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# Reply server mig-output massager

#

#   Copyright (C) 1995, 1996, 1999, 2007, 2008 Free Software Foundation, Inc.

#

#   Written by Miles Bader <miles@gnu.ai.mit.edu>

#

#   This program is free software; you can redistribute it and/or

#   modify it under the terms of the GNU General Public License as

#   published by the Free Software Foundation; either version 2, or (at

#   your option) any later version.

#

#   This program is distributed in the hope that it will be useful, but

#   WITHOUT ANY WARRANTY; without even the implied warranty of

#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

#   General Public License for more details.

#

#   You should have received a copy of the GNU General Public License

#   along with this program; if not, write to the Free Software

#   Foundation, Inc., 51 Franklin Street, Fifth Floor,

#   Boston, MA 02110-1301, USA.

#

# This awk script hacks the output of mig-generated reply server code

# so that it allows replies with just the error-code in them (as this is

# how mig returns errors).

#

# It is highly, highly, dependent on the exact format of mig output.  Ick.

#

BEGIN { parse_phase = 0; }

/^}/ { parse_phase = 0; }

parse_phase == 0 && /^mig_internal void _X[a-zA-Z0-9_]*_reply/ {

  # The start of a mig server routine.  Reset everything.  Note that we only

  # mess with rpcs that have the suffix `_reply'.

  num_args = 0;

  num_checks = 0;

  parse_phase = 1;

  print; next;

}

parse_phase == 1 && /^[\t ]*typedef struct/ {

  # The first structure in the server routine should describe the arguments

  parse_phase = 2;

  print; next;

}

parse_phase == 2 {

  # The message header field in the args structure, which skip.

  parse_phase = 3;

  print; next;

}

parse_phase == 3 && /}/ {

  # The args structure is over.

  if (num_args > 1)

    parse_phase = 5;

  else

    # There's no extra args that could screw up the normal mechanism for

    # error returns, so we don't have to insert any new code.

    parse_phase = 0;

  print; next;

}

parse_phase == 3 {

  # The type field for an argument.

  arg_type_code_name[num_args] = $2;

  sub (/;$/, "", arg_type_code_name[num_args]) # Get rid of the semi-colon

  parse_phase = 4;

  print; next;

}

parse_phase == 4 {

  # The value field for an argument.

  arg_name[num_args] = $2;

  sub (/;$/, "", arg_name[num_args]) # Get rid of the semi-colon

  arg_type[num_args] = $1;

  num_args++;

  parse_phase = 3;

  print; next;

}

parse_phase == 5 && /^[ \t]*(auto|static) const mach_msg_type_t/ {

  # The type check structure for an argument.

  arg_check_name[num_checks] = $4;

  num_checks++;

  print; next;

}

parse_phase == 5 && /^[ \t]*mig_external kern_return_t/ {

  # The declaration of the user server function for this rpc.

  user_function_name = $3;

  print; next;

}

parse_phase == 5 && /^#if[ \t]TypeCheck/ {

  # The first args type checking statement; we need to insert our chunk of

  # code that bypasses all the type checks if this is an error return, after

  # which we're done until we get to the next function.  Handily, the size

  # of mig's Reply structure is also the size of the alternate Request

  # structure that we want to check for.

  print "\tif (In0P->Head.msgh_size == sizeof (Reply)";

  print "\t    && ! (In0P->Head.msgh_bits & MACH_MSGH_BITS_COMPLEX)";

  print "\t    && *(int *)&In0P->" arg_type_code_name[0] " == *(int *)&" arg_check_name[0];

  print "\t    && In0P->" arg_name[0] " != 0)";

  print "\t  /* Error return, only the error code argument is passed.  */";

  print "\t  {";

  # Force the function into a type that only takes the first two args, via

  # the temp variable SFUN (is there another way to correctly do this cast?).

  # This is possibly bogus, but easier than supplying bogus values for all

  # the other args (we can't just pass 0 for them, as they might not be scalar).

  printf ("\t    kern_return_t (*sfun)(mach_port_t");

  for (i = 0; i < num_args; i++)

    printf (", %s", arg_type[i]);

  printf (") = %s;\n", user_function_name);

  print "\t    OutP->RetCode = (*(kern_return_t (*)(mach_port_t, kern_return_t))sfun) (In0P->Head.msgh_request_port, In0P->" arg_name[0] ");";

  print "\t    return;";

  print "\t  }";

  print "";

  parse_phase = 0;

  print; next;

}

{ print; }