1# Reply server mig-output massager
2#
3#   Copyright (C) 1995-2020 Free Software Foundation, Inc.
4#
5#   Written by Miles Bader <miles@gnu.ai.mit.edu>
6#
7#   This program is free software; you can redistribute it and/or
8#   modify it under the terms of the GNU General Public License as
9#   published by the Free Software Foundation; either version 3, or (at
10#   your option) any later version.
11#
12#   This program is distributed in the hope that it will be useful, but
13#   WITHOUT ANY WARRANTY; without even the implied warranty of
14#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15#   General Public License for more details.
16#
17#   You should have received a copy of the GNU General Public License
18#   along with this program.  If not, see <http://www.gnu.org/licenses/>.
19#
20# This awk script hacks the output of mig-generated reply server code
21# so that it allows replies with just the error-code in them (as this is
22# how mig returns errors).
23#
24# It is highly, highly, dependent on the exact format of mig output.  Ick.
25#
26
27BEGIN { parse_phase = 0; }
28
29/^}/ { parse_phase = 0; }
30
31parse_phase == 0 && /^mig_internal void _X[a-zA-Z0-9_]*_reply/ {
32  # The start of a mig server routine.  Reset everything.  Note that we only
33  # mess with rpcs that have the suffix `_reply'.
34  num_args = 0;
35  num_checks = 0;
36  parse_phase = 1;
37  print; next;
38}
39
40parse_phase == 1 && /^[\t ]*typedef struct/ {
41  # The first structure in the server routine should describe the arguments
42  parse_phase = 2;
43  print; next;
44}
45
46parse_phase == 2 {
47  # The message header field in the args structure, which skip.
48  parse_phase = 3;
49  print; next;
50}
51
52parse_phase == 3 && /} Request/ {
53  # The args structure is over.
54  if (num_args > 1)
55    parse_phase = 5;
56  else
57    # There's no extra args that could screw up the normal mechanism for
58    # error returns, so we don't have to insert any new code.
59    parse_phase = 0;
60  print; next;
61}
62
63parse_phase == 3 && num_args == 0 {
64  # The type field for an argument.
65  # This won't be accurate in case of unions being used in the Request struct,
66  # but that doesn't matter, as we'll only be looking at arg_type_code_name[0],
67  # which will not be a union type.
68  arg_type_code_name[num_args] = $2;
69  sub (/;$/, "", arg_type_code_name[num_args]) # Get rid of the semi-colon
70  parse_phase = 4;
71  print; next;
72}
73
74parse_phase == 3 && num_args == 1 {
75  # We've got more than one argument (but we don't care what it is).
76  num_args++;
77  print; next;
78}
79
80parse_phase == 3 {
81  # We've know everything we need; now just wait for the end of the Request
82  # struct.
83  print; next;
84}
85
86parse_phase == 4 {
87  # The value field for an argument.
88  # This won't be accurate in case of unions being used in the Request struct,
89  # but that doesn't matter, as we'll only be looking at arg_name[0], which
90  # will not be a union type.
91  arg_name[num_args] = $2;
92  sub (/;$/, "", arg_name[num_args]) # Get rid of the semi-colon
93  num_args++;
94  parse_phase = 3;
95  print; next;
96}
97
98parse_phase == 5 && /^[ \t]*(auto |static )?const mach_msg_type_t/ {
99  # The type check structure for an argument.
100  arg_check_name[num_checks] = $(NF - 2);
101  num_checks++;
102  print; next;
103}
104
105parse_phase == 5 && /^[ \t]*mig_external kern_return_t/ {
106  # The declaration of the user server function for this rpc.
107  user_function_name = $3;
108  print; next;
109}
110
111parse_phase == 5 && /^#if[ \t]TypeCheck/ {
112  # Keep going if we have not yet collected the type check structures.
113  if (num_checks == 0)
114    {
115      print; next;
116    }
117
118  # The first args type checking statement; we need to insert our chunk of
119  # code that bypasses all the type checks if this is an error return, after
120  # which we're done until we get to the next function.  Handily, the size
121  # of mig's Reply structure is also the size of the alternate Request 
122  # structure that we want to check for.
123  print "\tif (In0P->Head.msgh_size == sizeof (Reply)";
124  print "\t    && ! (In0P->Head.msgh_bits & MACH_MSGH_BITS_COMPLEX)";
125  print "\t    && ! BAD_TYPECHECK(&In0P->" arg_type_code_name[0] ", &" arg_check_name[0] ")";
126  print "\t    && In0P->" arg_name[0] " != 0)";
127  print "\t  /* Error return, only the error code argument is passed.  */";
128  print "\t  {";
129  # Force the function user_function_name into a type that only takes the first
130  # two arguments.
131  # This is possibly bogus, but easier than supplying bogus values for all
132  # the other args (we can't just pass 0 for them, as they might not be scalar).
133  print "\t    void * __error_call = " user_function_name ";";
134  print "\t    OutP->RetCode = (*(kern_return_t (*)(mach_port_t, kern_return_t)) __error_call) (In0P->Head.msgh_request_port, In0P->" arg_name[0] ");";
135  print "\t    return;";
136  print "\t  }";
137  print "";
138  parse_phase = 0;
139  print; next;
140}
141
142{ print; }
143