pyrox.dev
1From 9b5a023a5dc3127da15253f7acad71019395ebe1 Mon Sep 17 00:00:00 2001
2From: Pablo Galindo <Pablogsal@gmail.com>
3Date: Thu, 8 Oct 2020 19:50:37 +0100
4Subject: [PATCH] [3.7] bpo-41976: Fix the fallback to gcc of
5 ctypes.util.find_library when using gcc>9 (GH-22598). (GH-22601)
6
7(cherry picked from commit 27ac19cca2c639caaf6fedf3632fe6beb265f24f)
8
9Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>
10---
11 Lib/ctypes/test/test_find.py | 12 ++++++-
12 Lib/ctypes/util.py | 32 +++++++++++++++----
13 .../2020-10-08-18-22-28.bpo-41976.Svm0wb.rst | 3 ++
14 3 files changed, 39 insertions(+), 8 deletions(-)
15 create mode 100644 Misc/NEWS.d/next/Library/2020-10-08-18-22-28.bpo-41976.Svm0wb.rst
16
17diff --git a/Lib/ctypes/test/test_find.py b/Lib/ctypes/test/test_find.py
18index b99fdcba7b28f..92ac1840ad7d4 100644
19--- a/Lib/ctypes/test/test_find.py
20+++ b/Lib/ctypes/test/test_find.py
21@@ -1,4 +1,5 @@
22 import unittest
23+import unittest.mock
24 import os.path
25 import sys
26 import test.support
27@@ -72,7 +73,7 @@ def test_shell_injection(self):
28
29 @unittest.skipUnless(sys.platform.startswith('linux'),
30 'Test only valid for Linux')
31-class LibPathFindTest(unittest.TestCase):
32+class FindLibraryLinux(unittest.TestCase):
33 def test_find_on_libpath(self):
34 import subprocess
35 import tempfile
36@@ -111,6 +112,15 @@ def test_find_on_libpath(self):
37 # LD_LIBRARY_PATH)
38 self.assertEqual(find_library(libname), 'lib%s.so' % libname)
39
40+ def test_find_library_with_gcc(self):
41+ with unittest.mock.patch("ctypes.util._findSoname_ldconfig", lambda *args: None):
42+ self.assertNotEqual(find_library('c'), None)
43+
44+ def test_find_library_with_ld(self):
45+ with unittest.mock.patch("ctypes.util._findSoname_ldconfig", lambda *args: None), \
46+ unittest.mock.patch("ctypes.util._findLib_gcc", lambda *args: None):
47+ self.assertNotEqual(find_library('c'), None)
48+
49
50 if __name__ == "__main__":
51 unittest.main()
52diff --git a/Lib/ctypes/util.py b/Lib/ctypes/util.py
53index 97973bce001d9..0c2510e1619c8 100644
54--- a/Lib/ctypes/util.py
55+++ b/Lib/ctypes/util.py
56@@ -93,6 +93,12 @@ def find_library(name):
57 # Andreas Degert's find functions, using gcc, /sbin/ldconfig, objdump
58 import re, tempfile
59
60+ def _is_elf(filename):
61+ "Return True if the given file is an ELF file"
62+ elf_header = b'\x7fELF'
63+ with open(filename, 'br') as thefile:
64+ return thefile.read(4) == elf_header
65+
66 def _findLib_gcc(name):
67 # Run GCC's linker with the -t (aka --trace) option and examine the
68 # library name it prints out. The GCC command will fail because we
69@@ -299,17 +312,22 @@ def _findLib_ld(name):
70 stderr=subprocess.PIPE,
71 universal_newlines=True)
72 out, _ = p.communicate()
73- res = re.search(expr, os.fsdecode(out))
74- if res:
75- result = res.group(0)
76- except Exception as e:
77+ res = re.findall(expr, os.fsdecode(out))
78+ for file in res:
79+ # Check if the given file is an elf file: gcc can report
80+ # some files that are linker scripts and not actual
81+ # shared objects. See bpo-41976 for more details
82+ if not _is_elf(file):
83+ continue
84+ return os.fsdecode(file)
85+ except Exception:
86 pass # result will be None
87 return result
88
89 def find_library(name):
90 # See issue #9998
91 return _findSoname_ldconfig(name) or \
92- _get_soname(_findLib_gcc(name) or _findLib_ld(name))
93+ _get_soname(_findLib_gcc(name)) or _get_soname(_findLib_ld(name))
94
95 ################################################################
96 # test code
97diff --git a/Misc/NEWS.d/next/Library/2020-10-08-18-22-28.bpo-41976.Svm0wb.rst b/Misc/NEWS.d/next/Library/2020-10-08-18-22-28.bpo-41976.Svm0wb.rst
98new file mode 100644
99index 0000000000000..c8b3fc771845e
100--- /dev/null
101+++ b/Misc/NEWS.d/next/Library/2020-10-08-18-22-28.bpo-41976.Svm0wb.rst
102@@ -0,0 +1,3 @@
103+Fixed a bug that was causing :func:`ctypes.util.find_library` to return
104+``None`` when triying to locate a library in an environment when gcc>=9 is
105+available and ``ldconfig`` is not. Patch by Pablo Galindo