offset):
+    offset = fdt32_to_cpu(offset)
+    name = fdt_string(fdt, offset)
+    return name
+
+def fdt32_to_cpu(val):
+    return struct.unpack("=I", struct.pack(">I", val))[0]
+
+def Data(prop):
+    set_prop(prop)
+    return get_prop_data()
+%}
+
+%include "typemaps.i"
+%include "cstring.i"
+
+%typemap(in) void* = char*;
+
+typedef int fdt32_t;
+
+struct fdt_property {
+        fdt32_t tag;
+        fdt32_t len;
+        fdt32_t nameoff;
+        char data[0];
+};
+
+/*
+ * This is a work-around since I'm not sure of a better way to copy out the
+ * contents of a string. This is used in dtoc/GetProps(). The intent is to
+ * pass in a pointer to a property and access the data field at the end of
+ * it. Ideally the Data() function above would be able to do this directly,
+ * but I'm not sure how to do that. Needs another look.
+ */
+#pragma SWIG nowarn=454
+%inline %{
+    static struct fdt_property *cur_prop;
+
+    void set_prop(struct fdt_property *prop) {
+        cur_prop = prop;
+    }
+%}
+
+%cstring_output_allocate_size(char **s, int *sz, free(*$1));
+%inline %{
+    void get_prop_data(char **s, int *sz) {
+        *sz = fdt32_to_cpu(cur_prop->len);
+        *s = (char *)malloc(*sz);
+        if (!*s)
+            *sz = 0;
+        else
+            memcpy(*s, cur_prop + 1, *sz);
+    }
+%}
+
+%typemap(in) (const void *) {
+  if (!PyByteArray_Check($input)) {
+    SWIG_exception_fail(SWIG_TypeError, "in method '" "$symname" "', argument "
+                       "$argnum"" of type '" "$type""'");
+  }
+  $1 = (void *) PyByteArray_AsString($input);
+}
+
+int fdt_path_offset(const void *fdt, const char *path);
+int fdt_first_property_offset(const void *fdt, int nodeoffset);
+int fdt_next_property_offset(const void *fdt, int offset);
+const char *fdt_get_name(const void *fdt, int nodeoffset, int *OUTPUT);
+const char *fdt_string(const void *fdt, int stroffset);
+const struct fdt_property *fdt_get_property_by_offset(const void *fdt,
+                                                      int offset,
+                                                      int *OUTPUT);
+const char *fdt_strerror(int errval);
+int fdt_first_subnode(const void *fdt, int offset);
+int fdt_next_subnode(const void *fdt, int offset);
+
+%typemap(in) (void *) {
+  if (!PyByteArray_Check($input)) {
+    SWIG_exception_fail(SWIG_TypeError, "in method '" "$symname" "', argument "
+                       "$argnum"" of type '" "$type""'");
+  }
+  $1 = PyByteArray_AsString($input);
+}
+
+int fdt_delprop(void *fdt, int nodeoffset, const char *name);
+
+int fdt_pack(void *fdt);
+
+int fdt_totalsize(const void *fdt);
+int fdt_off_dt_struct(const void *fdt);
diff --git a/pylibfdt/setup.py b/pylibfdt/setup.py
new file mode 100644
index 0000000..8f8618e
--- /dev/null
+++ b/pylibfdt/setup.py
@@ -0,0 +1,34 @@
+#!/usr/bin/env python
+
+"""
+setup.py file for SWIG libfdt
+"""
+
+from distutils.core import setup, Extension
+import os
+import sys
+
+progname = sys.argv[0]
+cflags = sys.argv[1]
+files = sys.argv[2:]
+
+if cflags:
+    cflags = [flag for flag in cflags.split(' ') if flag]
+else:
+    cflags = None
+
+libfdt_module = Extension(
+    '_libfdt',
+    sources = files,
+    extra_compile_args =  cflags
+)
+
+sys.argv = [progname, '--quiet', 'build_ext', '--inplace']
+
+setup (name = 'libfdt',
+       version = '0.1',
+       author      = "SWIG Docs",
+       description = """Simple swig libfdt from docs""",
+       ext_modules = [libfdt_module],
+       py_modules = ["libfdt"],
+       )
-- 
2.8.0.rc3.226.g39d4020

