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 _end[], COMMON_BUFSIZE = $1"
  40         {
  41         echo "enum { COMMON_BUFSIZE = $1 };"
  42         echo "extern char _end[]; /* linker-provided label */"
  43         echo "#define bb_common_bufsiz1 _end"
  44         echo "#define setup_common_bufsiz() ((void)0)"
  45         } | regenerate "$common_bufsiz_h"
  46         echo "$2" >"$common_bufsiz_h.method"
  47         $exitcmd
  48 }
  49
  50 generate_1k_and_exit() {
  51         generate_big_and_exit 1024 "1k"
  52 }
  53
  54
  55 generate_malloc_and_exit() {
  56         $debug && echo "Configuring: bb_common_bufsiz1[] is malloced"
  57         {
  58         echo "enum { COMMON_BUFSIZE = 1024 };"
  59         echo "extern char *const bb_common_bufsiz1;"
  60         echo "void setup_common_bufsiz(void);"
  61         } | regenerate "$common_bufsiz_h"
  62         echo "malloc" >"$common_bufsiz_h.method"
  63         $exitcmd
  64 }
  65
  66 round_down_COMMON_BUFSIZE() {
  67         COMMON_BUFSIZE=$(( ($1-32) & 0xfffffe0 ))
  68         COMMON_BUFSIZE=$(( COMMON_BUFSIZE < 1024 ? 1024 : COMMON_BUFSIZE ))
  69 }
  70
  71 # User does not want any funky stuff?
  72 test x"$CONFIG_FEATURE_USE_BSS_TAIL" = x"y" || generate_std_and_exit
  73
  74 # The script is run two times: before compilation, when it needs to
  75 # (re)generate $common_bufsiz_h, and directly after successful build,
  76 # when it needs to assess whether the build is ok to use at all (not buggy),
  77 # and (re)generate $common_bufsiz_h for a future build.
  78
  79 if $postcompile; then
  80         # Postcompile needs to create/delete OK/FAIL files
  81
  82         test -f busybox_unstripped || exit 1
  83         test -f "$common_bufsiz_h.method" || exit 1
  84
  85         # How the build was done?
  86         method=`cat -- "$common_bufsiz_h.method"`
  87
  88         # Get _end address
  89         END=`$NM busybox_unstripped | grep ' . _end$'| cut -d' ' -f1`
  90         test x"$END" = x"" && generate_std_and_exit
  91         $debug && echo "END:0x$END $((0x$END))"
  92         END=$((0x$END))
  93
  94         # Get PAGE_SIZE
  95         {
  96         echo "#include <sys/user.h>"
  97         echo "#if defined(PAGE_SIZE) && PAGE_SIZE > 0"
  98         echo "char page_size[PAGE_SIZE];"
  99         echo "#endif"
 100         } >page_size_$$.c
 101         $CC -c "page_size_$$.c" || exit 1
 102         PAGE_SIZE=`$NM --size-sort "page_size_$$.o" | cut -d' ' -f1`
 103         rm "page_size_$$.c" "page_size_$$.o"
 104         test x"$PAGE_SIZE" = x"" && exit 1
 105         $debug && echo "PAGE_SIZE:0x$PAGE_SIZE $((0x$PAGE_SIZE))"
 106         PAGE_SIZE=$((0x$PAGE_SIZE))
 107         test $PAGE_SIZE -lt 512 && exit 1
 108
 109         # How much space between _end[] and next page?
 110         PAGE_MASK=$((PAGE_SIZE-1))
 111         TAIL_SIZE=$(( (-END) & PAGE_MASK ))
 112         $debug && echo "TAIL_SIZE:$TAIL_SIZE bytes"
 113
 114         if test x"$method" = x"1k" || test x"$method" = x"big"; then
 115                 if test $TAIL_SIZE -lt 1024; then
 116                         # _end[] has no enough space for bb_common_bufsiz1[]
 117                         echo "Warning! Space in _end[] is too small ($TAIL_SIZE bytes)!"
 118                         echo "Rerun make to build a binary which doesn't use it!"
 119                         rm -- "$common_bufsiz_h.1k.OK" 2>/dev/null
 120                         { md5sum <.config | cut -d' ' -f1; stat -c "%Y" .config; } >"$common_bufsiz_h.1k.FAIL"
 121                         rm busybox_unstripped busybox 2>/dev/null
 122 # Note: here we can do either a "malloc" or "std" build.
 123 # "malloc" gives a bit bigger code:
 124 #     text  bss filename
 125 #   804355 5385 busybox.std
 126 #   804618 4361 busybox.malloc
 127 # but may have a smaller .bss (not guaranteed!). Use "pmap -x" to verify.
 128                         exitcmd="exit 1"
 129                         generate_malloc_and_exit
 130                 else
 131                         PREV_SIZE=1024
 132                         test x"$method" = x"big" && PREV_SIZE=`cat -- "$common_bufsiz_h.1k.OK"`
 133                         round_down_COMMON_BUFSIZE $PREV_SIZE
 134                         PREV_BUFSIZE=$COMMON_BUFSIZE
 135
 136                         rm -- "$common_bufsiz_h.1k.FAIL" 2>/dev/null
 137                         echo $TAIL_SIZE >"$common_bufsiz_h.1k.OK"
 138                         round_down_COMMON_BUFSIZE $TAIL_SIZE
 139                         # emit message only if COMMON_BUFSIZE is indeed larger
 140                         test $COMMON_BUFSIZE -gt $PREV_BUFSIZE \
 141                                 && echo "Rerun make to use larger COMMON_BUFSIZE ($COMMON_BUFSIZE)"
 142 #TODO: test $PREV_BUFSIZE -lt $TAIL_SIZE && PANIC!!!
 143 #Code size with COMMON_BUFSIZE > 1024 may be bigger than code with COMMON_BUFSIZE = 1024!
 144 #(currently we just hope "-32 and round down to 32" saves us)
 145
 146                         test $COMMON_BUFSIZE = 1024 && generate_1k_and_exit
 147                         generate_big_and_exit $COMMON_BUFSIZE "big"
 148                 fi
 149         fi
 150 fi
 151
 152 # Based on past success/fail of 1k build, decide next build type
 153
 154 if test -f "$common_bufsiz_h.1k.OK"; then
 155         # Previous build succeeded fitting 1k into _end[].
 156         # Try bigger COMMON_BUFSIZE if possible.
 157         TAIL_SIZE=`cat -- "$common_bufsiz_h.1k.OK"`
 158         round_down_COMMON_BUFSIZE $TAIL_SIZE
 159         test $COMMON_BUFSIZE = 1024 && generate_1k_and_exit
 160         generate_big_and_exit $COMMON_BUFSIZE "big"
 161 fi
 162
 163 if test -f "$common_bufsiz_h.1k.FAIL"; then
 164         # Previous build FAILED to fit 1k into _end[].
 165         # Was it with same .config?
 166         oldcfg=`cat -- "$common_bufsiz_h.1k.FAIL"`
 167         curcfg=`md5sum <.config | cut -d' ' -f1; stat -c "%Y" .config`
 168         # If yes, then build a "malloced" version
 169         if test x"$oldcfg" = x"$curcfg"; then
 170                 echo "Will not try 1k build, it failed before. Touch .config to override"
 171 # Note: here we can do either a "malloc" or "std" build.
 172                 generate_malloc_and_exit
 173         fi
 174         # else: try 1k version
 175         echo "New .config, will try 1k build"
 176         rm -- "$common_bufsiz_h.1k.FAIL"
 177         generate_1k_and_exit
 178 fi
 179
 180 # There was no 1k build yet. Try it.
 181 generate_1k_and_exit