> If a program is doing this then trying to fdopendir/readdir, it's a
> bug in the program. A directory opened with O_SEARCH is only usable
> for search (attempting to access a file/directory in that directory
> by name, using one of the *at functions) not for reading. Unix has
> always distinguished search (+x) and read (+r) permission for
> directories and O_SEARCH vs O_RDONLY is similar.
Well, that's probably the worst kind of bugs, since it was caused by misinterpretation of the documentation.
That was written intentionally due to misunderstanding, so I really want to clarify the situation here.
So does it mean that descriptors opened with O_SEARCH are usable only for *at functions?
I've been under the impression that it's part of the O_PATH functionality, not O_SEARCH.
> It's been an ongoing fight even trying to get the kernel to reserve a
> bit number for them. It looks like the correct course of action (the
> one that's compatible with their non-action) is going to be using
> O_PATH|3 for both of them. This allows userspace open to process
> O_SEARCH and O_EXEC slightly differently from O_PATH (O_NOFOLLOW has
> different semantics) and the kernel will ignore the extra access mode
> bits with O_PATH anyway.
At the same time, if I understand you correctly, you mean that O_PATH is a different beast than O_SEARCH.
I've found a mail in the DragonFly mailing list, which also slightly touches this topic[0].
They also propose to use value 3 as currently unused value; I don't know if it is implemented yet.
FWIW, neither OpenBSD nor FreeBSD provide O_SEARCH flag; the latter provides O_EXEC though.
I finally have a good access to the Internet so I managed to find a detailed discussion on this topic[1].
Sorry guys (and especially you, Rich) that I didn't find it before; it would have saved some questions earlier.
Rich, could you please elaborate on the exact semantics of O_SEARCH flag?
Again, thank you very much for your answer and for your patience!