builtins/psize.sh

   1 #! /bin/sh
   2 #
   3 # psize.sh -- determine this system's pipe size, and write a define to
   4 #             pipesize.h so ulimit.c can use it.
   5
   6 : ${TMPDIR:=/tmp}
   7 # try to use mktemp(1) if the system supports it
   8 { TMPFILE="`mktemp $TMPDIR/pipsize.XXXXXX 2>/dev/null`"; } 2>/dev/null
   9 used_mktemp=true
  10
  11 if [ -z "$TMPFILE" ]; then
  12         TMPNAME=pipsize.$$
  13         TMPFILE=$TMPDIR/$TMPNAME
  14         used_mktemp=false
  15 fi
  16
  17 trap 'rm -f "$TMPFILE" ; exit 1' 1 2 3 6 15
  18 trap 'rm -f "$TMPFILE"' 0
  19
  20 echo "/*"
  21 echo " * pipesize.h"
  22 echo " *"
  23 echo " * This file is automatically generated by psize.sh"
  24 echo " * Do not edit!"
  25 echo " */"
  26 echo ""
  27
  28 #
  29 # Try to avoid tempfile races.  We can't really check for the file's
  30 # existance before we run psize.aux, because `test -e' is not portable,
  31 # `test -h' (test for symlinks) is not portable, and `test -f' only
  32 # checks for regular files.  If we used mktemp(1), we're ahead of the
  33 # game.
  34 #
  35 $used_mktemp || rm -f "$TMPFILE"
  36
  37 ./psize.aux 2>"$TMPFILE" | sleep 3
  38
  39 if [ -s "$TMPFILE" ]; then
  40         echo "#define PIPESIZE `cat "$TMPFILE"`"
  41 else
  42         echo "#define PIPESIZE 512"
  43 fi
  44
  45 exit 0