[M3devel] Juno (X) networking problem on AMD64_FREEBSD
Jay
jay.krell at cornell.edu
Sun Jan 11 23:02:18 CET 2009
Do you know the right way?
PPC_LINUX "just worked", and I can check Solaris and Darwin.
I don't want to edit /etc/hosts -- I use DHCP.
Though DHCP has been bothering me -- only for some of my machines do names resolve, so I end using IP addresses, which change sometimes, and I loop over them running ssh to all of them and "see what I get", not ideal.
- Jay> To: jay.krell at cornell.edu> Date: Sun, 11 Jan 2009 08:02:18 -0800> From: mika at async.caltech.edu> CC: m3devel at elegosoft.com> Subject: Re: [M3devel] Juno (X) networking problem on AMD64_FREEBSD> > This is a screwy thing in Modula-3. A bug I would call it.> > I've noticed a lot of networking M3 programs don't work right unless> the return value of Unix's "hostname" maps to a real IP address via> gethostbyname. I accomplish it in practice by adding my hostname> to /etc/hosts.> > This is obviously not the right way to fix it... > > Mika> > Jay writes:> >--_9e67232c-a064-417d-879e-227a77e310f9_> >Content-Type: text/plain; charset="iso-8859-1"> >Content-Transfer-Encoding: quoted-printable> >> >> >Hi. Unix network programming question..> >AMD64_FREEBSD:> >$DISPLAY is set to point back to Cygwin host.It works for PPC_LINUX.> >[jay at fbsdamd64a /cm3/bin]$ ./Juno> >****** runtime error:*** Exception "IPError.FatalError" not in RAISES li=> >st*** file "../src/common/IPError.m3"=2C line 27***> >Abort trap: 6 (core dumped)[jay at fbsdamd64a /cm3/bin]$> >IP.m3:> >=20> >PROCEDURE GetHostAddr(): Address =3D VAR hname: ARRAY [0..255] OF CHAR=3B => > BEGIN LOCK mu DO IF Unix.gethostname(ADR(hname[0])=2C BYTESIZE(hna=> >me)) # 0 THEN IPError.Die ()=3B END=3B VAR h :=3D Unetdb.g=> >ethostbyname(ADR(hname[0]))=3B BEGIN IF h =3D NIL THEN IPError.Die()=> >=3B END=3B RETURN GetAddress(h)=3B END=3B END=3B END GetHos=> >tAddr=3B> >PROCEDURE GetAddress (ent: Unetdb.struct_hostent_star): Address =3D VAR ua=> >: Uin.struct_in_addr=3B BEGIN <* ASSERT ent.h_length <=3D BYTESIZE(Addr=> >ess) *> ua :=3D LOOPHOLE(ent.h_addr_list=2C UNTRACED => >REF UNTRACED REF Uin.struct_in_addr)^^=3B RETURN LOOPHOLE(ua.s_addr=2C A=> >ddress)=3B END GetAddress=3B> >=20> >gethostbyname is failing.> >=20> >Analogous C code also fails:> >=20> >[jay at fbsdamd64a /cm3/bin]$ cat ~/5.c#include <assert.h>#include <netdb.h>#i=> >nclude <stdio.h>#include <errno.h>typedef struct hostent hostent_t=3B> >=20> >int main(){ char hostname[200]=3B hostent_t* h=3B int i=3B> > i =3D gethostname(hostname=2C 200)=3B assert(i =3D=3D 0)=3B printf("hostna=> >me: %s\n"=2C hostname)=3B h =3D gethostbyname(hostname)=3B herror("foo")=3B=> > printf("%p %d %d\n"=2C h=2C errno=2C h_errno)=3B assert(h)=3B return 0=3B}> >=20> >herror says "unknown host".