From e6a2f4cc5a47d3022bdf5ca2cacbaa5a8c5baf7a Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Thu, 21 Apr 2016 16:26:30 +0200 Subject: libbb: make bb_common_bufsiz1 1 kbyte, add capability to use bss tail for it The config item is FEATURE_USE_BSS_TAIL. When it is off (default): function old new delta read_config 210 228 +18 doCommands 2279 2294 +15 ipneigh_list_or_flush 763 772 +9 ipaddr_list_or_flush 1256 1261 +5 display_process_list 1301 1306 +5 conspy_main 1378 1383 +5 do_lzo_compress 352 355 +3 do_lzo_decompress 565 567 +2 push 46 44 -2 inetd_main 2136 2134 -2 uevent_main 421 418 -3 addLines 97 92 -5 bb_common_bufsiz1 8193 1024 -7169 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 8/5 up/down: 62/-7181) Total: -7119 bytes text data bss dec hex filename 829850 4086 9080 843016 cdd08 busybox_old 829901 4086 1904 835891 cc133 busybox_unstripped FEATURE_USE_BSS_TAIL=y: read_config 210 228 +18 doCommands 2279 2294 +15 ipneigh_list_or_flush 763 772 +9 ipaddr_list_or_flush 1256 1261 +5 display_process_list 1301 1306 +5 conspy_main 1378 1383 +5 do_lzo_compress 352 355 +3 do_lzo_decompress 565 567 +2 inetd_main 2136 2134 -2 bb_common_bufsiz1 8193 - -8193 ------------------------------------------------------------------------------ (add/remove: 0/1 grow/shrink: 8/1 up/down: 62/-8195) Total: -8133 bytes text data bss dec hex filename 829850 4086 9080 843016 cdd08 busybox_old 829911 4086 880 834877 cbd3d busybox_unstripped FIXME: setup_common_bufsiz() calls are missing. Signed-off-by: Denys Vlasenko --- scripts/generate_BUFSIZ.sh | 114 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 114 insertions(+) create mode 100755 scripts/generate_BUFSIZ.sh (limited to 'scripts') diff --git a/scripts/generate_BUFSIZ.sh b/scripts/generate_BUFSIZ.sh new file mode 100755 index 000000000..afe9eee1e --- /dev/null +++ b/scripts/generate_BUFSIZ.sh @@ -0,0 +1,114 @@ +#!/bin/sh +# Called from top-level directory a-la +# +# scripts/generate_BUFSIZ.sh include/common_bufsiz.h + +. ./.config || exit 1 + +debug=false + +common_bufsiz_h=$1 + +test x"$NM" = x"" && NM="${CONFIG_CROSS_COMPILER_PREFIX}nm" +test x"$CC" = x"" && CC="${CONFIG_CROSS_COMPILER_PREFIX}gcc" + +regenerate() { + cat >"$1.$$" + test -f "$1" && diff "$1.$$" "$1" >/dev/null && rm "$1.$$" && return + mv "$1.$$" "$1" +} + +generate_std_and_exit() { + $debug && echo "Default: bb_common_bufsiz1[] in bss" + { + echo "enum { COMMON_BUFSIZE = 1024 };" + echo "extern char bb_common_bufsiz1[];" + echo "#define setup_common_bufsiz() ((void)0)" + } | regenerate "$common_bufsiz_h" + exit 0 +} + +# User does not want any funky stuff? +test x"$CONFIG_FEATURE_USE_BSS_TAIL" = x"y" || generate_std_and_exit + +test -f busybox_unstripped || { + # We did not try anything yet + $debug && echo "Will try to fit bb_common_bufsiz1[] into _end[]" + { + echo "enum { COMMON_BUFSIZE = 1024 };" + echo "extern char _end[]; /* linker-provided label */" + echo "#define bb_common_bufsiz1 _end" + echo "#define setup_common_bufsiz() ((void)0)" + } | regenerate "$common_bufsiz_h" + echo 1024 >"$common_bufsiz_h.BUFSIZE" + exit 0 +} + +# Get _end address +END=`$NM busybox_unstripped | grep ' . _end$'| cut -d' ' -f1` +test x"$END" = x"" && generate_std_and_exit +$debug && echo "END:0x$END $((0x$END))" +END=$((0x$END)) + +# Get PAGE_SIZE +echo "\ +#include +#if defined(PAGE_SIZE) && PAGE_SIZE > 0 +char page_size[PAGE_SIZE]; +#else +char page_size[1]; +#endif +" >page_size_$$.c +$CC -c "page_size_$$.c" || generate_std_and_exit +PAGE_SIZE=`$NM --size-sort "page_size_$$.o" | cut -d' ' -f1` +rm "page_size_$$.c" "page_size_$$.o" +test x"$PAGE_SIZE" = x"" && generate_std_and_exit +$debug && echo "PAGE_SIZE:0x$PAGE_SIZE $((0x$PAGE_SIZE))" +PAGE_SIZE=$((0x$PAGE_SIZE)) +test $PAGE_SIZE -lt 1024 && generate_std_and_exit + +# How much space between _end[] and next page? +PAGE_MASK=$((PAGE_SIZE-1)) +REM=$(( (-END) & PAGE_MASK )) +$debug && echo "REM:$REM" + +if test $REM -lt 1024; then + # _end[] has no enough space for bb_common_bufsiz1[], + # users will need to malloc it. + { + echo "enum { COMMON_BUFSIZE = 1024 };" + echo "extern char *bb_common_bufsiz1;" + echo "void setup_common_bufsiz(void);" + } | regenerate "$common_bufsiz_h" + # Check that we aren't left with a buggy binary: + if test -f "$common_bufsiz_h.BUFSIZE"; then + rm "$common_bufsiz_h.BUFSIZE" + echo "Warning! Space in _end[] is too small ($REM bytes)!" + echo "Rerun make to build a binary which doesn't use it!" + exit 1 + fi + exit 0 +fi + +# _end[] has REM bytes for bb_common_bufsiz1[] +OLD=1024 +test -f "$common_bufsiz_h.BUFSIZE" && OLD=`cat "$common_bufsiz_h.BUFSIZE"` +$debug && echo "OLD:$OLD" +{ +echo "enum { COMMON_BUFSIZE = $REM };" +echo "extern char _end[]; /* linker-provided label */" +echo "#define bb_common_bufsiz1 _end" +echo "#define setup_common_bufsiz() ((void)0)" +} | regenerate "$common_bufsiz_h" +echo $REM >"$common_bufsiz_h.BUFSIZE" + +# Check that code did not grow too much and thus _end[] did not shink: +if test $OLD -gt $REM; then + echo "Warning! Space in _end[] has decreased from $OLD to $REM bytes!" + echo "Rerun make!" + exit 1 +fi + +if test $OLD != $REM; then + echo "Space in _end[] is $REM bytes. Rerun make to use larger COMMON_BUFSIZE." +fi -- cgit v1.2.3