From: Jeff Johnston <jjohnstn@redhat.com>
To: jdoubleu <hi@jdoubleu.de>
Cc: Newlib <newlib@sourceware.org>
Subject: Re: [PATCH] add tests for tzset(3)
Date: Wed, 27 Apr 2022 15:30:29 -0400 [thread overview]
Message-ID: <CAOox84utHgaPzdv1Ad5bOmjeYUN3OXD2P2LhwrM7C8t_qOOj3w@mail.gmail.com> (raw)
In-Reply-To: <2a909d6a-cdfd-0642-68de-7082c9fb0e0a@jdoubleu.de>
[-- Attachment #1: Type: text/plain, Size: 3528 bytes --]
I have taken a stab at creating a tzset_r.c that handles errors by setting
timezone to unnamed UTC.
Let me know if there are any issues.
-- Jeff J.
On Fri, Apr 15, 2022 at 6:10 AM jdoubleu <hi@jdoubleu.de> wrote:
> On Thu, Apr 14, 2022 at 12:31 PM Brian Inglis wrote:
> > I am still not hearing from where the requirement originates to set
> > UTC/GMT/etc or do anything other than leave everything as is.
> > Is this glibc behaviour, and why not /etc/localtime or /etc/timezone?
>
> On 4/14/2022 9:23 PM, Jeff Johnston wrote:
> > It is glibc behaviour as I mentioned in my note. The following is also
> > from man tzset
>
> Aside from glibc, the BSD man page[1] also states:
> > If the TZ environment variable [..] cannot be interpreted as a direct
> specification, UTC is used.
> Where "direct specification" is the formatted string.
>
> The POSIX standard does not seem to explicitly state what happens in an
> error case, besides[2]:
> > The interpretation of these fields is unspecified if either field is
> less than three bytes [..], > more than {TZNAME_MAX} bytes, or if they
> contain characters other
> than those specified.and[3]
> > If TZ is absent from the environment, implementation-defined default
> timezone information shall be used.
>
> [1]: https://man.openbsd.org/tzset
> [2]:
>
> https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_03
> [2]:
> https://pubs.opengroup.org/onlinepubs/9699919799/functions/tzset.html#
>
>
> Cheers
> ---
> 🙎🏻♂️ jdoubleu
> On 4/14/2022 9:23 PM, Jeff Johnston wrote:
> > On Thu, Apr 14, 2022 at 12:31 PM Brian Inglis <
> > Brian.Inglis@systematicsw.ab.ca> wrote:
> >
> >> I am still not hearing from where the requirement originates to set
> >> UTC/GMT/etc or do anything other than leave everything as is.
> >> Is this glibc behaviour, and why not /etc/localtime or /etc/timezone?
> >>
> >>
> > It is glibc behaviour as I mentioned in my note. The following is also
> > from man tzset
> >
> > If the TZ variable does not appear in the environment, the tzname
> > vari‐
> > able is initialized with the best approximation of local wall
> > clock
> > time, as specified by the tzfile(5)-format file localtime found
> in
> > the
> > system timezone directory (see below). (One also often
> > sees
> > /etc/localtime used here, a symlink to the right file in the
> > system
> > timezone directory.)
> >
> > If the TZ variable does appear in the environment but its
> value
> > is
> > empty or its value cannot be interpreted using any of the formats
> > spec‐
> > ified below, Coordinated Universal Time (UTC) is used.
> >
> > Note about if its value is specified and cannot be interpreted using any
> of
> > the formats specified.
> > If there is an error, then that clause would apply. In glibc's case, it
> is
> > less than 3 chars and invalid
> > chars. In our case, exceeding the max limit would also apply.
> >
> > From glibc: tzset.c
> >
> > /* Clear out old state and reset to unnamed UTC. */
> > memset (tz_rules, '\0', sizeof tz_rules);
> > tz_rules[0].name = tz_rules[1].name = "";
> >
> > /* Get the standard timezone name. */
> > if (parse_tzname (&tz, 0) && parse_offset (&tz, 0))
> >
> > If the parse_tzname fails or parsing the dst name fails, unnamed UTC is
> > used.
> >
> > -- Jeff J.
