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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 $0`/prebuilt-common.sh
30
31VERBOSE=no
32VERBOSE2=no
33
34PROGRAM_PARAMETERS="<src-dir> <dst-dir>"
35PROGRAM_DESCRIPTION=\
36"This program is used to parse all shared libraries in <src-dir>
37and extract, for each one of them, the list of functions and variables
38that it exports.
39
40For some of these libraries, it will remove symbols that are not meant
41to be imported (unless you use --no-symbol-filtering)
42
43These lists will then be saved into two files:
44
45  <dst-dir>/<libname>.functions.txt
46  <dst-dir>/<libname>.variables.txt
47"
48
49NO_FILTERING=
50register_var_option "--no-symbol-filtering" NO_FILTERING "Disable symbol filtering"
51
52extract_parameters "$@"
53
54parse_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
78parse_params $PARAMETERS
79
80READELF=readelf
81
82# $1: shared library path
83get_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
89get_library_variables ()
90{
91    $READELF -s -D -W $1 | awk '$5 ~ /OBJECT/ && $6 ~ /GLOBAL|WEAK/ && $8 !~ /UND/ { print $9; }' | sort -u
92}
93
94# Temp file used to list shared library symbol exclusions
95# See set_symbol_excludes and extract_shared_library_xxxx functions below
96SYMBOL_EXCLUDES=/tmp/ndk-$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
100SYMBOL_INCLUDES=/tmp/ndk-$USER/ndk-symbol-includes.txt
101
102# Temp file used to filter symbols
103SYMBOL_TMPFILE=/tmp/ndk-$USER/ndk-symbols-list.txt
104
105# Reset the symbol exclusion list to its default
106reset_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    > $SYMBOL_INCLUDES
116}
117
118# Add new exclusion patterns to SYMBOL_EXCLUDES
119set_symbol_excludes ()
120{
121    (echo "$@" | tr ' ' '\n') >> $SYMBOL_EXCLUDES
122}
123
124# Add new inclusion patterns to SYMBOL_INCLUDES
125set_symbol_includes ()
126{
127    (echo "$@" | tr ' ' '\n') >> $SYMBOL_INCLUDES
128}
129
130# Clear symbol exclusion/inclusion files
131clear_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
138filter_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
146filter_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 $LIB in
156        libc.so)
157            # Remove a few internal symbols that should not be exposed
158            # from the C library (we plan to clean that up soon by using the
159            # "hidden" visibility attribute in the near future).
160            #
161            set_symbol_excludes \
162                '^the_' '^dns_' 'load_domain_search_list' 'res_get_dns_changed' \
163                '^_resolv_cache' '^_dns_getht' '^_thread_atexit' \
164                '^free_malloc_leak_info' 'fake_gmtime_r' 'fake_localtime_r' \
165                '^gAllocationsMutex' '^gHashTable' '^gMallocLeakZygoteChild'
166            ;;
167        libstdc++.so)
168            # This is the only library that is allowed to export C++ symbols for now.
169            set_symbol_includes '^_Z.*'
170            ;;
171        liblog.so)
172            set_symbol_excludes '^.*'         # exclude everything
173            set_symbol_includes '^__android_' # except __android_xxxx functions
174            ;;
175        libOpenSLES.so)
176            set_symbol_excludes '^_' '^MPH_' # remove MPH_to_xxx definitions
177            ;;
178        libGLESv*.so)
179            # Exclude non-OES extension entry points
180            set_symbol_excludes 'EXT$'
181            set_symbol_excludes 'AMD$'
182            set_symbol_excludes 'ANGLE$'
183            set_symbol_excludes 'APPLE$'
184            set_symbol_excludes 'IMG$'
185            set_symbol_excludes 'NV$'
186            set_symbol_excludes 'QCOM$'
187            ;;
188    esac
189    filter_symbols "$SYMBOL_TMPFILE"
190}
191
192for LIB in $(cd $SRCDIR && ls lib*.so); do
193    SRCLIB=$SRCDIR/$LIB
194    log "Extracting symbols from $LIB"
195    FUNCS=$(get_library_functions $SRCLIB)
196    VARS=$(get_library_variables $SRCLIB)
197    if [ -z "$NO_FILTERING" ]; then
198        FUNCS=$(filter_library_symbols $LIB $FUNCS)
199        VARS=$(filter_library_symbols $LIB $VARS)
200    fi
201    NUMFUNCS=$(echo $FUNCS | wc -w)
202    NUMVARS=$(echo $VARS | wc -w)
203    log "    Found $NUMFUNCS functions and $NUMVARS variables"
204    (echo "$FUNCS" | tr ' ' '\n') > $DSTDIR/$LIB.functions.txt
205    (echo "$VARS" | tr ' ' '\n') > $DSTDIR/$LIB.variables.txt
206done
207