[Toybox] toybox host command

enh enh at google.com
Thu Dec 27 10:42:29 PST 2018


does this help?

diff --git a/toys/pending/host.c b/toys/pending/host.c
index 50de1d34..558b581b 100644
--- a/toys/pending/host.c
+++ b/toys/pending/host.c
@@ -71,7 +71,7 @@ void host_main(void)
       i, j, ret, sec, count, rcode, qlen, alen, pllen = 0;
   unsigned ttl, pri, v[5];
   unsigned char qbuf[280], abuf[512], *p;
-  char *name, *nsname, rrname[256], plname[640], ptrbuf[64];
+  char *name, *nsname, rrname[256], plname[640], ptrbuf[64+8+1];
   struct addrinfo *ai, iplit_hints = { .ai_flags = AI_NUMERICHOST };

   name = *toys.optargs;

currently host.c writes off the end of `ptrbuf` for an IPv6 address.
(though sadly only GCC is clever enough to do the arithmetic to spot
that --- clang misses this one.)

On Fri, Dec 21, 2018 at 9:26 PM Rob Landley <rob at landley.net> wrote:
>
> On 12/20/18 5:11 PM, J Martin wrote:
> > Hello,
> > I was wondering if the host command is functional?
>
> It's in pending, so it's not fully reviewed and cleaned up, but it seems to work
> when I tried it?
>
>   $ ./host landley.net
>   landley.net has address 208.113.171.142
>
>
> > I have had no success in
> > getting it to run on Windows 10 under Mobaxterm 11.
> >
> > It just returns with no output.
>
> Window Subsystem for Linux is basically an inverted version of Wine:
>
>   https://en.wikipedia.org/wiki/Wine_(software)
>
> As with QEMU's application emulation, it intercepts and translates system calls,
> and doesn't necessarily implement all of them.
>
> (Or are you using cygwin? Or mingw? Or midipix?)
>
> > /etc/resolv.conf is valid and has correct info.
> > Thanks for any input!
> > Jeff
>
> Toybox isn't reading /etc/resolv.conf, it's #including <resolv.h> and having
> libc do stuff for it.
>
> > this is from strace:
> > <snip>
> >    49  132541 [main] toybox 12836 fcntl64: 0 = fcntl(3, 2, 0x1)
> >    67  132608 [main] toybox 12836 fhandler_socket::bind: 0 =
> > setsockopt(SO_EXCLUSIVEADDRUSE), Win32 error 0
> >   143  132751 [main] toybox 12836 cygwin_bind: 0 = bind(3, 0x64BF4C, 16)
>
> You're using cygwin.
>
> I don't have a windows machine. I've never written a windows program. (I went
> from a Atari 800 to C64 to Amiga to Dos to Desqview to OS/2 to Linux, wih
> divergences into Solaris and AIX and a little bit of ancient MacOS, 6 months on
> JavaOS, a couple horrible mainframe things, bare metal embedded things...)
>
> I'm mostly familiar with Cygwin because EMX had a similar translation layer for
> OS/2 (and years later I worked with somebody at TimeSys who maintained a chunk
> of a cygwin fork), but lemme see if I can figure anything out here...
>
> >    52  132803 [main] toybox 12836 getpid: 12836 = getpid()
> >    72  132875 [main] toybox 12836 __set_errno: void __set_winsock_errno(const
> > char*, int):224 setting errno 11
> >    51  132926 [main] toybox 12836 __set_winsock_errno: recv_internal:1613 -
> > winsock error 10035 -> errno 11
> >    52  132978 [main] toybox 12836 cygwin_recvfrom: -1 = recvfrom(3, 0x64C6C0,
> > 512, 0x0, 0x0, 0x0), errno 11
>
> Hmmm... 11 is EAGAIN, which is just weird. (Is errno-base.h stable across
> architectures?)
>
> >   294  133272 [main] toybox 12836 cygwin_sendto: 27 = sendto(3, 0x64C5A8, 27,
> > 0x0, 0x612A4F00, 16)
> >    55  133327 [main] toybox 12836 pselect: pselect (4, 0x64BF3C, 0x0, 0x0,
> > 0x64BED8, 0x0)
> >    51  133378 [main] toybox 12836 pselect: to->tv_sec 5, to->tv_nsec 0, us 5000000
> >    92  133470 [main] toybox 12836 dtable::select_read:  fd 3
> >    45  133515 [main] toybox 12836 select: sel.always_ready 0
> >   172  133687 [main] toybox 12836 start_thread_socket: stuff_start 0x64BCC4
> > --- Process 12836 thread 9800 created
> > --- Process 12836, exception 406d1388 at 76A34172
>
> Toybox isn't threaded, I have no _clue_ what's going on here.
>
> >  2102  135789 [socksel] toybox 12836 cygthread::stub: thread 'socksel', id
> > 0x2648, stack_ptr 0x4FFCD60
> >    56  135845 [socksel] toybox 12836 thread_socket: stuff_start 0x64BCC4,
> > timeout 4294967295
> >    56  135901 [main] toybox 12836 select_stuff::wait: m 4, us 5000000,
> > wmfo_timeout -1
> >    93  135994 [socksel] toybox 12836 peek_socket: read_ready: 1, write_ready: 0,
> > except_ready: 0
> >    51  136045 [socksel] toybox 12836 thread_socket: leaving thread_socket
