Change the checksum into a runtime option instead

configure.ac

@@ -179,16 +179,17 @@ if test x${enable_tracing} = xyes; then
 fi
 
 
-ccache_checksum='CCACHE_CHECKSUM=md4 '
+ccache_checksum="md4"
 AC_ARG_ENABLE(blake2,
   [AS_HELP_STRING([--enable-blake2],
     [use blake2b checksum instead of md4])])
 if test x${enable_blake2} = xyes; then
     CPPFLAGS="$CPPFLAGS -DUSE_BLAKE2"
-    ccache_checksum='CCACHE_CHECKSUM=blake2b '
+    ccache_checksum="$ccache_checksum blake2b"
     AC_CHECK_HEADERS(blake2.h)
     AC_CHECK_LIB([b2],[blake2b])
 fi
+ccache_checksum="CHECKSUMS='$ccache_checksum' "
 AC_SUBST(ccache_checksum)
 
 dnl Linking on Windows needs ws2_32

doc/MANUAL.adoc

@@ -284,6 +284,11 @@ IN DIFFERENT DIRECTORIES>>.
     This setting allows you to choose the number of directory levels in the
     cache directory. The default is 2. The minimum is 1 and the maximum is 8.
 
+*checksum* (*CCACHE_CHECKSUM*)::
+
+    This setting specifies which checksum that ccache will use for the hashes.
+    The default is *md4*.
+
 *compiler* (*CCACHE_COMPILER* or (deprecated) *CCACHE_CC*)::
 
     This setting can be used to force the name of the compiler to use. If set

misc/performance

@@ -97,6 +97,8 @@ def test(tmp_dir, options, compiler_args, source_file):
 
     environment = {"CCACHE_DIR": ccache_dir, "PATH": environ["PATH"]}
     environment["CCACHE_COMPILERCHECK"] = options.compilercheck
+    if options.checksum:
+        environment["CCACHE_CHECKSUM"] = options.checksum
     if options.compression:
         environment["CCACHE_COMPRESS"] = "1"
     if options.hardlink:
@@ -252,6 +254,7 @@ def main(argv):
     op.add_option(
         "--compilercheck", help="specify compilercheck (default: mtime)"
     )
+    op.add_option("--checksum", help="hash checksum")
     op.add_option("--compression", help="use compression", action="store_true")
     op.add_option(
         "-d",
@@ -287,6 +290,7 @@ def main(argv):
     op.add_option("--xml", help="print results as XML", action="store_true")
     op.set_defaults(
         ccache=DEFAULT_CCACHE,
+        checksum="md4",
         compilercheck="mtime",
         directory=DEFAULT_DIRECTORY,
         hit_factor=DEFAULT_HIT_FACTOR,
@@ -316,6 +320,7 @@ def main(argv):
             % (" ".join(args), splitext(argv[-1])[0])
         )
         print("Compilercheck:", options.compilercheck)
+        print("Checksum:", options.checksum)
         print("Compression:", on_off(options.compression))
         print("Hardlink:", on_off(options.hardlink))
         print("Nostats:", on_off(options.nostats))

src/ccache.c

@@ -3697,6 +3697,8 @@ initialize(void)
 	cc_log("=== CCACHE %s STARTED =========================================",
 	       CCACHE_VERSION);
 
+	hash_checksum(conf->checksum);
+
 	if (conf->umask != UINT_MAX) {
 		umask(conf->umask);
 	}

src/conf.c

@@ -130,6 +130,7 @@ conf_create(void)
 	conf->base_dir = x_strdup("");
 	conf->cache_dir = format("%s/.ccache", get_home_directory());
 	conf->cache_dir_levels = 2;
+	conf->checksum = x_strdup("md4");
 	conf->compiler = x_strdup("");
 	conf->compiler_check = x_strdup("mtime");
 	conf->compression = false;
@@ -176,6 +177,7 @@ conf_free(struct conf *conf)
 	}
 	free(conf->base_dir);
 	free(conf->cache_dir);
+	free(conf->checksum);
 	free(conf->compiler);
 	free(conf->compiler_check);
 	free(conf->cpp_extension);
@@ -393,6 +395,7 @@ conf_print_items(struct conf *conf,
 	ok &= print_item(conf, "base_dir", printer, context);
 	ok &= print_item(conf, "cache_dir", printer, context);
 	ok &= print_item(conf, "cache_dir_levels", printer, context);
+	ok &= print_item(conf, "checksum", printer, context);
 	ok &= print_item(conf, "compiler", printer, context);
 	ok &= print_item(conf, "compiler_check", printer, context);
 	ok &= print_item(conf, "compression", printer, context);

