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RFC [PATCH] BZ#1077902: New API gettimezone
- From: P J P <pj dot pandit at yahoo dot co dot in>
- To: "libc-alpha at sourceware dot org" <libc-alpha at sourceware dot org>
- Date: Thu, 3 Apr 2014 12:28:06 +0800 (SGT)
- Subject: RFC [PATCH] BZ#1077902: New API gettimezone
- Authentication-results: sourceware.org; auth=none
- References:
- Reply-to: P J P <pj dot pandit at yahoo dot co dot in>
Hello,
WRT BZ#1077902 [1], please see the patch below to introduce a new API gettimezone(). It builds successfully with the glibc Makefile, though I could not test the API from the new library. It uses TZ_VERSION & TZ_FILE macros because they aren't defined in timezone/tzfile.h.
There is #defines TZDEFAULT "localtime", but that is not sufficient to access '/etc/localtime'. There is also #define TZDIR /usr/local/etc/zoneinfo, which seems misplaced. On f19 machine, the zoneinfo is stored under /usr/share/zoneinfo.
===
diff --git a/ChangeLog b/ChangeLog
index 7e530ef..e2cdbcf 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2014-04-03 P J P <pj.pandit@yahoo.co.in>
+
+ [BZ #1077902]
+ * time/gettimezone.c: new API to query POSIX TZ variable string.
+
2014-04-02 Joseph Myers <joseph@codesourcery.com>
[BZ #16799]
diff --git a/time/Makefile b/time/Makefile
index b7f3dba..8bcc5ca 100644
--- a/time/Makefile
+++ b/time/Makefile
@@ -31,7 +31,7 @@ routines := offtime asctime clock ctime ctime_r difftime \
stime dysize timegm ftime \
getdate strptime strptime_l \
strftime wcsftime strftime_l wcsftime_l \
- timespec_get
+ timespec_get gettimezone
aux := era alt_digit lc-time-cleanup
tests := test_time clocktest tst-posixtz tst-strptime tst_wcsftime \
diff --git a/time/Versions b/time/Versions
index fd83818..957d2bf 100644
--- a/time/Versions
+++ b/time/Versions
@@ -25,7 +25,7 @@ libc {
ftime;
# g*
- getitimer; gettimeofday; gmtime; gmtime_r;
+ getitimer; gettimeofday; gmtime; gmtime_r; gettimezone;
# l*
localtime; localtime_r;
diff --git a/time/gettimezone.c b/time/gettimezone.c
new file mode 100644
index 0000000..88b2141
--- /dev/null
+++ b/time/gettimezone.c
@@ -0,0 +1,109 @@
+/* Copyright (C) 1991-2014 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <err.h>
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <timezone/tzfile.h>
+
+#define TZ_VERSION '2'
+#define TZ_FILE "/etc/"TZDEFAULT
+
+
+/* gettimezone: reads local timezone definition from '/etc/localtime'
+ and returns a POSIX TZ environment variable string or NULL in case
+ of an error; See: tzfile(5), tzset(3).
+
+ std offset dst [offset],start[/time],end[/time]
+
+ Ex: TZ="NZST-12:00:00NZDT-13:00:00,M10.1.0,M3.3.0" */
+char *
+gettimezone (const char *tzname)
+{
+ int n = 0;
+ FILE *fp = NULL;
+ char *tz = NULL, s[4];
+
+ errno = 0;
+ if (!tzname)
+ tzname = TZ_FILE;
+
+ fp = fopen (tzname, "rce");
+ if (!fp)
+ return tz;
+
+ if (fread (s, sizeof (char), 4, fp) != 4)
+ goto err;
+ if (strncmp (TZ_MAGIC, s, 4))
+ goto err;
+
+ if (fread (s, sizeof (char), 1, fp) != 1)
+ goto err;
+ if (TZ_VERSION != *s && TZ_VERSION != (*s - 1))
+ goto err;
+
+ if (fseek (fp, -1, SEEK_END) < 0)
+ goto err;
+ if (fread (s, sizeof (char), 1, fp) != 1)
+ goto err;
+ if ('\n' != *s)
+ goto err;
+
+ n = -2;
+ while (!fseek (fp, n, SEEK_END))
+ {
+ if (fread (s, sizeof (char), 1, fp) != 1)
+ goto err;
+ if ('\n' == *s)
+ break;
+
+ n--;
+ }
+ fseek (fp, ++n, SEEK_END);
+
+ n = -(n + 1);
+ tz = calloc (n, sizeof (char));
+ if (!tz)
+ goto err;
+
+ if (fread (tz, sizeof (char), n, fp) != n)
+ {
+ free (tz);
+ tz = NULL;
+ }
+
+err:
+ fclose (fp);
+ return tz;
+}
+
+
+/* int
+main (int argc, char *argv[])
+{
+ char *tz = NULL;
+
+ tz = gettimezone (NULL);
+ printf ("tz: %s\n", tz);
+ if (tz)
+ free (tz);
+
+ return 0;
+} */
===
--
[1] https://bugzilla.redhat.com/show_bug.cgi?id=1077902#c2
Thank you.
---
Regards
-Prasad
http://feedmug.com