> >
>
>
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From 0b5e905696ec12e6408e9330ef4e87ac6a57751d Mon Sep 17 00:00:00 2001
From: Jeff Johnston <jjohnstn@redhat.com>
Date: Wed, 27 Apr 2022 15:27:00 -0400
Subject: [PATCH] Modify tzset_r.c to handle errors
- change __tzset_r so errors end up setting the timezone to
unnamed UTC
---
newlib/libc/time/tzset_r.c | 56 +++++++++++++++++++++++++++++++++-------------
1 file changed, 40 insertions(+), 16 deletions(-)
diff --git a/newlib/libc/time/tzset_r.c b/newlib/libc/time/tzset_r.c
index 9cb30b1..4d4baff 100644
--- a/newlib/libc/time/tzset_r.c
+++ b/newlib/libc/time/tzset_r.c
@@ -23,6 +23,7 @@ _tzset_unlocked_r (struct _reent *reent_ptr)
unsigned short hh, mm, ss, m, w, d;
int sign, n;
int i, ch;
+ long offset0, offset1;
__tzinfo_type *tz = __gettzinfo ();
if ((tzenv = _getenv_r (reent_ptr, "TZ")) == NULL)
@@ -44,6 +45,12 @@ _tzset_unlocked_r (struct _reent *reent_ptr)
if (prev_tzenv != NULL)
strcpy (prev_tzenv, tzenv);
+ /* default to unnamed UTC in case of error */
+ _timezone = 0;
+ _daylight = 0;
+ _tzname[0] = "";
+ _tzname[1] = "";
+
/* ignore implementation-specific format specifier */
if (*tzenv == ':')
++tzenv;
@@ -85,8 +92,7 @@ _tzset_unlocked_r (struct _reent *reent_ptr)
if (sscanf (tzenv, "%hu%n:%hu%n:%hu%n", &hh, &n, &mm, &n, &ss, &n) < 1)
return;
- tz->__tzrule[0].offset = sign * (ss + SECSPERMIN * mm + SECSPERHOUR * hh);
- _tzname[0] = __tzname_std;
+ offset0 = sign * (ss + SECSPERMIN * mm + SECSPERHOUR * hh);
tzenv += n;
/* allow POSIX angle bracket < > quoted signed alphanumeric tz abbr e.g. <MESZ+0330> */
@@ -95,12 +101,16 @@ _tzset_unlocked_r (struct _reent *reent_ptr)
++tzenv;
/* quit if no items, too few or too many chars, or no close quote '>' */
- if (sscanf (tzenv, "%10[-+0-9A-Za-z]%n", __tzname_dst, &n) <= 0
- || n < TZNAME_MIN || TZNAME_MAX < n || '>' != tzenv[n])
+ if (sscanf (tzenv, "%10[-+0-9A-Za-z]%n", __tzname_dst, &n) <= 0 && tzenv[0] == '>')
{ /* No dst */
- _tzname[1] = _tzname[0];
- _timezone = tz->__tzrule[0].offset;
- _daylight = 0;
+ _tzname[0] = __tzname_std;
+ _tzname[1] = _tzname[0];
+ tz->__tzrule[0].offset = offset0;
+ _timezone = offset0;
+ return;
+ }
+ else if (n < TZNAME_MIN || TZNAME_MAX < n || '>' != tzenv[n])
+ { /* error */
return;
}
@@ -109,17 +119,20 @@ _tzset_unlocked_r (struct _reent *reent_ptr)
else
{
/* allow POSIX unquoted alphabetic tz abbr e.g. MESZ */
- if (sscanf (tzenv, "%10[A-Za-z]%n", __tzname_dst, &n) <= 0
- || n < TZNAME_MIN || TZNAME_MAX < n)
+ if (sscanf (tzenv, "%10[A-Za-z]%n", __tzname_dst, &n) <= 0)
{ /* No dst */
- _tzname[1] = _tzname[0];
- _timezone = tz->__tzrule[0].offset;
- _daylight = 0;
+ _tzname[0] = __tzname_std;
+ _tzname[1] = _tzname[0];
+ tz->__tzrule[0].offset = offset0;
+ _timezone = offset0;
+ return;
+ }
+ else if (n < TZNAME_MIN || TZNAME_MAX < n)
+ { /* error */
return;
}
}
- _tzname[1] = __tzname_dst;
tzenv += n;
