uutils · jtracey · May 10, 2025
diff --git a/.github/workflows/CICD.yml b/.github/workflows/CICD.yml
@@ -5,7 +5,7 @@ name: CICD
 # spell-checker:ignore (jargon) SHAs deps dequote softprops subshell toolchain fuzzers dedupe devel profdata
 # spell-checker:ignore (people) Peltoche rivy dtolnay Anson dawidd
 # spell-checker:ignore (shell/tools) binutils choco clippy dmake dpkg esac fakeroot fdesc fdescfs gmake grcov halium lcov libclang libfuse libssl limactl mkdir nextest nocross pacman popd printf pushd redoxer rsync rustc rustfmt rustup shopt sccache utmpdump xargs
-# spell-checker:ignore (misc) aarch alnum armhf bindir busytest coreutils defconfig DESTDIR gecos getenforce gnueabihf issuecomment maint manpages msys multisize noconfirm nullglob onexitbegin onexitend pell runtest Swatinem tempfile testsuite toybox uutils
+# spell-checker:ignore (misc) aarch alnum armhf bindir busytest coreutils defconfig DESTDIR dylib gecos getenforce gnueabihf issuecomment maint manpages msys multisize noconfirm nullglob onexitbegin onexitend pell runtest Swatinem tempfile testsuite toybox uutils

