Workaround for udev reader race condition (and panic)

If we try to close udev reader while an event is read it causes a panic in
bufio. Workaround this problem by using CloseOnExec for the udev reader
file descriptor. The descriptor is closed much later, at exec()
when goroutines are stopped. So no race would happen.

Closes #22 (hopefully)

Author: anatol

Diff for: init/go.mod

@@ -16,3 +16,6 @@ require (
 	golang.org/x/term v0.0.0-20201210144234-2321bbc49cbf // indirect
 	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b
 )
+
+// workaround for https://github.com/anatol/booster/issues/22
+replace github.com/s-urbaniak/uevent => github.com/stapelberg/uevent v1.0.1-0.20200422145418-40d619f351bf

Diff for: init/go.sum

@@ -145,8 +145,6 @@ github.com/prometheus/tsdb v0.7.1/go.mod h1:qhTCs0VvXwvX/y3TZrWD7rabWM+ijKTux40T
 github.com/rogpeppe/fastuuid v0.0.0-20150106093220-6724a57986af/go.mod h1:XWv6SoW27p1b0cqNHllgS5HIMJraePCO15w5zCzIWYg=
 github.com/russross/blackfriday v1.5.2/go.mod h1:JO/DiYxRf+HjHt06OyowR9PTA263kcR/rfWxYHBV53g=
 github.com/russross/blackfriday/v2 v2.0.1/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
-github.com/s-urbaniak/uevent v1.0.0 h1:y1e40TmDfCU0l1o/MBpimGJgo2UzTTqBl/0GF6vx/io=
-github.com/s-urbaniak/uevent v1.0.0/go.mod h1:h83SVc1NQj/EubPaK4hWyiG217xLYr+fS+Jf10COrG0=
 github.com/shurcooL/sanitized_anchor_name v1.0.0/go.mod h1:1NzhyTcUVG4SuEtjjoZeVRXNmyL/1OwPU0+IJeTBvfc=
 github.com/sirupsen/logrus v1.2.0/go.mod h1:LxeOpSwHxABJmUn/MG1IvRgCAasNZTLOkJPxbbu5VWo=
 github.com/smartystreets/assertions v0.0.0-20180927180507-b2de0cb4f26d/go.mod h1:OnSkiWE9lh6wB0YB77sQom3nweQdgAjqCqsofrRNTgc=
@@ -161,6 +159,8 @@ github.com/spf13/jwalterweatherman v1.0.0/go.mod h1:cQK4TGJAtQXfYWX+Ddv3mKDzgVb6
 github.com/spf13/pflag v1.0.3/go.mod h1:DYY7MBk1bdzusC3SYhjObp+wFpr4gzcvqqNjLnInEg4=
 github.com/spf13/viper v1.3.2/go.mod h1:ZiWeW+zYFKm7srdB9IoDzzZXaJaI5eL9QjNiN/DMA2s=
 github.com/spf13/viper v1.4.0/go.mod h1:PTJ7Z/lr49W6bUbkmS1V3by4uWynFiR9p7+dSq/yZzE=
+github.com/stapelberg/uevent v1.0.1-0.20200422145418-40d619f351bf h1:Sj5ZN92aCALFDJhK/CT+VftmtSXAM27uBg6H+g7R9Hw=
+github.com/stapelberg/uevent v1.0.1-0.20200422145418-40d619f351bf/go.mod h1:txmMh4YRKuLIG6J2EBeGcACqbKUl5ZUYYOtguW4TqbM=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=

Diff for: init/main.go

@@ -429,8 +429,8 @@ func switchRoot() error {
 // Cleanup the state before handing off the machine to the new init
 func cleanup() {
 	// We need to close our uevent connection, otherwise it will stay open forever and mess with the new init. .
-	// See https://github.com/s-urbaniak/uevent/pull/1
-	_ = udevReader.Close()
+	// See https://github.com/s-urbaniak/uevent/pull/1 and https://github.com/anatol/booster/issues/22
+	// _ = udevReader.Close()
 
 	shutdownNetwork()
 }