src/conf.h

@@ -7,6 +7,7 @@ struct conf {
 	char *base_dir;
 	char *cache_dir;
 	unsigned cache_dir_levels;
+	char *checksum;
 	char *compiler;
 	char *compiler_check;
 	bool compression;

src/confitems.gperf

@@ -23,6 +23,7 @@ struct conf_item;
 base_dir,                   ITEM_V(base_dir, env_string, absolute_path)
 cache_dir,                  ITEM(cache_dir, env_string)
 cache_dir_levels,           ITEM_V(cache_dir_levels, unsigned, dir_levels)
+checksum,                   ITEM(checksum, string)
 compiler,                   ITEM(compiler, string)
 compiler_check,             ITEM(compiler_check, string)
 compression,                ITEM(compression, bool)

src/envtoconfitems.gperf

@@ -13,6 +13,7 @@ struct env_to_conf_item;
 %%
 BASEDIR, "base_dir"
 CC, "compiler"
+CHECKSUM, "checksum"
 COMPILER, "compiler"
 COMPILERCHECK, "compiler_check"
 COMPRESS, "compression"

src/hash.c

@@ -25,13 +25,19 @@
 
 #define HASH_DELIMITER "\000cCaChE"
 
+enum {
+	CHECKSUM_MD4 = 0,
+	CHECKSUM_BLAKE2B
+};
+
+static int hash_csum = CHECKSUM_MD4;
+
 struct hash {
 #ifdef USE_BLAKE2
 	blake2b_state state;
 	size_t total;
-#else
-	struct mdfour md;
 #endif
+	struct mdfour md;
 	FILE *debug_binary;
 	FILE *debug_text;
 };
@@ -42,11 +48,12 @@ do_hash_buffer(struct hash *hash, const void *s, size_t len)
 	assert(s);
 
 #ifdef USE_BLAKE2
-	blake2b_update(&hash->state, (const uint8_t *)s, len);
-	hash->total += len;
-#else
-	mdfour_update(&hash->md, (const unsigned char *)s, len);
+	if (hash_csum == CHECKSUM_BLAKE2B) {
+		blake2b_update(&hash->state, (const uint8_t *)s, len);
+		hash->total += len;
+	} else
 #endif
+	mdfour_update(&hash->md, (const unsigned char *)s, len);
 	if (len > 0 && hash->debug_binary) {
 		(void) fwrite(s, 1, len, hash->debug_binary);
 	}
@@ -60,31 +67,50 @@ do_debug_text(struct hash *hash, const void *s, size_t len)
 	}
 }
 
+// Change the checksum being used
+bool hash_checksum(const char *checksum)
+{
+	if (str_eq(checksum, "md4")) {
+		hash_csum = CHECKSUM_MD4;
+		return true;
+	} else if (str_eq(checksum, "blake2b")) {
+		hash_csum = CHECKSUM_BLAKE2B;
+		return true;
+	}
+	return false;
+}
+
 struct hash *
 hash_init(void)
 {
 	struct hash *hash = malloc(sizeof(struct hash));
+	hash_reset(hash);
+	return hash;
+}
+
+void
+hash_reset(struct hash *hash)
+{
 #ifdef USE_BLAKE2
 	blake2b_init(&hash->state, 16);
 	hash->total = 0;
-#else
-	mdfour_begin(&hash->md);
 #endif
+	mdfour_begin(&hash->md);
 	hash->debug_binary = NULL;
 	hash->debug_text = NULL;
-	return hash;
 }
 
 struct hash *
 hash_copy(struct hash *hash)
 {
 	struct hash *result = malloc(sizeof(struct hash));
 #ifdef USE_BLAKE2
-	result->state = hash->state;
-	result->total = hash->total;
-#else
-	result->md = hash->md;
+	if (hash_csum == CHECKSUM_BLAKE2B) {
+		result->state = hash->state;
+		result->total = hash->total;
+	} else
 #endif
+	result->md = hash->md;
 	result->debug_binary = NULL;
 	result->debug_text = NULL;
 	return result;
@@ -111,10 +137,11 @@ size_t
 hash_input_size(struct hash *hash)
 {
 #ifdef USE_BLAKE2
-	return hash->total;
-#else
-	return hash->md.totalN + hash->md.tail_len;
+	if (hash_csum == CHECKSUM_BLAKE2B) {
+		return hash->total;
+	} else
 #endif
+	return hash->md.totalN + hash->md.tail_len;
 }
 
 void
@@ -137,13 +164,14 @@ void
 hash_result_as_bytes(struct hash *hash, unsigned char *out)
 {
 #ifdef USE_BLAKE2
-	// make a copy before altering state
-	struct hash *copy = hash_copy(hash);
-	blake2b_final(&copy->state, out, 16);
-	free(copy);
-#else
-	mdfour_result(&hash->md, out);
+	if (hash_csum == CHECKSUM_BLAKE2B) {
+		// make a copy before altering state
+		struct hash *copy = hash_copy(hash);
+		blake2b_final(&copy->state, out, 16);
+		free(copy);
+	} else
 #endif
+	mdfour_result(&hash->md, out);
 }
 
 bool

src/hash.h

@@ -21,9 +21,15 @@
 
 struct hash;
 
