diff options
Diffstat (limited to 'include/uapi/linux/fcntl.h')
| -rw-r--r-- | include/uapi/linux/fcntl.h | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/include/uapi/linux/fcntl.h b/include/uapi/linux/fcntl.h index a15ac2fa4b20..f291ab4f94eb 100644 --- a/include/uapi/linux/fcntl.h +++ b/include/uapi/linux/fcntl.h @@ -90,10 +90,28 @@ #define DN_ATTRIB 0x00000020 /* File changed attibutes */ #define DN_MULTISHOT 0x80000000 /* Don't remove notifier */ +/* Reserved kernel ranges [-100], [-10000, -40000]. */ #define AT_FDCWD -100 /* Special value for dirfd used to indicate openat should use the current working directory. */ +/* + * The concept of process and threads in userland and the kernel is a confusing + * one - within the kernel every thread is a 'task' with its own individual PID, + * however from userland's point of view threads are grouped by a single PID, + * which is that of the 'thread group leader', typically the first thread + * spawned. + * + * To cut the Gideon knot, for internal kernel usage, we refer to + * PIDFD_SELF_THREAD to refer to the current thread (or task from a kernel + * perspective), and PIDFD_SELF_THREAD_GROUP to refer to the current thread + * group leader... + */ +#define PIDFD_SELF_THREAD -10000 /* Current thread. */ +#define PIDFD_SELF_THREAD_GROUP -10001 /* Current thread group leader. */ + +#define FD_PIDFS_ROOT -10002 /* Root of the pidfs filesystem */ +#define FD_INVALID -10009 /* Invalid file descriptor: -10000 - EBADF = -10009 */ /* Generic flags for the *at(2) family of syscalls. */ |