 env:
  PROJECT_NAME: coreutils
@@ -513,25 +513,25 @@ jobs:
      fail-fast: false
      matrix:
        job:
-          # - { os , target , cargo-options , default-features,  features , use-cross , toolchain, skip-tests, workspace-tests, skip-package, skip-publish }
-          - { os: ubuntu-latest  , target: arm-unknown-linux-gnueabihf , features: feat_os_unix_gnueabihf , use-cross: use-cross , skip-tests: true }
-          - { os: ubuntu-24.04-arm  , target: aarch64-unknown-linux-gnu   , features: feat_os_unix_gnueabihf }
-          - { os: ubuntu-latest  , target: aarch64-unknown-linux-musl  , features: feat_os_unix      , use-cross: use-cross , skip-tests: true }
-          # - { os: ubuntu-latest  , target: x86_64-unknown-linux-gnu    , features: feat_selinux           , use-cross: use-cross }
-          - { os: ubuntu-latest  , target: i686-unknown-linux-gnu      , features: "feat_os_unix,test_risky_names", use-cross: use-cross }
-          - { os: ubuntu-latest  , target: i686-unknown-linux-musl     , features: feat_os_unix      , use-cross: use-cross }
-          - { os: ubuntu-latest  , target: x86_64-unknown-linux-gnu    , features: "feat_os_unix,test_risky_names", use-cross: use-cross }
-          - { os: ubuntu-latest  , target: x86_64-unknown-linux-gnu    , features: "feat_os_unix,uudoc"   , use-cross: no, workspace-tests: true }
-          - { os: ubuntu-latest  , target: x86_64-unknown-linux-musl   , features: feat_os_unix      , use-cross: use-cross }
-          - { os: ubuntu-latest  , target: x86_64-unknown-redox        , features: feat_os_unix_redox     , use-cross: redoxer , skip-tests: true }
-          - { os: ubuntu-latest  , target: wasm32-unknown-unknown      , default-features: false, features: uucore/format, skip-tests: true, skip-package: true, skip-publish: true }
-          - { os: macos-latest   , target: aarch64-apple-darwin        , features: feat_os_macos, workspace-tests: true } # M1 CPU
-          - { os: macos-13       , target: x86_64-apple-darwin         , features: feat_os_macos, workspace-tests: true }
-          - { os: windows-latest , target: i686-pc-windows-msvc        , features: feat_os_windows }
+          # - { os , target , cargo-options , default-features , features , dyn , use-cross , toolchain , skip-tests , workspace-tests , skip-package , skip-publish }
+          - { os: ubuntu-latest    , target: arm-unknown-linux-gnueabihf , features: feat_os_unix_gnueabihf , use-cross: use-cross , skip-tests: true }
+          - { os: ubuntu-24.04-arm , target: aarch64-unknown-linux-gnu   , features: feat_os_unix_gnueabihf , dyn: true }
+          - { os: ubuntu-latest    , target: aarch64-unknown-linux-musl  , features: feat_os_unix           , use-cross: use-cross , skip-tests: true }
+          # - { os: ubuntu-latest   , target: x86_64-unknown-linux-gnu    , features: feat_selinux           , use-cross: use-cross }
+          - { os: ubuntu-latest    , target: i686-unknown-linux-gnu      , features: "feat_os_unix,test_risky_names" , dyn: true , use-cross: use-cross }
+          - { os: ubuntu-latest    , target: i686-unknown-linux-musl     , features: feat_os_unix           , use-cross: use-cross }
+          - { os: ubuntu-latest    , target: x86_64-unknown-linux-gnu    , features: "feat_os_unix,test_risky_names" , dyn: true , use-cross: use-cross }
+          - { os: ubuntu-latest    , target: x86_64-unknown-linux-gnu    , features: "feat_os_unix,uudoc"   , use-cross: no, workspace-tests: true }
+          - { os: ubuntu-latest    , target: x86_64-unknown-linux-musl   , features: feat_os_unix           , use-cross: use-cross }
+          - { os: ubuntu-latest    , target: x86_64-unknown-redox        , features: feat_os_unix_redox     , dyn: true , use-cross: redoxer , skip-tests: true }
+          - { os: ubuntu-latest    , target: wasm32-unknown-unknown      , default-features: false, features: uucore/format, skip-tests: true, skip-package: true, skip-publish: true }
+          - { os: macos-latest     , target: aarch64-apple-darwin        , features: feat_os_macos          , dyn: true , workspace-tests: true } # M1 CPU
+          - { os: macos-13         , target: x86_64-apple-darwin         , features: feat_os_macos          , dyn: true , workspace-tests: true }
+          - { os: windows-latest   , target: i686-pc-windows-msvc        , features: feat_os_windows }
          # TODO: Re-enable after rust-onig release: https://github.com/rust-onig/rust-onig/issues/193
          # - { os: windows-latest , target: x86_64-pc-windows-gnu       , features: feat_os_windows }
-          - { os: windows-latest , target: x86_64-pc-windows-msvc      , features: feat_os_windows }
-          - { os: windows-latest , target: aarch64-pc-windows-msvc     , features: feat_os_windows, use-cross: use-cross , skip-tests: true }      
+          - { os: windows-latest   , target: x86_64-pc-windows-msvc      , features: feat_os_windows }
+          - { os: windows-latest   , target: aarch64-pc-windows-msvc     , features: feat_os_windows , use-cross: use-cross , skip-tests: true }
    steps:
    - uses: actions/checkout@v4
      with:
@@ -765,6 +765,23 @@ jobs:
        ## Build
        ${{ steps.vars.outputs.CARGO_CMD }} ${{ steps.vars.outputs.CARGO_CMD_OPTIONS }} build --release \
        --target=${{ matrix.job.target }} ${{ matrix.job.cargo-options }} ${{ steps.vars.outputs.CARGO_FEATURES_OPTION }} ${{ steps.vars.outputs.CARGO_DEFAULT_FEATURES_OPTION }}
+    - name: Build dynamic library
+      if: matrix.job.dyn == true
+      shell: bash
+      run: |
+        ## Build dynamic library
+        ${{ steps.vars.outputs.CARGO_CMD }} ${{ steps.vars.outputs.CARGO_CMD_OPTIONS }} rustc --release --target-dir ./target/${{ matrix.job.target }}/dynamic --crate-type=dylib --lib \
+        --target=${{ matrix.job.target }} ${{ matrix.job.cargo-options }} ${{ steps.vars.outputs.CARGO_FEATURES_OPTION }},dynamic ${{ steps.vars.outputs.CARGO_DEFAULT_FEATURES_OPTION }}
+        ## Build the multicall shim
+        ${{ steps.vars.outputs.CARGO_CMD }} ${{ steps.vars.outputs.CARGO_CMD_OPTIONS }} build --release --target-dir ./target/${{ matrix.job.target }}/dynamic \
+        --target=${{ matrix.job.target }} ${{ matrix.job.cargo-options }} ${{ steps.vars.outputs.CARGO_FEATURES_OPTION }},dynamic ${{ steps.vars.outputs.CARGO_DEFAULT_FEATURES_OPTION }}
+    - name: Check dynamic library
+      if: matrix.job.dyn == true && matrix.job.skip-tests != true
+      shell: bash
+      run: |
+        export LD_LIBRARY_PATH="./target/${{ matrix.job.target }}/dynamic/:$LD_LIBRARY_PATH"
+        ${{ steps.vars.outputs.CARGO_CMD }} ${{ steps.vars.outputs.CARGO_CMD_OPTIONS }} run --release --target-dir ./target/${{ matrix.job.target }}/dynamic \
+        --target=${{ matrix.job.target }} ${{ matrix.job.cargo-options }} ${{ steps.vars.outputs.CARGO_FEATURES_OPTION }},dynamic ${{ steps.vars.outputs.CARGO_DEFAULT_FEATURES_OPTION }}
    - name: Test
      if: matrix.job.skip-tests != true
      shell: bash

