WIP fix race

.github/workflows/ci.yaml

@@ -1,60 +0,0 @@
-name: CI
-on: push
-jobs:
-    build-and-test:
-        runs-on: ubuntu-20.04
-        strategy:
-            fail-fast: false
-            matrix:
-                include:
-                    - arch: amd64
-                      manylinux_arch: x86_64
-                      docker_image: debian:buster
-
-                    - arch: arm64
-                      manylinux_arch: aarch64
-                      docker_image: arm64v8/debian:buster
-
-                    - arch: ppc64le
-                      manylinux_arch: ppc64le
-                      docker_image: ppc64le/debian:buster
-
-                    - arch: s390x
-                      manylinux_arch: s390x
-                      docker_image: s390x/debian:buster
-
-        env:
-            BASE_IMAGE: ${{ matrix.docker_image }}
-
-        steps:
-            - uses: actions/checkout@v2
-
-            - name: Set up QEMU
-              id: qemu
-              uses: docker/setup-qemu-action@v1
-              if: ${{ matrix.arch != 'amd64' }}
-              with:
-                image: tonistiigi/binfmt:latest
-
-            - name: Build Docker image
-              run: make docker-image
-
-            - name: Run python tests
-              run: docker run --rm -v $(pwd):/mnt:rw dumb-init-build /mnt/ci/docker-python-test
-
-            - name: Build Debian package
-              run: docker run --init --rm -v $(pwd):/mnt:rw dumb-init-build make -C /mnt builddeb
-
-            - name: Test built Debian package
-              # XXX: This uses the clean base image (not the build one) to make
-              # sure it installs in a clean image without any hidden dependencies.
-              run: docker run --rm -v $(pwd):/mnt:rw ${{ matrix.docker_image }} /mnt/ci/docker-deb-test
-
-            - name: Build wheels
-              run: sudo make python-dists-${{ matrix.manylinux_arch }}
-
-            - name: Upload build artifacts
-              uses: actions/upload-artifact@v2
-              with:
-                  name: ${{ matrix.arch }}
-                  path: dist

.pre-commit-config.yaml

@@ -1,7 +1,8 @@
 repos:
 -   repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v4.4.0
+    rev: v1.2.3
     hooks:
+    -   id: autopep8-wrapper
     -   id: check-added-large-files
     -   id: check-docstring-first
     -   id: check-executables-have-shebangs
@@ -11,33 +12,15 @@ repos:
     -   id: detect-private-key
     -   id: double-quote-string-fixer
     -   id: end-of-file-fixer
+    -   id: flake8
     -   id: name-tests-test
     -   id: requirements-txt-fixer
     -   id: trailing-whitespace
--   repo: https://github.com/pre-commit/mirrors-autopep8
-    rev: v2.0.0
-    hooks:
-    -   id: autopep8
--   repo: https://github.com/pycqa/flake8
-    rev: 6.0.0
-    hooks:
-    -   id: flake8
 -   repo: https://github.com/asottile/reorder_python_imports
-    rev: v3.9.0
+    rev: v1.0.1
     hooks:
     -   id: reorder-python-imports
-        args: ['--py3-plus']
 -   repo: https://github.com/Lucas-C/pre-commit-hooks
-    rev: v1.3.1
+    rev: v1.1.5
     hooks:
     -   id: remove-tabs
--   repo: https://github.com/asottile/pyupgrade
-    rev: v3.3.0
-    hooks:
-    -   id: pyupgrade
-        args: ['--py3-plus']
--   repo: https://github.com/asottile/add-trailing-comma
-    rev: v2.3.0
-    hooks:
-    -   id: add-trailing-comma
-        args: ['--py36-plus']

.travis.yml

@@ -0,0 +1,19 @@
+language: c
+services:
+    - docker
+
+matrix:
+    include:
+        - env: ITEST_TARGET=itest_trusty
+        - env: ITEST_TARGET=itest_xenial
+        - env: ITEST_TARGET=itest_bionic
+        - env: ITEST_TARGET=itest_stretch
+        - env: ITEST_TARGET=itest_tox
+        - os: linux-ppc64le
+          env: ITEST_TARGET=itest_stretch
+
+script:
+   - make "$ITEST_TARGET"
+
+after_script:
+   - ci/artifact-upload

CONTRIBUTING.md

@@ -29,11 +29,11 @@ The process to release a new version is:
 4. Commit the changes and tag the commit like `v1.0.0`.
 5. `git push --tags origin master`
 6. Wait for Travis to run, then find and download the binary and Debian
-   packages for all architectures; there will be links printed at the
+   packages for both amd64 and ppc64el; there will be links printed at the end
-   end of the Travis output. Put these into your `dist` directory.
+   of the Travis output. Put these into your `dist` directory.
 7. Run `make release`
 8. Run `twine upload --skip-existing dist/*.tar.gz dist/*.whl` to upload the
    new version to PyPI
-9. Upload the resulting Debian packages, binaries, and sha256sums file (all
+9. Upload the resulting Debian package, binary (inside the `dist` directory),
-   inside the `dist` directory) to a new [GitHub
+   and sha256sums file to a new [GitHub
    release](https://github.com/Yelp/dumb-init/releases)

Dockerfile

@@ -1,28 +1,24 @@
-ARG BASE_IMAGE=debian:buster
+FROM debian:stretch
-FROM $BASE_IMAGE
 
 LABEL maintainer="Chris Kuehl <ckuehl@yelp.com>"
 
