GCC 7.1 fixes

cmd/ztest/Makefile.am

@@ -1,6 +1,8 @@
 include $(top_srcdir)/config/Rules.am
 
-AM_CFLAGS += $(DEBUG_STACKFLAGS) $(FRAME_LARGER_THAN)
+# -Wnoformat-truncation to get rid of compiler warning for unchecked
+#  truncating snprintfs on gcc 7.1.1.
+AM_CFLAGS += $(DEBUG_STACKFLAGS) $(FRAME_LARGER_THAN) $(NO_FORMAT_TRUNCATION)
 AM_CPPFLAGS += -DDEBUG
 
 DEFAULT_INCLUDES += \

config/user-no-format-truncation.m4

@@ -0,0 +1,22 @@
+dnl #
+dnl # Check if gcc supports -Wno-format-truncation option.
+dnl #
+AC_DEFUN([ZFS_AC_CONFIG_USER_NO_FORMAT_TRUNCATION], [
+	AC_MSG_CHECKING([for -Wno-format-truncation support])
+
+	saved_flags="$CFLAGS"
+	CFLAGS="$CFLAGS -Wno-format-truncation"
+
+	AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [])],
+	[
+		NO_FORMAT_TRUNCATION=-Wno-format-truncation
+		AC_MSG_RESULT([yes])
+	],
+	[
+		NO_FORMAT_TRUNCATION=
+		AC_MSG_RESULT([no])
+	])
+
+	CFLAGS="$saved_flags"
+	AC_SUBST([NO_FORMAT_TRUNCATION])
+])

config/user.m4

@@ -17,6 +17,7 @@ AC_DEFUN([ZFS_AC_CONFIG_USER], [
 	ZFS_AC_CONFIG_USER_RUNSTATEDIR
 	ZFS_AC_CONFIG_USER_MAKEDEV_IN_SYSMACROS
 	ZFS_AC_CONFIG_USER_MAKEDEV_IN_MKDEV
+	ZFS_AC_CONFIG_USER_NO_FORMAT_TRUNCATION
 
 	ZFS_AC_TEST_FRAMEWORK
 

lib/libspl/include/assert.h

@@ -40,6 +40,20 @@ libspl_assert(const char *buf, const char *file, const char *func, int line)
 	abort();
 }
 
+/* printf version of libspl_assert */
+static inline void
+libspl_assertf(const char *file, const char *func, int line, char *format, ...)
+{
+	va_list args;
+
+	va_start(args, format);
+	vfprintf(stderr, format, args);
+	fprintf(stderr, "\n");
+	fprintf(stderr, "ASSERT at %s:%d:%s()", file, line, func);
+	va_end(args);
+	abort();
+}
+
 #ifdef verify
 #undef verify
 #endif
@@ -55,13 +69,9 @@ libspl_assert(const char *buf, const char *file, const char *func, int line)
 do {									\
 	const TYPE __left = (TYPE)(LEFT);				\
 	const TYPE __right = (TYPE)(RIGHT);				\
-	if (!(__left OP __right)) {					\
-		char *__buf = alloca(256);				\
-		(void) snprintf(__buf, 256,				\
-		    "%s %s %s (0x%llx %s 0x%llx)", #LEFT, #OP, #RIGHT,	\
-		    (u_longlong_t)__left, #OP, (u_longlong_t)__right);	\
-		libspl_assert(__buf, __FILE__, __FUNCTION__, __LINE__);	\
-	}								\
+	if (!(__left OP __right))					\
+		libspl_assertf(__FILE__, __FUNCTION__, __LINE__,	\
+		    "%s %s %s (0x%llx %s 0x%llx)", #LEFT, #OP, #RIGHT);	\
 } while (0)
 
 #define	VERIFY3S(x, y, z)	VERIFY3_IMPL(x, y, z, int64_t)

lib/libzfs/libzfs_dataset.c

@@ -3566,8 +3566,9 @@ zfs_check_snap_cb(zfs_handle_t *zhp, void *arg)
 	char name[ZFS_MAX_DATASET_NAME_LEN];
 	int rv = 0;
 
-	(void) snprintf(name, sizeof (name),
-	    "%s@%s", zhp->zfs_name, dd->snapname);
+	if (snprintf(name, sizeof (name), "%s@%s", zhp->zfs_name,
+	    dd->snapname) >= sizeof (name))
+		return (EINVAL);
 
 	if (lzc_exists(name))
 		verify(nvlist_add_boolean(dd->nvl, name) == 0);
@@ -3788,8 +3789,9 @@ zfs_snapshot_cb(zfs_handle_t *zhp, void *arg)
 	int rv = 0;
 
 	if (zfs_prop_get_int(zhp, ZFS_PROP_INCONSISTENT) == 0) {
-		(void) snprintf(name, sizeof (name),
-		    "%s@%s", zfs_get_name(zhp), sd->sd_snapname);
+		if (snprintf(name, sizeof (name), "%s@%s", zfs_get_name(zhp),
+		    sd->sd_snapname) >= sizeof (name))
+			return (EINVAL);
 
 		fnvlist_add_boolean(sd->sd_nvl, name);
 