> >Stack is:> > at ../src/runtime/ex_frame/RTExFrame.m3:58#13 0x0000000801a7f2b3 in RTH=> >ooks__Raise (M3_AJWxb1_ex=3DError accessing memory address 0x8000ffffd278: => >Bad address.) at ../src/runtime/common/RTHooks.m3:79#14 0x000000080169c8=> >d3 in IPError__Die () at ../src/common/IPError.m3:27#15 0x0000000801698a3e => >in IP__GetHostAddr (M3_BCxjPn__result=3DError accessing memory address 0x80=> >00ffffd338: Bad address.) at ../src/POSIX/IP.m3:82#16 0x00000008012133d0=> > in XSharedMem__SameHost (M3_AQuuui_trsl=3DError accessing memory address 0=> >x8000ffffd4d8: Bad address.) at ../src/xvbt/XSharedMem.m3:96#17 0x000000=> >0801212ab7 in XSharedMem__InitXClient (M3_AQuuui_v=3DError accessing memory=> > address 0x8000ffffd648: Bad address.) at ../src/xvbt/XSharedMem.m3:29#1=> >8 0x0000000801211819 in XExtensions__InitXClient (M3_AQuuui_xclient=3DError=> > accessing memory address 0x8000ffffd7f8: Bad address.) at ../src/xvbt/X=> >Extensions.m3:14#19 0x00000008012467a4 in XClientF__Connect (M3_Bd56fi_inst=> >=3D0x1879b=2C M3_AQuuui_trsl=3D0x6) at ../src/xvbt/XClientF.m3:583---Typ=> >e <return> to continue=2C or q <return> to quit---(More stack frames follow=> >...)(gdb)> >(* return TRUE if server and client are on same host *)PROCEDURE SameHost (=> >trsl: XClient.T): BOOLEAN =3D VAR display :=3D DisplayH=> >ost(trsl)=3B displayAddr: IP.Address=3B BEGIN IF display =3D NIL THE=> >N RETURN TRUE=3B END=3B> > TRY IF NOT IP.GetHostByName(display=2C displayAddr) THEN RETURN FA=> >LSE=3B END=3B RETURN displayAddr =3D IP.GetHostAddr()=3B EXCEPT => >| IP.Error =3D> RETURN FALSE=3B END=3B END SameHost=3B> >=20> >Thoughts?> >=20> >Perhaps my network isn't setup well=2C like I should add the local machine => >to /etc/hosts.I think this can be made to fail gracefully though.It seems l=> >ike it has nothing to do with AMD64_FREEBSD=2C but could have to do with Fr=> >eeBSD.> >=20> >Seems like SocketPosix has nearly the exact same code but appearsmore forgi=> >ving.. IOError instead of Fatal?> >=20> >SocketPosix.m3:> >=20> >PROCEDURE GetHostAddr (): Address RAISES {OSError.E} =3D VAR host : AR=> >RAY [0..255] OF CHAR=3B info : Unetdb.struct_hostent_star=3B ua : U=> >in.struct_in_addr=3B BEGIN IF Unix.gethostname (ADR (host[0])=2C BYTESI=> >ZE (host)) # 0 THEN IOError (Unexpected)=3B END=3B> > info :=3D Unetdb.gethostbyname (ADR (host[0]))=3B IF info =3D NIL TH=> >EN IOError (Unexpected)=3B END=3B <* ASSERT info.h_length <=3D BYTESIZE => >(Address) *>> > ua :=3D LOOPHOLE(info.h_addr_list=2C UNTRACED REF UNT=> >RACED REF Uin.struct_in_addr)^^=3B RETURN LOOPHOLE (ua.s_addr=2C Address=> >)=3B END GetHostAddr=3B> >=20> >=20> >It is again disappointing to see such code duplication.> >=20> >=20> >I guess SameHost can duplicate the logic to predict the error state and ret=> >urn false upon error?> >Duplicating the logic for a third time. :(> >=20> > - Jay=> >> >--_9e67232c-a064-417d-879e-227a77e310f9_> >Content-Type: text/html; charset="iso-8859-1"> >Content-Transfer-Encoding: quoted-printable> >> ><html>> ><head>> ><style>> >.hmmessage P> >{> >margin:0px=3B> >padding:0px> >}> >body.hmmessage> >{> >font-size: 10pt=3B> >font-family:Verdana> >}> ></style>> ></head>> ><body class=3D'hmmessage'>> >Hi. Unix network programming question..<BR>> ><BR>AMD64_FREEBSD:<BR>> ><BR>$DISPLAY is set to point back to Cygwin host.<BR>It works for PPC_LINUX=> >.