Merge pull request #1 from peterbourgon/zombietest

Zombie test

.gitignore

@@ -1,6 +1,9 @@
 runsvinit
 runsvinit-*-*
 examples/runsvinit-linux-amd64*
+zombietest/zombie
+zombietest/runsvinit
+*.uptodate
 
 # Compiled Object files, Static and Dynamic libs (Shared Objects)
 *.o

circle.yml

@@ -0,0 +1,8 @@
+machine:
+  services:
+    - docker
+
+test:
+  override:
+    - go test -v
+    - make CIRCLECI=true SUDO=sudo RM= -C zombietest

main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"flag"
 	"log"
 	"os"
 	"os/exec"
@@ -13,6 +14,9 @@ import (
 const etcService = "/etc/service"
 
 func main() {
+	reap := flag.Bool("reap", true, "reap orphan children")
+	flag.Parse()
+
 	log.SetFlags(0)
 
 	runsvdir, err := exec.LookPath("runsvdir")
@@ -35,7 +39,12 @@ func main() {
 		log.Printf("warning: I'm not PID 1, I'm PID %d", pid)
 	}
 
-	go reapAll()
+	if *reap {
+		log.Print("reaping zombies")
+		go reapLoop()
+	} else {
+		log.Print("NOT reaping zombies")
+	}
 
 	supervisor := cmd(runsvdir, etcService)
 	if err := supervisor.Start(); err != nil {
@@ -53,31 +62,33 @@ func main() {
 	}
 }
 
-func reapAll() {
+// From https://github.com/ramr/go-reaper/blob/master/reaper.go
+func reapLoop() {
 	c := make(chan os.Signal)
 	signal.Notify(c, syscall.SIGCHLD)
 	for range c {
-		go reapOne()
+		reapChildren()
 	}
 }
 
-// From https://github.com/ramr/go-reaper/blob/master/reaper.go
-func reapOne() {
-	var (
-		ws  syscall.WaitStatus
-		pid int
-		err error
-	)
+func reapChildren() {
 	for {
-		pid, err = syscall.Wait4(-1, &ws, 0, nil)
-		if err != syscall.EINTR {
-			break
+		var (
+			ws  syscall.WaitStatus
+			pid int
+			err error
+		)
+		for {
+			pid, err = syscall.Wait4(-1, &ws, 0, nil)
+			if err != syscall.EINTR {
+				break
+			}
 		}
+		if err == syscall.ECHILD {
+			return // done
+		}
+		log.Printf("reaped child process %d (%+v)", pid, ws)
 	}
-	if err == syscall.ECHILD {
-		return
-	}
-	log.Printf("reaped child process %d (%+v)", pid, ws)
 }
 
 type signaler interface {

zombietest/Dockerfile

@@ -0,0 +1,11 @@
+FROM alpine:latest
+RUN echo "http://dl-4.alpinelinux.org/alpine/edge/testing" >>/etc/apk/repositories && \
+    apk add --update runit && \
+    rm -rf /var/cache/apk/*
+
+COPY zombie /
+RUN mkdir -p /etc/service/zombie
+COPY run-zombie /etc/service/zombie/run
+
+COPY /runsvinit /
+

zombietest/Makefile

@@ -0,0 +1,27 @@
+GO?=go
+SUDO?=
+RM?=--rm
+
+.PHONY: test clean
+
+test: .test.uptodate
+	./test.bash
+
+.test.uptodate: runsvinit zombie run-zombie Dockerfile
+	$(SUDO) docker build -t zombietest .
+	touch $@
+
+runsvinit: ../*.go
+	env GOOS=linux GOARCH=amd64 $(GO) build -o $@ github.com/peterbourgon/runsvinit
+
+zombie: .build.uptodate
+	$(SUDO) docker run $(RM) -v $(shell pwd):/mount zombietest-build cc -Wall -Werror -o /mount/zombie /zombie.c
+
+.build.uptodate: build/zombie.c build/Dockerfile
+	$(SUDO) docker build -t zombietest-build build/
+	touch $@
+
+clean:
+	rm -rf .test.uptodate .build.uptodate runsvinit zombie
+	$(SUDO) docker stop zombietest zombietest-build >/dev/null 2>&1 || true
+	$(SUDO) docker rm zombietest zombietest-build >/dev/null 2>&1 || true

zombietest/README.md

@@ -0,0 +1,24 @@
+# zombietest
+
+This directory contains an integration test to prove runsvinit is actually
+reaping zombies. `make` builds and executes the test as follows:
+
+1. We produce a linux/amd64 runsvinit binary by setting GOOS/GOARCH and
+   invoking the Go compiler. Requires Go 1.5, or Go 1.4 built with the
+   appropriate cross-compile options.
+
+2. The build/zombie.c program spawns five zombies and exits. We compile it for
+   linux/amd64 via a zombietest-build container. We do this so `make` works
+   from a Mac. This requires a working Docker installation.
+
+3. Once we have linux/amd64 runsvinit and zombie binaries, we produce a
+   zombietest container via the Dockerfile. That container contains a single
+   runit service, /etc/service/zombie, which supervises the zombie binary. We
+   provide no default ENTRYPOINT, so we can supply it at runtime.
+
+4. Once the zombietest container is built, we invoke the test.bash script.
+   That launches a version of the container with runsvinit set to NOT reap
+   zombies, and after 1 second, verifies that zombies exist. Then, it launches
+   a version of the container with runsvinit set to reap zombies, and after 1
+   second, verifies that no zombies exist.
+

zombietest/build/Dockerfile

@@ -0,0 +1,3 @@
+FROM alpine:latest
+RUN apk add --update gcc musl-dev && rm -rf /var/cache/apk/*
+COPY zombie.c /

zombietest/build/zombie.c

@@ -0,0 +1,18 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+
+int main() {
+        pid_t pid;
+        int i; 
+        for (i = 0; i<5; i++)  {  
+                pid = fork();
+                if (pid > 0) {
+                        printf("Zombie #%d born\n", i + 1);
+                } else {
+                        printf("Brains...\n");
+                        exit(0);
+                }  
+        }  
+        return 0; 
+}

zombietest/run-zombie

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+exec /zombie

zombietest/test.bash

@@ -0,0 +1,47 @@
+#!/bin/bash
+
+function zombies() {
+	if [ -z "$CIRCLECI" ]
+	then
+		docker exec $C ps -o pid,stat | grep Z | wc -l
+	else
+		# https://circleci.com/docs/docker#docker-exec
+		sudo lxc-attach -n "$(docker inspect --format '{{.Id}}' $C)" -- sh -c "ps -o pid,stat | grep Z | wc -l"
+	fi
+}
+
+function stop_rm() {
+	docker stop $1
+	docker rm $1
+}
+
+SLEEP=1
+RC=0
+
+C=$(docker run -d zombietest /runsvinit -reap=false)
+sleep $SLEEP
+NOREAP=$(zombies)
+echo -n without reaping, we have $NOREAP zombies...
+if [ "$NOREAP" -le "0" ]
+then
+	echo " FAIL"
+	RC=1
+else
+	echo " good"
+fi
+stop_rm $C
+
+C=$(docker run -d zombietest /runsvinit)
+sleep $SLEEP
+YESREAP=$(zombies)
+echo -n with reaping, we have $YESREAP zombies...
+if [ "$YESREAP" -gt "0" ]
+then
+	echo " FAIL"
+	RC=1
+else
+	echo " good"
+fi
+stop_rm $C
+
+exit $RC