[PATCH 2/4] Add tests for pylibfdt

[Simon Glass]

Signed-off-by: Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
---

 tests/pylibfdt_tests.py | 179 ++++++++++++++++++++++++++++++++++++++++++++++++
 tests/run_tests.sh      |  19 ++++-
 2 files changed, 197 insertions(+), 1 deletion(-)
 create mode 100644 tests/pylibfdt_tests.py

diff --git a/tests/pylibfdt_tests.py b/tests/pylibfdt_tests.py
new file mode 100644
index 0000000..c406ac9
--- /dev/null
+++ b/tests/pylibfdt_tests.py
@@ -0,0 +1,179 @@
+# pylibfdt - Tests for Flat Device Tree manipulation in Python
+# Copyright (C) 2016 Google, Inc.
+# Written by Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
+#
+# libfdt is dual licensed: you can use it either under the terms of
+# the GPL, or the BSD license, at your option.
+#
+#  a) This library 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 library 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 library; if not, write to the Free
+#     Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
+#     MA 02110-1301 USA
+#
+# Alternatively,
+#
+#  b) Redistribution and use in source and binary forms, with or
+#     without modification, are permitted provided that the following
+#     conditions are met:
+#
+#     1. Redistributions of source code must retain the above
+#        copyright notice, this list of conditions and the following
+#        disclaimer.
+#     2. Redistributions in binary form must reproduce the above
+#        copyright notice, this list of conditions and the following
+#        disclaimer in the documentation and/or other materials
+#        provided with the distribution.
+#
+#     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+#     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+#     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+#     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+#     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+#     CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+#     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+#     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+#     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+#     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+#     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+#     OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+#     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+
+import sys
+import unittest
+
+sys.path.append('../pylibfdt')
+import libfdt
+
+class PyLibfdtTests(unittest.TestCase):
+    """Test class for pylibfdt.
+
+    Properties:
+        fdt: Device tree file used for testing
+    """
+
+    def setUp(self):
+        """Read in the device tree we use for testing"""
+        self.fdt = self._ReadFdt('test_tree1.dtb')
+
+    def _ReadFdt(self, fname):
+        """Read a device tree file into a bytearray ready for use
+
+        Args:
+            fname: Filename to read from
+
+        Returns:
+            Fdt bytearray suitable for passing to libfdt functions
+        """
+        return bytearray(open(fname).read())
+
+    def GetPropList(self, node_path):
+        """Read a list of properties from a node
+
+        Args:
+            node_path: Full path to node, e.g. '/subnode@1/subsubnode'
+
+        Returns:
+            List of property names for that node, e.g. ['compatible', 'reg']
+        """
+        prop_list = []
+        node = libfdt.fdt_path_offset(self.fdt, node_path)
+        poffset = libfdt.fdt_first_property_offset(self.fdt, node)
+        while poffset >= 0:
+            pdata, plen = libfdt.fdt_get_property_by_offset(self.fdt, poffset)
+            prop_list.append(libfdt.String(self.fdt, pdata.nameoff))
+            poffset = libfdt.fdt_next_property_offset(self.fdt, poffset)
+        return prop_list
+
+    def testImport(self):
+        """Check that we can import the library correctly"""
+        self.assertEquals(type(libfdt), type(sys))
+
+    def testPathOffset(self):
+        """Check that we can find the offset of a node"""
