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(set_time_zone_rule):

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Work around localtime cache bug in SunOS 4.1.3_U1 and SunOS 4.1.4.
This commit is contained in:
Richard M. Stallman 1996-06-05 15:08:18 +00:00
parent ed8a2c3a28
commit aafe514744
1 changed files with 48 additions and 0 deletions
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48
src/editfns.c
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@ -939,11 +939,14 @@ set_time_zone_rule (tzstring)
int envptrs;
char **from, **to, **newenv;
/* Make the ENVIRON vector longer with room for TZSTRING. */
for (from = environ; *from; from++)
continue;
envptrs = from - environ + 2;
newenv = to = (char **) xmalloc (envptrs * sizeof (char *)
+ (tzstring ? strlen (tzstring) + 4 : 0));
/* Add TZSTRING to the end of environ, as a value for TZ. */
if (tzstring)
{
char *t = (char *) (to + envptrs);
@ -952,6 +955,9 @@ set_time_zone_rule (tzstring)
*to++ = t;
}
/* Copy the old environ vector elements into NEWENV,
but don't copy the TZ variable.
So we have only one definition of TZ, which came from TZSTRING. */
for (from = environ; *from; from++)
if (strncmp (*from, "TZ=", 3) != 0)
*to++ = *from;
@ -959,7 +965,49 @@ set_time_zone_rule (tzstring)
environ = newenv;
/* If we do have a TZSTRING, NEWENV points to the vector slot where
the TZ variable is stored. If we do not have a TZSTRING,
TO points to the vector slot which has the terminating null. */
#ifdef LOCALTIME_CACHE
{
/* In SunOS 4.1.3_U1 and 4.1.4, if TZ has a value like
"US/Pacific" that loads a tz file, then changes to a value like
"XXX0" that does not load a tz file, and then changes back to
its original value, the last change is (incorrectly) ignored.
Also, if TZ changes twice in succession to values that do
not load a tz file, tzset can dump core (see Sun bug#1225179).
The following code works around these bugs. */
/* These two values are known to load tz files in buggy implementations.
Their values shouldn't matter in non-buggy implementations. */
char *tz1 = "TZ=GMT0";
char *tz2 = "TZ=GMT1";
if (tzstring)
{
/* Temporarily set TZ to a value that loads a tz file
and that differs from tzstring. */
char *tz = *newenv;
*newenv = strcmp (tzstring, tz1 + 3) == 0 ? tz2 : tz1;
tzset ();
*newenv = tz;
}
else
{
/* The implied tzstring is unknown, so temporarily set TZ to
two different values that each load a tz file. */
*to = tz1;
to[1] = 0;
tzset ();
*to = tz2;
tzset ();
*to = 0;
}
/* Now TZ has the desired value, and tzset can be invoked safely. */
}
tzset ();
#endif
}