1#!/usr/bin/perl -w
2# Derive #define directives from specially formatted 'case ...:' statements.
3
4# Copyright (C) 2003-2023 Free Software Foundation, Inc.
5
6# This program is free software: you can redistribute it and/or modify
7# it under the terms of the GNU General Public License as published by
8# the Free Software Foundation, either version 3 of the License, or
9# (at your option) any later version.
10
11# This program is distributed in the hope that it will be useful,
12# but WITHOUT ANY WARRANTY; without even the implied warranty of
13# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14# GNU General Public License for more details.
15
16# You should have received a copy of the GNU General Public License
17# along with this program.  If not, see <https://www.gnu.org/licenses/>.
18
19use strict;
20
21use Getopt::Long;
22
23(my $VERSION = '$Revision: 1.5 $ ') =~ tr/[0-9].//cd;
24(my $ME = $0) =~ s|.*/||;
25
26END
27{
28  # Nobody ever checks the status of print()s.  That's okay, because
29  # if any do fail, we're guaranteed to get an indicator when we close()
30  # the filehandle.
31  #
32  # Close stdout now, and if there were no errors, return happy status.
33  # If stdout has already been closed by the script, though, do nothing.
34  defined fileno STDOUT
35    or return;
36  close STDOUT
37    and return;
38
39  # Errors closing stdout.  Indicate that, and hope stderr is OK.
40  warn "$ME: closing standard output: $!\n";
41
42  # Don't be so arrogant as to assume that we're the first END handler
43  # defined, and thus the last one invoked.  There may be others yet
44  # to come.  $? will be passed on to them, and to the final _exit().
45  #
46  # If it isn't already an error, make it one (and if it _is_ an error,
47  # preserve the value: it might be important).
48  $? ||= 1;
49}
50
51sub usage ($)
52{
53  my ($exit_code) = @_;
54  my $STREAM = ($exit_code == 0 ? *STDOUT : *STDERR);
55  if ($exit_code != 0)
56    {
57      print $STREAM "Try '$ME --help' for more information.\n";
58    }
59  else
60    {
61      print $STREAM <<EOF;
62Usage: $ME [OPTIONS] FILE
63
64FIXME: describe
65
66OPTIONS:
67
68  There are two modes of operation, the default, which is to emit
69  #define directives derived from specially formatted 'case' statements,
70  and that with --local, which is to emit a static inline function
71  mapping S_MAGIC_* values to 1, 0, -1, corresponding to known-local,
72  known-remote/distributed/network and unknown, respectively.
73
74   --local    emit an is_local_fs_type function
75   --help     display this help and exit
76   --version  output version information and exit
77
78EOF
79    }
80  exit $exit_code;
81}
82
83{
84  # The default is to print S_MAGIC_* definitions.
85  my $emit_magic = 1;
86
87  GetOptions
88    (
89     local => sub { $emit_magic = 0 },
90     help => sub { usage 0 },
91     version => sub { print "$ME version $VERSION\n"; exit },
92    ) or usage 1;
93
94  my $fail = 0;
95
96  @ARGV < 1
97    and (warn "$ME: missing FILE arguments\n"), $fail = 1;
98  1 < @ARGV
99    and (warn "$ME: too many arguments\n"), $fail = 1;
100  $fail
101    and usage 1;
102
103  my $file = $ARGV[0];
104
105  open FH, $file
106    or die "$ME: can't open '$file' for reading: $!\n";
107
108  # For each line like this:
109  #   case S_MAGIC_ROMFS: /* 0x7275 */
110  # emit one like this:
111  #   # define S_MAGIC_ROMFS 0x7275
112  # Fail if there is a 'case S_MAGIC_.*' line without
113  # a properly formed comment.
114
115  my $map_comment = <<EOF;
116/* Map each S_MAGIC_* value to 1, 0 or -1.
117   1 if it is known to be a remote file system type,
118   0 if it is known to be a local file system type, or -1 otherwise.  */
119EOF
120  my $magic_comment = <<EOF;
121/* Define the magic numbers as given by statfs(2).
122   Please send additions to bug-coreutils\@gnu.org and meskes\@debian.org.
123   This file is generated automatically from $file. */
124EOF
125  print $emit_magic ? $magic_comment : $map_comment;
126
127  $emit_magic
128    and print "\n#if defined __linux__ || defined __ANDROID__\n";
129  $emit_magic
130    or print "static inline int\n"
131      . "is_local_fs_type (unsigned long int magic)\n"
132      . "{\n  switch (magic)\n    {\n";
133
134  while (defined (my $line = <FH>))
135    {
136      $line =~ /^[ \t]+case S_MAGIC_/
137        or next;
138      $line =~
139        m!^[ \t]+case (S_MAGIC_\w+): /\* (0x[0-9A-Fa-f]+) (local|remote) \*/!
140        or (warn "$ME:$file:$.: malformed case S_MAGIC_... line"),
141          $fail = 1, next;
142      my $name = $1;
143      my $magic = $2;
144      my $local = $3 eq 'local' ? 1 : 0;
145      print $emit_magic
146        ? "# define $name $magic\n"
147        : "      case $name: return $local;\n";
148    }
149
150  $emit_magic
151    and print <<\EOF;
152#elif defined __GNU__
153# include <hurd/hurd_types.h>
154#endif
155EOF
156  $emit_magic
157    or printf "      default: return -1;\n    }\n}\n";
158
159  close FH;
160
161  exit $fail;
162}
163