+        self.assertEquals(libfdt.fdt_path_offset(self.fdt, '/'), 0)
+        self.assertEquals(libfdt.fdt_path_offset(self.fdt, '/subnode@1'), 124)
+
+    def testPropertyOffset(self):
+        """Walk through all the properties in the root node"""
+        self.assertEquals(libfdt.fdt_first_property_offset(self.fdt, 0), 8)
+        self.assertEquals(libfdt.fdt_next_property_offset(self.fdt, 8), 32)
+        self.assertEquals(libfdt.fdt_next_property_offset(self.fdt, 32), 48)
+        self.assertEquals(libfdt.fdt_next_property_offset(self.fdt, 48), 68)
+        self.assertEquals(libfdt.fdt_next_property_offset(self.fdt, 68), 92)
+        self.assertEquals(libfdt.fdt_next_property_offset(self.fdt, 92), 108)
+        self.assertEquals(libfdt.fdt_next_property_offset(self.fdt, 108), -1)
+
+    def testGetName(self):
+        """Check that we can get the name of a node"""
+        self.assertEquals(libfdt.fdt_get_name(self.fdt, 0), ['', 0])
+        node = libfdt.fdt_path_offset(self.fdt, '/subnode@1/subsubnode')
+        self.assertEquals(libfdt.fdt_get_name(self.fdt, node),
+                          ['subsubnode', 10])
+
+    def testGetString(self):
+        """Test that we can get a string from the string table"""
+        node = libfdt.fdt_path_offset(self.fdt, '/subnode@2')
+        poffset = libfdt.fdt_first_property_offset(self.fdt, node)
+        pdata, plen = libfdt.fdt_get_property_by_offset(self.fdt, poffset)
+        self.assertEquals(libfdt.String(self.fdt, pdata.nameoff), 'reg')
+
+    def testGetPropertyByOffset(self):
+        """Check that we can read the name and contents of a property"""
+        root = libfdt.fdt_path_offset(self.fdt, '/')
+        poffset = libfdt.fdt_first_property_offset(self.fdt, root)
+        pdata, plen = libfdt.fdt_get_property_by_offset(self.fdt, poffset)
+        self.assertEquals(libfdt.fdt32_to_cpu(pdata.tag), 3)
+        self.assertEquals(libfdt.fdt32_to_cpu(pdata.len), 11)
+        self.assertEquals(libfdt.String(self.fdt, pdata.nameoff), 'compatible')
+        self.assertEquals(libfdt.Data(pdata), 'test_tree1\0')
+
+    def testStrError(self):
+        """Check that we can get an error string"""
+        self.assertEquals(libfdt.fdt_strerror(-1), 'FDT_ERR_NOTFOUND')
+
+    def testFirstNextSubnode(self):
+        """Check that we can walk through subnodes"""
+        node_list = []
+        node = libfdt.fdt_first_subnode(self.fdt, 0)
+        while node >= 0:
+            node_list.append(libfdt.fdt_get_name(self.fdt, node)[0])
+            node = libfdt.fdt_next_subnode(self.fdt, node)
+        self.assertEquals(node_list, ['subnode@1', 'subnode@2'])
+
+    def testDeleteProperty(self):
+        """Test that we can delete a property"""
+        node_name = '/subnode@1'
+        self.assertEquals(self.GetPropList(node_name),
+                          ['compatible', 'reg', 'prop-int'])
+        node = libfdt.fdt_path_offset(self.fdt, '/%s' % node_name)
+        self.assertEquals(libfdt.fdt_delprop(self.fdt, node, 'reg'), 0)
+        self.assertEquals(self.GetPropList(node_name),
+                          ['compatible', 'prop-int'])
+
+    def testHeader(self):
+        """Test that we can access the header values"""
+        self.assertEquals(libfdt.fdt_totalsize(self.fdt), 693)
+        self.assertEquals(libfdt.fdt_off_dt_struct(self.fdt), 88)
+
+    def testPack(self):
+        """Test that we can pack the tree after deleting something"""
+        self.assertEquals(libfdt.fdt_totalsize(self.fdt), 693)
+        node = libfdt.fdt_path_offset(self.fdt, '/subnode@2')
+        self.assertEquals(libfdt.fdt_delprop(self.fdt, node, 'prop-int'), 0)
+        self.assertEquals(libfdt.fdt_totalsize(self.fdt), 693)
+        self.assertEquals(libfdt.fdt_pack(self.fdt), 0)
+        self.assertEquals(libfdt.fdt_totalsize(self.fdt), 677)
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/tests/run_tests.sh b/tests/run_tests.sh
index e4139dd..707702d 100755
--- a/tests/run_tests.sh
+++ b/tests/run_tests.sh
@@ -720,6 +720,20 @@ fdtdump_tests () {
     run_fdtdump_test fdtdump.dts
 }
 