/* otherwise we have a dst name, look for the offset */
@@ -138,9 +151,9 @@ _tzset_unlocked_r (struct _reent *reent_ptr)
n = 0;
if (sscanf (tzenv, "%hu%n:%hu%n:%hu%n", &hh, &n, &mm, &n, &ss, &n) <= 0)
- tz->__tzrule[1].offset = tz->__tzrule[0].offset - 3600;
+ offset1 = offset0 - 3600;
else
- tz->__tzrule[1].offset = sign * (ss + SECSPERMIN * mm + SECSPERHOUR * hh);
+ offset1 = sign * (ss + SECSPERMIN * mm + SECSPERHOUR * hh);
tzenv += n;
@@ -211,13 +224,24 @@ _tzset_unlocked_r (struct _reent *reent_ptr)
n = 0;
if (*tzenv == '/')
- sscanf (tzenv, "/%hu%n:%hu%n:%hu%n", &hh, &n, &mm, &n, &ss, &n);
+ if (sscanf (tzenv, "/%hu%n:%hu%n:%hu%n", &hh, &n, &mm, &n, &ss, &n) <= 0)
+ {
+ /* error in time format, restore tz rules to default and return */
+ struct __tzrule_struct default_tzrule = {'J', 0, 0, 0, 0, (time_t)0, 0L };
+ tz->__tzrule[0] = default_tzrule;
+ tz->__tzrule[1] = default_tzrule;
+ return;
+ }
tz->__tzrule[i].s = ss + SECSPERMIN * mm + SECSPERHOUR * hh;
tzenv += n;
}
+ tz->__tzrule[0].offset = offset0;
+ tz->__tzrule[1].offset = offset1;
+ _tzname[0] = __tzname_std;
+ _tzname[1] = __tzname_dst;
__tzcalc_limits (tz->__tzyear);
_timezone = tz->__tzrule[0].offset;
_daylight = tz->__tzrule[0].offset != tz->__tzrule[1].offset;
--
1.8.3.1
next prev parent reply other threads:[~2022-04-27 19:30 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-07 15:58 jdoubleu
2022-04-08 21:21 ` Jeff Johnston
2022-04-10 8:43 ` Dimitar Dimitrov
2022-04-10 17:55 ` jdoubleu
2022-04-10 21:00 ` Dimitar Dimitrov
2022-04-11 11:17 ` jdoubleu
2022-04-11 17:27 ` Dimitar Dimitrov
2022-04-12 11:19 ` jdoubleu
2022-04-12 18:33 ` Brian Inglis
2022-04-07 23:34 ` [PATCH v2 0/2] add tzset/_r POSIX angle bracket <> support in TZ env var Brian Inglis
2022-04-07 23:34 ` [PATCH v2 1/2] newlib/libc/time/tzset.c: doc update POSIX angle bracket <> support Brian Inglis
2022-04-07 23:34 ` [PATCH v2 2/2] newlib/libc/time/tzset_r.c(_tzset_unlocked_r): " Brian Inglis
2022-04-08 19:11 ` [PATCH v2 0/2] add tzset/_r POSIX angle bracket <> support in TZ env var Jeff Johnston
2022-04-13 17:53 ` [PATCH] add tests for tzset(3) Brian Inglis
2022-04-13 20:33 ` Jeff Johnston
2022-04-13 22:19 ` Brian Inglis
2022-04-14 8:59 ` jdoubleu
2022-04-14 16:31 ` Brian Inglis
2022-04-14 19:23 ` Jeff Johnston
2022-04-15 10:10 ` jdoubleu
2022-04-27 19:30 ` Jeff Johnston [this message]
2022-05-14 14:39 ` jdoubleu
2022-05-16 16:05 ` Dimitar Dimitrov
2022-05-16 17:38 ` Jeff Johnston
2022-05-17 8:45 ` [PATCH] update tzset tests jdoubleu
2022-05-18 18:48 ` Dimitar Dimitrov
2022-05-18 20:56 ` Keith Packard
2022-05-19 8:47 ` jdoubleu
2022-05-22 9:51 ` [PATCH v2] " jdoubleu
2022-05-22 21:02 ` Dimitar Dimitrov
2022-05-27 15:46 ` Jeff Johnston
2022-04-13 22:21 ` [PATCH] add tests for tzset(3) Brian Inglis
2022-04-29 15:46 Jeff Johnston
2022-05-12 18:35 ` jdoubleu
2022-05-16 17:49 ` Jeff Johnston
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