+// Change the checksum being used.
+bool hash_checksum(const char *checksum);
+
 // Create a new hash.
 struct hash *hash_init(void);
 
+// Reset hash to the initial state.
+void hash_reset(struct hash *hash);
+
 // Create a new hash from an existing hash state.
 struct hash *hash_copy(struct hash *hash);
 

test/run

@@ -234,8 +234,6 @@ run_suite() {
 TEST() {
     CURRENT_TEST=$1
 
-    checksum=$CCACHE_CHECKSUM
-
     while read name; do
         unset $name
     done <<EOF
@@ -249,9 +247,6 @@ EOF
     export CCACHE_LOGFILE=$ABS_TESTDIR/ccache.log
     export CCACHE_NODIRECT=1
 
-    # export current checksum used
-    export CCACHE_CHECKSUM=$checksum
-
     # Many tests backdate files, which updates their ctimes. In those tests, we
     # must ignore ctimes. Might as well do so everywhere.
     DEFAULT_SLOPPINESS=include_file_ctime
@@ -402,6 +397,7 @@ direct
 direct_gcc
 depend
 basedir
+checksum
 compression
 readonly
 readonly_direct

test/suites/base.bash

@@ -1072,6 +1072,10 @@ EOF
     # -------------------------------------------------------------------------
     TEST "--hash-file"
 
+    for CCACHE_CHECKSUM in ${CHECKSUMS:-md4}
+    do
+        export CCACHE_CHECKSUM
+
     >empty
     $CCACHE --hash-file empty > hash.out
     printf "a" | $CCACHE --hash-file - >> hash.out
@@ -1087,11 +1091,13 @@ EOF
     fi
 
     if grep "$hash_0" hash.out >/dev/null 2>&1 && \
-       grep "$hash_1" hash.out >/dev/null 2>&1; then
+    grep "$hash_1" hash.out >/dev/null 2>&1; then
         : OK
     else
         test_failed "Unexpected output of --hash-file"
     fi
+
+    done
 }
 
 # =============================================================================

test/suites/checksum.bash

@@ -0,0 +1,24 @@
+SUITE_checksum_SETUP() {
+    generate_code 1 test.c
+}
+
+SUITE_checksum() {
+
+    for CHECKSUM in ${CHECKSUMS:-md4}
+    do
+
+    # -------------------------------------------------------------------------
+    TEST "Test $CHECKSUM"
+
+    CCACHE_CHECKSUM=$CHECKSUM $CCACHE_COMPILE -c test.c
+    expect_stat 'cache hit (direct)' 0
+    expect_stat 'cache hit (preprocessed)' 0
+    expect_stat 'cache miss' 1
+
+    CCACHE_CHECKSUM=$CHECKSUM $CCACHE_COMPILE -c test.c
+    expect_stat 'cache hit (direct)' 0
+    expect_stat 'cache hit (preprocessed)' 1
+    expect_stat 'cache miss' 1
+
+    done
+}

test/suites/direct.bash

@@ -901,6 +901,10 @@ EOF
     # -------------------------------------------------------------------------
     TEST "--dump-manifest"
 
+    for CCACHE_CHECKSUM in ${CHECKSUMS:-md4}
+    do
+        export CCACHE_CHECKSUM
+
     $CCACHE_COMPILE test.c -c -o test.o
 
     manifest=`find $CCACHE_DIR -name '*.manifest'`
@@ -919,13 +923,15 @@ EOF
     fi
 
     if grep "Hash: $checksum_test1_h" manifest.dump >/dev/null 2>&1 && \
-       grep "Hash: $checksum_test2_h" manifest.dump >/dev/null 2>&1 && \
-       grep "Hash: $checksum_test3_h" manifest.dump >/dev/null 2>&1; then
+    grep "Hash: $checksum_test2_h" manifest.dump >/dev/null 2>&1 && \
+    grep "Hash: $checksum_test3_h" manifest.dump >/dev/null 2>&1; then
         : OK
     else
         test_failed "Unexpected output of --dump-manifest"
     fi
 
+    done
+
     # -------------------------------------------------------------------------
     TEST "Argument-less -B and -L"