[pseudo] [PATCH v2 1/4] ports/linux/guts: Add open_tree wrapper

[frezidok1@gmail.com]

From: Dmitry Sakhonchik <frezidok1@gmail.com>

[YOCTO #16379]

OPEN_TREE_CLONE is not handled since it requires CAP_SYS_ADMIN and is outside the common pseudo use case.

Signed-off-by: Dmitry Sakhonchik <frezidok1@gmail.com>
---
 ports/linux/guts/open_tree.c | 46 ++++++++++++++++++++++++++++++++++++
 ports/linux/portdefs.h       |  9 +++++++
 ports/linux/wrapfuncs.in     |  1 +
 3 files changed, 56 insertions(+)
 create mode 100644 ports/linux/guts/open_tree.c

diff --git a/ports/linux/guts/open_tree.c b/ports/linux/guts/open_tree.c
new file mode 100644
index 0000000..6c2aad9
--- /dev/null
+++ b/ports/linux/guts/open_tree.c
@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2026 Yocto Project
+ * guts/COPYRIGHT for information.
+ *
+ * SPDX-License-Identifier: LGPL-2.1-only
+ *
+ * int open_tree(int dirfd, const char *path, unsigned int flags)
+ *	int rc = -1;
+ */
+
+	struct stat64 buf;
+	int save_errno;
+	char *pseudo_path;
+
+	if (real_open_tree) {
+		pseudo_debug(PDBGF_SYSCALL, "open_tree, calling open_tree.\n");
+		rc = real_open_tree(dirfd, path, flags);
+	} else {
+		pseudo_debug(PDBGF_SYSCALL, "open_tree, calling syscall.\n");
+		rc = real_syscall(SYS_open_tree, dirfd, path, flags);
+	}
+
+	pseudo_path = pseudo_root_path(__func__, __LINE__, dirfd, path, 0);
+
+	if (rc != -1) {
+		save_errno = errno;
+		int stat_rc;
+
+		stat_rc = real___fxstatat64(_STAT_VER, dirfd, pseudo_path, &buf, (flags & AT_SYMLINK_NOFOLLOW) ? AT_SYMLINK_NOFOLLOW : 0);
+
+		pseudo_debug(PDBGF_FILE, "open_tree(path %s), flags %o, stat rc %d, stat mode %o\n",
+			pseudo_path, flags, stat_rc, buf.st_mode);
+
+		if (stat_rc != -1) {
+			pseudo_client_op(OP_OPEN, 0, rc, dirfd, pseudo_path, &buf);
+		} else {
+			pseudo_debug(PDBGF_FILE, "open_tree(fd %d, path %d/%s, flags %d) succeeded, but stat failed (%s).\n",
+				rc, dirfd, pseudo_path, flags, strerror(errno));
+			pseudo_client_op(OP_OPEN, 0, rc, dirfd, pseudo_path, 0);
+		}
+		errno = save_errno;
+	}
+
+/*	return rc;
+ * }
+ */
diff --git a/ports/linux/portdefs.h b/ports/linux/portdefs.h
index 1f1a41a..565fed9 100644
--- a/ports/linux/portdefs.h
+++ b/ports/linux/portdefs.h
@@ -82,3 +82,12 @@ extern int unshare(int flags);
 
 #define SYS_openat2 __NR_openat2
 #endif
+
+#ifndef SYS_open_tree
+
+#ifndef __NR_open_tree
+#define __NR_open_tree 428
+#endif
+
+#define SYS_open_tree __NR_open_tree
+#endif
diff --git a/ports/linux/wrapfuncs.in b/ports/linux/wrapfuncs.in
index 3cea20a..a51e9a0 100644
--- a/ports/linux/wrapfuncs.in
+++ b/ports/linux/wrapfuncs.in
@@ -10,6 +10,7 @@ int lchown(const char *path, uid_t owner, gid_t group); /* flags=AT_SYMLINK_NOFO
 int __fxstatat(int ver, int dirfd, const char *path, struct stat *buf, int flags);
 int openat(int dirfd, const char *path, int flags, ...{mode_t mode}); /* flags=((flags&O_NOFOLLOW)||((flags&(O_CREAT|O_EXCL))==(O_CREAT|O_EXCL))), noignore_path=1 */
 int __openat_2(int dirfd, const char *path, int flags); /* flags=((flags&O_NOFOLLOW)||((flags&(O_CREAT|O_EXCL))==(O_CREAT|O_EXCL))), noignore_path=1 */
+int open_tree(int dirfd, const char *path, unsigned int flags); /* noignore_path=1 */
 int mknod(const char *path, mode_t mode, dev_t dev); /* real_func=pseudo_mknod */
 int mknodat(int dirfd, const char *path, mode_t mode, dev_t dev); /* real_func=pseudo_mknodat */
 int __xmknod(int ver, const char *path, mode_t mode, dev_t *dev); /* flags=AT_SYMLINK_NOFOLLOW */