+pylibfdt_tests () {
+    TMP=/tmp/tests.stderr.$$
+    python pylibfdt_tests.py 2> ${TMP}
+    result=$(head -1 ${TMP} | awk \
+        '{ for (i = 1; i <= length($0); i++) { \
+            result = substr($0,i,1); fail = fail + (result == "F"); \
+            ok = ok + (result == ".")}; } END { print fail,  ok, fail + ok}')
+
+    # Extract the test results and add them to our totals
+    tot_fail=$((tot_fail + $(echo $result | cut -d" " -f 1)))
+    tot_pass=$((tot_pass + $(echo $result | cut -d" " -f 2)))
+    tot_tests=$((tot_tests + $(echo $result | cut -d" " -f 3)))
+}
+
 while getopts "vt:me" ARG ; do
     case $ARG in
 	"v")
@@ -738,7 +752,7 @@ while getopts "vt:me" ARG ; do
 done
 
 if [ -z "$TESTSETS" ]; then
-    TESTSETS="libfdt utilfdt dtc dtbs_equal fdtget fdtput fdtdump"
+    TESTSETS="libfdt utilfdt dtc dtbs_equal fdtget fdtput fdtdump pylibfdt"
 fi
 
 # Make sure we don't have stale blobs lying around
@@ -767,6 +781,9 @@ for set in $TESTSETS; do
 	"fdtdump")
 	    fdtdump_tests
 	    ;;
+	"pylibfdt")
+	    pylibfdt_tests
+	    ;;
     esac
 done
 
-- 
2.8.0.rc3.226.g39d4020

[PATCH 3/4] Mention pylibfdt in the documentation

[Simon Glass]

Add a note about pylibfdt in the README.

Full documentation for pylibfdt will need to be provided also.

Signed-off-by: Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
---

 README | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/README b/README
index f92008f..dee77c8 100644
--- a/README
+++ b/README
@@ -7,6 +7,12 @@ DTC and LIBFDT are maintained by:
 David Gibson <david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org>
 Jon Loeliger <jdl-CYoMK+44s/E@public.gmane.org>
 
+A Python library is also available. To build this you will need to install
+swig and Python development files. On Debian distributions:
+
+   sudo apt-get install swig python-dev
+
+
 Mailing list
 ------------
 The following list is for discussion about dtc and libfdt implementation
-- 
2.8.0.rc3.226.g39d4020

[PATCH 4/4] RFC: Build pylibfdt as part of the normal build process

[Simon Glass]

Possible this needs to be made optional. For now just hook it up.

Signed-off-by: Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
---

 Makefile | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 32dcfcf..4996cfd 100644
--- a/Makefile
+++ b/Makefile
@@ -115,7 +115,7 @@ BIN += fdtput
 
 SCRIPTS = dtdiff
 
-all: $(BIN) libfdt
+all: $(BIN) libfdt pylibfdt
 
 
 ifneq ($(DEPTARGETS),)
@@ -202,6 +202,19 @@ dist:
 	cat ../dtc-$(dtc_version).tar | \
 		gzip -9 > ../dtc-$(dtc_version).tar.gz
 
