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      1 #!/bin/sh
      2 #
      3 # Copyright (C) 2011 The Android Open Source Project
      4 #
      5 # Licensed under the Apache License, Version 2.0 (the "License");
      6 # you may not use this file except in compliance with the License.
      7 # You may obtain a copy of the License at
      8 #
      9 #      http://www.apache.org/licenses/LICENSE-2.0
     10 #
     11 # Unless required by applicable law or agreed to in writing, software
     12 # distributed under the License is distributed on an "AS IS" BASIS,
     13 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     14 # See the License for the specific language governing permissions and
     15 # limitations under the License.
     16 #
     17 # gen-system-symbols.sh
     18 #
     19 # This tool is used to read the shared library from a source directory
     20 # (SRC) and extract the list of functions and variables.
     21 #
     22 # Then, for each library, it will generate in (DST) two text files
     23 # named <library>.functions.txt and <library>.variables.txt
     24 #
     25 
     26 # Only runs on Linux because it requires the "readelf" utility
     27 #
     28 
     29 . `dirname $0`/prebuilt-common.sh
     30 
     31 VERBOSE=no
     32 
     33 PROGRAM_PARAMETERS="<src-dir> <dst-dir>"
     34 PROGRAM_DESCRIPTION=\
     35 "This program is used to parse all shared libraries in <src-dir>
     36 and extract, for each one of them, the list of functions and variables
     37 that it exports.
     38 
     39 For some of these libraries, it will remove symbols that are not meant
     40 to be imported (unless you use --no-symbol-filtering)
     41 
     42 These lists will then be saved into two files:
     43 
     44   <dst-dir>/<libname>.functions.txt
     45   <dst-dir>/<libname>.variables.txt
     46 "
     47 
     48 NO_FILTERING=
     49 register_var_option "--no-symbol-filtering" NO_FILTERING "Disable symbol filtering"
     50 
     51 extract_parameters "$@"
     52 
     53 parse_params ()
     54 {
     55     SRCDIR=$1
     56     DSTDIR=$2
     57 
     58     if [ -z "$SRCDIR" ]; then
     59         dump "ERROR: Missing first parameter (source directory path), see --help"
     60         exit 1
     61     fi
     62 
     63     if [ -z "$DSTDIR" ]; then
     64         dump "ERROR: Missing second parameter (destination directory path), see --help"
     65         exit 1
     66     fi
     67 
     68     if [ ! -d "$SRCDIR" ]; then
     69         dump "ERROR: Not a source directory: $SRCDIR"
     70         exit 1
     71     fi
     72 
     73     mkdir -p $DSTDIR
     74     fail_panic "Could not create destination directory: $DSTDIR"
     75 }
     76 
     77 parse_params $PARAMETERS
     78 
     79 READELF=readelf
     80 
     81 # $1: shared library path
     82 get_library_functions ()
     83 {
     84     $READELF -s -D -W $1 | awk '$5 ~ /FUNC/ && $6 ~ /GLOBAL|WEAK/ && $8 !~ /UND/ { print $9; }' | sort -u
     85 }
     86 
     87 # $1: shared library path
     88 get_library_variables ()
     89 {
     90     $READELF -s -D -W $1 | awk '$5 ~ /OBJECT/ && $6 ~ /GLOBAL|WEAK/ && $8 !~ /UND/ { print $9; }' | sort -u
     91 }
     92 
     93 # Temp file used to list shared library symbol exclusions
     94 # See set_symbol_excludes and extract_shared_library_xxxx functions below
     95 SYMBOL_EXCLUDES=$TMPDIR/ndk-symbol-excludes.txt
     96 
     97 # Temp file used to list shared library symbol inclusions, these
     98 # are essentially overrides to the content of SYMBOL_EXCLUDES
     99 SYMBOL_INCLUDES=$TMPDIR/ndk-symbol-includes.txt
    100 
    101 # Temp file used to filter symbols
    102 SYMBOL_TMPFILE=$TMPDIR/ndk-symbols-list.txt
    103 
    104 # Reset the symbol exclusion list to its default
    105 reset_symbol_excludes ()
    106 {
    107     # By default, do not export C++ mangled symbol, which all start with _Z
    108     echo '^_Z' > $SYMBOL_EXCLUDES
    109 
    110     # __INIT_ARRAY__, __FINI_ARRAY__ and _GLOBAL_OFFSET_TABLE_ are special symbols
    111     # that should normally be hidden.