+# The default mirrors are too flaky to run reliably in CI.
+RUN sed -E \
+    '/security\.debian/! s@http://[^/]+/@http://mirrors.kernel.org/@' \
+    -i /etc/apt/sources.list
+
 # Install the bare minimum dependencies necessary for working with Debian
 # packages. Build dependencies should be added under "Build-Depends" inside
 # debian/control instead.
-RUN : \
+RUN DEBIAN_FRONTEND=noninteractive apt-get update && \
-    && apt-get update \
+    apt-get install -y --no-install-recommends \
-    && DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
         build-essential \
         devscripts \
         equivs \
         lintian \
-        python3-distutils \
+    && rm -rf /var/lib/apt/lists/* && apt-get clean
-        python3-setuptools \
+WORKDIR /mnt
-        python3-pip \
-    && apt-get clean \
-    && rm -rf /var/lib/apt/lists/*
-WORKDIR /tmp/mnt
 
-COPY debian/control /control
+ENTRYPOINT apt-get update && \
-RUN : \
+    mk-build-deps -i --tool 'apt-get --no-install-recommends -y' && \
-    && apt-get update \
+    make builddeb
-    && mk-build-deps --install --tool 'apt-get -y --no-install-recommends' /control \
-    && apt-get clean \
-    && rm -rf /var/lib/apt/lists/*

Makefile

@@ -26,21 +26,18 @@ clean-tox:
 .PHONY: release
 release: python-dists
 	cd dist && \
-		sha256sum --binary dumb-init_$(VERSION)_amd64.deb dumb-init_$(VERSION)_x86_64 dumb-init_$(VERSION)_ppc64el.deb dumb-init_$(VERSION)_ppc64le dumb-init_$(VERSION)_s390x.deb dumb-init_$(VERSION)_s390x dumb-init_$(VERSION)_arm64.deb dumb-init_$(VERSION)_aarch64 \
+		sha256sum --binary dumb-init_$(VERSION)_amd64.deb dumb-init_$(VERSION)_amd64 dumb-init_$(VERSION)_ppc64el.deb dumb-init_$(VERSION)_ppc64el \
 		> sha256sums
 
 .PHONY: python-dists
-python-dists: python-dists-x86_64 python-dists-aarch64 python-dists-ppc64le python-dists-s390x
+python-dists: VERSION.h
-
-.PHONY: python-dists-%
-python-dists-%: VERSION.h
 	python setup.py sdist
 	docker run \
 		--user $$(id -u):$$(id -g) \
-		-v `pwd`/dist:/dist:rw \
+		-v $(PWD)/dist:/dist:rw \
-		quay.io/pypa/manylinux2014_$*:latest \
+		quay.io/pypa/manylinux1_x86_64:latest \
 		bash -exc ' \
-			/opt/python/cp38-cp38/bin/pip wheel --wheel-dir /tmp /dist/*.tar.gz && \
+			/opt/python/cp35-cp35m/bin/pip wheel --wheel-dir /tmp /dist/*.tar.gz && \
 			auditwheel repair --wheel-dir /dist /tmp/*.whl --wheel-dir /dist \
 		'
 
@@ -52,16 +49,16 @@ builddeb:
 	# Extract the built binary from the Debian package
 	dpkg-deb --fsys-tarfile dist/dumb-init_$(VERSION)_$(shell dpkg --print-architecture).deb | \
 		tar -C dist --strip=3 -xvf - ./usr/bin/dumb-init
-	mv dist/dumb-init dist/dumb-init_$(VERSION)_$(shell uname -m)
+	mv dist/dumb-init dist/dumb-init_$(VERSION)_$(shell dpkg --print-architecture)
 
 .PHONY: builddeb-docker
 builddeb-docker: docker-image
 	mkdir -p dist
-	docker run --init --user $$(id -u):$$(id -g) -v $(PWD):/tmp/mnt dumb-init-build make builddeb
+	docker run -v $(PWD):/mnt dumb-init-build
 
 .PHONY: docker-image
 docker-image:
-	docker build $(if $(BASE_IMAGE),--build-arg BASE_IMAGE=$(BASE_IMAGE)) -t dumb-init-build .
+	docker build -t dumb-init-build .
 
 .PHONY: test
 test:
@@ -71,3 +68,25 @@ test:
 .PHONY: install-hooks
 install-hooks:
 	tox -e pre-commit -- install -f --install-hooks
+
+ITEST_TARGETS = itest_trusty itest_xenial itest_bionic itest_stretch
+
+.PHONY: itest $(ITEST_TARGETS)
+itest: $(ITEST_TARGETS)
+
+itest_trusty: _itest-ubuntu-trusty
+itest_xenial: _itest-ubuntu-xenial
+itest_bionic: _itest-ubuntu-bionic
+itest_stretch: _itest-debian-stretch
+
+itest_tox:
+	$(DOCKER_RUN_TEST) ubuntu:bionic /mnt/ci/docker-tox-test
+
+_itest-%: _itest_deb-% _itest_python-%
+	@true
+
+_itest_python-%:
+	$(DOCKER_RUN_TEST) $(shell sed 's/-/:/' <<< "$*") /mnt/ci/docker-python-test
+
+_itest_deb-%: builddeb-docker
+	$(DOCKER_RUN_TEST) $(shell sed 's/-/:/' <<< "$*") /mnt/ci/docker-deb-test

README.md

@@ -1,6 +1,7 @@
 dumb-init
 ========
 
+[![Travis CI](https://travis-ci.org/Yelp/dumb-init.svg?branch=master)](https://travis-ci.org/Yelp/dumb-init/)
 [![PyPI version](https://badge.fury.io/py/dumb-init.svg)](https://pypi.python.org/pypi/dumb-init)
 
