The Tcpdump Group git mirrors - libpcap/blob - runlex.sh

   1 #! /bin/sh
   2
   3 #
   4 # runlex.sh
   5 # Script to run Lex/Flex.
   6 # First argument is the (quoted) name of the command; if it's null, that
   7 # means that neither Flex nor Lex was found, so we report an error and
   8 # quit.
   9 #
  10 # @(#) $Header: /tcpdump/master/libpcap/runlex.sh,v 1.4 2007-12-31 03:38:39 guy Exp $
  11 #
  12
  13 #
  14 # Get the name of the command to run, and then shift to get the arguments.
  15 #
  16 if [ $# -eq 0 ]
  17 then
  18         echo "Usage: runlex <lex/flex command to run> [ arguments ]" 1>&2
  19         exit 1
  20 fi
  21 LEX="$1"
  22 shift
  23
  24 #
  25 # Check whether we have Lex or Flex.
  26 #
  27 if [ -z "${LEX}" ]
  28 then
  29         echo "Neither lex nor flex was found" 1>&2
  30         exit 1
  31 fi
  32
  33 #
  34 # Process the flags.  We don't use getopt because we don't want to
  35 # embed complete knowledge of what options are supported by Lex/Flex.
  36 #
  37 flags=""
  38 outfile=lex.yy.c
  39 while [ $# -ne 0 ]
  40 do
  41         case "$1" in
  42
  43         -o*)
  44                 #
  45                 # Set the output file name.
  46                 #
  47                 outfile=`echo "$1" | sed 's/-o\(.*\)/\1/'`
  48                 ;;
  49
  50         -*)
  51                 #
  52                 # Add this to the list of flags.
  53                 #
  54                 flags="$flags $1"
  55                 ;;
  56
  57         --|*)
  58                 #
  59                 # End of flags.
  60                 #
  61                 break
  62                 ;;
  63         esac
  64         shift
  65 done
  66
  67 #
  68 # Is it Lex, or is it Flex?
  69 #
  70 if [ "${LEX}" = flex ]
  71 then
  72         #
  73         # It's Flex.
  74         #
  75         have_flex=yes
  76
  77         #
  78         # Does it support the --noFUNCTION options?  If so, we pass
  79         # --nounput, as at least some versions that support those
  80         # options don't support disabling yyunput by defining
  81         # YY_NO_UNPUT.
  82         #
  83         if flex --help | egrep noFUNCTION >/dev/null
  84         then
  85                 flags="$flags --nounput"
  86
  87                 #
  88                 # Does it support -R, for generating reentrant scanners?
  89                 # If so, we're not currently using that feature, but
  90                 # it'll generate some unused functions anyway - and there
  91                 # won't be any header file declaring them, so there'll be
  92                 # defined-but-not-declared warnings.  Therefore, we use
  93                 # --noFUNCTION options to suppress generating those
  94                 # functions.
  95                 #
  96                 if flex --help | egrep reentrant >/dev/null
  97                 then
  98                         flags="$flags --noyyget_lineno --noyyget_in --noyyget_out --noyyget_leng --noyyget_text --noyyset_lineno --noyyset_in --noyyset_out"
  99                 fi
 100         fi
 101 else
 102         #
 103         # It's Lex.
 104         #
 105         have_flex=no
 106 fi
 107
 108 #
 109 # OK, run it.
 110 # If it's lex, it doesn't support -o, so we just write to
 111 # lex.yy.c and, if it succeeds, rename it to the right name,
 112 # otherwise we remove lex.yy.c.
 113 # If it's flex, it supports -o, so we use that - flex with -P doesn't
 114 # write to lex.yy.c, it writes to a lex.{prefix from -P}.c.
 115 #
 116 if [ $have_flex = yes ]
 117 then
 118         ${LEX} $flags -o"$outfile" "$@"
 119
 120         #
 121         # Did it succeed?
 122         #
 123         status=$?
 124         if [ $status -ne 0 ]
 125         then
 126                 #
 127                 # No.  Exit with the failing exit status.
 128                 #
 129                 exit $status
 130         fi
 131
 132         #
 133         # Flex has the annoying habit of stripping all but the last
 134         # component of the "-o" flag argument and using that as the
 135         # place to put the output.  This gets in the way of building
 136         # in a directory different from the source directory.  Try
 137         # to work around this.
 138         #
 139         # Is the outfile where we think it is?
 140         #
 141         outfile_base=`basename "$outfile"`
 142         if [ "$outfile_base" != "$outfile" -a \( ! -r "$outfile" \) -a -r "$outfile_base" ]
 143         then
 144                 #
 145                 # No, it's not, but it is in the current directory.  Put it
 146                 # where it's supposed to be.
 147                 #
 148                 mv "$outfile_base" "$outfile"
 149
 150                 #
 151                 # Did that succeed?
 152                 #
 153                 status=$?
 154                 if [ $status -ne 0 ]
 155                 then
 156                         #
 157                         # No.  Exit with the failing exit status.
 158                         #
 159                         exit $status
 160                 fi
 161         fi
 162 else
 163         ${LEX} $flags "$@"
 164
 165         #
 166         # Did it succeed?
 167         #
 168         status=$?
 169         if [ $status -ne 0 ]
 170         then
 171                 #
 172                 # No.  Get rid of any lex.yy.c file we generated, and
 173                 # exit with the failing exit status.
 174                 #
 175                 rm -f lex.yy.c
 176                 exit $status
 177         fi
 178
 179         #
 180         # OK, rename lex.yy.c to the right output file.
 181         #
 182         mv lex.yy.c "$outfile"
 183
 184         #
 185         # Did that succeed?
 186         #
 187         status=$?
 188         if [ $status -ne 0 ]
 189         then
 190                 #
 191                 # No.  Get rid of any lex.yy.c file we generated, and
 192                 # exit with the failing exit status.
 193                 #
 194                 rm -f lex.yy.c
 195                 exit $status
 196         fi
 197 fi
 198
 199 #
 200 # OK, now let's generate a header file declaring the relevant functions
 201 # defined by the .c file; if the .c file is .../foo.c, the header file
 202 # will be .../foo.h.
 203 #
 204 # This works around some other Flex suckage, wherein it doesn't declare
 205 # the lex routine before defining it, causing compiler warnings.
 206 # XXX - newer versions of Flex support --header-file=, to generate the
 207 # appropriate header file.  With those versions, we should use that option.
 208 #
 209
 210 #
 211 # Get the name of the prefix; scan the source files for a %option prefix
 212 # line.  We use the last one.
 213 #
 214 prefix=`sed -n 's/%option[      ][      ]*prefix="\(.*\)".*/\1/p' "$@" | tail -1`
 215 if [ ! -z "$prefix" ]
 216 then
 217         prefixline="#define yylex ${prefix}lex"
 218 fi
 219
 220 #
 221 # Construct the name of the header file.
 222 #
 223 header_file=`dirname "$outfile"`/`basename "$outfile" .c`.h
 224
 225 #
 226 # Spew out the declaration.
 227 #
 228 cat <<EOF >$header_file
 229 /* This is generated by runlex.sh.  Do not edit it. */
 230 $prefixline
 231 #ifndef YY_DECL
 232 #define YY_DECL int yylex(void)
 233 #endif
 234 YY_DECL;
 235 EOF