[launchd-dev] Setting up an AF_UNIX based launchd server

[mailist at ericgorr.net]

On Mon, 25 Jul 2011 10:51:51 +0100, Quinn "The Eskimo!" wrote:
> On 24 Jul 2011, at 23:15, mailist at ericgorr.net wrote:
>
>> One question is how should /var/tmp/net.ericgorr.testserver/Socket 
>> be created?
>
> This is your fundamental problem.  The launchd infrastructure will
> take care of creating the UNIX domain socket for you, but it won't
> create intermediate directories.  So the socket has to live within a
> directory that already exists.  The standard path is for your service
> would be "/var/run/net.ericgorr.testserver.socket" ("/var/run" not
> "/var/tmp", and ".socket" not "/socket").

Ok. So, using /var/run and .socket also takes care of the issue 
mentioned in the CFLocalServer sample code:

	// This routine is called to safely bind the UNIX domain socket
	// specified by sockFD to the path specificed by socketPath.  To avoid
	// security problems, socketPath must point it to a sticky directory
	// (such as "/var/tmp").  This allows us to create the socket with
	// very specific permissions, without us having to worry about a 
malicious
	// process switching stuff out from underneath us.

I got a little farther, but my client still won't connect. After 
rebuilding the server and loading it into launchd, I do see:

     srw-rw-rw-   1 root  daemon     0 Jul 25 06:54 
net.ericgorr.testserver.socket=

in /var/run

In common.h, I now have:

     #define kServerSocketPath "/var/run/net.ericgorr.testserver.socket"

and the client_connect function in the client code remained:


int client_connect( void )
{
     int socketFD = socket( AF_UNIX, SOCK_STREAM, 0 );
     assert( socketFD != -1 );

     struct sockaddr_un addr;

     addr.sun_len    = sizeof( addr );
     addr.sun_family = AF_UNIX;

     strcpy( addr.sun_path, kServerSocketPath );

     int result;
     int err;

     result  = connect( socketFD, (struct sockaddr *)&socketFD, sizeof( 
socketFD ) );
     err     = MoreUNIXErrno( result );
     CFShow( CFStringCreateWithFormat( NULL, NULL, CFSTR( 
"client_connect: %d" ), err ) );

     assert( err == 0 );

     return socketFD;
}


However, errno is still set to 2.

I have updated the sample project at: 
http://ericgorr.net/pq/AF_UNIX.zip


Thank you.