time: time_t is signed, and mktime() is happy to return negative time

Passing a year such as 1960 to mktime() will result in a negative return
value. This is quite confusing, as the man page claims that on failure
the call will return -1...

Given that our own usec_t type is unsigned, and we can't express times
before 1970 hence, let's consider all negative times returned by
mktime() as invalid, regardless if just -1, or anything else negative.

diff --git a/src/basic/calendarspec.c b/src/basic/calendarspec.c
index 2e5622699dc359c52ead5c1d61ad2236b8a17f02..35dfb6a3dba60cd35f3e24049e759c74094a2429 100644 (file)
--- a/src/basic/calendarspec.c
+++ b/src/basic/calendarspec.c
@@ -1020,7 +1020,7 @@ static int find_end_of_month(struct tm *tm, bool utc, int day) {
         t.tm_mon++;
         t.tm_mday = 1 - day;
 
-        if (mktime_or_timegm(&t, utc) == (time_t) -1 ||
+        if (mktime_or_timegm(&t, utc) < 0 ||
             t.tm_mon != tm->tm_mon)
                 return -1;
 
@@ -1086,7 +1086,7 @@ static bool tm_out_of_bounds(const struct tm *tm, bool utc) {
 
         t = *tm;
 
-        if (mktime_or_timegm(&t, utc) == (time_t) -1)
+        if (mktime_or_timegm(&t, utc) < 0)
                 return true;
 
         /*
@@ -1115,7 +1115,7 @@ static bool matches_weekday(int weekdays_bits, const struct tm *tm, bool utc) {
                 return true;
 
         t = *tm;
-        if (mktime_or_timegm(&t, utc) == (time_t) -1)
+        if (mktime_or_timegm(&t, utc) < 0)
                 return false;
 
         k = t.tm_wday == 0 ? 6 : t.tm_wday - 1;
@@ -1238,7 +1238,7 @@ int calendar_spec_next_usec(const CalendarSpec *spec, usec_t usec, usec_t *next)
                 return r;
 
         t = mktime_or_timegm(&tm, spec->utc);
-        if (t == (time_t) -1)
+        if (t < 0)
                 return -EINVAL;
 
         *next = (usec_t) t * USEC_PER_SEC + tm_usec;

diff --git a/src/basic/time-util.c b/src/basic/time-util.c
index 1310c76336e10edbe27161c92bac37ec58ea0463..2b44cdf0b1c97165cee88bddd39e9ab92f6248f6 100644 (file)
--- a/src/basic/time-util.c
+++ b/src/basic/time-util.c
@@ -185,7 +185,7 @@ usec_t triple_timestamp_by_clock(triple_timestamp *ts, clockid_t clock) {
 usec_t timespec_load(const struct timespec *ts) {
         assert(ts);
 
-        if (ts->tv_sec == (time_t) -1 && ts->tv_nsec == (long) -1)
+        if (ts->tv_sec < 0 || ts->tv_nsec < 0)
                 return USEC_INFINITY;
 
         if ((usec_t) ts->tv_sec > (UINT64_MAX - (ts->tv_nsec / NSEC_PER_USEC)) / USEC_PER_SEC)
@@ -199,7 +199,7 @@ usec_t timespec_load(const struct timespec *ts) {
 nsec_t timespec_load_nsec(const struct timespec *ts) {
         assert(ts);
 
-        if (ts->tv_sec == (time_t) -1 && ts->tv_nsec == (long) -1)
+        if (ts->tv_sec < 0 || ts->tv_nsec < 0)
                 return NSEC_INFINITY;
 
         if ((nsec_t) ts->tv_sec >= (UINT64_MAX - ts->tv_nsec) / NSEC_PER_SEC)
@@ -226,8 +226,7 @@ struct timespec *timespec_store(struct timespec *ts, usec_t u)  {
 usec_t timeval_load(const struct timeval *tv) {
         assert(tv);
 
-        if (tv->tv_sec == (time_t) -1 &&
-            tv->tv_usec == (suseconds_t) -1)
+        if (tv->tv_sec < 0 || tv->tv_usec < 0)
                 return USEC_INFINITY;
 
         if ((usec_t) tv->tv_sec > (UINT64_MAX - tv->tv_usec) / USEC_PER_SEC)
@@ -830,7 +829,7 @@ parse_usec:
 
 from_tm:
         x = mktime_or_timegm(&tm, utc);
-        if (x == (time_t) -1)
+        if (x < 0)
                 return -EINVAL;
 
         if (weekday >= 0 && tm.tm_wday != weekday)