 
@@ -173,7 +174,7 @@ If you don't have an internal apt server, you can use `dpkg -i` to install the
 One possibility is with the following commands in your Dockerfile:
 
 ```Dockerfile
-RUN wget https://github.com/Yelp/dumb-init/releases/download/v1.2.5/dumb-init_1.2.5_amd64.deb
+RUN wget https://github.com/Yelp/dumb-init/releases/download/v1.2.1/dumb-init_1.2.1_amd64.deb
 RUN dpkg -i dumb-init_*.deb
 ```
 
@@ -184,7 +185,7 @@ Since dumb-init is released as a statically-linked binary, you can usually just
 plop it into your images. Here's an example of doing that in a Dockerfile:
 
 ```Dockerfile
-RUN wget -O /usr/local/bin/dumb-init https://github.com/Yelp/dumb-init/releases/download/v1.2.5/dumb-init_1.2.5_x86_64
+RUN wget -O /usr/local/bin/dumb-init https://github.com/Yelp/dumb-init/releases/download/v1.2.1/dumb-init_1.2.1_amd64
 RUN chmod +x /usr/local/bin/dumb-init
 ```
 

VERSION

@@ -1 +1 @@
-1.2.5
+1.2.1

VERSION.h

@@ -1,6 +1,6 @@
 // THIS FILE IS AUTOMATICALLY GENERATED
 // Run `make VERSION.h` to update it after modifying VERSION.
 unsigned char VERSION[] = {
-  0x31, 0x2e, 0x32, 0x2e, 0x35, 0x0a
+  0x31, 0x2e, 0x32, 0x2e, 0x31, 0x0a
 };
 unsigned int VERSION_len = 6;

ci/docker

@@ -0,0 +1,18 @@
+# The default mirrors are too flaky to run reliably in CI.
+sed -E \
+    '/security\.debian/! s@http://[^/]+/@http://mirrors.kernel.org/@' \
+    -i /etc/apt/sources.list
+
+apt-get update
+apt-get install -y --no-install-recommends \
+    build-essential \
+    procps \
+    python \
+    python-dev \
+    python-pip \
+    python-setuptools
+
+cp -r /mnt/ /test
+cd /test
+
+# vim: ft=sh

ci/docker-deb-test

@@ -1,12 +1,10 @@
 #!/bin/bash -eux
 set -o pipefail
 
-apt-get update
+. /mnt/ci/docker
-apt-get -y --no-install-recommends install python3-pip procps
 
-cd /mnt
 dpkg -i dist/*.deb
-pip3 install -r requirements-dev.txt
+pip install -r requirements-dev.txt
-pytest tests/
+py.test tests/
 
 exec dumb-init /mnt/tests/test-zombies

ci/docker-python-test

@@ -1,12 +1,12 @@
 #!/bin/bash -eux
-set -euo pipefail
+set -o pipefail
 
-cd /mnt
+. /mnt/ci/docker
 
-python3 setup.py clean
+python setup.py clean
-python3 setup.py sdist
+python setup.py sdist
-pip3 install -vv dist/*.tar.gz
+pip install -vv dist/*.tar.gz
-pip3 install -r requirements-dev.txt
+pip install -r requirements-dev.txt
-pytest-3 -vv tests/
+py.test tests/
 
-exec dumb-init /mnt/tests/test-zombies
+exec dumb-init /mnt/tests/test-zombies \

ci/docker-tox-test

@@ -0,0 +1,13 @@
+#!/bin/bash -eux
+set -o pipefail
+
+. /mnt/ci/docker
+
+apt-get update
+apt-get install -y --no-install-recommends \
+    git \
+    python2.7-dev \
+    python3.6-dev \
+    tox
+
+tox

debian/changelog

@@ -1,46 +1,3 @@
-dumb-init (1.2.5) unstable; urgency=medium
-
-  * Change the working directory in the parent process to "/" after forking.
-
-    https://github.com/Yelp/dumb-init/pull/210
-
-    Thanks to @Villemoes for the patch!
-
- -- Chris Kuehl <ckuehl@yelp.com>  Thu, 10 Dec 2020 10:54:47 -0800
-
-dumb-init (1.2.4) unstable; urgency=medium
-
-  * Actually fix the bug that can cause `--help` or `--version` to crash in
-    some scenarios.
-
-    https://github.com/Yelp/dumb-init/pull/215
-
-    Thanks to @suve for the patch!
-
- -- Chris Kuehl <ckuehl@yelp.com>  Mon, 07 Dec 2020 11:58:06 -0800
-
-dumb-init (1.2.3) unstable; urgency=medium
-
-  * Fix a bug that can cause `--help` or `--version` to crash in some
-    scenarios.
-
-    https://github.com/Yelp/dumb-init/pull/213
-
-    Thanks to @suve for the patch!
-
- -- Chris Kuehl <ckuehl@yelp.com>  Wed, 02 Dec 2020 10:43:02 -0800
-
-dumb-init (1.2.2) unstable; urgency=medium
-
-  * Fix a race condition which can cause the child to receive SIGHUP and
-    SIGCONT very shortly after start (#174).
-
-    In general this was very rare, but some environments (especially some
-    container and virtualization environments) appear to encounter it at a
-    much higher rate, possibly due to scheduler quirks.
-
- -- Chris Kuehl <ckuehl@yelp.com>  Wed, 01 Aug 2018 16:36:22 -0700
-
 dumb-init (1.2.1) unstable; urgency=medium
 
