WSAStartup issue on Windows

[Hoernchen]

Building using the mingw script produces a version that does not work on Windows:

E:\projects\wg2>wget2.exe http://www.google.com
�[31mFailed to resolve www.google.de:80 (Either the application has not called WSAStartup, or WSAStartup failed. )

[rockdaboot]

@gvanem Didn't you send us a WSAStartup patch !? Sorry, I was sure we had that applied, but can't find it any more. Could you resend it to me ?

[gvanem]

Ok, here is what I sent you in an email:

--- a/src/wget.c 2016-11-08 19:54:27
+++ b/src/wget.c 2016-11-08 20:25:53
@@ -135,6 +135,37 @@
 int
        nthreads;

+#if defined(_WIN32)
+static void
+ws_cleanup (void)
+{
+  WSACleanup ();
+}
+
+/* Perform Windows specific initialization.  */
+static void
+ws_startup (void)
+{
+  WSADATA data;
+  WORD requested = MAKEWORD (1, 1);
+  int err = WSAStartup (requested, &data);
+  if (err != 0)
+    {
+      fprintf (stderr, _("wget: Couldn't find usable socket driver.\n"));
+      exit (1);
+    }
+
+  if (data.wVersion < requested)
+    {
+      fprintf (stderr, _("wget: Couldn't find usable socket driver.\n"));
+      WSACleanup ();
+      exit (1);
+    }
+
+  atexit (ws_cleanup);
+}
+#endif
+
 void set_exit_status(int status)
 {
        // use Wget exit status scheme:
@@ -857,11 +888,12 @@
        textdomain("wget");
 #endif

-#if defined(_WIN32) || defined(_WIN64)
+#if defined(_WIN32)
        // not sure if this is needed for Windows
        // signal(SIGPIPE, SIG_IGN);
        signal(SIGTERM, nop);
        signal(SIGINT, nop);
+       ws_startup();
 #else
        // need to set some signals
        struct sigaction sig_action;

This is almost an exact copy & paste from Wget.
Note the removal of #if defined(_WIN32) || defined(_WIN64). For Win64, _WIN32 is also defined.

[rockdaboot]

@gvanem Thx, just found a gnulib module doing that. I integrated the socket startup/cleanup function deeper within the library, so that the examples benefit as well.

After reading https://msdn.microsoft.com/en-us/library/windows/desktop/ms742213%28v=vs.85%29.aspx, I decided to use socket version 2.2. Any objections ?

Could you test the latest commit and report back, please !?

[gvanem]

Doesn't work; WSAStartup() isn't called since wget_global_init() isn't called AFAICS. At least not in a src/*.c file. But in examples/*.c though 😸 .

I just added a wget_global_init(NULL) in main() (is that syntax OK?). This works better, but still some problems somewhere with mixing GNUlib fd-handles with Winsock-handles.

[rockdaboot]

Init NULL is OK, i'll fix wget.c when back from lunch. Do you know which network functions need handles and which need fds ?

[gvanem]

I suspect there is some problem with GnuLib's shimming of poll(). Would be nice if Wget2 had an option (in $WGET2) to use select(). That just works. The speed gain of using poll() is AFAICS negligible (comparing with nmap --nsock-engine=poll vs. nmap --nsock-engine=select).

[rockdaboot]

Regarding gnulib docs, mingw poll() should be ok: https://www.gnu.org/software/gnulib/manual/html_node/poll.html
If not, we should investigate and open a bug against gnulib.
AFAIR, there weren't any problems when cross-compiling on Linux (MinGW) and executing wget2 with wine. I'll try again, but without a reproducer, I won't do anything.

[rockdaboot]

@gvanem Found a problem in gnulib/poll.c with MinGW - likely the same problem that you have.

Before make, change lib/poll.c. In windows_compute_revents_socket(), before

      if (r > 0 || error == WSAENOTCONN)
        happened |= (POLLIN | POLLRDNORM) & sought;

insert

if (r==-1 && error==0)
  r=1;

Not sure why, but recv() returns -1 (with error==0) when the socket is ready to read.
The above change let wget2 download correctly.
Basically the recv with MSG_PEEK is useless ... but why ? Maybe because the socket/handle is still non-blocking ? Do you have any idea ?

[gvanem]

The above change let wget2 download correctly.

It works sometimes. Other times I get a crash in rpl_select(). I'm using WSAPoll() until this is fixed.
But there are so many other issues with Wget2 on Windows; like ANSI-sequences for colours, PThreads etc.

[rockdaboot]

Well, wget2 is documented to be POSIX + C99. That excludes Windows ATM. But color seqs should be easy... You are invited to provide patches, else there currently is no Win developer who does.

[rockdaboot]

BTW, the gnulib poll emulation for Win looks messy. If there is a WSAPoll, that should be used. But again, only a Win dev could make that.

[gvanem]

Some of my hacks is in libwget/mswindows.* at http://www.watt-32.net/misc/wget2-win-hacks.zip.
This uses WSAPoll(), implements a simple trace-macro and an ANSI decoder. not thread safe.

[rockdaboot]

wine doesn't know WSAPoll, again I can't test...

[rockdaboot]

Just stumbled upon https://daniel.haxx.se/blog/2012/10/10/wsapoll-is-broken/ (sigh).