<BR>> ><BR>[jay at fbsdamd64a /cm3/bin]$ ./Juno<BR>> ><BR>***<BR>*** runtime error:<BR>*** =3B =3B =3B Exception "IPE=> >rror.FatalError" not in RAISES list<BR>*** =3B =3B =3B file "..=> >/src/common/IPError.m3"=2C line 27<BR>***<BR>> ><BR>Abort trap: 6 (core dumped)<BR>[jay at fbsdamd64a /cm3/bin]$<BR>> ><BR>IP.m3:<BR>> > =3B<BR>> >PROCEDURE GetHostAddr(): Address =3D<BR> =3B VAR hname: ARRAY [0..255] => OF CHAR=3B<BR> =3B BEGIN<BR> =3B =3B =3B LOCK mu DO<BR>&nbs=> >p=3B =3B =3B =3B =3B IF Unix.gethostname(ADR(hname[0])=2C B=> >YTESIZE(hname)) # 0 THEN<BR> =3B =3B =3B =3B =3B => >=3B =3B IPError.Die ()=3B<BR> =3B =3B =3B =3B =3B E=> >ND=3B<BR> =3B =3B =3B =3B =3B VAR h :=3D Unetdb.gethost=> >byname(ADR(hname[0]))=3B BEGIN<BR> =3B =3B =3B =3B =3B&=> >nbsp=3B =3B IF h =3D NIL THEN IPError.Die()=3B END=3B<BR> =3B => >=3B =3B =3B =3B =3B =3B RETURN GetAddress(h)=3B<BR>&nbs=> >p=3B =3B =3B =3B =3B END=3B<BR> =3B =3B =3B END=> >=3B<BR> =3B END GetHostAddr=3B<BR>> ><BR>PROCEDURE GetAddress (ent: Unetdb.struct_hostent_star): Address =3D<BR>=> > =3B VAR ua: Uin.struct_in_addr=3B<BR> =3B BEGIN<BR> =3B => >=3B =3B <=3B* ASSERT ent.h_length <=3B=3D BYTESIZE(Address) *>=3B=> ><BR> =3B =3B =3B ua :=3D LOOPHOLE(ent.h_addr_list=2C<BR> => >=3B =3B =3B =3B =3B =3B =3B =3B =3B =3B=> > =3B =3B =3B =3B =3B =3B =3B =3B =3B UN=> >TRACED REF UNTRACED REF Uin.struct_in_addr)^^=3B<BR> =3B =3B => >=3B RETURN LOOPHOLE(ua.s_addr=2C Address)=3B<BR> =3B END GetAddress=3B<=> >BR>> > =3B<BR>> >gethostbyname is failing.<BR>> ><BR> =3B<BR>> >Analogous C code also fails:<BR>> > =3B<BR>> ><BR>[jay at fbsdamd64a /cm3/bin]$ cat ~/5.c<BR>#include <=3Bassert.h>=3B<B=> >R>#include <=3Bnetdb.h>=3B<BR>#include <=3Bstdio.h>=3B<BR>#include => ><=3Berrno.h>=3B<BR>typedef struct hostent hostent_t=3B<BR>> > =3B<BR>> >int main()<BR>{<BR> =3Bchar hostname[200]=3B<BR> =3Bhostent_t* h=3B=> ><BR> =3Bint i=3B<BR>> > =3Bi =3D gethostname(hostname=2C 200)=3B<BR> =3Bassert(i =3D=3D 0)=> >=3B<BR> =3Bprintf("hostname: %s\n"=2C hostname)=3B<BR> =3Bh =3D get=> >hostbyname(hostname)=3B<BR> =3Bherror("foo")=3B<BR> =3Bprintf("%p %=> >d %d\n"=2C h=2C errno=2C h_errno)=3B<BR> =3Bassert(h)=3B<BR> =3Bret=> >urn 0=3B<BR>}<BR>> > =3B<BR>> >herror says "unknown host".<BR>> ><BR>Stack is:<BR>> > =3B =3B =3B at ../src/runtime/ex_frame/RTExFrame.m3:58<BR>#13 => >0x0000000801a7f2b3 in RTHooks__Raise (M3_AJWxb1_ex=3DError accessing memory=> > ad<BR>dress 0x8000ffffd278: Bad address.<BR>)<BR> =3B =3B =3B => >at ../src/runtime/common/RTHooks.m3:79<BR>#14 0x000000080169c8d3 in IPError=> >__Die () at ../src/common/IPError.m3:27<BR>#15 0x0000000801698a3e in IP__Ge=> >tHostAddr (M3_BCxjPn__result=3DError accessing mem<BR>ory address 0x8000fff=> >fd338: Bad address.<BR>)<BR> =3B =3B =3B at ../src/POSIX/IP.m3:=> >82<BR>#16 0x00000008012133d0 in XSharedMem__SameHost (M3_AQuuui_trsl=3DErro=> >r accessing m<BR>emory address 0x8000ffffd4d8: Bad address.<BR>)<BR> => >=3B =3B =3B at ../src/xvbt/XSharedMem.m3:96<BR>#17 0x0000000801212a=> >b7 in XSharedMem__InitXClient (M3_AQuuui_v=3DError accessing m<BR>emory add=> >ress 0x8000ffffd648: Bad address.