   * Fix verbose debug logging for ignored signals.

debian/control

@@ -2,14 +2,16 @@ Source: dumb-init
 Section: utils
 Priority: extra
 Maintainer: Chris Kuehl <ckuehl@yelp.com>
+Uploaders: Kent Wills <rkwills@yelp.com>
 Build-Depends:
  debhelper (>= 9),
  help2man,
  musl-tools,
 ## Tests:
  procps,
- python3,
+ python,
- python3-pytest,
+ python-mock,
+ python-pytest,
 Standards-Version: 3.9.7
 Homepage: https://github.com/Yelp/dumb-init
 Vcs-Browser: https://github.com/Yelp/dumb-init

debian/rules

@@ -31,4 +31,4 @@ override_dh_builddeb:
 override_dh_auto_test:
 	find . -name '*.pyc' -delete
 	find . -name '__pycache__' -delete
-	PATH=.:$$PATH timeout --signal=KILL 60 pytest-3 -vv tests/
+	PATH=.:$$PATH timeout --signal=KILL 60 py.test -vv tests/

dumb-init.c

@@ -94,7 +94,7 @@ void handle_signal(int signum) {
     DEBUG("Received signal %d.\n", signum);
 
     if (signal_temporary_ignores[signum] == 1) {
-        DEBUG("Ignoring tty hand-off signal %d.\n", signum);
+        DEBUG("Ignoring signal %d during its first receive.\n", signum);
         signal_temporary_ignores[signum] = 0;
     } else if (signum == SIGCHLD) {
         int status, exit_status;
@@ -126,7 +126,7 @@ void handle_signal(int signum) {
 
 void print_help(char *argv[]) {
     fprintf(stderr,
-        "dumb-init v%.*s"
+        "dumb-init v%s"
         "Usage: %s [option] command [[arg] ...]\n"
         "\n"
         "dumb-init is a simple process supervisor that forwards signals to children.\n"
@@ -144,7 +144,7 @@ void print_help(char *argv[]) {
         "   -V, --version        Print the current version and exit.\n"
         "\n"
         "Full help is available online at https://github.com/Yelp/dumb-init\n",
-        VERSION_len, VERSION,
+        VERSION,
         argv[0]
     );
 }
@@ -175,10 +175,9 @@ void parse_rewrite_signum(char *arg) {
 }
 
 void set_rewrite_to_sigstop_if_not_defined(int signum) {
-    if (signal_rewrite[signum] == -1) {
+    if (signal_rewrite[signum] == -1)
         signal_rewrite[signum] = SIGSTOP;
 }
-}
 
 char **parse_command(int argc, char *argv[]) {
     int opt;
@@ -199,7 +198,7 @@ char **parse_command(int argc, char *argv[]) {
                 debug = 1;
                 break;
             case 'V':
-                fprintf(stderr, "dumb-init v%.*s", VERSION_len, VERSION);
+                fprintf(stderr, "dumb-init v%s", VERSION);
                 exit(0);
             case 'c':
                 use_setsid = 0;
@@ -256,9 +255,8 @@ int main(int argc, char *argv[]) {
     sigprocmask(SIG_BLOCK, &all_signals, NULL);
 
     int i = 0;
-    for (i = 1; i <= MAXSIG; i++) {
+    for (i = 1; i <= MAXSIG; i++)
         signal(i, dummy);
-    }
 
     /*
      * Detach dumb-init from controlling tty, so that the child's session can
@@ -326,11 +324,6 @@ int main(int argc, char *argv[]) {
     } else {
         /* parent */
         DEBUG("Child spawned with PID %d.\n", child_pid);
-        if (chdir("/") == -1) {
-             DEBUG("Unable to chdir(\"/\") (errno=%d %s)\n",
-                   errno,
-                   strerror(errno));
-        }
         for (;;) {
             int signum;
             sigwait(&all_signals, &signum);

pytest.ini

@@ -1,2 +1,2 @@
 [pytest]
-timeout = 20
+timeout = 5

requirements-dev.txt

@@ -1,6 +1,4 @@
+mock
 pre-commit>=0.5.0
 pytest
-# TODO: This pin is to work around an issue where the system pytest is too old.
+pytest-timeout
-# We should fix this by not depending on the system pytest/python packages at
-# some point.
-pytest-timeout<2.0.0

setup.py

@@ -1,9 +1,11 @@
+from __future__ import print_function
+
 import os.path
 import subprocess
 import tempfile
-
 from distutils.command.build import build as orig_build
 from distutils.core import Command
+
 from setuptools import Distribution
 from setuptools import Extension
 from setuptools import setup
@@ -56,8 +58,7 @@ class install_cexe(Command):
         # this initializes attributes based on other commands' attributes
         self.set_undefined_options('build', ('build_scripts', 'build_dir'))
         self.set_undefined_options(
-            'install', ('install_scripts', 'install_dir'),
+            'install', ('install_scripts', 'install_dir'))
-        )
 
     def run(self):
 
@@ -123,7 +124,6 @@ setup(
     author='Yelp',
     url='https://github.com/Yelp/dumb-init/',
     platforms='linux',
-    packages=[],
     c_executables=[Extension('dumb-init', ['dumb-init.c'])],
     cmdclass={
         'bdist_wheel': bdist_wheel,

testing/__init__.py

@@ -8,6 +8,9 @@ from contextlib import contextmanager
 from subprocess import PIPE
 from subprocess import Popen
 
