Add support for `sockaddr_un` on Windows. (#6513)

* Windows: Fix warning about undefined if_indextoname()

* Windows: Fix UNIXSocket on MINGW and make .pair more reliable

* Windows: Use nonblock=true for read tests with scheduler

* Windows: Move socket detection from File.socket? to File.stat

Add S_IFSOCK to Windows and interpret reparse points accordingly.
Enable tests that work now.

* Windows: Use wide-char functions to UNIXSocket

This fixes behaviour with non-ASCII characters.
It also fixes deletion of temporary UNIXSocket.pair files.

* Windows: Add UNIXSocket tests for specifics of Windows impl.

* Windows: fix VC build due to missing _snwprintf

Avoid usage of _snwprintf, since it fails linking ruby.dll like so:

  linking shared-library x64-vcruntime140-ruby320.dll
  x64-vcruntime140-ruby320.def : error LNK2001: unresolved external symbol snwprintf
  x64-vcruntime140-ruby320.def : error LNK2001: unresolved external symbol vsnwprintf_l

whereas linking miniruby.exe succeeds.

This patch uses snprintf on the UTF-8 string instead.

Also remove branch GetWindowsDirectoryW, since it doesn't work.

* Windows: Fix dangling symlink test failures

Co-authored-by: Lars Kanis <kanis@comcard.de>

9 files changed, 39 insertions, 26 deletions

diff --git a/ext/socket/extconf.rb b/ext/socket/extconf.rb
index 8998bb5c2f..73bbc8e687 100644
--- a/ext/socket/extconf.rb
+++ b/ext/socket/extconf.rb
@@ -316,6 +316,7 @@ end
   netpacket/packet.h
   net/ethernet.h
   sys/un.h
+  afunix.h
   ifaddrs.h
   sys/ioctl.h
   sys/sockio.h
diff --git a/ext/socket/init.c b/ext/socket/init.c
index ac28f5c329..557d4374a5 100644
--- a/ext/socket/init.c
+++ b/ext/socket/init.c
@@ -209,7 +209,7 @@ rsock_s_recvfrom(VALUE socket, int argc, VALUE *argv, enum sock_recv_type from)
         else
             return rb_assoc_new(str, Qnil);
 
-#ifdef HAVE_SYS_UN_H
+#ifdef HAVE_TYPE_STRUCT_SOCKADDR_UN
       case RECV_UNIX:
         return rb_assoc_new(str, rsock_unixaddr(&arg.buf.un, arg.alen));
 #endif
diff --git a/ext/socket/lib/socket.rb b/ext/socket/lib/socket.rb
index d756a32a5a..c96e48e8f0 100644
--- a/ext/socket/lib/socket.rb
+++ b/ext/socket/lib/socket.rb
@@ -197,7 +197,7 @@ class Addrinfo
     sock = Socket.new(self.pfamily, self.socktype, self.protocol)
     begin
       sock.ipv6only! if self.ipv6?
-      sock.setsockopt(:SOCKET, :REUSEADDR, 1)
+      sock.setsockopt(:SOCKET, :REUSEADDR, 1) unless self.pfamily == Socket::PF_UNIX
       sock.bind(self)
       sock.listen(backlog)
     rescue Exception
diff --git a/ext/socket/option.c b/ext/socket/option.c
index 2dbe6379c4..0d818d0c70 100644
--- a/ext/socket/option.c
+++ b/ext/socket/option.c
@@ -670,10 +670,10 @@ rb_if_indextoname(const char *succ_prefix, const char *fail_prefix, unsigned int
 {
 #if defined(HAVE_IF_INDEXTONAME)
     char ifbuf[IFNAMSIZ];
-    if (if_indextoname(ifindex, ifbuf) == NULL)
-        return snprintf(buf, len, "%s%u", fail_prefix, ifindex);
-    else
+    if (if_indextoname(ifindex, ifbuf))
         return snprintf(buf, len, "%s%s", succ_prefix, ifbuf);
+    else
+        return snprintf(buf, len, "%s%u", fail_prefix, ifindex);
 #else
 #   ifndef IFNAMSIZ
 #       define IFNAMSIZ (sizeof(unsigned int)*3+1)
@@ -1229,7 +1229,7 @@ sockopt_inspect(VALUE self)
         else
             rb_str_catf(ret, " optname:%d", optname);
     }
-#ifdef HAVE_SYS_UN_H
+#ifdef HAVE_TYPE_STRUCT_SOCKADDR_UN
     else if (family == AF_UNIX) {
         rb_str_catf(ret, " level:%d", level);
 
