scripts/generate_BUFSIZ.sh

   1 #!/bin/sh
   2 # Called from top-level directory a-la
   3 #
   4 # scripts/generate_BUFSIZ.sh include/common_bufsiz.h
   5
   6 . ./.config || exit 1
   7
   8 debug=false
   9 #debug=true
  10
  11 postcompile=false
  12 test x"$1" = x"--post" && { postcompile=true; shift; }
  13
  14 common_bufsiz_h=$1
  15
  16 test x"$NM" = x"" && NM="${CONFIG_CROSS_COMPILER_PREFIX}nm"
  17 test x"$CC" = x"" && CC="${CONFIG_CROSS_COMPILER_PREFIX}gcc"
  18
  19 exitcmd="exit 0"
  20
  21 regenerate() {
  22         cat >"$1.$$"
  23         test -f "$1" && diff "$1.$$" "$1" >/dev/null && rm "$1.$$" && return
  24         mv "$1.$$" "$1"
  25 }
  26
  27 generate_std_and_exit() {
  28         $debug && echo "Configuring: bb_common_bufsiz1[] in bss"
  29         {
  30         echo "enum { COMMON_BUFSIZE = 1024 };"
  31         echo "extern char bb_common_bufsiz1[];"
  32         echo "#define setup_common_bufsiz() ((void)0)"
  33         } | regenerate "$common_bufsiz_h"
  34         echo "std" >"$common_bufsiz_h.method"
  35         $exitcmd
  36 }
  37
  38 generate_big_and_exit() {
  39         $debug && echo "Configuring: bb_common_bufsiz1[] in bss, COMMON_BUFSIZE = $1"
  40         {
  41         echo "enum { COMMON_BUFSIZE = $1 };"
  42         echo "extern char bb_common_bufsiz1[];"
  43         echo "#define setup_common_bufsiz() ((void)0)"
  44         } | regenerate "$common_bufsiz_h"
  45         echo "$2" >"$common_bufsiz_h.method"
  46         $exitcmd
  47 }
  48
  49 generate_1k_and_exit() {
  50         generate_big_and_exit 1024 "1k"
  51 }
  52
  53 round_down_COMMON_BUFSIZE() {
  54         COMMON_BUFSIZE=1024
  55         test "$1" -le 32 && return
  56         COMMON_BUFSIZE=$(( ($1-32) & 0x0ffffff0 ))
  57         COMMON_BUFSIZE=$(( COMMON_BUFSIZE < 1024 ? 1024 : COMMON_BUFSIZE ))
  58 }
  59
  60 # User does not want any funky stuff?
  61 test x"$CONFIG_FEATURE_USE_BSS_TAIL" = x"y" || generate_std_and_exit
  62
  63 # The script is run two times: before compilation, when it needs to
  64 # (re)generate $common_bufsiz_h, and directly after successful build,
  65 # when it needs to assess whether the build is ok to use at all (not buggy),
  66 # and (re)generate $common_bufsiz_h for a future build.
  67
  68 if $postcompile; then
  69         # Postcompile needs to create/delete OK/FAIL files
  70
  71         test -f busybox_unstripped || exit 1
  72         test -f "$common_bufsiz_h.method" || exit 1
  73
  74         # How the build was done?
  75         method=`cat -- "$common_bufsiz_h.method"`
  76
  77         # Get _end address
  78         END=`$NM busybox_unstripped | grep ' . _end$'| cut -d' ' -f1`
  79         test x"$END" = x"" && generate_std_and_exit
  80         $debug && echo "END:0x$END $((0x$END))"
  81         END=$((0x$END))
  82
  83         # Get PAGE_SIZE
  84         {
  85         echo "#include <sys/user.h>"
  86         echo "#if defined(PAGE_SIZE) && PAGE_SIZE > 0"
  87         echo "char page_size[PAGE_SIZE];"
  88         echo "#endif"
  89         } >page_size_$$.c
  90         $CC -c "page_size_$$.c" || exit 1
  91         PAGE_SIZE=`$NM --size-sort "page_size_$$.o" | cut -d' ' -f1`
  92         rm "page_size_$$.c" "page_size_$$.o"
  93         test x"$PAGE_SIZE" = x"" && exit 1
  94         $debug && echo "PAGE_SIZE:0x$PAGE_SIZE $((0x$PAGE_SIZE))"
  95         PAGE_SIZE=$((0x$PAGE_SIZE))
  96         test $PAGE_SIZE -lt 1024 && exit 1
  97
  98         # How much space between _end[] and next page?
  99         PAGE_MASK=$((PAGE_SIZE-1))
 100         TAIL_SIZE=$(( (-END) & PAGE_MASK ))
 101         $debug && echo "TAIL_SIZE:$TAIL_SIZE bytes"
 102
 103         if test x"$method" = x"1k"; then
 104                 {
 105                 echo $TAIL_SIZE
 106                 md5sum <.config | cut -d' ' -f1
 107                 stat -c "%Y" .config
 108                 } >"$common_bufsiz_h.1k.OK"
 109                 round_down_COMMON_BUFSIZE $((1024 + TAIL_SIZE))
 110                 # emit message only if COMMON_BUFSIZE is indeed larger
 111                 test $COMMON_BUFSIZE -gt 1024 \
 112                         && echo "Rerun make to use larger COMMON_BUFSIZE ($COMMON_BUFSIZE)"
 113                 test $COMMON_BUFSIZE = 1024 && generate_1k_and_exit
 114                 generate_big_and_exit $COMMON_BUFSIZE "big"
 115         fi
 116 fi
 117
 118 # Based on past success/fail of 1k build, decide next build type
 119
 120 if test -f "$common_bufsiz_h.1k.OK"; then
 121         # previous 1k build succeeded
 122         oldcfg=`tail -n2 -- "$common_bufsiz_h.1k.OK"`
 123         curcfg=`md5sum <.config | cut -d' ' -f1; stat -c "%Y" .config`
 124         # config did not change
 125         if test x"$oldcfg" = x"$curcfg"; then
 126                 # Try bigger COMMON_BUFSIZE if possible
 127                 TAIL_SIZE=`head -n1 -- "$common_bufsiz_h.1k.OK"`
 128                 round_down_COMMON_BUFSIZE $((1024 + TAIL_SIZE))
 129                 test $COMMON_BUFSIZE = 1024 && generate_1k_and_exit
 130                 generate_big_and_exit $COMMON_BUFSIZE "big"
 131         fi
 132         # config did change
 133         rm -rf -- "$common_bufsiz_h.1k.OK"
 134 fi
 135
 136 # There was no 1k build yet. Try it.
 137 generate_1k_and_exit