parser: fix time zone offsets being dropped on Windows (#6368)

* parser: add test for time zones

This adds a unit test for parsing logs that contain time stamps with
a time zone offset.

This test deliberately fails on Windows; a subsequent commit fixes
the underlying issue and makes the test pass.

Signed-off-by: Jeff Erbrecht <[email protected]>

* time: add portable wrapper struct for tm

This wrapper struct adds an explicit time zone offset field on
platforms that do not include such a field within `struct tm`,
such as on Windows. This gives us a place to store parsed
time zone information so that we don't have to drop it.

Signed-off-by: Jeff Erbrecht <[email protected]>

* parser: use flb_tm wrapper struct

This updates the parser APIs to use flb_tm..

Signed-off-by: Jeff Erbrecht <[email protected]>

* strptime: use flb_tm instead of tm

This changes the strptime APIs to use flb_tm. Any implementation
conditional on FLB_HAVE_GMTOFF has been reverted since flb_tm
now has a field to store the time zone offset on all platforms.

Signed-off-by: Jeff Erbrecht <[email protected]>

* parser: json: use flb_tm

Signed-off-by: Jeff Erbrecht <[email protected]>

* parser: regex: use flb_tm

Signed-off-by: Jeff Erbrecht <[email protected]>

* parser: logfmt: use flb_tm

Signed-off-by: Jeff Erbrecht <[email protected]>

* parser: ltsv: use flb_tm

Signed-off-by: Jeff Erbrecht <[email protected]>

* parser: remove spurious trailing space

Signed-off-by: Jeff Erbrecht <[email protected]>

* parser: fix test

Signed-off-by: Jeff Erbrecht <[email protected]>

Signed-off-by: Jeff Erbrecht <[email protected]>

include/fluent-bit/flb_parser.h

@@ -73,17 +73,13 @@ enum {
     FLB_PARSER_TYPE_HEX,
 };
 
-static inline time_t flb_parser_tm2time(const struct tm *src)
+static inline time_t flb_parser_tm2time(const struct flb_tm *src)
 {
     struct tm tmp;
     time_t res;
 
-    tmp = *src;
-#ifdef FLB_HAVE_GMTOFF
-    res = timegm(&tmp) - src->tm_gmtoff;
-#else
-    res = timegm(&tmp);
-#endif
+    tmp = src->tm;
+    res = timegm(&tmp) - flb_tm_gmtoff(src);
     return res;
 }
 
@@ -109,7 +105,7 @@ void flb_parser_exit(struct flb_config *config);
 int flb_parser_tzone_offset(const char *str, int len, int *tmdiff);
 int flb_parser_time_lookup(const char *time, size_t tsize, time_t now,
                            struct flb_parser *parser,
-                           struct tm *tm, double *ns);
+                           struct flb_tm *tm, double *ns);
 int flb_parser_typecast(const char *key, int key_len,
                         const char *val, int val_len,
                         msgpack_packer *pck,

include/fluent-bit/flb_strptime.h

@@ -20,6 +20,6 @@
 #ifndef FLB_STRPTIME_H
 #define FLB_STRPTIME_H
 
-char *flb_strptime(const char *s, const char *format, struct tm *tm);
+char *flb_strptime(const char *s, const char *format, struct flb_tm *tm);
 
 #endif

include/fluent-bit/flb_time.h

@@ -30,6 +30,19 @@ struct flb_time {
     struct timespec tm;
 };
 
+struct flb_tm {
+    struct tm tm;
+#ifndef FLB_HAVE_GMTOFF
+    long int tm_gmtoff;
+#endif
+};
+
+#ifndef FLB_HAVE_GMTOFF
+#define flb_tm_gmtoff(x) (x)->tm_gmtoff
+#else
+#define flb_tm_gmtoff(x) (x)->tm.tm_gmtoff
+#endif
+
 /*
    to represent eventtime of fluentd
    see also

src/flb_parser.c

@@ -1016,7 +1016,7 @@ static int parse_subseconds(char *str, int len, double *subsec)
 int flb_parser_time_lookup(const char *time_str, size_t tsize,
                            time_t now,
                            struct flb_parser *parser,
-                           struct tm *tm, double *ns)
+                           struct flb_tm *tm, double *ns)
 {
     int ret;
     time_t time_now;
@@ -1059,8 +1059,8 @@ int flb_parser_time_lookup(const char *time_str, size_t tsize,
         gmtime_r(&time_now, &tmy);
 
         /* Make the timestamp default to today */
-        tm->tm_mon = tmy.tm_mon;
-        tm->tm_mday = tmy.tm_mday;
+        tm->tm.tm_mon = tmy.tm_mon;
+        tm->tm.tm_mday = tmy.tm_mday;
 
         uint64_t t = tmy.tm_year + 1900;
 
@@ -1127,11 +1127,9 @@ int flb_parser_time_lookup(const char *time_str, size_t tsize,
         }
     }
 
-#ifdef FLB_HAVE_GMTOFF
     if (parser->time_with_tz == FLB_FALSE) {
-        tm->tm_gmtoff = parser->time_offset;
+        flb_tm_gmtoff(tm) = parser->time_offset;
     }
-#endif
 
     return 0;
 }

src/flb_parser_json.c

@@ -53,7 +53,7 @@ int flb_parser_json_do(struct flb_parser *parser,
     msgpack_object *k = NULL;
     msgpack_object *v = NULL;
     time_t time_lookup;
-    struct tm tm = {0};
+    struct flb_tm tm = {0};
     struct flb_time *t;
 
     /* Convert incoming in_buf JSON message to message pack format */

src/flb_parser_logfmt.c

@@ -68,7 +68,7 @@ static int logfmt_parser(struct flb_parser *parser,
                          size_t *map_size)
 {
     int ret;
-    struct tm tm = {0};
+    struct flb_tm tm = {0};
     const unsigned char *key = NULL;
     size_t key_len = 0;
     const unsigned char *value = NULL;

src/flb_parser_ltsv.c

@@ -87,7 +87,7 @@ static int ltsv_parser(struct flb_parser *parser,
                        size_t *map_size)
 {
     int ret;
-    struct tm tm = {0};
+    struct flb_tm tm = {0};
     const unsigned char *label = NULL;
     size_t label_len = 0;
     const unsigned char *field = NULL;

src/flb_parser_regex.c

@@ -51,7 +51,7 @@ static void cb_results(const char *name, const char *value,
     char tmp[255];
     struct regex_cb_ctx *pcb = data;
     struct flb_parser *parser = pcb->parser;
-    struct tm tm = {0};
+    struct flb_tm tm = {0};
     (void) data;
 
     if (vlen == 0 && parser->skip_empty) {