@@ -1393,7 +1393,7 @@ sockopt_inspect(VALUE self)
         }
         break;
 
-#ifdef HAVE_SYS_UN_H
+#ifdef HAVE_TYPE_STRUCT_SOCKADDR_UN
       case AF_UNIX:
         switch (level) {
           case 0:
diff --git a/ext/socket/raddrinfo.c b/ext/socket/raddrinfo.c
index 636d1edda3..269edc4dad 100644
--- a/ext/socket/raddrinfo.c
+++ b/ext/socket/raddrinfo.c
@@ -644,7 +644,7 @@ rsock_ipaddr(struct sockaddr *sockaddr, socklen_t sockaddrlen, int norevlookup)
     return ary;
 }
 
-#ifdef HAVE_SYS_UN_H
+#ifdef HAVE_TYPE_STRUCT_SOCKADDR_UN
 static long
 unixsocket_len(const struct sockaddr_un *su, socklen_t socklen)
 {
@@ -1017,7 +1017,7 @@ addrinfo_list_new(VALUE node, VALUE service, VALUE family, VALUE socktype, VALUE
 }
 
 
-#ifdef HAVE_SYS_UN_H
+#ifdef HAVE_TYPE_STRUCT_SOCKADDR_UN
 static void
 init_unix_addrinfo(rb_addrinfo_t *rai, VALUE path, int socktype)
 {
@@ -1146,7 +1146,7 @@ addrinfo_initialize(int argc, VALUE *argv, VALUE self)
             break;
           }
 
-#ifdef HAVE_SYS_UN_H
+#ifdef HAVE_TYPE_STRUCT_SOCKADDR_UN
           case AF_UNIX: /* ["AF_UNIX", "/tmp/sock"] */
           {
             VALUE path = rb_ary_entry(sockaddr_ary, 1);
@@ -1286,7 +1286,7 @@ rsock_inspect_sockaddr(struct sockaddr *sockaddr_arg, socklen_t socklen, VALUE r
           }
 #endif
 
-#ifdef HAVE_SYS_UN_H
+#ifdef HAVE_TYPE_STRUCT_SOCKADDR_UN
           case AF_UNIX:
           {
             struct sockaddr_un *addr = &sockaddr->un;
@@ -1622,7 +1622,7 @@ addrinfo_mdump(VALUE self)
     afamily = rb_id2str(id);
 
     switch(afamily_int) {
-#ifdef HAVE_SYS_UN_H
+#ifdef HAVE_TYPE_STRUCT_SOCKADDR_UN
       case AF_UNIX:
       {
         sockaddr = rb_str_new(rai->addr.un.sun_path, rai_unixsocket_len(rai));
@@ -1715,7 +1715,7 @@ addrinfo_mload(VALUE self, VALUE ary)
 
     v = rb_ary_entry(ary, 1);
     switch(afamily) {
-#ifdef HAVE_SYS_UN_H
+#ifdef HAVE_TYPE_STRUCT_SOCKADDR_UN
       case AF_UNIX:
       {
         struct sockaddr_un uaddr;
@@ -2343,7 +2343,7 @@ addrinfo_ipv6_to_ipv4(VALUE self)
 
