Add option and test for reading without read_buf

src/sparsebundlefs.cpp

@@ -93,6 +93,7 @@ struct sparsebundle_t {
     struct {
         bool allow_other = false;
         bool allow_root = false;
+        bool noreadbuf = false;
     } options;
 };
 
@@ -495,13 +496,15 @@ static int sparsebundle_show_usage(char *program_name)
 
 enum {
     SPARSEBUNDLE_OPT_HANDLED = 0, SPARSEBUNDLE_OPT_IGNORED = 1,
-    SPARSEBUNDLE_OPT_DEBUG, SPARSEBUNDLE_OPT_ALLOW_OTHER, SPARSEBUNDLE_OPT_ALLOW_ROOT
+    SPARSEBUNDLE_OPT_DEBUG, SPARSEBUNDLE_OPT_ALLOW_OTHER, SPARSEBUNDLE_OPT_ALLOW_ROOT,
+    SPARSEBUNDLE_OPT_NOREADBUF
 };
 
 struct fuse_opt sparsebundle_options[] = {
     FUSE_OPT_KEY("-D",  SPARSEBUNDLE_OPT_DEBUG),
     FUSE_OPT_KEY("allow_other", SPARSEBUNDLE_OPT_ALLOW_OTHER),
     FUSE_OPT_KEY("allow_root", SPARSEBUNDLE_OPT_ALLOW_ROOT),
+    FUSE_OPT_KEY("noreadbuf", SPARSEBUNDLE_OPT_NOREADBUF),
     FUSE_OPT_END
 };
 
@@ -522,6 +525,10 @@ static int sparsebundle_opt_proc(void *data, const char *arg, int key, struct fu
         sparsebundle->options.allow_root = true;
         return SPARSEBUNDLE_OPT_IGNORED;
 
+    case SPARSEBUNDLE_OPT_NOREADBUF:
+        sparsebundle->options.noreadbuf = true;
+        return SPARSEBUNDLE_OPT_HANDLED;
+
     case FUSE_OPT_KEY_NONOPT:
         if (!sparsebundle->path) {
             sparsebundle->path = realpath(arg, 0);
@@ -612,7 +619,11 @@ int main(int argc, char **argv)
     sparsebundle_filesystem_operations.readdir = sparsebundle_readdir;
     sparsebundle_filesystem_operations.release = sparsebundle_release;
 #if FUSE_SUPPORTS_ZERO_COPY
-    sparsebundle_filesystem_operations.read_buf = sparsebundle_read_buf;
+    syslog(LOG_DEBUG, "fuse supports zero-copy");
+    if (sparsebundle.options.noreadbuf)
+        syslog(LOG_DEBUG, "disabling zero-copy");
+    else
+        sparsebundle_filesystem_operations.read_buf = sparsebundle_read_buf;
 #endif
 
     int ret = fuse_main(args.argc, args.argv, &sparsebundle_filesystem_operations, &sparsebundle);

tests/30_noreadbuf.tst

@@ -0,0 +1,23 @@
+#!/usr/bin/env testrunner.sh
+
+source "$(dirname "$0")/testhelpers.sh"
+
+function setup() {
+    mount_sparsebundle -o noreadbuf
+}
+
+function test_dmg_has_correct_number_of_blocks() {
+    hfsdump $dmg_file | grep "total_blocks: 268435456"
+}
+
+function test_dmg_contents_is_same_as_testdata() {
+    for f in $(ls $HFSFUSE_DIR/src); do
+        echo "Diffing $HFSFUSE_DIR/src/$f"
+        diff $HFSFUSE_DIR/src/$f <(hfsdump $dmg_file read "/src/$f")
+    done
+}
+
+function teardown() {
+    umount $mount_dir
+    rm -Rf $mount_dir
+}