    112     echo "^__INIT_ARRAY__" >> $SYMBOL_EXCLUDES
    113     echo "^__FINI_ARRAY__" >> $SYMBOL_EXCLUDES
    114     echo "^_GLOBAL_OFFSET_TABLE_" >> $SYMBOL_EXCLUDES
    115     > $SYMBOL_INCLUDES
    116 }
    117 
    118 # Add new exclusion patterns to SYMBOL_EXCLUDES
    119 set_symbol_excludes ()
    120 {
    121     (echo "$@" | tr ' ' '\n') >> $SYMBOL_EXCLUDES
    122 }
    123 
    124 # Add new inclusion patterns to SYMBOL_INCLUDES
    125 set_symbol_includes ()
    126 {
    127     (echo "$@" | tr ' ' '\n') >> $SYMBOL_INCLUDES
    128 }
    129 
    130 # Clear symbol exclusion/inclusion files
    131 clear_symbol_excludes ()
    132 {
    133     rm -f $SYMBOL_EXCLUDES $SYMBOL_INCLUDES
    134 }
    135 
    136 # Filter the list of symbols from a file
    137 # $1: path to symbol list file
    138 filter_symbols ()
    139 {
    140     (grep -v -f $SYMBOL_EXCLUDES $1 ; grep -f $SYMBOL_INCLUDES $1) | sort -u
    141 }
    142 
    143 # $1: Library name
    144 # $2+: List of symbols (functions or variables)
    145 # Out: sorted list of filtered symbols, based on library name
    146 filter_library_symbols ()
    147 {
    148     local LIB=$1
    149     shift
    150     local SYMBOLS="$@"
    151     (echo "$SYMBOLS" | tr ' ' '\n' | sort -u) > $SYMBOL_TMPFILE
    152 
    153     reset_symbol_excludes
    154 
    155     case $LIB in
    156         libc.so)
    157             # Remove a few internal symbols that should not be exposed
    158             # from the C library (we plan to clean that up soon by using the
    159             # "hidden" visibility attribute in the near future).
    160             #
    161             set_symbol_excludes \
    162                 '^the_' '^dns_' 'load_domain_search_list' 'res_get_dns_changed' \
    163                 '^_resolv_cache' '^_dns_getht' '^_thread_atexit' \
    164                 '^free_malloc_leak_info' 'fake_gmtime_r' 'fake_localtime_r' \
    165                 '^gAllocationsMutex' '^gHashTable' '^gMallocLeakZygoteChild'
    166             # libc.so now absort libstdc++ use to have, thus contains C++ symbols from now on
    167             set_symbol_includes '^_Z.*'
    168             ;;
    169         libstdc++.so)
    170             # This used to be the only library that is allowed to export C++ symbols for now.
    171             set_symbol_includes '^_Z.*'
    172             ;;
    173         liblog.so)
    174             set_symbol_excludes '^.*'         # exclude everything
    175             set_symbol_includes '^__android_' # except __android_xxxx functions
    176             ;;
    177         libOpenSLES.so)
    178             set_symbol_excludes '^_' '^MPH_' # remove MPH_to_xxx definitions
    179             ;;
    180         libGLESv*.so)
    181             # Exclude non-OES extension entry points
    182             set_symbol_excludes 'EXT$'
    183             set_symbol_excludes 'AMD$'
    184             set_symbol_excludes 'ANGLE$'
    185             set_symbol_excludes 'APPLE$'
    186             set_symbol_excludes 'IMG$'
    187             set_symbol_excludes 'NV$'
    188             set_symbol_excludes 'QCOM$'
    189             ;;
    190     esac
    191     filter_symbols "$SYMBOL_TMPFILE"
    192 }
    193 
    194 for LIB in $(cd $SRCDIR && ls lib*.so); do
    195     SRCLIB=$SRCDIR/$LIB
    196     log "Extracting symbols from $LIB"
    197     FUNCS=$(get_library_functions $SRCLIB)
    198     VARS=$(get_library_variables $SRCLIB)
    199     if [ -z "$NO_FILTERING" ]; then
    200         FUNCS=$(filter_library_symbols $LIB $FUNCS)
    201         VARS=$(filter_library_symbols $LIB $VARS)
    202     fi
    203     NUMFUNCS=$(echo $FUNCS | wc -w)
    204     NUMVARS=$(echo $VARS | wc -w)
    205     log "    Found $NUMFUNCS functions and $NUMVARS variables"
    206     (echo "$FUNCS" | tr ' ' '\n') > $DSTDIR/$LIB.functions.txt
    207     (echo "$VARS" | tr ' ' '\n') > $DSTDIR/$LIB.variables.txt
    208 done
    209