+
+#
+# Rules for pylibfdt
+#
+PYLIBFDT_srcdir = pylibfdt
+PYLIBFDT_objdir = pylibfdt
+
+include $(PYLIBFDT_srcdir)/Makefile.pylibfdt
+
+.PHONY: pylibfdt
+pylibfdt: $(PYLIBFDT_objdir)/_libfdt.so
+
+
 #
 # Release signing and uploading
 # This is for maintainer convenience, don't try this at home.
@@ -240,6 +253,7 @@ STD_CLEANFILES = *~ *.o *.$(SHAREDLIB_EXT) *.d *.a *.i *.s core a.out vgcore.* \
 clean: libfdt_clean tests_clean
 	@$(VECHO) CLEAN
 	rm -f $(STD_CLEANFILES)
+	rm -f $(PYLIBFDT_CLEANFILES)
 	rm -f $(VERSION_FILE)
 	rm -f $(BIN)
 	rm -f dtc-*.tar dtc-*.tar.sign dtc-*.tar.asc
-- 
2.8.0.rc3.226.g39d4020

Re: [PATCH 1/4] Add an initial Python library for libfdt

[David Gibson]

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On Thu, Nov 17, 2016 at 03:53:22PM -0700, Simon Glass wrote:
> Add Python bindings for a bare-bones set of libfdt functions. These allow
> navigating the tree and reading node names and properties.

Nice idea.  Some nits in the details..

> 
> Signed-off-by: Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
> ---
> 
>  pylibfdt/.gitignore        |   3 +
>  pylibfdt/Makefile.pylibfdt |  21 ++++++
>  pylibfdt/libfdt.swig       | 157 +++++++++++++++++++++++++++++++++++++++++++++
>  pylibfdt/setup.py          |  34 ++++++++++
>  4 files changed, 215 insertions(+)
>  create mode 100644 pylibfdt/.gitignore
>  create mode 100644 pylibfdt/Makefile.pylibfdt
>  create mode 100644 pylibfdt/libfdt.swig
>  create mode 100644 pylibfdt/setup.py
> 
> diff --git a/pylibfdt/.gitignore b/pylibfdt/.gitignore
> new file mode 100644
> index 0000000..5e8c5e3
> --- /dev/null
> +++ b/pylibfdt/.gitignore
> @@ -0,0 +1,3 @@
> +libfdt.py
> +libfdt.pyc
> +libfdt_wrap.c
> diff --git a/pylibfdt/Makefile.pylibfdt b/pylibfdt/Makefile.pylibfdt
> new file mode 100644
> index 0000000..fbdbca5
> --- /dev/null
> +++ b/pylibfdt/Makefile.pylibfdt
> @@ -0,0 +1,21 @@
> +# Makefile.pylibfdt
> +#
> +# This is not a complete Makefile of itself.  Instead, it is designed to
> +# be easily embeddable into other systems of Makefiles.

So, Makefile.libfdt is explicitly designed for easily embedding libfdt
in other projecs - even ones with weird build environments, like
bootloaders.  It's less clear that that's valuable for Python
wrappers.

