timespec: fill in other members

This problem was found when compiling GNU Emacs with
--enable-gcc-warnings on a platform where tv_sec is 64 bits and
tv_nsec is 32 bits, and struct timespec has padding.  GCC
-Wuse-of-uninitialized-value complained when a struct timespec
initialized only via assigning to tv_sec and tv_nsec was copied
via assignment (this was in lib/timespec.h’s make_timespec).
Although behavior is well-defined on this platform, the warning is
annoying and the behavior might not be well-defined on theoretical
platforms where struct timespec has other members.  To work around
this, initialize all the struct’s members.
* lib/getsockopt.c (rpl_getsockopt):
* lib/gettime.c (gettime):
* lib/gettimeofday.c (gettimeofday):
* lib/glthread/thread.c (gl_thread_self):
* lib/nanosleep.c (nanosleep):
* lib/parse-datetime.y (digits_to_date_time, set_hhmmss)
(signed_seconds, unsigned_seconds, yylex, parse_datetime_body):
* lib/poll.c (poll):
* lib/pselect.c (pselect):
* lib/pthread-cond.c (endlessly, pthread_cond_timedwait):
* lib/pthread-rwlock.c (pthread_rwlock_timedrdlock)
(pthread_rwlock_timedwrlock):
* lib/pthread_mutex_timedlock.c (pthread_mutex_timedlock):
* lib/select.c (rpl_select):
* lib/settime.c (settime):
* lib/stat-time.h (get_stat_atime, get_stat_ctime)
(get_stat_mtime, get_stat_birthtime):
* lib/thrd.c (rpl_thrd_current):
* lib/timespec.h (make_timespec):
* lib/timespec_getres.c (timespec_getres):
* lib/utimecmp.c (utimecmpat):
* lib/utimens.c (fdutimens):
When filling in a struct timespec or similar time-related structure
that might be copied elsewhere, also assign to any storage other
than tv_sec and tv_nsec, to avoid undefined behavior on (likely
theoretical) platforms where struct timespec has other members,
and also to avoid warnings from GCC and/or valgrind.

1 files changed, 11 insertions, 22 deletions

diff --git a/lib/stat-time.h b/lib/stat-time.h
index 5b2702356e..af084102da 100644
--- a/lib/stat-time.h
+++ b/lib/stat-time.h
@@ -122,10 +122,8 @@ get_stat_atime (struct stat const *st)
 #ifdef STAT_TIMESPEC
   return STAT_TIMESPEC (st, st_atim);
 #else
-  struct timespec t;
-  t.tv_sec = st->st_atime;
-  t.tv_nsec = get_stat_atime_ns (st);
-  return t;
+  return (struct timespec) { .tv_sec = st->st_atime,
+                             .tv_nsec = get_stat_atime_ns (st) };
 #endif
 }
 
@@ -136,10 +134,8 @@ get_stat_ctime (struct stat const *st)
 #ifdef STAT_TIMESPEC
   return STAT_TIMESPEC (st, st_ctim);
 #else
-  struct timespec t;
-  t.tv_sec = st->st_ctime;
-  t.tv_nsec = get_stat_ctime_ns (st);
-  return t;
+  return (struct timespec) { .tv_sec = st->st_ctime,
+                             .tv_nsec = get_stat_ctime_ns (st) };
 #endif
 }
 
@@ -150,10 +146,8 @@ get_stat_mtime (struct stat const *st)
 #ifdef STAT_TIMESPEC
   return STAT_TIMESPEC (st, st_mtim);
 #else
-  struct timespec t;
-  t.tv_sec = st->st_mtime;
-  t.tv_nsec = get_stat_mtime_ns (st);
-  return t;
+  return (struct timespec) { .tv_sec = st->st_mtime,
+                             .tv_nsec = get_stat_mtime_ns (st) };
 #endif
 }
 
@@ -168,8 +162,8 @@ get_stat_birthtime (_GL_UNUSED struct stat const *st)
      || defined HAVE_STRUCT_STAT_ST_BIRTHTIM_TV_NSEC)
   t = STAT_TIMESPEC (st, st_birthtim);
 #elif defined HAVE_STRUCT_STAT_ST_BIRTHTIMENSEC
-  t.tv_sec = st->st_birthtime;
-  t.tv_nsec = st->st_birthtimensec;
+  t = (struct timespec) { .tv_sec = st->st_birthtime,
+                          .tv_nsec = st->st_birthtimensec };
 #elif defined _WIN32 && ! defined __CYGWIN__
   /* Native Windows platforms (but not Cygwin) put the "file creation
      time" in st_ctime (!).  See
@@ -177,13 +171,11 @@ get_stat_birthtime (_GL_UNUSED struct stat const *st)
 # if _GL_WINDOWS_STAT_TIMESPEC
   t = st->st_ctim;
 # else
-  t.tv_sec = st->st_ctime;
-  t.tv_nsec = 0;
+  t = (struct timespec) { .tv_sec = st->st_ctime };
 # endif
 #else
   /* Birth time is not supported.  */
-  t.tv_sec = -1;
-  t.tv_nsec = -1;
+  t = (struct timespec) { .tv_sec = -1, .tv_nsec = -1 };
 #endif
 
 #if (defined HAVE_STRUCT_STAT_ST_BIRTHTIMESPEC_TV_NSEC \
@@ -195,10 +187,7 @@ get_stat_birthtime (_GL_UNUSED struct stat const *st)
      sometimes returns junk in the birth time fields; work around this
      bug if it is detected.  */
   if (! (t.tv_sec && 0 <= t.tv_nsec && t.tv_nsec < 1000000000))
-    {
-      t.tv_sec = -1;
-      t.tv_nsec = -1;
-    }
+    t = (struct timespec) { .tv_sec = -1, .tv_nsec = -1 };
 #endif
 
   return t;