Define PIDFD_EMPTY, the fsconfig-style configuration command and path key, and versioned run arguments for pidfd spawn builders. Add the initial ordered file-action records.
Store userspace pointers in full-width aligned containers on every ABI. Keep flags and reserved fields zero so later kernels can extend the structures without changing their initial layout. Suggested-by: Christian Brauner <[email protected]> Assisted-by: Codex:gpt-5.6-sol Signed-off-by: Li Chen <[email protected]> --- MAINTAINERS | 2 ++ include/uapi/linux/pidfd.h | 1 + include/uapi/linux/pidfd_spawn.h | 49 ++++++++++++++++++++++++++ tools/include/uapi/linux/pidfd_spawn.h | 49 ++++++++++++++++++++++++++ 4 files changed, 101 insertions(+) create mode 100644 include/uapi/linux/pidfd_spawn.h create mode 100644 tools/include/uapi/linux/pidfd_spawn.h diff --git a/MAINTAINERS b/MAINTAINERS index 8729cea57c3dd..b63bc1ee0171f 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -21287,7 +21287,9 @@ M: Christian Brauner <[email protected]> L: [email protected] S: Maintained T: git git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux.git +F: include/uapi/linux/pidfd_spawn.h F: samples/pidfd/ +F: tools/include/uapi/linux/pidfd_spawn.h F: tools/testing/selftests/clone3/ F: tools/testing/selftests/pidfd/ K: (?i)pidfd diff --git a/include/uapi/linux/pidfd.h b/include/uapi/linux/pidfd.h index 0919246a1611c..cad5b722e9f0e 100644 --- a/include/uapi/linux/pidfd.h +++ b/include/uapi/linux/pidfd.h @@ -10,6 +10,7 @@ /* Flags for pidfd_open(). */ #define PIDFD_NONBLOCK O_NONBLOCK #define PIDFD_THREAD O_EXCL +#define PIDFD_EMPTY (1U << 27) #ifdef __KERNEL__ #include <linux/sched.h> #define PIDFD_STALE CLONE_PIDFD diff --git a/include/uapi/linux/pidfd_spawn.h b/include/uapi/linux/pidfd_spawn.h new file mode 100644 index 0000000000000..46d61e72435cc --- /dev/null +++ b/include/uapi/linux/pidfd_spawn.h @@ -0,0 +1,49 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ + +#ifndef _UAPI_LINUX_PIDFD_SPAWN_H +#define _UAPI_LINUX_PIDFD_SPAWN_H + +#include <linux/types.h> + +#define PIDFD_SPAWN_RUN_SIZE_VER0 64 +#define PIDFD_SPAWN_ACTION_SIZE_VER0 32 + +/* Commands for pidfd_config(). */ +#define PIDFD_CONFIG_SET_STRING 0 + +/* String keys for pidfd_config(). */ +#define PIDFD_CONFIG_KEY_PATH "path" + +struct pidfd_spawn_run_args { + __u32 flags; + __u32 nr_actions; + /* The next four fields are full-width userspace virtual addresses. */ + __aligned_u64 path; + __aligned_u64 argv; + __aligned_u64 envp; + __aligned_u64 actions; + __u32 action_size; + __u32 reserved0; + __u64 reserved[2]; +}; + +enum pidfd_spawn_action_type { + PIDFD_SPAWN_ACTION_DUP2 = 0, + PIDFD_SPAWN_ACTION_CLOSE_RANGE = 1, + PIDFD_SPAWN_ACTION_FCHDIR = 2, +}; + +struct pidfd_spawn_action { + __u32 type; + __u32 flags; + /* + * DUP2 uses fd as the source and newfd as the destination. + * CLOSE_RANGE uses fd as the first and newfd as the last descriptor. + * FCHDIR uses fd as the directory descriptor and requires newfd to be 0. + */ + __u32 fd; + __u32 newfd; + __u64 reserved[2]; +}; + +#endif /* _UAPI_LINUX_PIDFD_SPAWN_H */ diff --git a/tools/include/uapi/linux/pidfd_spawn.h b/tools/include/uapi/linux/pidfd_spawn.h new file mode 100644 index 0000000000000..46d61e72435cc --- /dev/null +++ b/tools/include/uapi/linux/pidfd_spawn.h @@ -0,0 +1,49 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ + +#ifndef _UAPI_LINUX_PIDFD_SPAWN_H +#define _UAPI_LINUX_PIDFD_SPAWN_H + +#include <linux/types.h> + +#define PIDFD_SPAWN_RUN_SIZE_VER0 64 +#define PIDFD_SPAWN_ACTION_SIZE_VER0 32 + +/* Commands for pidfd_config(). */ +#define PIDFD_CONFIG_SET_STRING 0 + +/* String keys for pidfd_config(). */ +#define PIDFD_CONFIG_KEY_PATH "path" + +struct pidfd_spawn_run_args { + __u32 flags; + __u32 nr_actions; + /* The next four fields are full-width userspace virtual addresses. */ + __aligned_u64 path; + __aligned_u64 argv; + __aligned_u64 envp; + __aligned_u64 actions; + __u32 action_size; + __u32 reserved0; + __u64 reserved[2]; +}; + +enum pidfd_spawn_action_type { + PIDFD_SPAWN_ACTION_DUP2 = 0, + PIDFD_SPAWN_ACTION_CLOSE_RANGE = 1, + PIDFD_SPAWN_ACTION_FCHDIR = 2, +}; + +struct pidfd_spawn_action { + __u32 type; + __u32 flags; + /* + * DUP2 uses fd as the source and newfd as the destination. + * CLOSE_RANGE uses fd as the first and newfd as the last descriptor. + * FCHDIR uses fd as the directory descriptor and requires newfd to be 0. + */ + __u32 fd; + __u32 newfd; + __u64 reserved[2]; +}; + +#endif /* _UAPI_LINUX_PIDFD_SPAWN_H */ -- 2.52.0
