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

if os.name == "ce":

# search path according to MSDN:

# - absolute path specified by filename

# - The .exe launch directory

# - the Windows directory

# - ROM dll files (where are they?)

# - OEM specified search path: HKLM\Loader\SystemPath

def find_library(name):

return name

if 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 os.name == "posix":

# Andreas Degert's find functions, using gcc, /sbin/ldconfig, objdump

import re, tempfile

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.search(expr, trace)

if not res:

return None

return os.fsdecode(res.group(0))

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 = os.fsencode(

'\s+(lib%s\.[^\s]+)\s+\(%s' % (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 find_library(name):

return _findSoname_ldconfig(name) or _get_soname(_findLib_gcc(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"))

# getattr

## print cdll.m

## print cdll.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"))

else:

print(cdll.LoadLibrary("libm.so"))

print(cdll.LoadLibrary("libcrypt.so"))

print(find_library("crypt"))

if __name__ == "__main__":

test()