Re: [PATCH v3] Support for setitimer() on platforms lacking it
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Sep 7, 2012, 16:40 UTC
- Message-ID
- <7va9x1zszj.fsf@alter.siamese.dyndns.org>
- In-Reply-To
- <002201cd8cde$ea7cacc0$bf760640$@schmitz-digital.de>
"Joachim Schmitz" <jojo@schmitz-digital.de> writes:
Show 9 quoted lines
> HP NonStop (currently) doesn't have setitimer(). The previous attempt of an > emulation (reverted by this commit) was not a real substitute for a recurring > itimer (as here we also don't have SA_RESTART, so can't re-arm the timer). > As setitimer() is only used in cases of perceived latency and it doesn't affect > correctness, it now gets disabled entirely, if NO_SETITIMER is set. > HP NonStop does provide struct itimerval, but other platforms may not, so this > is taken care of in this commit too, by setting NO_STRUCT_ITIMERVAL. > > Signed-off-by: Joachim Schmitz <jojo@schmitz-digital.de>
The end-result looks simple and nice (thanks for NO_STRUCT_ITIMERVAL).
As we are not going to include the earlier failed attempt in our longer-term history (i.e. 'master', that never rewinds), however, I would prefer to see a replacement patch (as opposed to this one that incrementally updates the previous failed attempt). I could squash this into the previous one myself though ;-)
Thanks.
Show 102 quoted lines
> ---
> Makefile | 5 +++++
> compat/itimer.c | 50 --------------------------------------------------
> git-compat-util.h | 11 +++++++++--
> 3 files changed, 14 insertions(+), 52 deletions(-)
> delete mode 100644 compat/itimer.c
>
> diff --git a/Makefile b/Makefile
> index ac49320..7be555b 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -157,6 +157,11 @@ all::
> # Define NO_PREAD if you have a problem with pread() system call (e.g.
> # cygwin1.dll before v1.5.22).
> #
> +# Define NO_SETITIMER if you don't have setitimer()
> +#
> +# Define NO_STRUCT_ITIMERVAL if you don't have struct itimerval
> +# This also implies NO_SETITIMER
> +#
> # Define NO_THREAD_SAFE_PREAD if your pread() implementation is not
> # thread-safe. (e.g. compat/pread.c or cygwin)
> #
> diff --git a/compat/itimer.c b/compat/itimer.c
> deleted file mode 100644
> index 713f1ff..0000000
> --- a/compat/itimer.c
> +++ /dev/null
> @@ -1,50 +0,0 @@
> -#include "../git-compat-util.h"
> -
> -static int git_getitimer(int which, struct itimerval *value)
> -{
> - int ret = 0;
> -
> - switch (which) {
> - case ITIMER_REAL:
> - value->it_value.tv_usec = 0;
> - value->it_value.tv_sec = alarm(0);
> - ret = 0; /* if alarm() fails, we get a SIGLIMIT */
> - break;
> - case ITIMER_VIRTUAL: /* FALLTHRU */
> - case ITIMER_PROF: errno = ENOTSUP; ret = -1; break;
> - default: errno = EINVAL; ret = -1;
> - }
> - return ret;
> -}
> -
> -int git_setitimer(int which, const struct itimerval *value,
> - struct itimerval *ovalue)
> -{
> - int ret = 0;
> -
> - if (!value
> - || value->it_value.tv_usec < 0
> - || value->it_value.tv_usec > 1000000
> - || value->it_value.tv_sec < 0) {
> - errno = EINVAL;
> - return -1;
> - }
> -
> - else if (ovalue)
> - if (!git_getitimer(which, ovalue))
> - return -1; /* errno set in git_getitimer() */
> -
> - else
> - switch (which) {
> - case ITIMER_REAL:
> - alarm(value->it_value.tv_sec +
> - (value->it_value.tv_usec > 0) ? 1 : 0);
> - ret = 0; /* if alarm() fails, we get a SIGLIMIT */
> - break;
> - case ITIMER_VIRTUAL: /* FALLTHRU */
> - case ITIMER_PROF: errno = ENOTSUP; ret = -1; break;
> - default: errno = EINVAL; ret = -1;
> - }
> -
> - return ret;
> -}
> diff --git a/git-compat-util.h b/git-compat-util.h
> index 18089f0..4628d7a 100644
> --- a/git-compat-util.h
> +++ b/git-compat-util.h
> @@ -162,9 +162,16 @@
> #define probe_utf8_pathname_composition(a,b)
> #endif
>
> +#ifdef NO_STRUCT_ITIMERVAL
> +struct itimerval {
> + struct timeval it_interval;
> + struct timeval it_value;
> +}
> +#define NO_SETITIMER
> +#endif
> +
> #ifdef NO_SETITIMER
> -#define setitimer(a,b,c) git_setitimer((a),(b),(c))
> -extern int git_setitimer(int, const struct itimerval *, struct itimerval *);
> +#define setitimer(which,value,ovalue)
> #endif
>
> #ifdef MKDIR_WO_TRAILING_SLASH