1 files changed, 75 insertions, 24 deletions

diff --git a/lib/fstree/src/hardlink.c b/lib/fstree/src/hardlink.c
index 2165b5f..9686219 100644
--- a/lib/fstree/src/hardlink.c
+++ b/lib/fstree/src/hardlink.c
@@ -11,32 +11,10 @@
 
 #include <string.h>
 #include <stdlib.h>
+#include <assert.h>
 #include <errno.h>
 
-tree_node_t *fstree_add_hard_link(fstree_t *fs, const char *path,
-				  const char *target)
-{
-	struct stat sb;
-	tree_node_t *n;
-
-	memset(&sb, 0, sizeof(sb));
-	sb.st_mode = S_IFLNK | 0777;
-
-	n = fstree_add_generic(fs, path, &sb, target);
-	if (n != NULL) {
-		if (canonicalize_name(n->data.target)) {
-			free(n);
-			errno = EINVAL;
-			return NULL;
-		}
-
-		n->mode = FSTREE_MODE_HARD_LINK;
-	}
-
-	return n;
-}
-
-int fstree_resolve_hard_link(fstree_t *fs, tree_node_t *node)
+static int resolve_link(fstree_t *fs, tree_node_t *node)
 {
 	tree_node_t *start = node;
 
@@ -74,3 +52,76 @@ int fstree_resolve_hard_link(fstree_t *fs, tree_node_t *node)
 	node->link_count++;
 	return 0;
 }
+
+static int resolve_hard_links_dfs(fstree_t *fs, tree_node_t *n)
+{
+	tree_node_t *it;
+
+	if (n->mode == FSTREE_MODE_HARD_LINK) {
+		if (resolve_link(fs, n))
+			goto fail_link;
+
+		assert(n->mode == FSTREE_MODE_HARD_LINK_RESOLVED);
+		it = n->data.target_node;
+
+		if (S_ISDIR(it->mode) && it->data.dir.visited)
+			goto fail_link_loop;
+	} else if (S_ISDIR(n->mode)) {
+		n->data.dir.visited = true;
+
+		for (it = n->data.dir.children; it != NULL; it = it->next) {
+			if (resolve_hard_links_dfs(fs, it))
+				return -1;
+		}
+
+		n->data.dir.visited = false;
+	}
+
+	return 0;
+fail_link: {
+	char *path = fstree_get_path(n);
+	fprintf(stderr, "Resolving hard link '%s' -> '%s': %s\n",
+		path == NULL ? n->name : path, n->data.target,
+		strerror(errno));
+	free(path);
+}
+	return -1;
+fail_link_loop: {
+	char *npath = fstree_get_path(n);
+	char *tpath = fstree_get_path(it);
+	fprintf(stderr, "Hard link loop detected in '%s' -> '%s'\n",
+		npath == NULL ? n->name : npath,
+		tpath == NULL ? it->name : tpath);
+	free(npath);
+	free(tpath);
+}
+	return -1;
+}
+
+tree_node_t *fstree_add_hard_link(fstree_t *fs, const char *path,
+				  const char *target)
+{
+	struct stat sb;
+	tree_node_t *n;
+
+	memset(&sb, 0, sizeof(sb));
+	sb.st_mode = S_IFLNK | 0777;
+
+	n = fstree_add_generic(fs, path, &sb, target);
+	if (n != NULL) {
+		if (canonicalize_name(n->data.target)) {
+			free(n);
+			errno = EINVAL;
+			return NULL;
+		}
+
+		n->mode = FSTREE_MODE_HARD_LINK;
+	}
+
+	return n;
+}
+
+int fstree_resolve_hard_links(fstree_t *fs)
+{
+	return resolve_hard_links_dfs(fs, fs->root);
+}