diff --git a/Cargo.lock b/Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
@@ -1,7 +1,7 @@
 # coreutils (uutils)
 # * see the repository LICENSE, README, and CONTRIBUTING files for more information

-# spell-checker:ignore (libs) bigdecimal datetime serde bincode gethostid kqueue libselinux mangen memmap procfs uuhelp startswith constness expl
+# spell-checker:ignore (libs) bigdecimal datetime serde bincode gethostid kqueue libselinux libloading mangen memmap procfs uuhelp startswith constness expl

 [package]
 name = "coreutils"
@@ -36,6 +36,8 @@ expensive_tests = []
 test_risky_names = []
 # * only build `uudoc` when `--feature uudoc` is activated
 uudoc = ["zip", "dep:uuhelp_parser"]
+# * only build `coreutils` with dynamic loading when `--feature dynamic` is activated
+dynamic = ["libloading"]
 ## features
 # "feat_acl" == enable support for ACLs (access control lists; by using`--features feat_acl`)
 # NOTE:
@@ -304,6 +306,7 @@ iana-time-zone = "0.1.57"
 indicatif = "0.17.8"
 itertools = "0.14.0"
 libc = "0.2.172"
+libloading = "0.8.6"
 linux-raw-sys = "0.9"
 lscolors = { version = "0.20.0", default-features = false, features = [
  "gnu_legacy",
@@ -377,6 +380,7 @@ phf = { workspace = true }
 selinux = { workspace = true, optional = true }
 textwrap = { workspace = true }
 zip = { workspace = true, optional = true }
+libloading = { workspace = true, optional = true }

 uuhelp_parser = { optional = true, version = ">=0.0.19", path = "src/uuhelp_parser" }

@@ -542,6 +546,10 @@ phf_codegen = { workspace = true }
 name = "coreutils"
 path = "src/bin/coreutils.rs"

+[lib]
+name = "coreutils"
+path = "src/lib/coreutils.rs"
+
 [[bin]]
 name = "uudoc"
 path = "src/bin/uudoc.rs"

diff --git a/GNUmakefile b/GNUmakefile
@@ -1,7 +1,8 @@
-# spell-checker:ignore (misc) testsuite runtest findstring (targets) busytest toybox distclean pkgs nextest ; (vars/env) BINDIR BUILDDIR CARGOFLAGS DESTDIR DOCSDIR INSTALLDIR INSTALLEES MULTICALL DATAROOTDIR TESTDIR manpages
+# spell-checker:ignore (misc) testsuite runtest findstring libcoreutils dylib (targets) busytest toybox distclean pkgs nextest ; (vars/env) BINDIR BUILDDIR CARGOFLAGS DESTDIR DOCSDIR INSTALLDIR INSTALLEES MULTICALL DATAROOTDIR TESTDIR manpages

