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-rw-r--r--lib/fstree/hardlink.c65
1 files changed, 65 insertions, 0 deletions
diff --git a/lib/fstree/hardlink.c b/lib/fstree/hardlink.c
new file mode 100644
index 0000000..8a79d46
--- /dev/null
+++ b/lib/fstree/hardlink.c
@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * hardlink.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "config.h"
+
+#include "fstree.h"
+
+#include <string.h>
+#include <stdlib.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)
+{
+ tree_node_t *start = node;
+
+ while (node->mode == FSTREE_MODE_HARD_LINK ||
+ node->mode == FSTREE_MODE_HARD_LINK_RESOLVED) {
+ if (node->mode == FSTREE_MODE_HARD_LINK_RESOLVED) {
+ node = node->data.target_node;
+ } else {
+ node = fstree_get_node_by_path(fs, fs->root,
+ node->data.target,
+ false, false);
+ if (node == NULL)
+ return -1;
+ }
+
+ if (node == start) {
+ errno = EMLINK;
+ return -1;
+ }
+ }
+
+ start->mode = FSTREE_MODE_HARD_LINK_RESOLVED;
+ start->data.target_node = node;
+
+ node->link_count += 1;
+ return 0;
+}