Re: [msysGit] [PATCH/RFC 08/11] daemon: use explicit file descriptor

Sorry for the long delay in the reply, but I'm a little low on time
these days (and I've already spent some time trying to figure out what
I was thinking - I wrote these patches a while ago).

On Thu, Nov 26, 2009 at 11:03 PM, Johannes Sixt [off-list ref] wrote:

On Donnerstag, 26. November 2009, Erik Faye-Lund wrote:

quoted

@@ -372,37 +372,35 @@ static int run_service_command(const char **argv)

      cld.argv = argv;
      cld.git_cmd = 1;
      cld.err = -1;
+     cld.in = cld.out = fd;

You shouldn't do that. In fact, the next patch 9 has a hunk that correctly
calls dup() once.

OK, as long as it works as expected, sure. But perhaps this needs a
little change (see discussion later)

quoted

-     close(0);
-     close(1);

Here, stdin and stdout were closed and start_command() used both. But these
two new calls

quoted

+     exit(execute(0, addr));
...
+             return execute(0, peer);

are the only places where a value is assigned to fd. Now it is always only
stdin. Where does the old code initialize stdout? Shouldn't this place need a
change, too?

The "dup2(incoming, 0)"-call in handle() is AFAICT what makes it work
to use the forked process' stdin as both stdin and stdout for the
service-process pipe (since fd 0 now becomes a pipe that is both
readable and writable). This isn't exactly a pretty mechanism, and I
guess I should rework it. At the very least, I should remove the
"dup2(incoming, 1)"-call, but I'm open to other suggestions. Perhaps I
can change this patch to do the entire socket-passing (which is
currently in the next patch)?

-- 
Erik "kusma" Faye-Lund