@@ -4533,8 +4535,9 @@ zfs_hold_one(zfs_handle_t *zhp, void *arg)
 	char name[ZFS_MAX_DATASET_NAME_LEN];
 	int rv = 0;
 
-	(void) snprintf(name, sizeof (name),
-	    "%s@%s", zhp->zfs_name, ha->snapname);
+	if (snprintf(name, sizeof (name), "%s@%s", zhp->zfs_name,
+	    ha->snapname) >= sizeof (name))
+		return (EINVAL);
 
 	if (lzc_exists(name))
 		fnvlist_add_string(ha->nvl, name, ha->tag);
@@ -4653,8 +4656,11 @@ zfs_release_one(zfs_handle_t *zhp, void *arg)
 	int rv = 0;
 	nvlist_t *existing_holds;
 
-	(void) snprintf(name, sizeof (name),
-	    "%s@%s", zhp->zfs_name, ha->snapname);
+	if (snprintf(name, sizeof (name), "%s@%s", zhp->zfs_name,
+	    ha->snapname) >= sizeof (name)) {
+		ha->error = EINVAL;
+		rv = EINVAL;
+	}
 
 	if (lzc_get_holds(name, &existing_holds) != 0) {
 		ha->error = ENOENT;

lib/libzfs/libzfs_iter.c

@@ -204,8 +204,11 @@ zfs_iter_bookmarks(zfs_handle_t *zhp, zfs_iter_f func, void *data)
 		bmark_name = nvpair_name(pair);
 		bmark_props = fnvpair_value_nvlist(pair);
 
-		(void) snprintf(name, sizeof (name), "%s#%s", zhp->zfs_name,
-		    bmark_name);
+		if (snprintf(name, sizeof (name), "%s#%s", zhp->zfs_name,
+		    bmark_name) >= sizeof (name)) {
+			err = EINVAL;
+			goto out;
+		}
 
 		nzhp = make_bookmark_handle(zhp, name, bmark_props);
 		if (nzhp == NULL)

lib/libzfs/libzfs_sendrecv.c

@@ -1867,9 +1867,13 @@ zfs_send(zfs_handle_t *zhp, const char *fromsnap, const char *tosnap,
 			    drr_versioninfo, DMU_COMPOUNDSTREAM);
 			DMU_SET_FEATUREFLAGS(drr.drr_u.drr_begin.
 			    drr_versioninfo, featureflags);
-			(void) snprintf(drr.drr_u.drr_begin.drr_toname,
+			if (snprintf(drr.drr_u.drr_begin.drr_toname,
 			    sizeof (drr.drr_u.drr_begin.drr_toname),
-			    "%s@%s", zhp->zfs_name, tosnap);
+			    "%s@%s", zhp->zfs_name, tosnap) >=
+			    sizeof (drr.drr_u.drr_begin.drr_toname)) {
+				err = EINVAL;
+				goto stderr_out;
+			}
 			drr.drr_payloadlen = buflen;
 
 			err = dump_record(&drr, packbuf, buflen, &zc, outfd);

module/zfs/zfs_ioctl.c

@@ -3627,8 +3627,10 @@ zfs_ioc_destroy(zfs_cmd_t *zc)
 			 */
 			char namebuf[ZFS_MAX_DATASET_NAME_LEN + 6];
 
-			(void) snprintf(namebuf, sizeof (namebuf),
-			    "%s/%s", zc->zc_name, recv_clone_name);
+			if (snprintf(namebuf, sizeof (namebuf), "%s/%s",
+			    zc->zc_name, recv_clone_name) >=
+			    sizeof (namebuf))
+				return (SET_ERROR(EINVAL));
 
 			/*
 			 * Try to remove the hidden child (%recv) and after

module/zfs/zvol.c

@@ -2063,14 +2063,12 @@ zvol_rename_minors_impl(const char *oldname, const char *newname)
 {
 	zvol_state_t *zv, *zv_next;
 	int oldnamelen, newnamelen;
-	char *name;
 
 	if (zvol_inhibit_dev)
 		return;
 
 	oldnamelen = strlen(oldname);
 	newnamelen = strlen(newname);
-	name = kmem_alloc(MAXNAMELEN, KM_SLEEP);
 
 	mutex_enter(&zvol_state_lock);
 
@@ -2086,16 +2084,15 @@ zvol_rename_minors_impl(const char *oldname, const char *newname)
 		} else if (strncmp(zv->zv_name, oldname, oldnamelen) == 0 &&
 		    (zv->zv_name[oldnamelen] == '/' ||
 		    zv->zv_name[oldnamelen] == '@')) {
-			snprintf(name, MAXNAMELEN, "%s%c%s", newname,
+			char *name = kmem_asprintf("%s%c%s", newname,
 			    zv->zv_name[oldnamelen],
 			    zv->zv_name + oldnamelen + 1);
 			zvol_rename_minor(zv, name);
+			kmem_free(name, strlen(name + 1));
 		}
 	}
 
 	mutex_exit(&zvol_state_lock);
-
-	kmem_free(name, MAXNAMELEN);
 }
 
 typedef struct zvol_snapdev_cb_arg {