<BR>)<BR> =3B =3B =3B at ../sr=> >c/xvbt/XSharedMem.m3:29<BR>#18 0x0000000801211819 in XExtensions__InitXClie=> >nt (M3_AQuuui_xclient=3DError acce<BR>ssing memory address 0x8000ffffd7f8: => >Bad address.<BR>)<BR> =3B =3B =3B at ../src/xvbt/XExtensions.m3=> >:14<BR>#19 0x00000008012467a4 in XClientF__Connect (M3_Bd56fi_inst=3D0x1879=> >b=2C<BR> =3B =3B =3B M3_AQuuui_trsl=3D0x6) at ../src/xvbt/XClie=> >ntF.m3:583<BR>---Type <=3Breturn>=3B to continue=2C or q <=3Breturn&g=> >t=3B to quit---<BR>(More stack frames follow...)<BR>(gdb)<BR>> ><BR>(* return TRUE if server and client are on same host *)<BR>PROCEDURE Sa=> >meHost (trsl: XClient.T): BOOLEAN =3D<BR> =3B VAR<BR> =3B =3B&n=> >bsp=3B display =3B =3B =3B =3B =3B =3B =3B => >=3B =3B =3B =3B =3B =3B =3B =3B =3B :=3D Di=> >splayHost(trsl)=3B<BR> =3B =3B =3B displayAddr: IP.Address=3B<B=> >R> =3B BEGIN<BR> =3B =3B =3B IF display =3D NIL THEN RETURN=> > TRUE=3B END=3B<BR>> > =3B =3B =3B TRY<BR> =3B =3B =3B =3B =3B IF=> > NOT IP.GetHostByName(display=2C displayAddr) THEN RETURN FALSE=3B END=3B<B=> >R> =3B =3B =3B =3B =3B RETURN displayAddr =3D IP.GetHos=> >tAddr()=3B<BR> =3B =3B =3B EXCEPT<BR> =3B =3B =3B |=> > IP.Error =3D>=3B RETURN FALSE=3B<BR> =3B =3B =3B END=3B<BR>&=> >nbsp=3B END SameHost=3B<BR>> > =3B<BR>> >Thoughts?<BR>> > =3B<BR>> ><BR>Perhaps my network isn't setup well=2C like I should add the local mach=> >ine to /etc/hosts.<BR>I think this can be made to fail gracefully though.<B=> >R>It seems like it has nothing to do with AMD64_FREEBSD=2C but could have t=> >o do with FreeBSD.<BR>> ><BR> =3B<BR>> >Seems like SocketPosix has nearly the exact same code but appears<BR>more f=> >orgiving.. IOError instead of Fatal?<BR>> > =3B<BR>> ><BR>SocketPosix.m3:<BR>> > =3B<BR>> ><BR>PROCEDURE GetHostAddr (): Address<BR> =3B RAISES {OSError.E} =3D<BR=> >> =3B VAR<BR> =3B =3B =3B host : ARRAY [0..255] OF CHAR=3B<=> >BR> =3B =3B =3B info : Unetdb.struct_hostent_star=3B<BR> => >=3B =3B =3B ua =3B =3B : Uin.struct_in_addr=3B<BR> =3B => >BEGIN<BR> =3B =3B =3B IF Unix.gethostname (ADR (host[0])=2C BYT=> >ESIZE (host)) # 0 THEN<BR> =3B =3B =3B =3B =3B IOError => >(Unexpected)=3B<BR> =3B =3B =3B END=3B<BR>> > =3B =3B =3B info :=3D Unetdb.gethostbyname (ADR (host[0]))=3B<=> >BR> =3B =3B =3B IF info =3D NIL THEN IOError (Unexpected)=3B EN=> >D=3B<BR> =3B =3B =3B <=3B* ASSERT info.h_length <=3B=3D BYT=> >ESIZE (Address) *>=3B<BR>> > =3B =3B =3B ua :=3D LOOPHOLE(info.h_addr_list=2C<BR> =3B&n=> >bsp=3B =3B =3B =3B =3B =3B =3B =3B =3B => >=3B =3B =3B =3B =3B =3B =3B =3B UNTRACED REF UN=> >TRACED REF Uin.struct_in_addr)^^=3B<BR> =3B =3B =3B RETURN LOOP=> >HOLE (ua.s_addr=2C Address)=3B<BR> =3B END GetHostAddr=3B<BR>> > =3B<BR>> > =3B<BR>> >It is again disappointing to see such code duplication.<BR>> > =3B<BR>> > =3B<BR>> >I guess =3BSameHost can duplicate the logic to predict the error state => >and return false =3Bupon error?<BR>> >Duplicating the logic for a third time. :(<BR>> > =3B<BR>> ><BR> =3B- Jay<BR><BR></body>> ></html>=> >> >--_9e67232c-a064-417d-879e-227a77e310f9_--
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