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, 39 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 34e7d72130..3ed1b1ef8f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,44 @@
 2023-05-14  Paul Eggert  <eggert@cs.ucla.edu>
 
+	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.
+
 	year2038-recommended: Improve failure diagnostic.
 	* m4/largefile.m4 (AC_SYS_YEAR2038_RECOMMENDED): Sync from Autoconf.