Update `checkstyle` workflow env to ubuntu-20.04

- `checkstyle` workflow uses ubuntu-20.04 environment
- improved `mancheck.sh` readability

Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Signed-off-by: szubersk <szuberskidamian@gmail.com>
Closes #12713

9 files changed, 32 insertions, 10 deletions

diff --git a/.github/workflows/checkstyle.yaml b/.github/workflows/checkstyle.yaml
index 14a921099..553d5df39 100644
--- a/.github/workflows/checkstyle.yaml
+++ b/.github/workflows/checkstyle.yaml
@@ -6,7 +6,7 @@ on:
 
 jobs:
   checkstyle:
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-20.04
     steps:
     - uses: actions/checkout@v2
       with:
diff --git a/cmd/zdb/zdb.c b/cmd/zdb/zdb.c
index f2e1a0dc3..9de41cef2 100644
--- a/cmd/zdb/zdb.c
+++ b/cmd/zdb/zdb.c
@@ -4096,7 +4096,7 @@ cksum_record_compare(const void *x1, const void *x2)
 	const cksum_record_t *l = (cksum_record_t *)x1;
 	const cksum_record_t *r = (cksum_record_t *)x2;
 	int arraysize = ARRAY_SIZE(l->cksum.zc_word);
-	int difference;
+	int difference = 0;
 
 	for (int i = 0; i < arraysize; i++) {
 		difference = TREE_CMP(l->cksum.zc_word[i], r->cksum.zc_word[i]);
diff --git a/include/sys/zstd/zstd.h b/include/sys/zstd/zstd.h
index e87dda1b1..ca32a7464 100644
--- a/include/sys/zstd/zstd.h
+++ b/include/sys/zstd/zstd.h
@@ -210,12 +210,14 @@ zfs_get_hdrversion(const zfs_zstdhdr_t *blob)
 static inline void
 zfs_set_hdrversion(zfs_zstdhdr_t *blob, uint32_t version)
 {
+	/* cppcheck-suppress syntaxError */
 	BF32_SET(blob->raw_version_level, 0, 24, version);
 }
 
 static inline void
 zfs_set_hdrlevel(zfs_zstdhdr_t *blob, uint8_t level)
 {
+	/* cppcheck-suppress syntaxError */
 	BF32_SET(blob->raw_version_level, 24, 8, level);
 }
 
diff --git a/module/Makefile.in b/module/Makefile.in
index 089b3ff88..05c673231 100644
--- a/module/Makefile.in
+++ b/module/Makefile.in
@@ -114,7 +114,9 @@ modules_uninstall: modules_uninstall-@ac_system@
 
 cppcheck-Linux:
 	@CPPCHECK@ -j@CPU_COUNT@ --std=c99 --quiet --force --error-exitcode=2 \
-		--inline-suppr --suppress=noValidConfiguration \
+		--inline-suppr \
+		--suppress=unmatchedSuppression \
+		--suppress=noValidConfiguration \
 		--enable=warning,information -D_KERNEL \
 		--include=@LINUX_OBJ@/include/generated/autoconf.h \
 		--include=@top_srcdir@/zfs_config.h \
diff --git a/module/nvpair/nvpair.c b/module/nvpair/nvpair.c
index 5f427c8cf..9834dedd8 100644
--- a/module/nvpair/nvpair.c
+++ b/module/nvpair/nvpair.c
@@ -533,12 +533,14 @@ nvt_add_nvpair(nvlist_t *nvl, nvpair_t *nvp)
 	uint64_t index = hash & (priv->nvp_nbuckets - 1);
 
 	ASSERT3U(index, <, priv->nvp_nbuckets);
+	// cppcheck-suppress nullPointerRedundantCheck
 	i_nvp_t *bucket = tab[index];
 
 	/* insert link at the beginning of the bucket */
 	i_nvp_t *new_entry = NVPAIR2I_NVP(nvp);
 	ASSERT3P(new_entry->nvi_hashtable_next, ==, NULL);
 	new_entry->nvi_hashtable_next = bucket;
+	// cppcheck-suppress nullPointerRedundantCheck
 	tab[index] = new_entry;
 
 	priv->nvp_nentries++;
@@ -3270,6 +3272,8 @@ NVS_BUILD_XDRPROC_T(u_longlong_t);
 static int
 nvs_xdr_nvp_op(nvstream_t *nvs, nvpair_t *nvp)
 {
+	ASSERT(nvs != NULL && nvp != NULL);
+
 	data_type_t type;
 	char	*buf;
 	char	*buf_end = (char *)nvp + nvp->nvp_size;
@@ -3278,7 +3282,7 @@ nvs_xdr_nvp_op(nvstream_t *nvs, nvpair_t *nvp)
 	bool_t	ret = FALSE;
 	XDR	*xdr = nvs->nvs_private;
 
-	ASSERT(xdr != NULL && nvp != NULL);
+	ASSERT(xdr != NULL);
 