 # Config options
 PROFILE         ?= debug
+DYNAMIC         ?= n
 MULTICALL       ?= n
 COMPLETIONS     ?= y
 MANPAGES        ?= y
@@ -31,9 +32,11 @@ CARGOFLAGS ?=
 PREFIX ?= /usr/local
 DESTDIR ?=
 BINDIR ?= $(PREFIX)/bin
+LIBDIR ?= $(PREFIX)/lib
 DATAROOTDIR ?= $(PREFIX)/share

 INSTALLDIR_BIN=$(DESTDIR)$(BINDIR)
+INSTALLDIR_LIB=$(DESTDIR)$(LIBDIR)

 #prefix to apply to coreutils binary and all tool binaries
 PROG_PREFIX ?=
@@ -271,6 +274,17 @@ TEST_SPEC_FEATURE := selinux
 BUILD_SPEC_FEATURE := selinux
 endif

+ifeq (${DYNAMIC}, y)
+BUILD_SPEC_FEATURE += dynamic
+ifeq ($(OS),Windows_NT)
+LIBNAME := libcoreutils.dll
+else ifeq ($(shell uname -s),Darwin)
+LIBNAME := libcoreutils.dylib
+else
+LIBNAME := libcoreutils.so
+endif
+endif
+
 define TEST_BUSYBOX
 test_busybox_$(1):
 	-(cd $(BUSYBOX_SRC)/testsuite && bindir=$(BUILDDIR) ./runtest $(RUNTEST_ARGS) $(1))
@@ -299,10 +313,15 @@ else
 endif
 endif

+build-lib:
+ifeq (${DYNAMIC}, y)
+	${CARGO} rustc ${CARGOFLAGS} --features "${EXES} $(BUILD_SPEC_FEATURE)" ${PROFILE_CMD} --crate-type dylib --lib
+endif
+
 build-coreutils:
 	${CARGO} build ${CARGOFLAGS} --features "${EXES} $(BUILD_SPEC_FEATURE)" ${PROFILE_CMD} --no-default-features

-build: build-coreutils build-pkgs
+build: build-coreutils build-pkgs build-lib

 $(foreach test,$(filter-out $(SKIP_UTILS),$(PROGS)),$(eval $(call TEST_BUSYBOX,$(test))))

@@ -341,7 +360,7 @@ $(BUILDDIR)/busybox: busybox-src build-coreutils $(BUILDDIR)/.config
 	chmod +x $@

 prepare-busytest: $(BUILDDIR)/busybox
-	# disable inapplicable tests
+# disable inapplicable tests
 	-( cd "$(BUSYBOX_SRC)/testsuite" ; if [ -e "busybox.tests" ] ; then mv busybox.tests busybox.tests- ; fi ; )

 ifeq ($(EXES),)
@@ -395,7 +414,12 @@ else
 install-completions:
 endif

-install: build install-manpages install-completions
+install-lib:
+ifeq (${DYNAMIC}, y)
+	$(INSTALL) $(BUILDDIR)/$(LIBNAME) $(INSTALLDIR_LIB)/
+endif
+
+install: build install-manpages install-completions install-lib
 	mkdir -p $(INSTALLDIR_BIN)
 ifeq (${MULTICALL}, y)
 	$(INSTALL) $(BUILDDIR)/coreutils $(INSTALLDIR_BIN)/$(PROG_PREFIX)coreutils
@@ -413,6 +437,9 @@ endif
 uninstall:
 ifeq (${MULTICALL}, y)
 	rm -f $(addprefix $(INSTALLDIR_BIN)/,$(PROG_PREFIX)coreutils)
+endif
+ifeq (${DYNAMIC}, y)
+	rm -f $(INSTALLDIR_BIN)/$(LIBNAME)
 endif
 	rm -f $(addprefix $(INSTALLDIR_BIN)/$(PROG_PREFIX),$(PROGS))
 	rm -f $(INSTALLDIR_BIN)/$(PROG_PREFIX)[