> +#
> +
> +PYLIBFDT_srcs = $(addprefix $(LIBFDT_srcdir)/,$(LIBFDT_SRCS))
> +WRAP = $(PYLIBFDT_objdir)/libfdt_wrap.c
> +PYMODULE = $(PYLIBFDT_objdir)/_libfdt.so
> +
> +$(PYMODULE): $(PYLIBFDT_srcs) $(WRAP)
> +	@$(VECHO) PYMOD $@
> +	python $(PYLIBFDT_objdir)/setup.py "$(CPPFLAGS)" $^
> +	mv _libfdt.so $(PYMODULE)
> +
> +$(WRAP): $(PYLIBFDT_srcdir)/libfdt.swig
> +	@$(VECHO) SWIG $@
> +	swig -python -o $@ $<
> +
> +PYLIBFDT_cleanfiles = libfdt_wrap.c libfdt.py libfdt.pyc
> +PYLIBFDT_CLEANFILES = $(addprefix $(PYLIBFDT_objdir)/,$(PYLIBFDT_cleanfiles))
> diff --git a/pylibfdt/libfdt.swig b/pylibfdt/libfdt.swig
> new file mode 100644
> index 0000000..91887da
> --- /dev/null
> +++ b/pylibfdt/libfdt.swig
> @@ -0,0 +1,157 @@
> +/*
> + * pylibfdt - Flat Device Tree manipulation in Python
> + * Copyright (C) 2016 Google, Inc.
> + * Written by Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
> + *
> + * libfdt is dual licensed: you can use it either under the terms of
> + * the GPL, or the BSD license, at your option.
> + *
> + *  a) This library 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 library 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 library; if not, write to the Free
> + *     Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
> + *     MA 02110-1301 USA
> + *
> + * Alternatively,
> + *
> + *  b) Redistribution and use in source and binary forms, with or
> + *     without modification, are permitted provided that the following
> + *     conditions are met:
> + *
> + *     1. Redistributions of source code must retain the above
> + *        copyright notice, this list of conditions and the following
> + *        disclaimer.
> + *     2. Redistributions in binary form must reproduce the above
> + *        copyright notice, this list of conditions and the following
> + *        disclaimer in the documentation and/or other materials
> + *        provided with the distribution.
> + *
> + *     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
> + *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
> + *     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
> + *     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
> + *     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
> + *     CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
> + *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
> + *     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
> + *     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
> + *     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
> + *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
> + *     OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
> + *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
> + */
> +
> +%module libfdt
> +
> +%{
> +#define SWIG_FILE_WITH_INIT
> +#include "libfdt.h"
> +%}
> +
> +%pythoncode %{
> +
> +def Raise(errnum):
> +    raise ValueError('Error %s' % fdt_strerror(errnum))

So, first, I believe this and several things below break normal Python
capitalization conventions for functions (capital-followed-by-lower
generally indicates a class).

More importantly, wouldn't it make more sense to have an Exception
subclass for libfdt errors, rather than shuffling everything through
ValueError?

> +def Name(fdt, offset):
> +    name, len = fdt_get_name(fdt, offset)
> +    return name
> +
> +def String(fdt, offset):
> +    offset = fdt32_to_cpu(offset)
> +    name = fdt_string(fdt, offset)
> +    return name
> +
> +def fdt32_to_cpu(val):
> +    return struct.unpack("=I", struct.pack(">I", val))[0]
> +
> +def Data(prop):
> +    set_prop(prop)
> +    return get_prop_data()
> +%}
> +
> +%include "typemaps.i"
> +%include "cstring.i"
> +
> +%typemap(in) void* = char*;
> +
> +typedef int fdt32_t;
> +
> +struct fdt_property {
> +        fdt32_t tag;
> +        fdt32_t len;
> +        fdt32_t nameoff;
> +        char data[0];
> +};

Can't you include this directly from fdt.h?  That header is guaranteed
never to have actual function definitions, just data structures and
constants.

> +/*
> + * This is a work-around since I'm not sure of a better way to copy out the
> + * contents of a string. This is used in dtoc/GetProps(). The intent is to
> + * pass in a pointer to a property and access the data field at the end of
> + * it. Ideally the Data() function above would be able to do this directly,
> + * but I'm not sure how to do that. Needs another look.
> + */
> +#pragma SWIG nowarn=454
> +%inline %{
> +    static struct fdt_property *cur_prop;
> +
> +    void set_prop(struct fdt_property *prop) {
> +        cur_prop = prop;
> +    }

Eugh... a global variable making this totally non thread safe.  You
really need a better solution.  Property values you should be able to
represent nicely as Python strings (since unlike C strings, those can
include embedded \0).  Uh.. I guess that's 'bytes' for Python3

Of course, in the other direction, node and property names can't
include \0, so you probably need some sort of exception if a Python
string which includes them is passed in.

