(tzset_internal): Add new parameter which is nonzero if called through tzset. Use TZDEFAULT name including name comparison if the new parameter is zero. This means implicit tzset calls will not cause files to be opened and read by tzfile.c all the time.

1 files changed, 12 insertions, 5 deletions

diff --git a/time/tzset.c b/time/tzset.c
index aa866918e5..79cc610b38 100644
--- a/time/tzset.c
+++ b/time/tzset.c
@@ -72,7 +72,7 @@ static tz_rule tz_rules[2];
 static void compute_change __P ((tz_rule *rule, int year)) internal_function;
 static void tz_compute __P ((const struct tm *tm))
      internal_function;
-static void tzset_internal __P ((int always)) internal_function;
+static void tzset_internal __P ((int always, int explicit)) internal_function;
 
 /* List of buffers containing time zone strings. */
 struct tzstring_l
@@ -131,7 +131,7 @@ __tzname_max ()
 {
   __libc_lock_lock (tzset_lock);
 
-  tzset_internal (0);
+  tzset_internal (0, 0);
 
   __libc_lock_unlock (tzset_lock);
 
@@ -143,8 +143,9 @@ static char *old_tz;
 /* Interpret the TZ envariable.  */
 static void
 internal_function
-tzset_internal (always)
+tzset_internal (always, explicit)
      int always;
+     int explicit;
 {
   static int is_initialized;
   register const char *tz;
@@ -159,6 +160,12 @@ tzset_internal (always)
 
   /* Examine the TZ environment variable.  */
   tz = getenv ("TZ");
+  if (tz == NULL && !explicit)
+    /* Use the site-wide default.  This is a file name which means we
+       would not see changes to the file if we compare only the file
+       name for change.  We want to notice file changes if tzset() has
+       been called explicitly.  Leave TZ as NULL in this case.  */
+    tz = TZDEFAULT;
   if (tz && *tz == '\0')
     /* User specified the empty string; use UTC explicitly.  */
     tz = "Universal";
@@ -532,7 +539,7 @@ __tzset (void)
 {
   __libc_lock_lock (tzset_lock);
 
-  tzset_internal (1);
+  tzset_internal (1, 1);
 
   if (!__use_tzfile)
     {
@@ -565,7 +572,7 @@ __tz_convert (const time_t *timer, int use_localtime, struct tm *tp)
      POSIX.1 8.3.7.2 says that localtime_r is not required to set tzname.
      This is a good idea since this allows at least a bit more parallelism.
      By analogy we apply the same rule to gmtime_r.  */
-  tzset_internal (tp == &_tmbuf);
+  tzset_internal (tp == &_tmbuf, 0);
 
   if (__use_tzfile)
     __tzfile_compute (*timer, use_localtime, &leap_correction,