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1#!/bin/bash -eu
2# Copyright 2018 Google Inc.
3#
4# Licensed under the Apache License, Version 2.0 (the "License");
5# you may not use this file except in compliance with the License.
6# You may obtain a copy of the License at
7#
8#      http://www.apache.org/licenses/LICENSE-2.0
9#
10# Unless required by applicable law or agreed to in writing, software
11# distributed under the License is distributed on an "AS IS" BASIS,
12# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13# See the License for the specific language governing permissions and
14# limitations under the License.
15#
16################################################################################
17
18# "Build the project" is a no-op. There is no "./configure.sh && make" dance.
19# Wuffs' generated C files are "drop-in libraries" a la
20# http://gpfault.net/posts/drop-in-libraries.txt.html
21
22for f in fuzz/c/std/*_fuzzer.c*; do
23  # Extract the format name (such as "gzip", from the C or C++ file name,
24  # "fuzz/c/std/gzip_fuzzer.c") and make the "gzip_fuzzer" binary. First
25  # compile the (C or C++) Wuffs code...
26  extension="${f##*.}"
27  if [   "$extension" = "c" ]; then
28    echo "Building (C)   $f"
29    b=$(basename $f _fuzzer.c)
30    $CC  $CFLAGS   -c $f -o $WORK/${b}_fuzzer.o
31  elif [ "$extension" = "cc" ]; then
32    if [[ $LIB_FUZZING_ENGINE == *"DataFlow"* ]]; then
33      # Linking (below) with "--engine dataflow" works with the C fuzzers but
34      # not the C++ ones. With C++, we get errors like `undefined reference to
35      # `dfs$_ZNSt3__112basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEED2Ev'`
36      #
37      # This is possibly "DFsan instrumented dependencies"
38      # https://github.com/google/oss-fuzz/issues/3388
39      echo "Skipping (C++) $f"
40      continue
41    fi
42    echo "Building (C++) $f"
43    b=$(basename $f _fuzzer.cc)
44    $CXX $CXXFLAGS -c $f -o $WORK/${b}_fuzzer.o
45  else
46    continue
47  fi
48
49  # ...then link the (C++) fuzzing library.
50  $CXX $CXXFLAGS $WORK/${b}_fuzzer.o -o $OUT/${b}_fuzzer $LIB_FUZZING_ENGINE
51
52  # Make the optional "gzip_fuzzer_seed_corpus.zip" archive. This means
53  # extracting the "foo/bar/*.gz" out of the matching "gzip: foo/bar/*.gz"
54  # lines in fuzz/c/std/seed_corpora.txt.
55  #
56  # The seed_corpora.txt lines can contain multiple entries, combining
57  # independent corpora. A naive "zip --junk-paths" of all those files can fail
58  # if there are duplicate file names, which can easily happen if the file name
59  # is a hash of its contents and the contents are a (trivial) minimal
60  # reproducer. We use a de-duplication step of copying all of those files into
61  # a single directory. Doing that in a single "cp" or "mv" call can fail with
62  # "will not overwrite just-created 'foo/etc' with 'bar/etc'", so we make
63  # multiple calls, each copying one file at a time. Later duplicates overwrite
64  # earlier duplicates. It's OK if the contents aren't identical. The result is
65  # still a valid uber-corpus of seed files.
66  seeds=$(sed -n -e "/^$b:/s/^$b: *//p" fuzz/c/std/seed_corpora.txt)
67  if [ -n "$seeds" ]; then
68    mkdir ${b}_fuzzer_seed_corpus
69    for s in $seeds; do
70      cp $s ${b}_fuzzer_seed_corpus
71    done
72    zip --junk-paths --recurse-paths $OUT/${b}_fuzzer_seed_corpus.zip ${b}_fuzzer_seed_corpus
73    rm -rf ${b}_fuzzer_seed_corpus
74  fi
75done
76