#if 0
Compile with:
cc -O -D_REENTRANT -Kpic -G -z text -xstrconst -o lpq_letitgo.so lpq_letitgo.c

Usage is a bit challenging as you can't LD_PRELOAD modules to set-uid
apps. Following set-root-uid perl script covers up for it.

#!/usr/bin/perl -T

foreach $i (keys %ENV)
{  if ($i !~ /^(TZ|USER|LOGNAME|HOME|TMPDIR|PRINTER|LPDEST)$/)
   {  delete $ENV{$i};  }
}

$ENV{LD_PRELOAD}="/usr/local/lib/lpq_letitgo.so";
$ENV{_DROP_TO_RUID}="$<";
$<=$>;
exec ("/usr/ucb/lpq",@ARGV);
#endif

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <dlfcn.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <inet/common.h>
#include <poll.h>
#include <signal.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <unistd.h>

static int (*__lib_rresvport_af)(int *,int);
int	_setsockopt(int socket, int level, int option_name,
		    const void *option_value, unsigned int option_len);

int rresvport_af (int *alport, int af)
{ int ret;
  struct linger l={1,0};

    ret=(*__lib_rresvport_af)(alport,af);

    if (ret>=0) _setsockopt (ret,SOL_SOCKET,SO_LINGER,(void *)&l,sizeof(l));

  return ret;
}

#pragma init(setmeup)
static void setmeup()
{ int fd;
  char *env;
  uid_t uid;
  void *libh;

    if (getuid()==0 && (env=getenv("_DROP_TO_RUID")))
    {   if (uid = strtoul (env,NULL,10))
            setreuid (uid,-1);
    }

    if (!(libh = dlopen ("libsocket.so.1",RTLD_LAZY))) {
       fprintf (stderr,"can't dlopen(\"%s\").","libsocket.so.1");
       exit(1);
    }

    if (!(__lib_rresvport_af = (int (*)(int *,int))dlsym (libh,"rresvport_af"))) {
       fprintf (stderr, "can't link to \"%s\" from %s",
			"rresvport_af","libsocket.so.1");
       exit (1);
    }
}

#if 0
int setsockopt (int socket, int level, int option_name,
		const void *option_value, unsigned int option_len)
{ struct linger l={1,0};

    if (level==SOL_SOCKET && option_name==SO_LINGER)
	return _setsockopt (socket,level,option_name,(void *)&l,sizeof(l));
    else _setsockopt (socket,SOL_SOCKET,SO_LINGER,(void *)&l,sizeof(l));

    return _setsockopt (socket,level,option_name,option_value,option_len);
}
#endif