libzfs_sendrecv: Refactor find_redact_book

Factor out get_bookmarks, find_redact_pair, and get_redact_complete
helper functions to improve the readability of find_redact_book.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <freqlabs@FreeBSD.org>
Closes openzfs#12967

lib/libzfs/libzfs_sendrecv.c

@@ -1557,6 +1557,53 @@ redact_snaps_equal(const uint64_t *snaps1, uint64_t num_snaps1,
 	return (B_TRUE);
 }
 
+static int
+get_bookmarks(const char *path, nvlist_t **bmarksp)
+{
+	nvlist_t *props = fnvlist_alloc();
+	int error;
+
+	fnvlist_add_boolean(props, "redact_complete");
+	fnvlist_add_boolean(props, zfs_prop_to_name(ZFS_PROP_REDACT_SNAPS));
+	error = lzc_get_bookmarks(path, props, bmarksp);
+	fnvlist_free(props);
+	return (error);
+}
+
+static nvpair_t *
+find_redact_pair(nvlist_t *bmarks, const uint64_t *redact_snap_guids,
+    int num_redact_snaps)
+{
+	nvpair_t *pair;
+
+	for (pair = nvlist_next_nvpair(bmarks, NULL); pair;
+	    pair = nvlist_next_nvpair(bmarks, pair)) {
+
+		nvlist_t *bmark = fnvpair_value_nvlist(pair);
+		nvlist_t *vallist = fnvlist_lookup_nvlist(bmark,
+		    zfs_prop_to_name(ZFS_PROP_REDACT_SNAPS));
+		uint_t len = 0;
+		uint64_t *bmarksnaps = fnvlist_lookup_uint64_array(vallist,
+		    ZPROP_VALUE, &len);
+		if (redact_snaps_equal(redact_snap_guids,
+		    num_redact_snaps, bmarksnaps, len)) {
+			break;
+		}
+	}
+	return (pair);
+}
+
+static boolean_t
+get_redact_complete(nvpair_t *pair)
+{
+	nvlist_t *bmark = fnvpair_value_nvlist(pair);
+	nvlist_t *vallist = fnvlist_lookup_nvlist(bmark, "redact_complete");
+	boolean_t complete = fnvlist_lookup_boolean_value(vallist,
+	    ZPROP_VALUE);
+
+	return (complete);
+}
+
 /*
  * Check that the list of redaction snapshots in the bookmark matches the send
  * we're resuming, and return whether or not it's complete.
@@ -1570,17 +1617,12 @@ find_redact_book(libzfs_handle_t *hdl, const char *path,
     char **bookname)
 {
 	char errbuf[1024];
-	int error = 0;
-	nvlist_t *props = fnvlist_alloc();
 	nvlist_t *bmarks;
 
 	(void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
 	    "cannot resume send"));
 
-	fnvlist_add_boolean(props, "redact_complete");
-	fnvlist_add_boolean(props, zfs_prop_to_name(ZFS_PROP_REDACT_SNAPS));
-	error = lzc_get_bookmarks(path, props, &bmarks);
-	fnvlist_free(props);
+	int error = get_bookmarks(path, &bmarks);
 	if (error != 0) {
 		if (error == ESRCH) {
 			zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
@@ -1594,39 +1636,22 @@ find_redact_book(libzfs_handle_t *hdl, const char *path,
 		}
 		return (zfs_error(hdl, EZFS_BADPROP, errbuf));
 	}
-	nvpair_t *pair;
-	for (pair = nvlist_next_nvpair(bmarks, NULL); pair;
-	    pair = nvlist_next_nvpair(bmarks, pair)) {
-
-		nvlist_t *bmark = fnvpair_value_nvlist(pair);
-		nvlist_t *vallist = fnvlist_lookup_nvlist(bmark,
-		    zfs_prop_to_name(ZFS_PROP_REDACT_SNAPS));
-		uint_t len = 0;
-		uint64_t *bmarksnaps = fnvlist_lookup_uint64_array(vallist,
-		    ZPROP_VALUE, &len);
-		if (redact_snaps_equal(redact_snap_guids,
-		    num_redact_snaps, bmarksnaps, len)) {
-			break;
-		}
-	}
+	nvpair_t *pair = find_redact_pair(bmarks, redact_snap_guids,
+	    num_redact_snaps);
 	if (pair == NULL)  {
 		fnvlist_free(bmarks);
 		zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
 		    "no appropriate redaction bookmark exists"));
 		return (zfs_error(hdl, EZFS_BADPROP, errbuf));
 	}
-	char *name = nvpair_name(pair);
-	nvlist_t *bmark = fnvpair_value_nvlist(pair);
-	nvlist_t *vallist = fnvlist_lookup_nvlist(bmark, "redact_complete");
-	boolean_t complete = fnvlist_lookup_boolean_value(vallist,
-	    ZPROP_VALUE);
+	boolean_t complete = get_redact_complete(pair);
 	if (!complete) {
 		fnvlist_free(bmarks);
 		zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
 		    "incomplete redaction bookmark provided"));
 		return (zfs_error(hdl, EZFS_BADPROP, errbuf));
 	}
-	*bookname = strndup(name, ZFS_MAX_DATASET_NAME_LEN);
+	*bookname = strndup(nvpair_name(pair), ZFS_MAX_DATASET_NAME_LEN);
 	ASSERT3P(*bookname, !=, NULL);
 	fnvlist_free(bmarks);
 	return (0);