> >    99  136144 [main] toybox 12836 select_stuff::wait: wait_ret 2, m = 4.  verifying
> >    52  136196 [main] toybox 12836 select_stuff::wait: res after verify 0
> >    89  136285 [main] toybox 12836 select_stuff::wait: returning 0
>
> select_stuff?
>
> >    45  136330 [main] toybox 12836 select: sel.wait returns 0
> >    54  136384 [main] toybox 12836 peek_socket: read_ready: 1, write_ready: 0,
> > except_ready: 0
> >    53  136437 [main] toybox 12836 set_bits: me 0x20061AE0, testing fd 3 ()
> >    52  136489 [main] toybox 12836 set_bits: ready 1
> >    88  136577 [main] toybox 12836 select_stuff::cleanup: calling cleanup routines
> >    44  136621 [main] toybox 12836 socket_cleanup: si 0x20061B10 si->thread
> > 0x611CE950
> >   181  136802 [main] toybox 12836 socket_cleanup: returning
> >    48  136850 [main] toybox 12836 select_stuff::destroy: deleting select records
> >    90  136940 [main] toybox 12836 select_stuff::cleanup: calling cleanup routines
> >    46  136986 [main] toybox 12836 select_stuff::destroy: deleting select records
> >    47  137033 [main] toybox 12836 pselect: 1 = select (4, 0x64BF3C, 0x0, 0x0,
> > 0x64BED8)
> >   111  137144 [main] toybox 12836 cygwin_recvfrom: 27 = recvfrom(3, 0x64C6C0,
> > 512, 0x0, 0x64BF5C, 0x64BF38)
> >   401  137545 [main] toybox 12836 fhandler_pty_slave::write: pty0,
> > write(0x432E3C, 4)
> >    49  137594 [main] toybox 12836 fhandler_pty_common::process_opost_output:
> > (1902): pty output_mutex (0x1CC): waiting -1 ms
> >    51  137645 [main] toybox 12836 fhandler_pty_common::process_opost_output:
> > (1902): pty output_mutex: acquired
> >    53  137698 [main] toybox 12836 fhandler_pty_common::process_opost_output:
> > (1941): pty output_mutex(0x1CC) released
>
> Locking for a pseudo-terminal handler? How is a PTY involved here?
>
> > host   55  137753 [main] toybox 12836 write: 4 = write(2, 0x432E3C, 4)
> >   111  137864 [main] toybox 12836 fhandler_pty_slave::write: pty0,
> > write(0x43260F, 2)
> >    74  137938 [main] toybox 12836 fhandler_pty_common::process_opost_output:
> > (1902): pty output_mutex (0x1CC): waiting -1 ms
> >    46  137984 [main] toybox 12836 fhandler_pty_common::process_opost_output:
> > (1902): pty output_mutex: acquired
> >    69  138053 [main] toybox 12836 fhandler_pty_common::process_opost_output:
> > (1941): pty output_mutex(0x1CC) released
> > :    49  138102 [main] toybox 12836 write: 2 = write(2, 0x43260F, 2)
> >   218  138320 [main] toybox 12836 fhandler_pty_slave::write: pty0,
> > write(0x4342DE, 15)
> >    42  138362 [main] toybox 12836 fhandler_pty_common::process_opost_output:
> > (1902): pty output_mutex (0x1CC): waiting -1 ms
> >    49  138411 [main] toybox 12836 fhandler_pty_common::process_opost_output:
> > (1902): pty output_mutex: acquired
> >    52  138463 [main] toybox 12836 fhandler_pty_common::process_opost_output:
> > (1941): pty output_mutex(0x1CC) released
> > Host not found.   45  138508 [main] toybox 12836 write: 15 = write(2, 0x4342DE, 15)
> >   307  138815 [main] toybox 12836 fhandler_pty_slave::write: pty0,
> > write(0x611CBDF7, 1)
> >    45  138860 [main] toybox 12836 fhandler_pty_common::process_opost_output:
> > (1902): pty output_mutex (0x1CC): waiting -1 ms
> >    48  138908 [main] toybox 12836 fhandler_pty_common::process_opost_output:
> > (1902): pty output_mutex: acquired
> >    54  138962 [main] toybox 12836 fhandler_pty_common::process_opost_output:
> > (1941): pty output_mutex(0x1CC) released
> >
> >    47  139009 [main] toybox 12836 write: 1 = write(2, 0x611CBDF7, 1)
> >  1041  140050 [main] toybox 12836 do_exit: do_exit (256), exit_state 1
>
> What just exited?
>
> >    46  140096 [main] toybox 12836 void: 0x0 = signal (20, 0x1)
> >    51  140147 [main] toybox 12836 void: 0x0 = signal (1, 0x1)
> >    47  140194 [main] toybox 12836 void: 0x0 = signal (2, 0x1)
> >    46  140240 [main] toybox 12836 void: 0x0 = signal (3, 0x1)
>
> It's setting signal handlers?
>
>   $ strace ./host landley.net 2>&1 | grep signal
>   $
>
> Nothing...
>
> Sorry, I have no idea what's going on here. I kind of doubt toybox is
> responsible for any of this.
>
> Rob
> _______________________________________________
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> Toybox at lists.landley.net
> http://lists.landley.net/listinfo.cgi/toybox-landley.net



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