On Thu, Dec 13, 2018 at 01:16:45PM +0100, Dmitry Vyukov wrote: > On Thu, Dec 13, 2018 at 1:10 PM Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: > > > > On Thu, Dec 13, 2018 at 05:57:17AM -0600, Goldwyn Rodrigues wrote: > > > A user can open(O_WRONLY | O_RDWR) and the options are valid. > > > However, OPEN_FMODE() evaluates both FMODE_READ and FMODE_WRITE, > > > as negative. We also need to protect the lower layers from this > > > anomaly. > > > > > > Solve it by dropping O_WRONLY, so O_RDWR takes precedence. > > > > Congratulations, you've broken fdutils... Passing 3 in lower bits > > of open() flags is *not* the same as O_RDWR; behaiviour is > > different and deliberately chosen by existing userland code. > > > > IOW, NAK. > > I am eager to hear what it means then. Open for ioctls, basically. No read/write allowed, no checks for media writability, etc. done at open() time, both read and write *permissions* required from device node. Think of the things like formatting a floppy, for example...
