vfs_shadow_copy2: implement readdir()

RN: shadow_copy2 fails listing snapshotted dirs with shadow:fixinodes
BUG: https://bugzilla.samba.org/show_bug.cgi?id=15035

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>

Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Thu Mar 31 18:47:42 UTC 2022 on sn-devel-184

selftest/knownfail.d/samba3.blackbox.shadow_copy_torture

@@ -1 +0,0 @@
-^samba3.blackbox.shadow_copy_torture.fix inodes when listing directory\(fileserver\)

source3/modules/vfs_shadow_copy2.c

@@ -3331,6 +3331,96 @@ static int shadow_copy2_connect(struct vfs_handle_struct *handle,
 	return 0;
 }
 
+static struct dirent *shadow_copy2_readdir(vfs_handle_struct *handle,
+					   struct files_struct *dirfsp,
+					   DIR *dirp,
+					   SMB_STRUCT_STAT *sbuf)
+{
+	struct shadow_copy2_private *priv = NULL;
+	struct dirent *ent = NULL;
+	struct smb_filename atname;
+	struct smb_filename *full_fname = NULL;
+	time_t timestamp = 0;
+	char *stripped = NULL;
+	char *conv = NULL;
+	char *abspath = NULL;
+	bool converted = false;
+
+	SMB_VFS_HANDLE_GET_DATA(handle, priv, struct shadow_copy2_private,
+				return NULL);
+
+	ent = SMB_VFS_NEXT_READDIR(handle, dirfsp, dirp, sbuf);
+	if (ent == NULL) {
+		return NULL;
+	}
+	if (sbuf == NULL) {
+		return ent;
+	}
+	if (ISDOT(dirfsp->fsp_name->base_name) && ISDOTDOT(ent->d_name)) {
+		return ent;
+	}
+
+	atname = (struct smb_filename) {
+		.base_name = ent->d_name,
+		.twrp = dirfsp->fsp_name->twrp,
+		.flags = dirfsp->fsp_name->flags,
+	};
+
+	full_fname = full_path_from_dirfsp_atname(talloc_tos(),
+						  dirfsp,
+						  &atname);
+	if (full_fname == NULL) {
+		return NULL;
+	}
+
+	if (!shadow_copy2_strip_snapshot_converted(talloc_tos(),
+						   handle,
+						   full_fname,
+						   &timestamp,
+						   &stripped,
+						   &converted)) {
+		TALLOC_FREE(full_fname);
+		return NULL;
+	}
+
+	if (timestamp == 0 && !converted) {
+		/* Not a snapshot path, no need for convert_sbuf() */
+		TALLOC_FREE(stripped);
+		TALLOC_FREE(full_fname);
+		return ent;
+	}
+
+	if (timestamp == 0) {
+		abspath = make_path_absolute(talloc_tos(),
+					     priv,
+					     full_fname->base_name);
+		TALLOC_FREE(full_fname);
+		if (abspath == NULL) {
+			return NULL;
+		}
+	} else {
+		conv = shadow_copy2_convert(talloc_tos(),
+					    handle,
+					    stripped,
+					    timestamp);
+		TALLOC_FREE(stripped);
+		if (conv == NULL) {
+			return NULL;
+		}
+
+		abspath = make_path_absolute(talloc_tos(), priv, conv);
+		TALLOC_FREE(conv);
+		if (abspath == NULL) {
+			return NULL;
+		}
+	}
+
+	convert_sbuf(handle, abspath, sbuf);
+
+	TALLOC_FREE(abspath);
+	return ent;
+}
+
 static struct vfs_fn_pointers vfs_shadow_copy2_fns = {
 	.connect_fn = shadow_copy2_connect,
 	.disk_free_fn = shadow_copy2_disk_free,
@@ -3362,6 +3452,7 @@ static struct vfs_fn_pointers vfs_shadow_copy2_fns = {
 	.pwrite_recv_fn = shadow_copy2_pwrite_recv,
 	.connectpath_fn = shadow_copy2_connectpath,
 	.parent_pathname_fn = shadow_copy2_parent_pathname,
+	.readdir_fn = shadow_copy2_readdir,
 };
 
 static_decl_vfs;