> +%}
> +
> +%cstring_output_allocate_size(char **s, int *sz, free(*$1));
> +%inline %{
> +    void get_prop_data(char **s, int *sz) {
> +        *sz = fdt32_to_cpu(cur_prop->len);
> +        *s = (char *)malloc(*sz);
> +        if (!*s)
> +            *sz = 0;
> +        else
> +            memcpy(*s, cur_prop + 1, *sz);
> +    }
> +%}
> +
> +%typemap(in) (const void *) {
> +  if (!PyByteArray_Check($input)) {
> +    SWIG_exception_fail(SWIG_TypeError, "in method '" "$symname" "', argument "
> +                       "$argnum"" of type '" "$type""'");
> +  }
> +  $1 = (void *) PyByteArray_AsString($input);
> +}
> +
> +int fdt_path_offset(const void *fdt, const char *path);
> +int fdt_first_property_offset(const void *fdt, int nodeoffset);
> +int fdt_next_property_offset(const void *fdt, int offset);
> +const char *fdt_get_name(const void *fdt, int nodeoffset, int *OUTPUT);
> +const char *fdt_string(const void *fdt, int stroffset);
> +const struct fdt_property *fdt_get_property_by_offset(const void *fdt,
> +                                                      int offset,
> +                                                      int *OUTPUT);
> +const char *fdt_strerror(int errval);
> +int fdt_first_subnode(const void *fdt, int offset);
> +int fdt_next_subnode(const void *fdt, int offset);
> +
> +%typemap(in) (void *) {
> +  if (!PyByteArray_Check($input)) {
> +    SWIG_exception_fail(SWIG_TypeError, "in method '" "$symname" "', argument "
> +                       "$argnum"" of type '" "$type""'");
> +  }
> +  $1 = PyByteArray_AsString($input);
> +}
> +
> +int fdt_delprop(void *fdt, int nodeoffset, const char *name);
> +
> +int fdt_pack(void *fdt);
> +
> +int fdt_totalsize(const void *fdt);
> +int fdt_off_dt_struct(const void *fdt);
> diff --git a/pylibfdt/setup.py b/pylibfdt/setup.py
> new file mode 100644
> index 0000000..8f8618e
> --- /dev/null
> +++ b/pylibfdt/setup.py
> @@ -0,0 +1,34 @@
> +#!/usr/bin/env python
> +
> +"""
> +setup.py file for SWIG libfdt
> +"""
> +
> +from distutils.core import setup, Extension
> +import os
> +import sys
> +
> +progname = sys.argv[0]
> +cflags = sys.argv[1]
> +files = sys.argv[2:]
> +
> +if cflags:
> +    cflags = [flag for flag in cflags.split(' ') if flag]
> +else:
> +    cflags = None
> +
> +libfdt_module = Extension(
> +    '_libfdt',
> +    sources = files,
> +    extra_compile_args =  cflags
> +)
> +
> +sys.argv = [progname, '--quiet', 'build_ext', '--inplace']
> +
> +setup (name = 'libfdt',
> +       version = '0.1',
> +       author      = "SWIG Docs",
> +       description = """Simple swig libfdt from docs""",
> +       ext_modules = [libfdt_module],
> +       py_modules = ["libfdt"],
> +       )

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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Re: [PATCH 1/4] Add an initial Python library for libfdt

[Simon Glass]

