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? Thanks, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/
