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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 $0`/prebuilt-common.sh
     30 
     31 VERBOSE=no
     32 VERBOSE2=no
     33 
     34 PROGRAM_PARAMETERS="<src-dir> <dst-dir>"
     35 PROGRAM_DESCRIPTION=\
     36 "This program is used to parse all shared libraries in <src-dir>
     37 and extract, for each one of them, the list of functions and variables
     38 that it exports.
     39 
     40 For some of these libraries, it will remove symbols that are not meant
     41 to be imported (unless you use --no-symbol-filtering)
     42 
     43 These lists will then be saved into two files:
     44 
     45   <dst-dir>/<libname>.functions.txt
     46   <dst-dir>/<libname>.variables.txt
     47 "
     48 
     49 NO_FILTERING=
     50 register_var_option "--no-symbol-filtering" NO_FILTERING "Disable symbol filtering"
     51 
     52 extract_parameters "$@"
     53 
     54 parse_params ()
     55 {
     56     SRCDIR=$1
     57     DSTDIR=$2
     58 
     59     if [ -z "$SRCDIR" ]; then
     60         dump "ERROR: Missing first parameter (source directory path), see --help"
     61         exit 1
     62     fi
     63 
     64     if [ -z "$DSTDIR" ]; then
     65         dump "ERROR: Missing second parameter (destination directory path), see --help"
     66         exit 1
     67     fi
     68 
     69     if [ ! -d "$SRCDIR" ]; then
     70         dump "ERROR: Not a source directory: $SRCDIR"
     71         exit 1
     72     fi
     73 
     74     mkdir -p $DSTDIR
     75     fail_panic "Could not create destination directory: $DSTDIR"
     76 }
     77 
     78 parse_params $PARAMETERS
     79 
     80 READELF=readelf
     81 
     82 # $1: shared library path
     83 get_library_functions ()
     84 {
     85     $READELF -s -D -W $1 | awk '$5 ~ /FUNC/ && $6 ~ /GLOBAL|WEAK/ && $8 !~ /UND/ { print $9; }' | sort -u
     86 }
     87 
     88 # $1: shared library path
     89 get_library_variables ()
     90 {
     91     $READELF -s -D -W $1 | awk '$5 ~ /OBJECT/ && $6 ~ /GLOBAL|WEAK/ && $8 !~ /UND/ { print $9; }' | sort -u
     92 }
     93 
     94 # Temp file used to list shared library symbol exclusions
     95 # See set_symbol_excludes and extract_shared_library_xxxx functions below
     96 SYMBOL_EXCLUDES=/tmp/ndk-$USER/ndk-symbol-excludes.txt
     97 
     98 # Temp file used to list shared library symbol inclusions, these
     99 # are essentially overrides to the content of SYMBOL_EXCLUDES
    100 SYMBOL_INCLUDES=/tmp/ndk-$USER/ndk-symbol-includes.txt
    101 
    102 # Temp file used to filter symbols
    103 SYMBOL_TMPFILE=/tmp/ndk-$USER/ndk-symbols-list.txt
    104 
    105 # Reset the symbol exclusion list to its default
    106 reset_symbol_excludes ()
    107 {
    108     # By default, do not export C++ mangled symbol, which all start with _Z
    109     echo '^_Z' > $SYMBOL_EXCLUDES
    110 
    111     # __INIT_ARRAY__ and __FINI_ARRAY__ are special symbols that should
    112     # normally be hidden.
    113     echo "^__INIT_ARRAY__" >> $SYMBOL_EXCLUDES
    114     echo "^__FINI_ARRAY__" >> $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 $LIB in
    156         libc.so)
    157             # Remove a few internal symbols that should not be exposed
    158             # from the C library (we plan to clean that up soon by using the
    159             # "hidden" visibility attribute in the near future).
    160             #
    161             set_symbol_excludes \
    162                 '^the_' '^dns_' 'load_domain_search_list' 'res_get_dns_changed' \
    163                 '^_resolv_cache' '^_dns_getht' '^_thread_atexit' \
    164                 '^free_malloc_leak_info' 'fake_gmtime_r' 'fake_localtime_r' \
    165                 '^gAllocationsMutex' '^gHashTable' '^gMallocLeakZygoteChild'
    166             ;;
    167         libstdc++.so)
    168             # This is the only library that is allowed to export C++ symbols for now.
    169             set_symbol_includes '^_Z.*'
    170             ;;
    171         liblog.so)
    172             set_symbol_excludes '^.*'         # exclude everything
    173             set_symbol_includes '^__android_' # except __android_xxxx functions
    174             ;;
    175         libOpenSLES.so)
    176             set_symbol_excludes '^_' '^MPH_' # remove MPH_to_xxx definitions
    177             ;;
    178     esac
    179     filter_symbols "$SYMBOL_TMPFILE"
    180 }
    181 
    182 for LIB in $(cd $SRCDIR && ls lib*.so); do
    183     SRCLIB=$SRCDIR/$LIB
    184     log "Extracting symbols from $LIB"
    185     FUNCS=$(get_library_functions $SRCLIB)
    186     VARS=$(get_library_variables $SRCLIB)
    187     if [ -z "$NO_FILTERING" ]; then
    188         FUNCS=$(filter_library_symbols $LIB $FUNCS)
    189         VARS=$(filter_library_symbols $LIB $VARS)
    190     fi
    191     NUMFUNCS=$(echo $FUNCS | wc -w)
    192     NUMVARS=$(echo $VARS | wc -w)
    193     log "    Found $NUMFUNCS functions and $NUMVARS variables"
    194     (echo "$FUNCS" | tr ' ' '\n') > $DSTDIR/$LIB.functions.txt
    195     (echo "$VARS" | tr ' ' '\n') > $DSTDIR/$LIB.variables.txt
    196 done
    197