Hi David,

On 17 November 2016 at 17:36, David Gibson <david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org> wrote:
> On Thu, Nov 17, 2016 at 03:53:22PM -0700, Simon Glass wrote:
>> Add Python bindings for a bare-bones set of libfdt functions. These allow
>> navigating the tree and reading node names and properties.
>
> Nice idea.  Some nits in the details..
>
>>
>> Signed-off-by: Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
>> ---
>>
>>  pylibfdt/.gitignore        |   3 +
>>  pylibfdt/Makefile.pylibfdt |  21 ++++++
>>  pylibfdt/libfdt.swig       | 157 +++++++++++++++++++++++++++++++++++++++++++++
>>  pylibfdt/setup.py          |  34 ++++++++++
>>  4 files changed, 215 insertions(+)
>>  create mode 100644 pylibfdt/.gitignore
>>  create mode 100644 pylibfdt/Makefile.pylibfdt
>>  create mode 100644 pylibfdt/libfdt.swig
>>  create mode 100644 pylibfdt/setup.py
>>
>> diff --git a/pylibfdt/.gitignore b/pylibfdt/.gitignore
>> new file mode 100644
>> index 0000000..5e8c5e3
>> --- /dev/null
>> +++ b/pylibfdt/.gitignore
>> @@ -0,0 +1,3 @@
>> +libfdt.py
>> +libfdt.pyc
>> +libfdt_wrap.c
>> diff --git a/pylibfdt/Makefile.pylibfdt b/pylibfdt/Makefile.pylibfdt
>> new file mode 100644
>> index 0000000..fbdbca5
>> --- /dev/null
>> +++ b/pylibfdt/Makefile.pylibfdt
>> @@ -0,0 +1,21 @@
>> +# Makefile.pylibfdt
>> +#
>> +# This is not a complete Makefile of itself.  Instead, it is designed to
>> +# be easily embeddable into other systems of Makefiles.
>
> So, Makefile.libfdt is explicitly designed for easily embedding libfdt
> in other projecs - even ones with weird build environments, like
> bootloaders.  It's less clear that that's valuable for Python
> wrappers.

OK, but what should i do instead?

Regards,
Simon

Re: [PATCH 1/4] Add an initial Python library for libfdt

[David Gibson]

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On Thu, Nov 24, 2016 at 11:08:00AM -0700, Simon Glass wrote:
> Hi David,
> 
> On 17 November 2016 at 17:36, David Gibson <david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org> wrote:
> > On Thu, Nov 17, 2016 at 03:53:22PM -0700, Simon Glass wrote:
> >> Add Python bindings for a bare-bones set of libfdt functions. These allow
> >> navigating the tree and reading node names and properties.
> >
> > Nice idea.  Some nits in the details..
> >
> >>
> >> Signed-off-by: Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
> >> ---
> >>
> >>  pylibfdt/.gitignore        |   3 +
> >>  pylibfdt/Makefile.pylibfdt |  21 ++++++
> >>  pylibfdt/libfdt.swig       | 157 +++++++++++++++++++++++++++++++++++++++++++++
> >>  pylibfdt/setup.py          |  34 ++++++++++
> >>  4 files changed, 215 insertions(+)
> >>  create mode 100644 pylibfdt/.gitignore
> >>  create mode 100644 pylibfdt/Makefile.pylibfdt
> >>  create mode 100644 pylibfdt/libfdt.swig
> >>  create mode 100644 pylibfdt/setup.py
> >>
> >> diff --git a/pylibfdt/.gitignore b/pylibfdt/.gitignore
> >> new file mode 100644
> >> index 0000000..5e8c5e3
> >> --- /dev/null
> >> +++ b/pylibfdt/.gitignore
> >> @@ -0,0 +1,3 @@
> >> +libfdt.py
> >> +libfdt.pyc
> >> +libfdt_wrap.c
> >> diff --git a/pylibfdt/Makefile.pylibfdt b/pylibfdt/Makefile.pylibfdt
> >> new file mode 100644
> >> index 0000000..fbdbca5
> >> --- /dev/null
> >> +++ b/pylibfdt/Makefile.pylibfdt
> >> @@ -0,0 +1,21 @@
> >> +# Makefile.pylibfdt
> >> +#
> >> +# This is not a complete Makefile of itself.  Instead, it is designed to
> >> +# be easily embeddable into other systems of Makefiles.
> >
> > So, Makefile.libfdt is explicitly designed for easily embedding libfdt
> > in other projecs - even ones with weird build environments, like
> > bootloaders.  It's less clear that that's valuable for Python
> > wrappers.
> 
> OK, but what should i do instead?

Sorry, I just meant that that copied comment doesn't really make sense
in its entirity here.  Otherwise the makefile is fine.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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