[newlib-cygwin] Avoid excessive locking and calling tzset in time functions.

[Corinna Vinschen <corinna at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=b3a09ae34bd691c95bc41a594a40a808455d748a

commit b3a09ae34bd691c95bc41a594a40a808455d748a
Author: Corinna Vinschen <corinna@vinschen.de>
Date:   Tue Mar 31 11:22:50 2015 +0200

    Avoid excessive locking and calling tzset in time functions.
    
    	* libc/time/lcltime_r.c (localtime_r): Call _tzset_unlocked inside
    	TZ lock.
    	* libc/time/mktime.c (mktime):  Ditto.
    	* libc/time/strftime.c (strftime, wcsftime): Ditto.  Guard against
    	calling _tzset_unlocked more than once (baring recursion).
    
    Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

Diff:
---
 newlib/ChangeLog             |  8 ++++++++
 newlib/libc/time/lcltime_r.c |  2 +-
 newlib/libc/time/mktime.c    |  4 ++--
 newlib/libc/time/strftime.c  | 16 ++++++++++++++--
 4 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/newlib/ChangeLog b/newlib/ChangeLog
index 420354e..e615421 100644
--- a/newlib/ChangeLog
+++ b/newlib/ChangeLog
@@ -1,5 +1,13 @@
 2015-03-31  Corinna Vinschen  <vinschen@redhat.com>
 
+	* libc/time/lcltime_r.c (localtime_r): Call _tzset_unlocked inside
+	TZ lock.
+	* libc/time/mktime.c (mktime):  Ditto.
+	* libc/time/strftime.c (strftime, wcsftime): Ditto.  Guard against
+	calling _tzset_unlocked more than once (baring recursion).
+
+2015-03-31  Corinna Vinschen  <vinschen@redhat.com>
+
 	* libc/time/local.h (_tzset_unlocked_r): Add prototype.
 	(_tzset_unlocked): Ditto.
 	* libc/time/tzset.c (_tzset_unlocked): New function, call
diff --git a/newlib/libc/time/lcltime_r.c b/newlib/libc/time/lcltime_r.c
index 8a69e40..3342e99 100644
--- a/newlib/libc/time/lcltime_r.c
+++ b/newlib/libc/time/lcltime_r.c
@@ -31,8 +31,8 @@ _DEFUN (localtime_r, (tim_p, res),
   year = res->tm_year + YEAR_BASE;
   ip = __month_lengths[isleap(year)];
 
-  tzset ();
   TZ_LOCK;
+  _tzset_unlocked ();
   if (_daylight)
     {
       if (year == tz->__tzyear || __tzcalc_limits (year))
diff --git a/newlib/libc/time/mktime.c b/newlib/libc/time/mktime.c
index 8669fbd..44c0257 100644
--- a/newlib/libc/time/mktime.c
+++ b/newlib/libc/time/mktime.c
@@ -197,10 +197,10 @@ _DEFUN(mktime, (tim_p),
   /* compute total seconds */
   tim += (days * _SEC_IN_DAY);
 
-  tzset ();
-
   TZ_LOCK;
 
+  _tzset_unlocked ();
+
   if (_daylight)
     {
       int tm_isdst;
diff --git a/newlib/libc/time/strftime.c b/newlib/libc/time/strftime.c
index 72f06d3..9e67734 100644
--- a/newlib/libc/time/strftime.c
+++ b/newlib/libc/time/strftime.c
@@ -703,6 +703,7 @@ _DEFUN (strftime, (s, maxsize, format, tim_p),
   CHAR alt;
   CHAR pad;
   unsigned long width;
+  int tzset_called = 0;
 
   struct lc_time_T *_CurrentTimeLocale = __get_current_time_locale ();
   for (;;)
@@ -1283,7 +1284,13 @@ recurse:
           if (tim_p->tm_isdst >= 0)
             {
 	      long offset;
-	      tzset ();
+
+	      TZ_LOCK;
+	      if (!tzset_called)
+		{
+		  _tzset_unlocked ();
+		  tzset_called = 1;
+		}
 
 #if defined (__CYGWIN__)
 	      /* Cygwin must check if the application has been built with or
@@ -1302,6 +1309,7 @@ recurse:
 		 but have to use __tzrule for daylight savings.  */
 	      offset = -tz->__tzrule[tim_p->tm_isdst > 0].offset;
 #endif
+	      TZ_UNLOCK;
 	      len = snprintf (&s[count], maxsize - count, CQ("%+03ld%.2ld"),
 			      offset / SECSPERHOUR,
 			      labs (offset / SECSPERMIN) % 60L);
@@ -1314,8 +1322,12 @@ recurse:
 	      size_t size;
 	      const char *tznam = NULL;
 
-	      tzset ();
 	      TZ_LOCK;
+	      if (!tzset_called)
+		{
+		  _tzset_unlocked ();
+		  tzset_called = 1;
+		}
 #if defined (__CYGWIN__)
 	      /* See above. */
 	      extern const char *__cygwin_gettzname (const struct tm *tmp);