[RFC PATCH v1 04/13] exec: add spawn template UAPI definitions

[Li Chen <me@linux.beauty>]

Add the userspace ABI structures and flags for creating a spawn
template and spawning a process from it. The ABI carries argv, envp,
and per-spawn fd actions while leaving policy decisions in userspace.

Signed-off-by: Li Chen <me@linux.beauty>
---
 MAINTAINERS                         |  1 +
 include/uapi/linux/spawn_template.h | 62 +++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+)
 create mode 100644 include/uapi/linux/spawn_template.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 3dd58a16f06a9..d7b1191e33ca0 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9739,6 +9739,7 @@ F:	include/linux/elf.h
 F:	include/uapi/linux/auxvec.h
 F:	include/uapi/linux/binfmts.h
 F:	include/uapi/linux/elf.h
+F:	include/uapi/linux/spawn_template.h
 F:	kernel/fork.c
 F:	mm/vma_exec.c
 F:	tools/testing/selftests/exec/
diff --git a/include/uapi/linux/spawn_template.h b/include/uapi/linux/spawn_template.h
new file mode 100644
index 0000000000000..84f026fdf9090
--- /dev/null
+++ b/include/uapi/linux/spawn_template.h
@@ -0,0 +1,62 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _UAPI_LINUX_SPAWN_TEMPLATE_H
+#define _UAPI_LINUX_SPAWN_TEMPLATE_H
+
+#include <linux/openat2.h>
+#include <linux/types.h>
+
+#define SPAWN_TEMPLATE_CREATE_CLOEXEC		(1ULL << 0)
+#define SPAWN_TEMPLATE_SPAWN_INHERIT_FDS	(1ULL << 0)
+
+enum spawn_template_action_type {
+	SPAWN_TEMPLATE_ACTION_CLOSE = 0,
+	SPAWN_TEMPLATE_ACTION_DUP2 = 1,
+	SPAWN_TEMPLATE_ACTION_FCHDIR = 2,
+	SPAWN_TEMPLATE_ACTION_OPEN = 3,
+	SPAWN_TEMPLATE_ACTION_CLOSE_RANGE = 4,
+	SPAWN_TEMPLATE_ACTION_SIGMASK = 5,
+	SPAWN_TEMPLATE_ACTION_SIGDEFAULT = 6,
+};
+
+struct spawn_template_action {
+	__u32 type;
+	__u32 flags;
+	__s32 fd;
+	__s32 newfd;
+	__aligned_u64 arg;
+};
+
+struct spawn_template_open {
+	__aligned_u64 path;
+	struct open_how how;
+};
+
+struct spawn_template_sigset {
+	__aligned_u64 sigset;
+	__u64 sigsetsize;
+};
+
+struct spawn_template_create_args {
+	__aligned_u64 flags;
+	__s32 execfd;
+	__u32 exec_flags;
+	__aligned_u64 filename;
+	__aligned_u64 actions;
+	__aligned_u64 actions_len;
+	__aligned_u64 reserved[4];
+};
+
+struct spawn_template_spawn_args {
+	__aligned_u64 flags;
+	__aligned_u64 pidfd;
+	__aligned_u64 argv;
+	__aligned_u64 envp;
+	__aligned_u64 actions;
+	__aligned_u64 actions_len;
+	__aligned_u64 reserved[4];
+};
+
+#define SPAWN_TEMPLATE_CREATE_ARGS_SIZE_VER0	72
+#define SPAWN_TEMPLATE_SPAWN_ARGS_SIZE_VER0	80
+
+#endif /* _UAPI_LINUX_SPAWN_TEMPLATE_H */
-- 
2.52.0