+from py._path.local import LocalPath
+
+
 # these signals cause dumb-init to suspend itself
 SUSPEND_SIGNALS = frozenset([
     signal.SIGTSTP,
@@ -17,8 +20,8 @@ SUSPEND_SIGNALS = frozenset([
 
 NORMAL_SIGNALS = frozenset(
     set(range(1, 32)) -
-    {signal.SIGKILL, signal.SIGSTOP, signal.SIGCHLD} -
+    set([signal.SIGKILL, signal.SIGSTOP, signal.SIGCHLD]) -
-    SUSPEND_SIGNALS,
+    SUSPEND_SIGNALS
 )
 
 
@@ -34,7 +37,7 @@ def print_signals(args=()):
         stdout=PIPE,
     )
     line = proc.stdout.readline()
-    m = re.match(b'^ready \\(pid: ([0-9]+)\\)\n$', line)
+    m = re.match(b'^ready \(pid: ([0-9]+)\)\n$', line)
     assert m, line
 
     yield proc, m.group(1).decode('ascii')
@@ -46,25 +49,15 @@ def print_signals(args=()):
 def child_pids(pid):
     """Return a list of direct child PIDs for the given PID."""
     children = set()
-    for p in os.listdir('/proc'):
+    for p in LocalPath('/proc').listdir():
         try:
-            with open(os.path.join('/proc', p, 'stat')) as f:
+            stat = open(p.join('stat').strpath).read()
-                stat = f.read()
+            m = re.match('^\d+ \(.+?\) [a-zA-Z] (\d+) ', stat)
-            m = re.match(
-                r'^\d+ \(.+?\) '
-                # This field, state, is normally a single letter, but can be
-                # "0" if there are some unusual security settings that prevent
-                # reading the process state (happens under GitHub Actions with
-                # QEMU for some reason).
-                '[0a-zA-Z] '
-                r'(\d+) ',
-                stat,
-            )
             assert m, stat
             ppid = int(m.group(1))
             if ppid == pid:
-                children.add(int(p))
+                children.add(int(p.basename))
-        except OSError:
+        except IOError:
             # Happens when the process exits after listing it, or between
             # opening stat and reading it.
             pass
@@ -74,23 +67,22 @@ def child_pids(pid):
 def pid_tree(pid):
     """Return a list of all descendant PIDs for the given PID."""
     children = child_pids(pid)
-    return {
+    return set(
         pid
         for child in children
         for pid in pid_tree(child)
-    } | children
+    ) | children
 
 
 def is_alive(pid):
     """Return whether a process is running with the given PID."""
-    return os.path.isdir(os.path.join('/proc', str(pid)))
+    return LocalPath('/proc').join(str(pid)).isdir()
 
 
 def process_state(pid):
     """Return a process' state, such as "stopped" or "running"."""
-    with open(os.path.join('/proc', str(pid), 'status')) as f:
+    status = LocalPath('/proc').join(str(pid), 'status').read()
-        status = f.read()
+    m = re.search('^State:\s+[A-Z] \(([a-z]+)\)$', status, re.MULTILINE)
-    m = re.search(r'^State:\s+[A-Z] \(([a-z]+)\)$', status, re.MULTILINE)
     return m.group(1)
 
 

testing/print_signals.py

@@ -4,6 +4,8 @@
 Since all signals are printed and otherwise ignored, you'll need to send
 SIGKILL (kill -9) to this process to actually end it.
 """
+from __future__ import print_function
+
 import os
 import signal
 import sys
@@ -11,7 +13,7 @@ import time
 
 
 CATCHABLE_SIGNALS = frozenset(
-    set(range(1, 32)) - {signal.SIGKILL, signal.SIGSTOP, signal.SIGCHLD},
+    set(range(1, 32)) - set([signal.SIGKILL, signal.SIGSTOP, signal.SIGCHLD])
 )
 
 
@@ -20,7 +22,7 @@ last_signal = None
 
 
 def unbuffered_print(line):
-    sys.stdout.write('{}\n'.format(line))
+    sys.stdout.write('{0}\n'.format(line))
     sys.stdout.flush()
 
 
@@ -32,7 +34,7 @@ if __name__ == '__main__':
     for signum in CATCHABLE_SIGNALS:
         signal.signal(signum, print_signal)
 
-    unbuffered_print('ready (pid: {})'.format(os.getpid()))
+    unbuffered_print('ready (pid: {0})'.format(os.getpid()))
 
     # loop forever just printing signals
     while True:

tests/child_processes_test.py

@@ -17,7 +17,7 @@ def spawn_and_kill_pipeline():
     proc = Popen((
         'dumb-init',
         'sh', '-c',
-        "yes 'oh, hi' | tail & yes error | tail >&2",
+        "yes 'oh, hi' | tail & yes error | tail >&2"
     ))
 
     def assert_living_pids():
@@ -32,7 +32,7 @@ def spawn_and_kill_pipeline():
 
 
 def living_pids(pids):
-    return {pid for pid in pids if is_alive(pid)}
+    return set(pid for pid in pids if is_alive(pid))
 
 
 @pytest.mark.usefixtures('both_debug_modes', 'setsid_enabled')
@@ -80,7 +80,7 @@ def spawn_process_which_dies_with_children():
             # we need to sleep before the shell exits, or dumb-init might send
             # TERM to print_signals before it has had time to register custom
             # signal handlers
-            '{python} -m testing.print_signals & sleep 1'.format(
+            '{python} -m testing.print_signals & sleep 0.1'.format(
                 python=sys.executable,
             ),
         ),
@@ -91,7 +91,7 @@ def spawn_process_which_dies_with_children():
 
