[msgpack-c] move seeds to source repo (#1360)

* remove fetching seeds from my corpus, fetch instead from src repo

* conditionally zip up fuzzer seed corpora for any fuzzer passed in

* Simplify build steps

We already know that the fuzzers are being iterated over due to the loop
and globbing. As such, we can use more of the fuzzer name and reduce
repetition. This should allow us to add fuzzers/corpora to the src repo
and no need to change anything about the build script or dockerfile

projects/msgpack-c/Dockerfile

@@ -18,6 +18,5 @@ FROM gcr.io/oss-fuzz-base/base-builder
 MAINTAINER chriswwolfe@gmail.com
 RUN apt-get update && apt-get install -y cmake
 RUN git clone --depth 1 https://github.com/msgpack/msgpack-c.git msgpack-c
-RUN git clone --depth 1 https://github.com/derwolfe/msgpack-corpora.git msgpack-corpora
 WORKDIR msgpack-c
 COPY build.sh $SRC/

projects/msgpack-c/build.sh

@@ -21,10 +21,15 @@ cmake -DCMAKE_C_COMPILER="$CC" -DCMAKE_CXX_COMPILER="$CXX" \
 make -j$(nproc) all
 
 for f in $SRC/msgpack-c/fuzz/*_fuzzer.cpp; do
-    fuzzer=$(basename "$f" _fuzzer.cpp)
+    # NOTE(derwolfe): the naming scheme for fuzzers and seed corpora is
+    # fuzzer = something_something_fuzzer.cpp
+    # seed corpus = something_something_fuzzer_seed_corpus
+    fuzzer=$(basename "$f" .cpp)
     $CXX $CXXFLAGS -std=c++11 -Iinclude -I"$SRC/msgpack-c/include" \
-         "$f" -o "$OUT/${fuzzer}_fuzzer" \
+         "$f" -o "$OUT/${fuzzer}" \
          -lFuzzingEngine "$SRC/msgpack-c/libmsgpackc.a"
-done
 
-zip -rj "$OUT/unpack_pack_fuzzer_seed_corpus.zip" "$SRC/msgpack-corpora/packed/"
+    if [ -d "$SRC/msgpack-c/fuzz/${fuzzer}_seed_corpus" ]; then
+        zip -rj "$OUT/${fuzzer}_seed_corpus.zip" "$SRC/msgpack-c/fuzz/${fuzzer}_seed_corpus/"
+    fi
+done