 #endif
 
-#ifdef HAVE_SYS_UN_H
+#ifdef HAVE_TYPE_STRUCT_SOCKADDR_UN
 /*
  * call-seq:
  *   addrinfo.unix_path => path
@@ -2491,7 +2491,7 @@ addrinfo_s_udp(VALUE self, VALUE host, VALUE port)
             INT2NUM(PF_UNSPEC), INT2NUM(SOCK_DGRAM), INT2NUM(IPPROTO_UDP), INT2FIX(0));
 }
 
-#ifdef HAVE_SYS_UN_H
+#ifdef HAVE_TYPE_STRUCT_SOCKADDR_UN
 
 /*
  * call-seq:
@@ -2629,7 +2629,7 @@ rsock_init_addrinfo(void)
     rb_define_singleton_method(rb_cAddrinfo, "ip", addrinfo_s_ip, 1);
     rb_define_singleton_method(rb_cAddrinfo, "tcp", addrinfo_s_tcp, 2);
     rb_define_singleton_method(rb_cAddrinfo, "udp", addrinfo_s_udp, 2);
-#ifdef HAVE_SYS_UN_H
+#ifdef HAVE_TYPE_STRUCT_SOCKADDR_UN
     rb_define_singleton_method(rb_cAddrinfo, "unix", addrinfo_s_unix, -1);
 #endif
 
@@ -2670,7 +2670,7 @@ rsock_init_addrinfo(void)
     rb_define_method(rb_cAddrinfo, "ipv6_to_ipv4", addrinfo_ipv6_to_ipv4, 0);
 #endif
 
-#ifdef HAVE_SYS_UN_H
+#ifdef HAVE_TYPE_STRUCT_SOCKADDR_UN
     rb_define_method(rb_cAddrinfo, "unix_path", addrinfo_unix_path, 0);
 #endif
 
diff --git a/ext/socket/rubysocket.h b/ext/socket/rubysocket.h
index 9ec893ee8c..5f803ba0da 100644
--- a/ext/socket/rubysocket.h
+++ b/ext/socket/rubysocket.h
@@ -33,6 +33,9 @@
 #endif
 
 #ifdef _WIN32
+#  include <winsock2.h>
+#  include <ws2tcpip.h>
+#  include <iphlpapi.h>
 #  if defined(_MSC_VER)
 #    undef HAVE_TYPE_STRUCT_SOCKADDR_DL
 #  endif
@@ -69,6 +72,11 @@
 #  include <sys/un.h>
 #endif
 
+#ifdef HAVE_AFUNIX_H
+// Windows doesn't have sys/un.h, but it does have afunix.h just to be special:
+#  include <afunix.h>
+#endif
+
 #if defined(HAVE_FCNTL)
 #  ifdef HAVE_SYS_SELECT_H
 #    include <sys/select.h>
@@ -268,7 +276,7 @@ extern VALUE rb_cIPSocket;
 extern VALUE rb_cTCPSocket;
 extern VALUE rb_cTCPServer;
 extern VALUE rb_cUDPSocket;
-#ifdef HAVE_SYS_UN_H
+#ifdef HAVE_TYPE_STRUCT_SOCKADDR_UN
 extern VALUE rb_cUNIXSocket;
 extern VALUE rb_cUNIXServer;
 #endif
@@ -336,7 +344,7 @@ VALUE rsock_sockaddr_obj(struct sockaddr *addr, socklen_t len);
 
 int rsock_revlookup_flag(VALUE revlookup, int *norevlookup);
 
-#ifdef HAVE_SYS_UN_H
+#ifdef HAVE_TYPE_STRUCT_SOCKADDR_UN
 VALUE rsock_unixpath_str(struct sockaddr_un *sockaddr, socklen_t len);
 VALUE rsock_unixaddr(struct sockaddr_un *sockaddr, socklen_t len);
 socklen_t rsock_unix_sockaddr_len(VALUE path);
diff --git a/ext/socket/socket.c b/ext/socket/socket.c
index 5cf0835062..eb74f7a936 100644
--- a/ext/socket/socket.c
+++ b/ext/socket/socket.c
@@ -1383,7 +1383,7 @@ sock_s_unpack_sockaddr_in(VALUE self, VALUE addr)
     return rb_assoc_new(INT2NUM(ntohs(sockaddr->sin_port)), host);
 }
 
