BUG/MINOR: log: Don't use strftime() which can clobber timezone if chrooted
The strftime() function can call tzset() internally on some platforms.
When haproxy is chrooted, the /etc/localtime file is not found, and some
implementations will clobber the content of the current timezone.
The GMT offset is computed by diffing the times returned by gmtime_r() and
localtime_r(). These variants are guaranteed to not call tzset() and were
already used in haproxy while chrooted, so they should be safe.
This patch must be backported to 1.6 and 1.5.
(cherry picked from commit e2e5bde3f2f5345438f4972667725be2ca9aa5e1)
(cherry picked from commit e4db5185c1f6f74c509e8ca0ea3359322f5fd702)
diff --git a/include/common/standard.h b/include/common/standard.h
index 46104fe..e56cd9d 100644
--- a/include/common/standard.h
+++ b/include/common/standard.h
@@ -779,10 +779,11 @@
char *date2str_log(char *dest, struct tm *tm, struct timeval *date, size_t size);
/* Return the GMT offset for a specific local time.
+ * Both t and tm must represent the same time.
* The string returned has the same format as returned by strftime(... "%z", tm).
* Offsets are kept in an internal cache for better performances.
*/
-const char *get_gmt_offset(struct tm *tm);
+const char *get_gmt_offset(time_t t, struct tm *tm);
/* gmt2str_log: write a date in the format :
* "%02d/%s/%04d:%02d:%02d:%02d +0000" without using snprintf
@@ -793,10 +794,11 @@
/* localdate2str_log: write a date in the format :
* "%02d/%s/%04d:%02d:%02d:%02d +0000(local timezone)" without using snprintf
+ * Both t and tm must represent the same time.
* return a pointer to the last char written (\0) or
* NULL if there isn't enough space.
*/
-char *localdate2str_log(char *dst, struct tm *tm, size_t size);
+char *localdate2str_log(char *dst, time_t t, struct tm *tm, size_t size);
/* Dynamically allocates a string of the proper length to hold the formatted
* output. NULL is returned on error. The caller is responsible for freeing the