test/fuzzer: a simple fuzzer using libFuzzer

This commit adds some basic infrastructure for fuzzers, and adds a
fuzzer for the CUE sheet parser.

meson.build

@@ -112,6 +112,13 @@ if get_option('buildtype') != 'debug'
   ]
 endif
 
+if get_option('fuzzer')
+  fuzzer_flags = ['-fsanitize=fuzzer,address,undefined']
+  add_global_arguments(fuzzer_flags, language: 'cpp')
+  add_global_arguments(fuzzer_flags, language: 'c')
+  add_global_link_arguments(fuzzer_flags, language: 'cpp')
+endif
+
 add_global_arguments(common_cxxflags + compiler.get_supported_arguments(test_cxxflags), language: 'cpp')
 add_global_arguments(common_cflags + c_compiler.get_supported_arguments(test_cflags), language: 'c')
 add_global_link_arguments(compiler.get_supported_link_arguments(test_ldflags), language: 'cpp')
@@ -502,6 +509,7 @@ mpd = build_target(
     chromaprint_dep,
   ],
   link_args: link_args,
+  build_by_default: not get_option('fuzzer'),
   install: not is_android and not is_haiku,
 )
 
@@ -542,3 +550,7 @@ subdir('doc')
 if get_option('test')
   subdir('test')
 endif
+
+if get_option('fuzzer')
+  subdir('test/fuzzer')
+endif

meson_options.txt

@@ -17,6 +17,7 @@ option('systemd_user_unit_dir', type: 'string', description: 'systemd user servi
 #
 
 option('test', type: 'boolean', value: false, description: 'Build the unit tests and debug programs')
+option('fuzzer', type: 'boolean', value: false, description: 'Build fuzzers (requires libFuzzer)')
 
 #
 # Android

test/fuzzer/FuzzCueParser.cxx

@@ -0,0 +1,26 @@
+#include "playlist/cue/CueParser.hxx"
+#include "util/IterableSplitString.hxx"
+
+#include <string>
+#include <string_view>
+
+extern "C" {
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size);
+}
+
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
+{
+	CueParser parser;
+
+	const std::string_view src{(const char *)data, size};
+
+	for (const auto line : IterableSplitString(src, '\n')) {
+		parser.Feed(std::string(line).c_str());
+		parser.Get();
+	}
+
+	parser.Finish();
+	parser.Get();
+
+	return 0;
+}

test/fuzzer/meson.build

@@ -0,0 +1,9 @@
+executable(
+  'FuzzCueParser',
+  'FuzzCueParser.cxx',
+  '../../src/playlist/cue/CueParser.cxx',
+  include_directories: inc,
+  dependencies: [
+    tag_dep,
+  ],
+)