From: Cedric Ware <cedric.ware__bml@normalesup.org>
To: Bart Schaefer <schaefer@brasslantern.com>
Cc: Daniel Shahaf <d.s@daniel.shahaf.name>,
Sebastian Gniazdowski <sgniazdowski@gmail.com>,
Zsh hackers list <zsh-workers@zsh.org>
Subject: Re: [BUG] zsystem:34: flock: invalid timeout value: '0'
Date: Sat, 27 Jun 2020 09:13:50 +0200 [thread overview]
Message-ID: <20200627071350.zqkdhzbk3mfej2tz@phare.normalesup.org> (raw)
In-Reply-To: <CAH+w=7YuMOOSbsgop53ZpCGQZ=COGBSS_nMAyS7m6aQ_YmpukA@mail.gmail.com>
Hello,
Bart Schaefer (Friday 2020-06-26):
> It's pretty obvious that the patch caused the change:
>
> + if (timeout < 1e-6 || timeout > 1073741823.) {
> + zwarnnam(nam, "flock: invalid timeout value: '%s'",
> + optarg);
Yes, sorry, didn't catch the 0 case.
> Similarly:
>
> + if (timeout_param.u.d < 1
> + || timeout_param.u.d > 0.999 * LONG_MAX) {
> + zwarnnam(nam, "flock: invalid interval value: '%s'",
> + optarg);
I don't think so. This one is for the -i parameter, which is new,
it's not a behavior change. And IMO it doesn't make sense to allow
a zero interval.
> I don't know enough about dealing with the float-valued time specs to be
> sure what to do about it, i.e., why a limit above zero was considered
> necessary or whether zero needs to be a special case.
I didn't want to allow specifying a timeout below 1 microsecond,
because that's the granularity of zsleep(). One could still allow it
but silently treat it as 0. In any case, the 0 value itself should
indeed have been allowed. Here's a quick patch below, I've tested it,
but I don't have time right now to do much more.
Best regards,
Cedric Ware.
diff --git a/Src/Modules/system.c b/Src/Modules/system.c
index 972aa0767..638fe029e 100644
--- a/Src/Modules/system.c
+++ b/Src/Modules/system.c
@@ -591,13 +591,16 @@ bin_zsystem_flock(char *nam, char **args, UNUSED(Options ops), UNUSED(int func))
timeout_param.u.d : (double)timeout_param.u.l;
/*
+ * timeout can be 0 (no wait) but not so small as to be
+ * less than a microsecond.
* timeout must not overflow time_t, but little is known
* about this type's limits. Conservatively limit to 2^30-1
* (34 years). Then it can only overflow if time_t is only
* a 32-bit int and CLOCK_MONOTONIC is not supported, in which
* case there is a Y2038 problem anyway.
*/
- if (timeout < 1e-6 || timeout > 1073741823.) {
+ if (timeout != 0. &&
+ (timeout < 1e-6 || timeout > 1073741823.)) {
zwarnnam(nam, "flock: invalid timeout value: '%s'",
optarg);
return 1;
diff --git a/Test/V14system.ztst b/Test/V14system.ztst
index b8af96cda..06512fe05 100644
--- a/Test/V14system.ztst
+++ b/Test/V14system.ztst
@@ -13,7 +13,9 @@
%test
(
- zsystem flock -t 0.1 -i 0.000001 $tst_dir/file
+ zsystem flock -t 0 -i 0.000001 $tst_dir/file &&
+ zsystem flock -t 0.1 -i 0.000001 $tst_dir/file &&
+ zsystem flock -t 1 -i 0.000001 $tst_dir/file
)
0:zsystem flock valid time arguments
next prev parent reply other threads:[~2020-06-27 7:14 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-25 17:49 Sebastian Gniazdowski
2020-06-26 14:16 ` Daniel Shahaf
2020-06-26 19:42 ` Sebastian Gniazdowski
2020-06-27 1:47 ` Daniel Shahaf
2020-06-27 2:04 ` Bart Schaefer
2020-06-27 7:13 ` Cedric Ware [this message]
2020-06-27 7:27 ` Roman Perepelitsa
2020-06-27 17:01 ` Bart Schaefer
2020-06-27 17:12 ` Roman Perepelitsa
2020-06-27 17:58 ` Bart Schaefer
2020-06-27 18:09 ` Roman Perepelitsa
2020-06-27 20:38 ` Cedric Ware
2020-06-28 9:27 ` Roman Perepelitsa
2020-07-10 15:28 ` Sebastian Gniazdowski
2020-07-11 5:18 ` dana
2020-06-27 17:25 ` Sebastian Gniazdowski
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