# -*- coding: utf-8 -*-
# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
# See https://llvm.org/LICENSE.txt for license information.
# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
""" This module compiles the intercept library. """
import sys
import os
import os.path
import re
import tempfile
import shutil
import contextlib
import logging
__all__ = ["build_libear"]
def build_libear(compiler, dst_dir):
"""Returns the full path to the 'libear' library."""
try:
src_dir = os.path.dirname(os.path.realpath(__file__))
toolset = make_toolset(src_dir)
toolset.set_compiler(compiler)
toolset.set_language_standard("c99")
toolset.add_definitions(["-D_GNU_SOURCE"])
configure = do_configure(toolset)
configure.check_function_exists("execve", "HAVE_EXECVE")
configure.check_function_exists("execv", "HAVE_EXECV")
configure.check_function_exists("execvpe", "HAVE_EXECVPE")
configure.check_function_exists("execvp", "HAVE_EXECVP")
configure.check_function_exists("execvP", "HAVE_EXECVP2")
configure.check_function_exists("exect", "HAVE_EXECT")
configure.check_function_exists("execl", "HAVE_EXECL")
configure.check_function_exists("execlp", "HAVE_EXECLP")
configure.check_function_exists("execle", "HAVE_EXECLE")
configure.check_function_exists("posix_spawn", "HAVE_POSIX_SPAWN")
configure.check_function_exists("posix_spawnp", "HAVE_POSIX_SPAWNP")
configure.check_symbol_exists(
"_NSGetEnviron", "crt_externs.h", "HAVE_NSGETENVIRON"
)
configure.write_by_template(
os.path.join(src_dir, "config.h.in"), os.path.join(dst_dir, "config.h")
)
target = create_shared_library("ear", toolset)
target.add_include(dst_dir)
target.add_sources("ear.c")
target.link_against(toolset.dl_libraries())
target.link_against(["pthread"])
target.build_release(dst_dir)
return os.path.join(dst_dir, target.name)
except Exception:
logging.info("Could not build interception library.", exc_info=True)
return None
def execute(cmd, *args, **kwargs):
"""Make subprocess execution silent."""
import subprocess
kwargs.update({"stdout": subprocess.PIPE, "stderr": subprocess.STDOUT})
return subprocess.check_call(cmd, *args, **kwargs)
@contextlib.contextmanager
def TemporaryDirectory(**kwargs):
name = tempfile.mkdtemp(**kwargs)
try:
yield name
finally:
shutil.rmtree(name)
class Toolset(object):
"""Abstract class to represent different toolset."""
def __init__(self, src_dir):
self.src_dir = src_dir
self.compiler = None
self.c_flags = []
def set_compiler(self, compiler):
"""part of public interface"""
self.compiler = compiler
def set_language_standard(self, standard):
"""part of public interface"""
self.c_flags.append("-std=" + standard)
def add_definitions(self, defines):
"""part of public interface"""
self.c_flags.extend(defines)
def dl_libraries(self):
raise NotImplementedError()
def shared_library_name(self, name):
raise NotImplementedError()
def shared_library_c_flags(self, release):
extra = ["-DNDEBUG", "-O3"] if release else []
return extra + ["-fPIC"] + self.c_flags
def shared_library_ld_flags(self, release, name):
raise NotImplementedError()
class DarwinToolset(Toolset):
def __init__(self, src_dir):
Toolset.__init__(self, src_dir)
def dl_libraries(self):
return []
def shared_library_name(self, name):
return "lib" + name + ".dylib"
def shared_library_ld_flags(self, release, name):
extra = ["-dead_strip"] if release else []
return extra + ["-dynamiclib", "-install_name", "@rpath/" + name]
class UnixToolset(Toolset):
def __init__(self, src_dir):
Toolset.__init__(self, src_dir)
def dl_libraries(self):
return []
def shared_library_name(self, name):
return "lib" + name + ".so"
def shared_library_ld_flags(self, release, name):
extra = [] if release else []
return extra + ["-shared", "-Wl,-soname," + name]
class LinuxToolset(UnixToolset):
def __init__(self, src_dir):
UnixToolset.__init__(self, src_dir)
def dl_libraries(self):
return ["dl"]
def make_toolset(src_dir):
platform = sys.platform
if platform in {"win32", "cygwin"}:
raise RuntimeError("not implemented on this platform")
elif platform == "darwin":
return DarwinToolset(src_dir)
elif platform in {"linux", "linux2"}:
return LinuxToolset(src_dir)
else:
return UnixToolset(src_dir)
class Configure(object):
def __init__(self, toolset):
self.ctx = toolset
self.results = {"APPLE": sys.platform == "darwin"}
def _try_to_compile_and_link(self, source):
try:
with TemporaryDirectory() as work_dir:
src_file = "check.c"
with open(os.path.join(work_dir, src_file), "w") as handle:
handle.write(source)
execute([self.ctx.compiler, src_file] + self.ctx.c_flags, cwd=work_dir)
return True
except Exception:
return False
def check_function_exists(self, function, name):
template = "int FUNCTION(); int main() { return FUNCTION(); }"
source = template.replace("FUNCTION", function)
logging.debug("Checking function %s", function)
found = self._try_to_compile_and_link(source)
logging.debug(
"Checking function %s -- %s", function, "found" if found else "not found"
)
self.results.update({name: found})
def check_symbol_exists(self, symbol, include, name):
template = """#include <INCLUDE>
int main() { return ((int*)(&SYMBOL))[0]; }"""
source = template.replace("INCLUDE", include).replace("SYMBOL", symbol)
logging.debug("Checking symbol %s", symbol)
found = self._try_to_compile_and_link(source)
logging.debug(
"Checking symbol %s -- %s", symbol, "found" if found else "not found"
)
self.results.update({name: found})
def write_by_template(self, template, output):
def transform(line, definitions):
pattern = re.compile(r"^#cmakedefine\s+(\S+)")
m = pattern.match(line)
if m:
key = m.group(1)
if key not in definitions or not definitions[key]:
return "/* #undef {0} */{1}".format(key, os.linesep)
else:
return "#define {0}{1}".format(key, os.linesep)
return line
with open(template, "r") as src_handle:
logging.debug("Writing config to %s", output)
with open(output, "w") as dst_handle:
for line in src_handle:
dst_handle.write(transform(line, self.results))
def do_configure(toolset):
return Configure(toolset)
class SharedLibrary(object):
def __init__(self, name, toolset):
self.name = toolset.shared_library_name(name)
self.ctx = toolset
self.inc = []
self.src = []
self.lib = []
def add_include(self, directory):
self.inc.extend(["-I", directory])
def add_sources(self, source):
self.src.append(source)
def link_against(self, libraries):
self.lib.extend(["-l" + lib for lib in libraries])
def build_release(self, directory):
for src in self.src:
logging.debug("Compiling %s", src)
execute(
[
self.ctx.compiler,
"-c",
os.path.join(self.ctx.src_dir, src),
"-o",
src + ".o",
]
+ self.inc
+ self.ctx.shared_library_c_flags(True),
cwd=directory,
)
logging.debug("Linking %s", self.name)
execute(
[self.ctx.compiler]
+ [src + ".o" for src in self.src]
+ ["-o", self.name]
+ self.lib
+ self.ctx.shared_library_ld_flags(True, self.name),
cwd=directory,
)
def create_shared_library(name, toolset):
return SharedLibrary(name, toolset)
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