Add support to Unix Domain Sockets

There was already some degree of support, but as seen in this blog
post a few more changes were required:

https://samadhiweb.com/blog/2013.07.27.unixdomainsockets.html

fixes pharo-project#4046

src/Network-Kernel/NetNameResolver.class.st

@@ -58,6 +58,25 @@ NetNameResolver class >> addressForName: hostName timeout: secs [
 	^ result asSocketAddress
 ]
 
+{ #category : 'lookups' }
+NetNameResolver class >> addressForUnixDomain: path [
+	"Create a socket address that can be used on Socket newIPC connectTo:"
+
+	| deadline size result |
+	deadline := Time millisecondClockValue -> (60 * 1000).
+	result := nil.
+
+	self resolverMutex critical: [
+		(self waitForResolverReadyUntil: deadline)
+		ifTrue: [
+			self primGetAddressInfoHost: '' service: path flags: 0 family: 1 type: 0 protocol: 0.
+			size := self primGetAddressInfoSize.
+			result := ByteArray new: size withAll: 0.
+			self primGetAddressInfoResult: result.
+			^ result ]
+		ifFalse: [ ^ NameLookupFailure signalFor: path ] ]
+]
+
 { #category : 'address string utils' }
 NetNameResolver class >> addressFromIPv6String: aString [
 	"Return a ByteArray corresponding to an IPv6 address in text format"
@@ -575,11 +594,18 @@ NetNameResolver class >> stringFromAddress: addr [
 	"Return a string representing the given host address as four decimal bytes delimited with decimal points."
 	"NetNameResolver stringFromAddress: NetNameResolver localHostAddress"
 
-	| s |
+	| s size  |
 	(addr isKindOf: SocketAddress) ifTrue: [^addr printString copyUpTo: $( ].
+
+	"If size is AddressHeaderSize + sizeof (struct sockaddr_un), it's likely IPC"
+	size := addr size.
+	(size = 118) ifTrue: [ | limit |
+		limit := addr indexOf: 0 startingAt: 11 ifAbsent: size + 1.
+		^ (addr copyFrom: 11 to: limit - 1) asString ].
+
 	"If the incoming addr is a size 16 ByteArray, we assume it is
 	representing an IPv6 address."
-	(addr size = 16) ifTrue: [ ^ self stringFromIPv6Address: addr ].
+	(size = 16) ifTrue: [ ^ self stringFromIPv6Address: addr ].
 
 	"Otherwise write out in IPv4 format"
 	s := WriteStream on: ''.

src/Network-Kernel/Socket.class.st

@@ -15,13 +15,17 @@ Class {
 	#classVars : [
 		'Connected',
 		'DeadServer',
+		'IPv4SocketDomain',
+		'IPv6SocketDomain',
 		'InvalidSocket',
 		'OtherEndClosed',
 		'Registry',
 		'TCPSocketType',
 		'ThisEndClosed',
 		'UDPSocketType',
 		'Unconnected',
+		'UnixSocketDomain',
+		'UnspecSocketDomain',
 		'WaitingForConnection'
 	],
 	#category : 'Network-Kernel-Base',
@@ -62,6 +66,12 @@ Socket class >> initialize [
 	"Socket Types"
 	TCPSocketType := 0.
 	UDPSocketType := 1.
+
+	"Socket Domains"
+	UnspecSocketDomain := 0.
+	UnixSocketDomain := 1.
+	IPv4SocketDomain := 2.
+	IPv6SocketDomain := 10.
 
 	"Socket Status Values"
 	InvalidSocket := -1.
@@ -172,6 +182,15 @@ Socket class >> newAcceptCheck [
 	socket destroy
 ]
 
+{ #category : 'instance creation' }
+Socket class >> newIPC [
+	"Create a Unix Domain Socket and initialize it for interprocess communication"
+
+	self initializeNetwork.
+	^ [ super new initialize: TCPSocketType withDomain: UnixSocketDomain ]
+		  repeatWithGCIf: [ :socket | socket isValid not ]
+]
+
 { #category : 'instance creation' }
 Socket class >> newTCP [
 	"Create a socket and initialize it for TCP"
@@ -476,6 +495,19 @@ Socket >> closeAndDestroy: timeoutSeconds [
 			self destroy]
 ]
 
+{ #category : 'connection open/close' }
+Socket >> connectNonBlockingTo: hostAddress [
+	"Initiate a connection to the given port at the given host address. This operation will return immediately; follow it with waitForConnectionUntil: to wait until the connection is established."
+
+	| status |
+	self initializeNetwork.
+	status := self primSocketConnectionStatus: socketHandle.
+	(status == Unconnected)
+		ifFalse: [InvalidSocketStatusException signal: 'Socket status must Unconnected before opening a new connection'].
+
+	self primSocket: socketHandle connectTo: hostAddress
+]
+
 { #category : 'connection open/close' }
 Socket >> connectNonBlockingTo: hostAddress port: port [
 	"Initiate a connection to the given port at the given host address. This operation will return immediately; follow it with waitForConnectionUntil: to wait until the connection is established."
@@ -489,6 +521,13 @@ Socket >> connectNonBlockingTo: hostAddress port: port [
 	self primSocket: socketHandle connectTo: hostAddress port: port
 ]
 
+{ #category : 'public - line' }
+Socket >> connectTo: socketAddress [
+	"Connect method that can be used with Unix Domain Sockets."
+
+	self connectTo: socketAddress waitForConnectionFor: self class standardTimeout
+]
+
 { #category : 'connection open/close' }
 Socket >> connectTo: hostAddress port: port [
 	"Initiate a connection to the given port at the given host address.
@@ -508,6 +547,17 @@ Socket >> connectTo: hostAddress port: port waitForConnectionFor: timeout [
 					, (NetNameResolver stringFromAddress: hostAddress) , ':' , port asString]
 ]
 
+{ #category : 'connection open/close' }
+Socket >> connectTo: socketAddress waitForConnectionFor: timeout [
+	"Initiate a connection to the given socket address
+	Waits until the connection is established or time outs."
+
+	self connectNonBlockingTo: socketAddress.
+	self waitForConnectionFor: timeout ifTimedOut: [
+		ConnectionTimedOut signal: 'Cannot connect to ' ,
+			(NetNameResolver stringFromAddress: socketAddress) ]
+]
+
 { #category : 'connection open/close' }
 Socket >> connectToHostNamed: hostName port: portNumber [
 	| serverIP |
@@ -620,6 +670,11 @@ foo waitForConnectionUntil: (Socket standardDeadline).
 
 { #category : 'initialization' }
 Socket >> initialize: socketType [
+	self initialize: socketType withDomain: UnspecSocketDomain.
+]
+
+{ #category : 'initialization' }
+Socket >> initialize: socketType withDomain: socketDomain [
 	"Initialize a new socket handle. If socket creation fails, socketHandle will be set to nil."
 
 	| semaIndex readSemaIndex writeSemaIndex |
@@ -631,7 +686,7 @@ Socket >> initialize: socketType [
 	readSemaIndex := Smalltalk registerExternalObject: readSemaphore.
 	writeSemaIndex := Smalltalk registerExternalObject: writeSemaphore.
 	socketHandle := self
-		primSocketCreateNetwork: 0
+		primSocketCreateNetwork: socketDomain
 		type: socketType
 		receiveBufferSize: 8000
 		sendBufSize: 8000