import os import shutil import subprocess import sys # find_library(name) returns the pathname of a library, or None. if os.name == "nt": def _get_build_version(): """Return the version of MSVC that was used to build Python. For Python 2.3 and up, the version number is included in sys.version. For earlier versions, assume the compiler is MSVC 6. """ # This function was copied from Lib/distutils/msvccompiler.py prefix = "MSC v." i = sys.version.find(prefix) if i == -1: return 6 i = i + len(prefix) s, rest = sys.version[i:].split(" ", 1) majorVersion = int(s[:-2]) - 6 if majorVersion >= 13: majorVersion += 1 minorVersion = int(s[2:3]) / 10.0 # I don't think paths are affected by minor version in version 6 if majorVersion == 6: minorVersion = 0 if majorVersion >= 6: return majorVersion + minorVersion # else we don't know what version of the compiler this is return None def find_msvcrt(): """Return the name of the VC runtime dll""" version = _get_build_version() if version is None: # better be safe than sorry return None if version <= 6: clibname = 'msvcrt' elif version <= 13: clibname = 'msvcr%d' % (version * 10) else: # CRT is no longer directly loadable. See issue23606 for the # discussion about alternative approaches. return None # If python was built with in debug mode import importlib.machinery if '_d.pyd' in importlib.machinery.EXTENSION_SUFFIXES: clibname += 'd' return clibname+'.dll' def find_library(name): if name in ('c', 'm'): return find_msvcrt() # See MSDN for the REAL search order. for directory in os.environ['PATH'].split(os.pathsep): fname = os.path.join(directory, name) if os.path.isfile(fname): return fname if fname.lower().endswith(".dll"): continue fname = fname + ".dll" if os.path.isfile(fname): return fname return None elif os.name == "posix" and sys.platform == "darwin": from ctypes.macholib.dyld import dyld_find as _dyld_find def find_library(name): possible = ['lib%s.dylib' % name, '%s.dylib' % name, '%s.framework/%s' % (name, name)] for name in possible: try: return _dyld_find(name) except ValueError: continue return None elif sys.platform.startswith("aix"): # AIX has two styles of storing shared libraries # GNU auto_tools refer to these as svr4 and aix # svr4 (System V Release 4) is a regular file, often with .so as suffix # AIX style uses an archive (suffix .a) with members (e.g., shr.o, libssl.so) # see issue#26439 and _aix.py for more details from ctypes._aix import find_library elif os.name == "posix": # Andreas Degert's find functions, using gcc, /sbin/ldconfig, objdump import re, tempfile def _is_elf(filename): "Return True if the given file is an ELF file" elf_header = b'\x7fELF' with open(filename, 'br') as thefile: return thefile.read(4) == elf_header def _findLib_gcc(name): # Run GCC's linker with the -t (aka --trace) option and examine the # library name it prints out. The GCC command will fail because we # haven't supplied a proper program with main(), but that does not # matter. expr = os.fsencode(r'[^\(\)\s]*lib%s\.[^\(\)\s]*' % re.escape(name)) c_compiler = shutil.which('gcc') if not c_compiler: c_compiler = shutil.which('cc') if not c_compiler: # No C compiler available, give up return None temp = tempfile.NamedTemporaryFile() try: args = [c_compiler, '-Wl,-t', '-o', temp.name, '-l' + name] env = dict(os.environ) env['LC_ALL'] = 'C' env['LANG'] = 'C' try: proc = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, env=env) except OSError: # E.g. bad executable return None with proc: trace = proc.stdout.read() finally: try: temp.close() except FileNotFoundError: # Raised if the file was already removed, which is the normal # behaviour of GCC if linking fails pass res = re.findall(expr, trace) if not res: return None for file in res: # Check if the given file is an elf file: gcc can report # some files that are linker scripts and not actual # shared objects. See bpo-41976 for more details if not _is_elf(file): continue return os.fsdecode(file) if sys.platform == "sunos5": # use /usr/ccs/bin/dump on solaris def _get_soname(f): if not f: return None try: proc = subprocess.Popen(("/usr/ccs/bin/dump", "-Lpv", f), stdout=subprocess.PIPE, stderr=subprocess.DEVNULL) except OSError: # E.g. command not found return None with proc: data = proc.stdout.read() res = re.search(br'\[.*\]\sSONAME\s+([^\s]+)', data) if not res: return None return os.fsdecode(res.group(1)) else: def _get_soname(f): # assuming GNU binutils / ELF if not f: return None objdump = shutil.which('objdump') if not objdump: # objdump is not available, give up return None try: proc = subprocess.Popen((objdump, '-p', '-j', '.dynamic', f), stdout=subprocess.PIPE, stderr=subprocess.DEVNULL) except OSError: # E.g. bad executable return None with proc: dump = proc.stdout.read() res = re.search(br'\sSONAME\s+([^\s]+)', dump) if not res: return None return os.fsdecode(res.group(1)) if sys.platform.startswith(("freebsd", "openbsd", "dragonfly")): def _num_version(libname): # "libxyz.so.MAJOR.MINOR" => [ MAJOR, MINOR ] parts = libname.split(b".") nums = [] try: while parts: nums.insert(0, int(parts.pop())) except ValueError: pass return nums or [sys.maxsize] def find_library(name): ename = re.escape(name) expr = r':-l%s\.