 	/* name string */
 	if ((buf = NVP_NAME(nvp)) >= buf_end)
diff --git a/module/os/freebsd/zfs/vdev_geom.c b/module/os/freebsd/zfs/vdev_geom.c
index 4ffa21495..2ef4811a8 100644
--- a/module/os/freebsd/zfs/vdev_geom.c
+++ b/module/os/freebsd/zfs/vdev_geom.c
@@ -199,7 +199,6 @@ vdev_geom_orphan(struct g_consumer *cp)
 	 * async removal support to invoke a close on this
 	 * vdev once it is safe to do so.
 	 */
-	// cppcheck-suppress All
 	SLIST_FOREACH(elem, priv, elems) {
 		// cppcheck-suppress uninitvar
 		vdev_t *vd = elem->vd;
diff --git a/module/os/linux/spl/spl-generic.c b/module/os/linux/spl/spl-generic.c
index 91eeaccfd..5ea4fc635 100644
--- a/module/os/linux/spl/spl-generic.c
+++ b/module/os/linux/spl/spl-generic.c
@@ -657,6 +657,7 @@ hostid_read(uint32_t *hostid)
 		return (error);
 	}
 	size = stat.size;
+	// cppcheck-suppress sizeofwithnumericparameter
 	if (size < sizeof (HW_HOSTID_MASK)) {
 		filp_close(filp, 0);
 		return (EINVAL);
diff --git a/module/unicode/u8_textprep.c b/module/unicode/u8_textprep.c
index c1d9a325f..bce5f1962 100644
--- a/module/unicode/u8_textprep.c
+++ b/module/unicode/u8_textprep.c
@@ -865,7 +865,9 @@ do_decomp(size_t uv, uchar_t *u8s, uchar_t *s, int sz,
 		start_id = u8_decomp_b4_16bit_tbl[uv][b3_tbl][b4];
 		end_id = u8_decomp_b4_16bit_tbl[uv][b3_tbl][b4 + 1];
 	} else {
+		// cppcheck-suppress arrayIndexOutOfBoundsCond
 		start_id = u8_decomp_b4_tbl[uv][b3_tbl][b4];
+		// cppcheck-suppress arrayIndexOutOfBoundsCond
 		end_id = u8_decomp_b4_tbl[uv][b3_tbl][b4 + 1];
 	}
 
@@ -1012,7 +1014,9 @@ find_composition_start(size_t uv, uchar_t *s, size_t sz)
 		start_id = u8_composition_b4_16bit_tbl[uv][b3_tbl][b4];
 		end_id = u8_composition_b4_16bit_tbl[uv][b3_tbl][b4 + 1];
 	} else {
+		// cppcheck-suppress arrayIndexOutOfBoundsCond
 		start_id = u8_composition_b4_tbl[uv][b3_tbl][b4];
+		// cppcheck-suppress arrayIndexOutOfBoundsCond
 		end_id = u8_composition_b4_tbl[uv][b3_tbl][b4 + 1];
 	}
 
diff --git a/scripts/mancheck.sh b/scripts/mancheck.sh
index 6ae1fc5be..0793cc48f 100755
--- a/scripts/mancheck.sh
+++ b/scripts/mancheck.sh
@@ -11,7 +11,9 @@
 # AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
 # OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #
-# shellcheck disable=SC2086
+# shellcheck disable=SC2086,SC2250
+
+trap 'rm -f "$stdout_file" "$stderr_file" "$result_file"' EXIT
 
 if [ "$#" -eq 0 ]; then
     echo "Usage: $0 manpage-directory..."
@@ -25,7 +27,6 @@ fi
 
 IFS="
 "
-
 files="$(find "$@" -type f -name '*[1-9]*')" || exit 1
 
 add_excl="$(awk '
@@ -38,6 +39,15 @@ add_excl="$(awk '
 
 # Redirect to file instead of 2>&1ing because mandoc flushes inconsistently(?) which tears lines
 # https://github.com/openzfs/zfs/pull/12129/checks?check_run_id=2701608671#step:5:3
-etmp="$(mktemp)"
-! { mandoc -Tlint $files 2>"$etmp"; cat "$etmp"; rm -f "$etmp"; } |
-    grep -vE -e 'mandoc: outdated mandoc.db' -e 'STYLE: referenced manual not found' $add_excl >&2
+stdout_file="$(mktemp)"
+stderr_file="$(mktemp)"
+mandoc -Tlint $files 1>"$stdout_file" 2>"$stderr_file"
+result_file="$(mktemp)"
+grep -vhE -e 'mandoc: outdated mandoc.db' -e 'STYLE: referenced manual not found' $add_excl "$stdout_file" "$stderr_file" > "$result_file"
+
+if [ -s "$result_file" ]; then
+    cat "$result_file"
+    exit 1
+else
+    echo "no errors found"
+fi