diff --git a/README.md b/README.md
@@ -1,6 +1,6 @@
 <!-- markdownlint-disable MD033 MD041 MD002 -->
 <!-- markdownlint-disable commands-show-output no-duplicate-heading -->
-<!-- spell-checker:ignore markdownlint ; (options) DESTDIR UTILNAME manpages reimplementation oranda -->
+<!-- spell-checker:ignore markdownlint ; (options) DESTDIR UTILNAME dylib manpages reimplementation oranda -->
 <div class="oranda-hide">
 <div align="center">

@@ -129,6 +129,22 @@ the `--package` [aka `-p`] option). For example:
 cargo build -p uu_base32 -p uu_cat -p uu_echo -p uu_rm
 ```

+The multicall code can also be built as a dynamic library, and the multicall
+binary turned into a minimal shim to load it:
+
+```shell
+cargo rustc --release --features dynamic,unix --lib --crate-type dylib
+cargo build --release --features dynamic
+```
+
+Note that the shim multicall binary will not function unless the library is
+accessible in one of the dynamic loader's search paths—either a default library
+search path, or a modified environment. For example, on Linux:
+
+```shell
+LD_LIBRARY_PATH=$(pwd)/target/release/ ./target/release/coreutils
+```
+
 ### GNU Make

 Building using `make` is a simple process as well.
@@ -212,13 +228,26 @@ To install the multicall binary:
 make MULTICALL=y install
 ```

-Set install parent directory (default value is /usr/local):
+Set install parent directory (default value is `/usr/local`):

 ```shell
 # DESTDIR is also supported
 make PREFIX=/my/path install
 ```

+The dynamically liked multicall library and binary can be installed instead.
+Note, however, that while the standard local `/usr/local/bin` path for binaries
+is typically in the default `PATH` environment variable, the standard local
+`/usr/local/lib` path for libraries is typically *not* in the default library
+search paths. If you do not address this in a persistent manner, then do a
+default dynamic install, your system will likely to fail to fully boot. With
+that in mind, to install the dynamically linked library and shim multicall
+binary:
+
+```shell
+make MULTICALL=y DYNAMIC=y install
+```
+
 Installing with `make` installs shell completions for all installed utilities
 for `bash`, `fish` and `zsh`. Completions for `elvish` and `powershell` can also
 be generated; See `Manually install shell completions`.
@@ -295,6 +324,12 @@ To uninstall the multicall binary:
 make MULTICALL=y uninstall
 ```

+Similarly, for the dynamically linked library and binary:
+
+```shell
+make MULTICALL=y DYNAMIC=y uninstall
+```
+
 To uninstall from a custom parent directory:

 ```shell

diff --git a/build.rs b/build.rs
@@ -3,7 +3,7 @@
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.

-// spell-checker:ignore (vars) krate
+// spell-checker:ignore (vars) krate libloading

 use std::env;
 use std::fs::File;
@@ -32,11 +32,13 @@ pub fn main() {
            // Allow this as we have a bunch of info in the comments
            #[allow(clippy::match_same_arms)]
            match krate.as_ref() {
-                "default" | "macos" | "unix" | "windows" | "selinux" | "zip" => continue, // common/standard feature names
+                "default" | "macos" | "unix" | "windows" | "selinux" | "zip" | "libloading" => {
+                    continue;
+                } // common/standard feature names
                "nightly" | "test_unimplemented" | "expensive_tests" | "test_risky_names" => {
                    continue;
                } // crate-local custom features
-                "uudoc" => continue, // is not a utility
+                "uudoc" | "dynamic" => continue, // is not a utility
                "test" => continue, // over-ridden with 'uu_test' to avoid collision with rust core crate 'test'
                s if s.starts_with(FEATURE_PREFIX) => continue, // crate feature sets
                _ => {}             // util feature name