\S+ => \S*/(lib%s\.\S+)' % (ename, ename) expr = os.fsencode(expr) try: proc = subprocess.Popen(('/sbin/ldconfig', '-r'), stdout=subprocess.PIPE, stderr=subprocess.DEVNULL) except OSError: # E.g. command not found data = b'' else: with proc: data = proc.stdout.read() res = re.findall(expr, data) if not res: return _get_soname(_findLib_gcc(name)) res.sort(key=_num_version) return os.fsdecode(res[-1]) elif sys.platform == "sunos5": def _findLib_crle(name, is64): if not os.path.exists('/usr/bin/crle'): return None env = dict(os.environ) env['LC_ALL'] = 'C' if is64: args = ('/usr/bin/crle', '-64') else: args = ('/usr/bin/crle',) paths = None try: proc = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.DEVNULL, env=env) except OSError: # E.g. bad executable return None with proc: for line in proc.stdout: line = line.strip() if line.startswith(b'Default Library Path (ELF):'): paths = os.fsdecode(line).split()[4] if not paths: return None for dir in paths.split(":"): libfile = os.path.join(dir, "lib%s.so" % name) if os.path.exists(libfile): return libfile return None def find_library(name, is64 = False): return _get_soname(_findLib_crle(name, is64) or _findLib_gcc(name)) else: def _findSoname_ldconfig(name): import struct if struct.calcsize('l') == 4: machine = os.uname().machine + '-32' else: machine = os.uname().machine + '-64' mach_map = { 'x86_64-64': 'libc6,x86-64', 'ppc64-64': 'libc6,64bit', 'sparc64-64': 'libc6,64bit', 's390x-64': 'libc6,64bit', 'ia64-64': 'libc6,IA-64', } abi_type = mach_map.get(machine, 'libc6') # XXX assuming GLIBC's ldconfig (with option -p) regex = r'\s+(lib%s\.[^\s]+)\s+\(%s' regex = os.fsencode(regex % (re.escape(name), abi_type)) try: with subprocess.Popen(['/sbin/ldconfig', '-p'], stdin=subprocess.DEVNULL, stderr=subprocess.DEVNULL, stdout=subprocess.PIPE, env={'LC_ALL': 'C', 'LANG': 'C'}) as p: res = re.search(regex, p.stdout.read()) if res: return os.fsdecode(res.group(1)) except OSError: pass def _findLib_ld(name): # See issue #9998 for why this is needed expr = r'[^\(\)\s]*lib%s\.[^\(\)\s]*' % re.escape(name) cmd = ['ld', '-t'] libpath = os.environ.get('LD_LIBRARY_PATH') if libpath: for d in libpath.split(':'): cmd.extend(['-L', d]) cmd.extend(['-o', os.devnull, '-l%s' % name]) result = None try: p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, universal_newlines=True) out, _ = p.communicate() res = re.findall(expr, os.fsdecode(out)) for file in res: # Check if the given file is an elf file: gcc can report # some files that are linker scripts and not actual # shared objects. See bpo-41976 for more details if not _is_elf(file): continue return os.fsdecode(file) except Exception: pass # result will be None return result def find_library(name): # See issue #9998 return _findSoname_ldconfig(name) or \ _get_soname(_findLib_gcc(name)) or _get_soname(_findLib_ld(name)) ################################################################ # test code def test(): from ctypes import cdll if os.name == "nt": print(cdll.msvcrt) print(cdll.load("msvcrt")) print(find_library("msvcrt")) if os.name == "posix": # find and load_version print(find_library("m")) print(find_library("c")) print(find_library("bz2")) # load if sys.platform == "darwin": print(cdll.LoadLibrary("libm.dylib")) print(cdll.LoadLibrary("libcrypto.dylib")) print(cdll.LoadLibrary("libSystem.dylib")) print(cdll.LoadLibrary("System.framework/System")) # issue-26439 - fix broken test call for AIX elif sys.platform.startswith("aix"): from ctypes import CDLL if sys.maxsize < 2**32: print(f"Using CDLL(name, os.RTLD_MEMBER): {CDLL('libc.a(shr.o)', os.RTLD_MEMBER)}") print(f"Using cdll.LoadLibrary(): {cdll.LoadLibrary('libc.a(shr.o)')}") # librpm.so is only available as 32-bit shared library print(find_library("rpm")) print(cdll.LoadLibrary("librpm.so")) else: print(f"Using CDLL(name, os.RTLD_MEMBER): {CDLL('libc.a(shr_64.o)', os.RTLD_MEMBER)}") print(f"Using cdll.LoadLibrary(): {cdll.LoadLibrary('libc.a(shr_64.o)')}") print(f"crypt\t:: {find_library('crypt')}") print(f"crypt\t:: {cdll.LoadLibrary(find_library('crypt'))}") print(f"crypto\t:: {find_library('crypto')}") print(f"crypto\t:: {cdll.LoadLibrary(find_library('crypto'))}") else: print(cdll.LoadLibrary("libm.so")) print(cdll.LoadLibrary("libcrypt.so")) print(find_library("crypt")) if __name__ == "__main__": test()