     # read a line from print_signals, figure out its pid
     line = proc.stdout.readline()
-    match = re.match(b'ready \\(pid: ([0-9]+)\\)\n', line)
+    match = re.match(b'ready \(pid: ([0-9]+)\)\n', line)
     assert match, line
     child_pid = int(match.group(1))
 
@@ -129,14 +129,12 @@ def test_processes_dont_receive_term_on_exit_if_no_setsid():
     os.kill(child_pid, signal.SIGKILL)
 
 
-@pytest.mark.parametrize(
+@pytest.mark.parametrize('args', [
-    'args', [
     ('/doesnotexist',),
     ('--', '/doesnotexist'),
     ('-c', '/doesnotexist'),
     ('--single-child', '--', '/doesnotexist'),
-    ],
+])
-)
 @pytest.mark.usefixtures('both_debug_modes', 'both_setsid_modes')
 def test_fails_nonzero_with_bad_exec(args):
     """If dumb-init can't exec as requested, it should exit nonzero."""

tests/cli_test.py

@@ -12,34 +12,12 @@ def current_version():
     return open('VERSION').read().strip()
 
 
-def normalize_stderr(stderr):
-    # dumb-init prints out argv[0] in its usage message. This should always be
-    # just "dumb-init" under regular test scenarios here since that is how we
-    # call it, but in CI the use of QEMU causes the argv[0] to be replaced with
-    # the full path.
-    #
-    # This is supposed to be avoidable by:
-    #   1) Setting the "P" flag in the binfmt register:
-    #      https://en.wikipedia.org/wiki/Binfmt_misc#Registration
-    #      This can be done by setting the QEMU_PRESERVE_PARENT env var when
-    #      calling binfmt.
-    #
-    #   2) Setting the "QEMU_ARGV0" env var to empty string for *all*
-    #      processes:
-    #      https://bugs.launchpad.net/qemu/+bug/1835839
-    #
-    # I can get it working properly in CI outside of Docker, but for some
-    # reason not during Docker builds. This doesn't affect the built executable
-    # so I decided to just punt on it.
-    return re.sub(rb'(^|(?<=\s))[a-z/.]+/dumb-init', b'dumb-init', stderr)
-
-
 @pytest.mark.usefixtures('both_debug_modes', 'both_setsid_modes')
 def test_no_arguments_prints_usage():
     proc = Popen(('dumb-init'), stderr=PIPE)
     _, stderr = proc.communicate()
     assert proc.returncode != 0
-    assert normalize_stderr(stderr) == (
+    assert stderr == (
         b'Usage: dumb-init [option] program [args]\n'
         b'Try dumb-init --help for full usage.\n'
     )
@@ -50,7 +28,7 @@ def test_exits_invalid_with_invalid_args():
     proc = Popen(('dumb-init', '--yolo', '/bin/true'), stderr=PIPE)
     _, stderr = proc.communicate()
     assert proc.returncode == 1
-    assert normalize_stderr(stderr) in (
+    assert stderr in (
         b"dumb-init: unrecognized option '--yolo'\n",  # glibc
         b'dumb-init: unrecognized option: yolo\n',  # musl
     )
@@ -65,7 +43,7 @@ def test_help_message(flag, current_version):
     proc = Popen(('dumb-init', flag), stderr=PIPE)
     _, stderr = proc.communicate()
     assert proc.returncode == 0
-    assert normalize_stderr(stderr) == (
+    assert stderr == (
         b'dumb-init v' + current_version.encode('ascii') + b'\n'
         b'Usage: dumb-init [option] command [[arg] ...]\n'
         b'\n'
@@ -107,15 +85,15 @@ def test_verbose(flag):
     assert stdout == b'oh, hi\n'
 
     # child/parent race to print output after the fork(), can't guarantee exact order
-    assert re.search(b'(^|\n)\\[dumb-init\\] setsid complete\\.\n', stderr), stderr  # child
+    assert re.search(b'(^|\n)\[dumb-init\] setsid complete\.\n', stderr), stderr  # child
     assert re.search(  # parent
         (
-            '(^|\n)\\[dumb-init\\] Child spawned with PID [0-9]+\\.\n'
+            '(^|\n)\[dumb-init\] Child spawned with PID [0-9]+\.\n'
             '.*'  # child might print here
-            '\\[dumb-init\\] Received signal {signal.SIGCHLD}\\.\n'
+            '\[dumb-init\] Received signal {signal.SIGCHLD}\.\n'
-            '\\[dumb-init\\] A child with PID [0-9]+ exited with exit status 0.\n'
+            '\[dumb-init\] A child with PID [0-9]+ exited with exit status 0.\n'
-            '\\[dumb-init\\] Forwarded signal 15 to children\\.\n'
+            '\[dumb-init\] Forwarded signal 15 to children\.\n'
-            '\\[dumb-init\\] Child exited with status 0\\. Goodbye\\.\n$'
+            '\[dumb-init\] Child exited with status 0\. Goodbye\.\n$'
         ).format(signal=signal).encode('utf8'),
         stderr,
         re.DOTALL,
@@ -132,18 +110,17 @@ def test_verbose_and_single_child(flag1, flag2):
     assert stdout == b'oh, hi\n'
     assert re.match(
         (
-            '^\\[dumb-init\\] Child spawned with PID [0-9]+\\.\n'
+            '^\[dumb-init\] Child spawned with PID [0-9]+\.\n'
-            '\\[dumb-init\\] Received signal {signal.SIGCHLD}\\.\n'
+            '\[dumb-init\] Received signal {signal.SIGCHLD}\.\n'
-            '\\[dumb-init\\] A child with PID [0-9]+ exited with exit status 0.\n'
+            '\[dumb-init\] A child with PID [0-9]+ exited with exit status 0.\n'
-            '\\[dumb-init\\] Forwarded signal 15 to children\\.\n'
+            '\[dumb-init\] Forwarded signal 15 to children\.\n'
-            '\\[dumb-init\\] Child exited with status 0\\. Goodbye\\.\n$'
+            '\[dumb-init\] Child exited with status 0\. Goodbye\.\n$'
         ).format(signal=signal).encode('utf8'),
         stderr,
     )
 
