# Copyright 2013-2024 Lawrence Livermore National Security, LLC and other
# Spack Project Developers. See the top-level COPYRIGHT file for details.
#
# SPDX-License-Identifier: (Apache-2.0 OR MIT)
import glob
import os
import re
import sys
from llnl.util.lang import dedupe
import spack.util.elf as elf_utils
[docs]
def parse_ld_so_conf(conf_file="/etc/ld.so.conf"):
"""Parse glibc style ld.so.conf file, which specifies default search paths for the
dynamic linker. This can in principle also be used for musl libc.
Arguments:
conf_file (str or bytes): Path to config file
Returns:
list: List of absolute search paths
"""
# Parse in binary mode since it's faster
is_bytes = isinstance(conf_file, bytes)
if not is_bytes:
conf_file = conf_file.encode("utf-8")
# For globbing in Python2 we need to chdir.
cwd = os.getcwd()
try:
paths = _process_ld_so_conf_queue([conf_file])
finally:
os.chdir(cwd)
return list(paths) if is_bytes else [p.decode("utf-8") for p in paths]
def _process_ld_so_conf_queue(queue):
include_regex = re.compile(b"include\\s")
paths = []
while queue:
p = queue.pop(0)
try:
with open(p, "rb") as f:
lines = f.readlines()
except (IOError, OSError):
continue
for line in lines:
# Strip comments
comment = line.find(b"#")
if comment != -1:
line = line[:comment]
# Skip empty lines
line = line.strip()
if not line:
continue
is_include = include_regex.match(line) is not None
# If not an include, it's a literal path (no globbing here).
if not is_include:
# We only allow absolute search paths.
if os.path.isabs(line):
paths.append(line)
continue
# Finally handle includes.
include_path = line[8:].strip()
if not include_path:
continue
cwd = os.path.dirname(p)
os.chdir(cwd)
queue.extend(os.path.join(cwd, p) for p in glob.glob(include_path))
return dedupe(paths)
[docs]
def get_conf_file_from_dynamic_linker(dynamic_linker_name):
# We basically assume everything is glibc, except musl.
if "ld-musl-" not in dynamic_linker_name:
return "ld.so.conf"
# Musl has a dynamic loader of the form ld-musl-<arch>.so.1
# and a corresponding config file ld-musl-<arch>.path
idx = dynamic_linker_name.find(".")
if idx != -1:
return dynamic_linker_name[:idx] + ".path"
[docs]
def host_dynamic_linker_search_paths():
"""Retrieve the current host runtime search paths for shared libraries;
for GNU and musl Linux we try to retrieve the dynamic linker from the
current Python interpreter and then find the corresponding config file
(e.g. ld.so.conf or ld-musl-<arch>.path). Similar can be done for
BSD and others, but this is not implemented yet. The default paths
are always returned. We don't check if the listed directories exist."""
default_paths = ["/usr/lib", "/usr/lib64", "/lib", "/lib64"]
# Currently only for Linux (gnu/musl)
if not sys.platform.startswith("linux"):
return default_paths
# If everything fails, try this standard glibc path.
conf_file = "/etc/ld.so.conf"
# Try to improve on the default conf path by retrieving the location of the
# dynamic linker from our current Python interpreter, and figure out the
# config file location from there.
try:
with open(sys.executable, "rb") as f:
elf = elf_utils.parse_elf(f, dynamic_section=False, interpreter=True)
# If we have a dynamic linker, try to retrieve the config file relative
# to its prefix.
if elf.has_pt_interp:
dynamic_linker = elf.pt_interp_str.decode("utf-8")
dynamic_linker_name = os.path.basename(dynamic_linker)
conf_name = get_conf_file_from_dynamic_linker(dynamic_linker_name)
# Typically it is /lib/ld.so, but on Gentoo Prefix it is something
# like <long glibc prefix>/lib/ld.so. And on Debian /lib64 is actually
# a symlink to /usr/lib64. So, best effort attempt is to just strip
# two path components and join with etc/ld.so.conf.
possible_prefix = os.path.dirname(os.path.dirname(dynamic_linker))
possible_conf = os.path.join(possible_prefix, "etc", conf_name)
if os.path.exists(possible_conf):
conf_file = possible_conf
except (IOError, OSError, elf_utils.ElfParsingError):
pass
# Note: ld_so_conf doesn't error if the file does not exist.
return list(dedupe(parse_ld_so_conf(conf_file) + default_paths))