On 2020-03-30, Michael Kerrisk (man-pages) <mtk.manpages@xxxxxxxxx> wrote: > On 3/30/20 11:20 AM, Aleksa Sarai wrote: > > On 2020-03-30, Michael Kerrisk (man-pages) <mtk.manpages@xxxxxxxxx> wrote: > >> Hello Aleksa, > >> > >> On 2/2/20 4:19 PM, Aleksa Sarai wrote: > >>> Rather than trying to merge the new syscall documentation into open.2 > >>> (which would probably result in the man-page being incomprehensible), > >>> instead the new syscall gets its own dedicated page with links between > >>> open(2) and openat2(2) to avoid duplicating information such as the list > >>> of O_* flags or common errors. > >>> > >>> In addition to describing all of the key flags, information about the > >>> extensibility design is provided so that users can better understand why > >>> they need to pass sizeof(struct open_how) and how their programs will > >>> work across kernels. After some discussions with David Laight, I also > >>> included explicit instructions to zero the structure to avoid issues > >>> when recompiling with new headers.> > >>> Signed-off-by: Aleksa Sarai <cyphar@xxxxxxxxxx> > >> > >> I'm just editing this page, and have a question on one piece. > >> > >>> +Unlike > >>> +.BR openat (2), > >>> +it is an error to provide > >>> +.BR openat2 () > >>> +with a > >>> +.I mode > >>> +which contains bits other than > >>> +.IR 0777 , > >> > >> This piece appears not to be true, both from my reading of the > >> source code, and from testing (i.e., I wrote a a small program that > >> successfully called openat2() and created a file that had the > >> set-UID, set-GID, and sticky bits set). > >> > >> Is this a bug in the implementation or a bug in the manual page text? > > > > My bad -- it's a bug in the manual. The actual check (which does work, > > there are selftests for this) is: > > > > if (how->mode & ~S_IALLUGO) > > return -EINVAL; > > > > But when writing the man page I forgot that S_IALLUGO also includes > > those bits. Do you want me to send an updated version or would you > > prefer to clean it up? > > I'll clean it up. > > So, it should say, "bits other than 07777", right? Yes, that would be correct. -- Aleksa Sarai Senior Software Engineer (Containers) SUSE Linux GmbH <https://www.cyphar.com/>
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