Add getSocketName function

Author: d-torrance

M2/Macaulay2/d/actors2.dd

@@ -526,6 +526,22 @@ getPeerName(e:Expr):Expr := (
 	else WrongArg("an input file"))
     else WrongArg("a file"));
 setupfun("getPeerName", getPeerName);
+getSocketName(e:Expr):Expr := (
+    when e
+    -- # typical value: getSocketName, File, Sequence
+    is f:file do (
+	fd := 0;
+	if f.listener then fd = f.listenerfd
+	else if f.output then fd = f.outfd
+	else return WrongArg("a listener or output file");
+	host := new string len Ccode(int, "NI_MAXHOST") do provide ' ';
+	serv := new string len Ccode(int, "NI_MAXSERV") do provide ' ';
+	r := getsockname(fd, host, serv);
+	if r < 0 then buildErrorPacket(
+	    "can't get socket name: " + netstrerror(r))
+	else seq(toExpr(host), toExpr(serv)))
+    else WrongArg("a file"));
+setupfun("getSocketName", getSocketName);
 
 header "
     #if WITH_MYSQL

M2/Macaulay2/d/scclib.c

@@ -781,14 +781,18 @@ int system_openlistener(M2_string interface0,M2_string serv) {
      return sd;
      }
 
-int system_getpeername(int sockfd, M2_string host, M2_string serv) {
+int getpeerorsockname(int sockfd, M2_string host, M2_string serv, int peer) {
   struct sockaddr addr;
   socklen_t addrlen;
   int i, r;
   char hostbuf[NI_MAXHOST], servbuf[NI_MAXSERV];
 
   addrlen = sizeof addr;
-  r = getpeername(sockfd, &addr, &addrlen);
+  if (peer)
+    r = getpeername(sockfd, &addr, &addrlen);
+  else
+    r = getsockname(sockfd, &addr, &addrlen);
+
   if (r == ERROR)
     return ERROR;
 
@@ -809,6 +813,14 @@ int system_getpeername(int sockfd, M2_string host, M2_string serv) {
   return 0;
 }
 
+int system_getpeername(int sockfd, M2_string host, M2_string serv) {
+  return getpeerorsockname(sockfd, host, serv, 1);
+}
+
+int system_getsockname(int sockfd, M2_string host, M2_string serv) {
+  return getpeerorsockname(sockfd, host, serv, 0);
+}
+
 int system_errno(void) {
   return 
 #ifdef HAVE_HERROR

M2/Macaulay2/d/system.d

@@ -109,6 +109,7 @@ import netstrerror(errcode:int):string;
 import acceptBlocking(sd:int):int;
 import acceptNonblocking(sd:int):int;
 import getpeername(sockd:int,host:string,serv:string):int;
+import getsockname(sockd:int,host:string,serv:string):int;
 import syserrmsg():string;				    -- uses errno
 import atend(f:function():void):void;
 import run(command:string):int;

M2/Macaulay2/m2/exports.m2

@@ -733,6 +733,7 @@ export {
 	"getNonUnit",
 	"getPeerName",
 	"getPrimeWithRootOfUnity",
+	"getSocketName",
 	"getSymbol",
 	"getWWW",
 	"getc",