Examine.c: Fix memory leaks in Examine()

Fix memory leaks in Examine() reported by SAST analysis. Implement a
method to traverse and free all the nodes of the doubly linked list.
Replace for loop with while loop in order to improve redability of the
code and free allocated memory correctly.

Signed-off-by: Anna Sztukowska <[email protected]>

Examine.c

@@ -111,8 +111,10 @@ int Examine(struct mddev_dev *devlist,
 		close(fd);
 
 		if (err) {
-			if (st)
+			if (st) {
 				st->ss->free_super(st);
+				free(st);
+			}
 			continue;
 		}
 
@@ -152,19 +154,24 @@ int Examine(struct mddev_dev *devlist,
 			if (st->ss->export_examine_super)
 				st->ss->export_examine_super(st);
 			st->ss->free_super(st);
+			free(st);
 		} else {
 			printf("%s:\n",devlist->devname);
 			st->ss->examine_super(st, c->homehost);
 			st->ss->free_super(st);
+			free(st);
 		}
 	}
 	if (c->brief) {
-		struct array *ap;
-		for (ap = arrays; ap; ap = ap->next) {
+		struct array *ap = arrays, *next;
+
+		while (ap) {
 			char sep='=';
 			char *d;
 			int newline = 0;
 
+			next = ap->next;
+
 			ap->st->ss->brief_examine_super(ap->st, c->verbose > 0);
 			if (ap->spares && !ap->st->ss->external)
 				newline += printf("   spares=%d", ap->spares);
@@ -182,10 +189,15 @@ int Examine(struct mddev_dev *devlist,
 					printf("\n");
 				ap->st->ss->brief_examine_subarrays(ap->st, c->verbose);
 			}
-			ap->st->ss->free_super(ap->st);
-			/* FIXME free ap */
 			if (ap->spares || c->verbose > 0)
 				printf("\n");
+
+			ap->st->ss->free_super(ap->st);
+			free(ap->st);
+			dl_free_all(ap->devs);
+			free(ap);
+
+			ap = next;
 		}
 	}
 	return rv;

dlink.c

@@ -26,6 +26,21 @@ void dl_free(void *v)
     free(vv-1);
 }
 
+void dl_free_all(void *head)
+{
+	/* The list head is linked with the list tail so in order to free
+	 * all the elements properly there is a need to keep starting point.
+	 */
+	void *d = dl_next(head), *next;
+
+	while (d != head) {
+		next = dl_next(d);
+		dl_free(d);
+		d = next;
+	}
+	dl_free(head);
+}
+
 void dl_init(void *v)
 {
     dl_next(v) = v;

dlink.h

@@ -23,3 +23,4 @@ void dl_add(void*, void*);
 void dl_del(void*);
 void dl_free(void*);
 void dl_init(void*);
+void dl_free_all(void *head);