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