 
-@pytest.mark.parametrize(
+@pytest.mark.parametrize('extra_args', [
-    'extra_args', [
     ('-r',),
     ('-r', ''),
     ('-r', 'herp'),
@@ -154,8 +131,7 @@ def test_verbose_and_single_child(flag1, flag2):
     ('-r', '15:12', '-r'),
     ('-r', '15:12', '-r', '0'),
     ('-r', '15:12', '-r', '1:32'),
-    ],
+])
-)
 @pytest.mark.usefixtures('both_debug_modes', 'both_setsid_modes')
 def test_rewrite_errors(extra_args):
     proc = Popen(

tests/conftest.py

@@ -1,6 +1,6 @@
 import os
-from unittest import mock
 
+import mock
 import pytest
 
 

tests/cwd_test.py

@@ -1,28 +0,0 @@
-import os
-import shutil
-from subprocess import PIPE
-from subprocess import run
-
-import pytest
-
-
-@pytest.mark.usefixtures('both_debug_modes', 'both_setsid_modes')
-def test_working_directories():
-    """The child process must start in the working directory in which
-    dumb-init was invoked, but dumb-init itself should not keep a
-    reference to that."""
-
-    # We need absolute path to dumb-init since we pass cwd=/tmp to get
-    # predictable output - so we can't rely on dumb-init being found
-    # in the "." directory.
-    dumb_init = os.path.realpath(shutil.which('dumb-init'))
-    proc = run(
-        (
-            dumb_init,
-            'sh', '-c', 'readlink /proc/$PPID/cwd && readlink /proc/$$/cwd',
-        ),
-        cwd='/tmp', stdout=PIPE, stderr=PIPE,
-    )
-
-    assert proc.returncode == 0
-    assert proc.stdout == b'/\n/tmp\n'

tests/exit_status_test.py

@@ -11,19 +11,17 @@ def test_exit_status_regular_exit(exit_status):
     """dumb-init should exit with the same exit status as the process that it
     supervises when that process exits normally.
     """
-    proc = Popen(('dumb-init', 'sh', '-c', 'exit {}'.format(exit_status)))
+    proc = Popen(('dumb-init', 'sh', '-c', 'exit {0}'.format(exit_status)))
     proc.wait()
     assert proc.returncode == exit_status
 
 
-@pytest.mark.parametrize(
+@pytest.mark.parametrize('signal', [
-    'signal', [
     signal.SIGTERM,
     signal.SIGHUP,
     signal.SIGQUIT,
     signal.SIGKILL,
-    ],
+])
-)
 @pytest.mark.usefixtures('both_debug_modes', 'both_setsid_modes')
 def test_exit_status_terminated_by_signal(signal):
     """dumb-init should exit with status 128 + signal when the child process is
@@ -31,10 +29,8 @@ def test_exit_status_terminated_by_signal(signal):
     """
     # We use Python because sh is "dash" on Debian and "bash" on others.
     # https://github.com/Yelp/dumb-init/issues/115
-    proc = Popen((
+    proc = Popen(('dumb-init', sys.executable, '-c', 'import os; os.kill(os.getpid(), {0})'.format(
-        'dumb-init', sys.executable, '-c', 'import os; os.kill(os.getpid(), {})'.format(
         signal,
-        ),
+    )))
-    ))
     proc.wait()
     assert proc.returncode == 128 + signal

tests/proxies_signals_test.py

@@ -15,17 +15,16 @@ def test_proxies_signals():
     with print_signals() as (proc, _):
         for signum in NORMAL_SIGNALS:
             proc.send_signal(signum)
-            assert proc.stdout.readline() == '{}\n'.format(signum).encode('ascii')
+            assert proc.stdout.readline() == '{0}\n'.format(signum).encode('ascii')
 
 
 def _rewrite_map_to_args(rewrite_map):
     return chain.from_iterable(
-        ('-r', '{}:{}'.format(src, dst)) for src, dst in rewrite_map.items()
+        ('-r', '{0}:{1}'.format(src, dst)) for src, dst in rewrite_map.items()
     )
 
 
-@pytest.mark.parametrize(
+@pytest.mark.parametrize('rewrite_map,sequence,expected', [
-    'rewrite_map,sequence,expected', [
     (
         {},
         [signal.SIGTERM, signal.SIGQUIT, signal.SIGCONT, signal.SIGINT],
@@ -54,15 +53,14 @@ def _rewrite_map_to_args(rewrite_map):
         [1, 31],
         [31, 1],
     ),
-    ],
+])
-)
 @pytest.mark.usefixtures('both_debug_modes', 'both_setsid_modes')
 def test_proxies_signals_with_rewrite(rewrite_map, sequence, expected):
     """Ensure dumb-init can rewrite signals."""
     with print_signals(_rewrite_map_to_args(rewrite_map)) as (proc, _):
         for send, expect_receive in zip(sequence, expected):
             proc.send_signal(send)
-            assert proc.stdout.readline() == '{}\n'.format(expect_receive).encode('ascii')
+            assert proc.stdout.readline() == '{0}\n'.format(expect_receive).encode('ascii')
 
