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android / platform / external / selinux / 02f302fc
commit02f302fc5ba3afba2e864de75a88db13e497b416[log] [tgz]
authorOndrej Mosnacek <omosnace@redhat.com>Tue Oct 26 13:52:38 2021 +0200
committerPetr Lautrbach <plautrba@redhat.com>Tue Nov 23 10:03:18 2021 +0100
treec0978e62a5570016cb8104f5d399b07ea194c860
parenta578d1cecd328bb91c97fae4b2f05c44f9666be4 [diff]
selinux_restorecon: introduce selinux_restorecon_parallel(3)

Refactor selinux_restorecon(3) to allow for distributing the relabeling
to multiple threads and add a new function
selinux_restorecon_parallel(3), which allows specifying the number of
threads to use. The existing selinux_restorecon(3) function maintains
the same interface and maintains the same behavior (i.e. relabeling is
done on a single thread).

The parallel implementation takes a simple approach of performing all
the directory tree traversal in a critical section and only letting the
relabeling of individual objects run in parallel. Thankfully, this
approach turns out to be efficient enough in practice, as shown by
restorecon benchmarks (detailed in a subsequent patch that switches
setfiles & restorecon to use selinux_restorecon_parallel(3)).

Note that to be able to use the parallelism, the calling application/
library must be explicitly linked to the libpthread library (statically
or dynamically). This is necessary to mantain the requirement that
libselinux shouldn't explicitly link with libpthread. (I don't know what
exactly was the reason behind this requirement as the commit logs are
fuzzy, but special care has been taken in the past to maintain it, so I
didn't want to break it...)

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
8 files changed
tree: c0978e62a5570016cb8104f5d399b07ea194c860
  1. .circleci/
  2. .github/
  3. checkpolicy/
  4. dbus/
  5. gui/
  6. libselinux/
  7. libsemanage/
  8. libsepol/
  9. mcstrans/
  10. policycoreutils/
  11. python/
  12. restorecond/
  13. sandbox/
  14. scripts/
  15. secilc/
  16. semodule-utils/
  17. .gitignore
  18. .travis.yml
  19. CleanSpec.mk
  20. CONTRIBUTING.md
  21. lgtm.yml
  22. Makefile
  23. README.md
  24. VERSION
README.md

SELinux Userspace

SELinux logo Run Tests Run SELinux testsuite in a virtual machine OSS-Fuzz Status CIFuzz Status

Please submit all bug reports and patches to selinux@vger.kernel.org.

Subscribe by sending “subscribe selinux” in the body of an email to majordomo@vger.kernel.org.

Archive of this mailing list is available on https://lore.kernel.org/selinux/.

Installation

SELinux libraries and tools are packaged in several Linux distributions:

Building and testing

Build dependencies on Fedora:

# For C libraries and programs
dnf install \
    audit-libs-devel \
    bison \
    bzip2-devel \
    CUnit-devel \
    diffutils \
    flex \
    gcc \
    gettext \
    glib2-devel \
    make \
    libcap-devel \
    libcap-ng-devel \
    pam-devel \
    pcre-devel \
    xmlto

# For Python and Ruby bindings
dnf install \
    python3-devel \
    ruby-devel \
    swig

Build dependencies on Debian:

# For C libraries and programs
apt-get install --no-install-recommends --no-install-suggests \
    bison \
    flex \
    gawk \
    gcc \
    gettext \
    make \
    libaudit-dev \
    libbz2-dev \
    libcap-dev \
    libcap-ng-dev \
    libcunit1-dev \
    libglib2.0-dev \
    libpcre3-dev \
    pkgconf \
    python3 \
    python3-distutils \
    systemd \
    xmlto

# For Python and Ruby bindings
apt-get install --no-install-recommends --no-install-suggests \
    python3-dev \
    ruby-dev \
    swig

To build and install everything under a private directory, run:

make clean distclean

make DESTDIR=~/obj install install-rubywrap install-pywrap

On Debian PYTHON_SETUP_ARGS=--install-layout=deb needs to be set when installing the python wrappers in order to create the correct python directory structure.

To run tests with the built libraries and programs, several paths (relative to $DESTDIR) need to be added to variables $LD_LIBRARY_PATH, $PATH and $PYTHONPATH. This can be done using ./scripts/env_use_destdir:

DESTDIR=~/obj ./scripts/env_use_destdir make test

Some tests require the reference policy to be installed (for example in python/sepolgen). In order to run these ones, instructions similar to the ones in section install of ./.travis.yml can be executed.

To install as the default system libraries and binaries (overwriting any previously installed ones - dangerous!), on x86_64, run:

make LIBDIR=/usr/lib64 SHLIBDIR=/lib64 install install-pywrap relabel

or on x86 (32-bit), run:

make install install-pywrap relabel

This may render your system unusable if the upstream SELinux userspace lacks library functions or other dependencies relied upon by your distribution. If it breaks, you get to keep both pieces.

Setting CFLAGS

Setting CFLAGS during the make process will cause the omission of many defaults. While the project strives to provide a reasonable set of default flags, custom CFLAGS could break the build, or have other undesired changes on the build output. Thus, be very careful when setting CFLAGS. CFLAGS that are encouraged to be set when overriding are:

  • -fno-semantic-interposition for gcc or compilers that do not do this. clang does this by default. clang-10 and up will support passing this flag, but ignore it. Previous clang versions fail.

macOS

To install libsepol on macOS (mainly for policy analysis):

cd libsepol; make PREFIX=/usr/local install

This requires GNU coreutils:

brew install coreutils