On Sat, 2005-01-15 at 01:36 -0800, William Lee Irwin III wrote: > Matthias Lang <[EMAIL PROTECTED]> wrote: > >> The linux implementation of setitimer() doesn't behave quite as > >> expected. I found several problems: > >> 1. POSIX says that negative times should cause setitimer() to > >> return -1 and set errno to EINVAL. In linux, the call succeeds. > >> 2. POSIX says that time values with usec >= 1000000 should > >> cause the same behaviour. In linux, the call succeeds. > >> 3. If large time values are given, linux quietly truncates them > >> to the maximum time representable in jiffies. On 2.4.4 on PPC, > >> that's about 248 days. On 2.6.10 on x86, that's about 24 days. > >> POSIX doesn't really say what to do in this case, but looking at > >> established practice, i.e. "what BSD does", since the call comes > >> from BSD, *BSD returns -1 if the time is out of range. > > On Sat, Jan 15, 2005 at 01:30:13AM -0800, Andrew Morton wrote: > > These are things we probably cannot change now. All three are arguably > > sensible behaviour and do satisfy the principle of least surprise. So > > there may be apps out there which will break if we "fix" these things. > > If the kernel version was 2.7.0 then well maybe... > > We can easily do a "rolling upgrade" by adding new versions of the > system calls, giving glibc and apps grace periods to adjust to them, > and nuking the old versions in a few years.
but for 1: do we care? it is being more tolerant than allowed by a standard. Those who care can easily add the test in the userspace wrapper for 2: we again are more tolerant and dtrt; again. And again userspace wrapper can impose an additional restriction if it wants 3 is more nasty and needs thinking; we could consider a fix inside the kernel that actually does wait long enough I don't see a valid reason to restrict/reject input that is accepted now and dealt with reasonably because some standard says so (if you design a new api, following the standard is nice of course). I don't see "doesn't reject a condition that can reasonable be dealt with" as a good reason to go double ABI at all. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