-#ifdef HAVE_SYS_UN_H
+#ifdef HAVE_TYPE_STRUCT_SOCKADDR_UN
 
 /*
  * call-seq:
@@ -1471,7 +1471,7 @@ sockaddr_len(struct sockaddr *addr)
         return (socklen_t)sizeof(struct sockaddr_in6);
 #endif
 
-#ifdef HAVE_SYS_UN_H
+#ifdef HAVE_TYPE_STRUCT_SOCKADDR_UN
       case AF_UNIX:
         return (socklen_t)sizeof(struct sockaddr_un);
 #endif
@@ -2020,7 +2020,7 @@ Init_socket(void)
     rb_define_singleton_method(rb_cSocket, "sockaddr_in", sock_s_pack_sockaddr_in, 2);
     rb_define_singleton_method(rb_cSocket, "pack_sockaddr_in", sock_s_pack_sockaddr_in, 2);
     rb_define_singleton_method(rb_cSocket, "unpack_sockaddr_in", sock_s_unpack_sockaddr_in, 1);
-#ifdef HAVE_SYS_UN_H
+#ifdef HAVE_TYPE_STRUCT_SOCKADDR_UN
     rb_define_singleton_method(rb_cSocket, "sockaddr_un", sock_s_pack_sockaddr_un, 1);
     rb_define_singleton_method(rb_cSocket, "pack_sockaddr_un", sock_s_pack_sockaddr_un, 1);
     rb_define_singleton_method(rb_cSocket, "unpack_sockaddr_un", sock_s_unpack_sockaddr_un, 1);
diff --git a/ext/socket/unixserver.c b/ext/socket/unixserver.c
index 3a899cca1f..0ea5ac083c 100644
--- a/ext/socket/unixserver.c
+++ b/ext/socket/unixserver.c
@@ -10,7 +10,7 @@
 
 #include "rubysocket.h"
 
-#ifdef HAVE_SYS_UN_H
+#ifdef HAVE_TYPE_STRUCT_SOCKADDR_UN
 /*
  * call-seq:
  *   UNIXServer.new(path) => unixserver
@@ -101,7 +101,7 @@ unix_sysaccept(VALUE server)
 void
 rsock_init_unixserver(void)
 {
-#ifdef HAVE_SYS_UN_H
+#ifdef HAVE_TYPE_STRUCT_SOCKADDR_UN
     /*
      * Document-class: UNIXServer < UNIXSocket
      *
diff --git a/ext/socket/unixsocket.c b/ext/socket/unixsocket.c
index ecffbd4e92..26ab76fc9f 100644
--- a/ext/socket/unixsocket.c
+++ b/ext/socket/unixsocket.c
@@ -10,7 +10,7 @@
 
 #include "rubysocket.h"
 
-#ifdef HAVE_SYS_UN_H
+#ifdef HAVE_TYPE_STRUCT_SOCKADDR_UN
 struct unixsock_arg {
     struct sockaddr_un *sockaddr;
     socklen_t sockaddrlen;
@@ -43,6 +43,10 @@ unixsock_path_value(VALUE path)
         }
     }
 #endif
+#ifdef _WIN32
+    /* UNIXSocket requires UTF-8 per spec. */
+    path = rb_str_export_to_enc(path, rb_utf8_encoding());
+#endif
     return rb_get_path(path);
 }
 
@@ -571,7 +575,7 @@ unix_s_socketpair(int argc, VALUE *argv, VALUE klass)
 void
 rsock_init_unixsocket(void)
 {
-#ifdef HAVE_SYS_UN_H
+#ifdef HAVE_TYPE_STRUCT_SOCKADDR_UN
     /*
      * Document-class: UNIXSocket < BasicSocket
      *