[PATCH 01/10] common/verity: add and use _fsv_can_enable()

[Eric Biggers <ebiggers@kernel.org>]

From: Eric Biggers <ebiggers@google.com>

Replace _fsv_have_hash_algorithm() with a more general function
_fsv_can_enable() which checks whether 'fsverity enable' with the given
parameters works.  For now it is just used with --hash-alg or with no
parameters, but soon it will be used with --block-size too.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 common/verity     | 17 ++++++-----------
 tests/generic/575 |  2 +-
 tests/generic/577 |  2 +-
 3 files changed, 8 insertions(+), 13 deletions(-)

diff --git a/common/verity b/common/verity
index f98dcb07..1a53a7ea 100644
--- a/common/verity
+++ b/common/verity
@@ -42,13 +42,7 @@ _require_scratch_verity()
 	# The filesystem may have fs-verity enabled but not actually usable by
 	# default.  E.g., ext4 only supports verity on extent-based files, so it
 	# doesn't work on ext3-style filesystems.  So, try actually using it.
-	echo foo > $SCRATCH_MNT/tmpfile
-	_disable_fsverity_signatures
-	_fsv_enable $SCRATCH_MNT/tmpfile
-	local status=$?
-	_restore_prev_fsverity_signatures
-	rm -f $SCRATCH_MNT/tmpfile
-	if (( $status != 0 )); then
+	if ! _fsv_can_enable $SCRATCH_MNT/tmpfile; then
 		_notrun "$FSTYP verity isn't usable by default with these mkfs options"
 	fi
 
@@ -256,15 +250,16 @@ _fsv_create_enable_file()
 	_fsv_enable "$file" "$@"
 }
 
-_fsv_have_hash_algorithm()
+_fsv_can_enable()
 {
-	local hash_alg=$1
-	local test_file=$2
+	local test_file=$1
+	shift
+	local params=("$@")
 
 	_disable_fsverity_signatures
 	rm -f $test_file
 	head -c 4096 /dev/zero > $test_file
-	_fsv_enable --hash-alg=$hash_alg $test_file &>> $seqres.full
+	_fsv_enable $test_file "${params[@]}" &>> $seqres.full
 	local status=$?
 	_restore_prev_fsverity_signatures
 	rm -f $test_file
diff --git a/tests/generic/575 b/tests/generic/575
index ffa6b61d..0ece8826 100755
--- a/tests/generic/575
+++ b/tests/generic/575
@@ -71,7 +71,7 @@ test_alg()
 
 	_fsv_scratch_begin_subtest "Check for expected measurement values ($alg)"
 
-	if ! _fsv_have_hash_algorithm $alg $fsv_file; then
+	if ! _fsv_can_enable $fsv_file --hash-alg=$alg; then
 		if [ "$alg" = sha256 ]; then
 			_fail "Something is wrong - sha256 hash should always be available"
 		fi
diff --git a/tests/generic/577 b/tests/generic/577
index 5f7e0573..85d680df 100755
--- a/tests/generic/577
+++ b/tests/generic/577
@@ -112,7 +112,7 @@ _fsv_enable $fsv_file --signature=$sigfile.salted --salt=abcd
 cmp $fsv_file $fsv_orig_file
 
 echo -e "\n# Testing non-default hash algorithm"
-if _fsv_have_hash_algorithm sha512 $fsv_file; then
+if _fsv_can_enable $fsv_file --hash-alg=sha512; then
 	reset_fsv_file
 	_fsv_sign $fsv_orig_file $sigfile.sha512 --key=$keyfile \
 		--cert=$certfile --hash-alg=sha512 > /dev/null
-- 
2.38.1