В Thu, 27 Jan 2011 17:49:39 -0800 (PST) Davide Libenzi <[email protected]> пишет:
> On Fri, 28 Jan 2011, Alexander Gordeev wrote: > > > В Thu, 27 Jan 2011 16:53:39 -0800 (PST) > > Davide Libenzi <[email protected]> пишет: > > > > > On Fri, 28 Jan 2011, Alexander Gordeev wrote: > > > > > > > Hi! > > > > > > > > I've just found a problem with TFD_NONBLOCK flag that can be passed to > > > > timerfd_create. > > > > > > > > <uclibc>/libc/sysdeps/linux/common/sys/timerfd.h which is installed > > > > to /usr/include/sys/timerfd.h defines TFD_NONBLOCK as 04000 ie 0x800. > > > > BTW glibc/eglibc headers do the same thing. > > > > > > > > <linux>/include/linux/timerfd.h declares it as O_NONBLOCK which is > > > > defined in fcntl.h. Usually O_NONBLOCK is 0x800 too but some > > > > architectures including MIPS it redefine it: > > > > > > > > arch/mips/include/asm/fcntl.h:#define O_NONBLOCK 0x0080 > > > > arch/alpha/include/asm/fcntl.h:#define O_NONBLOCK 00004 > > > > arch/sparc/include/asm/fcntl.h:#define O_NONBLOCK 0x4000 > > > > arch/parisc/include/asm/fcntl.h:#define O_NONBLOCK 000200004 > > > > > > > > My tests show that kernel thinks that TFD_NONBLOCK is 0x80 on MIPS. I > > > > get what I want when I pass 0x80 and EINVAL when I pass 0x800. I don't > > > > know why there are such uncertain things in Linux. Probably the problem > > > > should be fixed in the kernel. > > > > > > > > Right now one cannot use timerfd_create(..., TFD_NONBLOCK) on MIPS but > > > > can use timerfd_create(..., O_NONBLOCK) instead. > > > > > > Ther kernel definition (include/linux/timerfd.h) maps it directly to > > > O_NONBLOCK, but I am noticing that glibc bolt in the value. > > > I don't think this is a kernel fix. > > > > Yes, but linux/timerfd.h is not installed so timerfd.h from *libc > > cannot include it. So adding it to include/linux/Kbuild would be a > > first step to make them not hard-code the value. Right? > > Glibc seems to wrap many files with their own definition. > I am not sure why they are actually doing it, but they must have a valid > reason. > It probably makes sense to just un-bolt the values from sys/timerfd.h and > link them to O_* values from fcntl.h. Great! This is probably the simplest solution. Hope they'll use it. However, I'm still curious why the value O_NONBLOCK value is architecture-specific? -- Alexander
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