Add xattr reader implementation to recover xattrs from squashfs

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 52 insertions, 0 deletions

diff --git a/lib/sqfs/xattr.c b/lib/sqfs/xattr.c
new file mode 100644
index 0000000..db8edf4
--- /dev/null
+++ b/lib/sqfs/xattr.c
@@ -0,0 +1,52 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * write_xattr.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "config.h"
+#include "squashfs.h"
+
+#include <string.h>
+
+static const struct {
+	const char *prefix;
+	E_SQFS_XATTR_TYPE type;
+} xattr_types[] = {
+	{ "user.", SQUASHFS_XATTR_USER },
+	{ "trusted.", SQUASHFS_XATTR_TRUSTED },
+	{ "security.", SQUASHFS_XATTR_SECURITY },
+};
+
+int sqfs_get_xattr_prefix_id(const char *key)
+{
+	size_t i, len;
+
+	for (i = 0; i < sizeof(xattr_types) / sizeof(xattr_types[0]); ++i) {
+		len = strlen(xattr_types[i].prefix);
+
+		if (strncmp(key, xattr_types[i].prefix, len) == 0 &&
+		    strlen(key) > len) {
+			return xattr_types[i].type;
+		}
+	}
+
+	return -1;
+}
+
+const char *sqfs_get_xattr_prefix(E_SQFS_XATTR_TYPE id)
+{
+	size_t i;
+
+	for (i = 0; i < sizeof(xattr_types) / sizeof(xattr_types[0]); ++i) {
+		if (xattr_types[i].type == id)
+			return xattr_types[i].prefix;
+	}
+
+	return NULL;
+}
+
+bool sqfs_has_xattr(const char *key)
+{
+	return sqfs_get_xattr_prefix_id(key) >= 0;
+}