On 2025-02-01 11:46:59+0100, Willy Tarreau wrote: > On Sat, Feb 01, 2025 at 11:41:58AM +0100, Thomas Weißschuh wrote: > > On 2025-02-01 11:34:38+0100, Willy Tarreau wrote: > > > On Thu, Jan 30, 2025 at 08:54:03PM +0100, Thomas Weißschuh wrote: > > > > From: Thomas Weißschuh <thomas.weissschuh@xxxxxxxxxxxxx> > > > > > > > > Add an allocation-free implementation of readdir() and related > > > > functions. The implementation is modelled after the one for FILE. > > > > > > I think you'd need to mention/remind the two important points that > > > come out of that choice, one being that DIR is a fake pointer that > > > instead stores ~fd so that it can be turned back to a valid FD, and > > > that subsequent readdir() calls will only work from the same file > > > unit since it relies on a local static storage. > > > > Point one is true. > > Point two not so much. It is fine to have multiple directories open at > > the same time. All state is kept inside the kernel. > > Only the *current* return value is in the static buffer. > > Excellent point! It also needs to be mentioned. Unfortunately POSIX is more specific in it's definition and forbids this: The returned pointer, and pointers within the structure, might be invalidated or the structure or the storage areas might be overwritten by a subsequent call to readdir() on the same directory stream. I see two possibilities: Allocate one 'struct dirent' as part of DIR. Only implement readdir_r(). While readdir_r() is deprecated (according to readdir(3) but not readdir(3p)) this seems to be due to ABI issues, which shouldn't matter for nolibc anyways. Personally I would prefer readdir_r(). <snip>
