On 2019-12-16, Florian Weimer fweimer@redhat.com wrote:
diff --git a/include/uapi/linux/fcntl.h b/include/uapi/linux/fcntl.h index 1d338357df8a..58c3a0e543c6 100644 --- a/include/uapi/linux/fcntl.h +++ b/include/uapi/linux/fcntl.h @@ -93,5 +93,40 @@ #define AT_RECURSIVE 0x8000 /* Apply to the entire subtree */ +/*
- Arguments for how openat2(2) should open the target path. If @resolve is
- zero, then openat2(2) operates very similarly to openat(2).
- However, unlike openat(2), unknown bits in @flags result in -EINVAL rather
- than being silently ignored. @mode must be zero unless one of {O_CREAT,
- O_TMPFILE} are set.
- @flags: O_* flags.
- @mode: O_CREAT/O_TMPFILE file mode.
- @resolve: RESOLVE_* flags.
- */
+struct open_how {
- __aligned_u64 flags;
- __u16 mode;
- __u16 __padding[3]; /* must be zeroed */
- __aligned_u64 resolve;
+};
+#define OPEN_HOW_SIZE_VER0 24 /* sizeof first published struct */ +#define OPEN_HOW_SIZE_LATEST OPEN_HOW_SIZE_VER0
+/* how->resolve flags for openat2(2). */ +#define RESOLVE_NO_XDEV 0x01 /* Block mount-point crossings
(includes bind-mounts). */+#define RESOLVE_NO_MAGICLINKS 0x02 /* Block traversal through procfs-style
"magic-links". */+#define RESOLVE_NO_SYMLINKS 0x04 /* Block traversal through all symlinks
(implies OEXT_NO_MAGICLINKS) */+#define RESOLVE_BENEATH 0x08 /* Block "lexical" trickery like
"..", symlinks, and absolutepaths which escape the dirfd. */+#define RESOLVE_IN_ROOT 0x10 /* Make all jumps to "/" and ".."
be scoped inside the dirfd(similar to chroot(2)). */#endif /* _UAPI_LINUX_FCNTL_H */
Would it be possible to move these to a new UAPI header?
In glibc, we currently do not #include <linux/fcntl.h>. We need some of the AT_* constants in POSIX mode, and the header is not necessarily namespace-clean. If there was a separate header for openat2 support, we could use that easily, and we would only have to maintain the baseline definitions (which never change).
Sure, (assuming nobody objects) I can move it to "linux/openat2.h".