 
 @pytest.mark.usefixtures('both_debug_modes', 'setsid_enabled')
@@ -80,12 +78,12 @@ def test_default_rewrites_can_be_overriden_with_setsid_enabled():
             assert process_state(proc.pid) in ['running', 'sleeping']
             proc.send_signal(send)
 
-            assert proc.stdout.readline() == '{}\n'.format(expect_receive).encode('ascii')
+            assert proc.stdout.readline() == '{0}\n'.format(expect_receive).encode('ascii')
             os.waitpid(proc.pid, os.WUNTRACED)
             assert process_state(proc.pid) == 'stopped'
 
             proc.send_signal(signal.SIGCONT)
-            assert proc.stdout.readline() == '{}\n'.format(signal.SIGCONT).encode('ascii')
+            assert proc.stdout.readline() == '{0}\n'.format(signal.SIGCONT).encode('ascii')
             assert process_state(proc.pid) in ['running', 'sleeping']
 
 
@@ -100,8 +98,8 @@ def test_ignored_signals_are_not_proxied():
     with print_signals(_rewrite_map_to_args(rewrite_map)) as (proc, _):
         proc.send_signal(signal.SIGTERM)
         proc.send_signal(signal.SIGINT)
-        assert proc.stdout.readline() == '{}\n'.format(signal.SIGQUIT).encode('ascii')
+        assert proc.stdout.readline() == '{0}\n'.format(signal.SIGQUIT).encode('ascii')
 
         proc.send_signal(signal.SIGWINCH)
         proc.send_signal(signal.SIGHUP)
-        assert proc.stdout.readline() == '{}\n'.format(signal.SIGHUP).encode('ascii')
+        assert proc.stdout.readline() == '{0}\n'.format(signal.SIGHUP).encode('ascii')

tests/shell_background_test.py

@@ -31,7 +31,7 @@ def test_shell_background_support_setsid():
             # and then both wake up again
             proc.send_signal(SIGCONT)
             assert (
-                proc.stdout.readline() == '{}\n'.format(SIGCONT).encode('ascii')
+                proc.stdout.readline() == '{0}\n'.format(SIGCONT).encode('ascii')
             )
             assert process_state(pid) in ['running', 'sleeping']
             assert process_state(proc.pid) in ['running', 'sleeping']
@@ -46,12 +46,12 @@ def test_shell_background_support_without_setsid():
         for signum in SUSPEND_SIGNALS:
             assert process_state(proc.pid) in ['running', 'sleeping']
             proc.send_signal(signum)
-            assert proc.stdout.readline() == '{}\n'.format(signum).encode('ascii')
+            assert proc.stdout.readline() == '{0}\n'.format(signum).encode('ascii')
             os.waitpid(proc.pid, os.WUNTRACED)
             assert process_state(proc.pid) == 'stopped'
 
             proc.send_signal(SIGCONT)
             assert (
-                proc.stdout.readline() == '{}\n'.format(SIGCONT).encode('ascii')
+                proc.stdout.readline() == '{0}\n'.format(SIGCONT).encode('ascii')
             )
             assert process_state(proc.pid) in ['running', 'sleeping']

tests/tty_test.py

@@ -77,7 +77,7 @@ def test_child_gets_controlling_tty_if_we_had_one():
         output = readall(sfd)
         assert os.waitpid(pid, 0) == (pid, 0), output
 
-        m = re.search(b'flags are: \\[\\[([a-zA-Z]+)\\]\\]\n', output)
+        m = re.search(b'flags are: \[\[([a-zA-Z]+)\]\]\n', output)
         assert m, output
 
         # "m" is job control
@@ -111,8 +111,8 @@ def test_sighup_sigcont_ignored_if_was_session_leader():
 
         output = readall(fd).decode('UTF-8')
 
-        assert 'Ignoring tty hand-off signal {}.'.format(signal.SIGHUP) in output
+        assert 'Ignoring signal {} during its first receive.'.format(signal.SIGHUP) in output
-        assert 'Ignoring tty hand-off signal {}.'.format(signal.SIGCONT) in output
+        assert 'Ignoring signal {} during its first receive.'.format(signal.SIGCONT) in output
 
         assert '[dumb-init] Forwarded signal {} to children.'.format(signal.SIGHUP) in output
         assert '[dumb-init] Forwarded signal {} to children.'.format(signal.SIGCONT) not in output

tox.ini

@@ -1,21 +1,20 @@
 [tox]
-envlist = py38,gcov
+envlist = py27,py36,gcov
 
 [testenv]
 deps = -r{toxinidir}/requirements-dev.txt
 commands =
-    pytest
+    python -m pytest
 
 [testenv:gcov]
 skip_install = True
-basepython = /usr/bin/python3.8
 commands =
     {toxinidir}/ci/gcov-build {envbindir}
     {[testenv]commands}
     {toxinidir}/ci/gcov-report
 
 [testenv:pre-commit]
-basepython = /usr/bin/python3.8
+basepython = /usr/bin/python3.6
 commands = pre-commit {posargs:run --all-files}
 
 [flake8]