Change most internal uses of __gettimeofday to __clock_gettime.

Since gettimeofday will shortly be implemented in terms of
clock_gettime on all platforms, internal code should use clock_gettime
directly; in addition to removing a layer of indirection, this will
allow us to remove the PLT-bypass gunk for gettimeofday.  (We can't
quite do that yet, but it'll be coming later in this patch series.)
In many cases, the changed code does fewer conversions.

The changed code always assumes __clock_gettime (CLOCK_REALTIME)
cannot fail.  Most of the call sites were assuming gettimeofday could
not fail, but a few places were checking for errors.  POSIX says
clock_gettime can only fail if the clock constant is invalid or
unsupported, and CLOCK_REALTIME is the one and only clock constant
that's required to be supported.  For consistency I grepped the entire
source tree for any other places that checked for errors from
__clock_gettime (CLOCK_REALTIME), found one, and changed it too.

(For the record, POSIX also says gettimeofday can never fail.)

(It would be nice if we could declare that GNU systems will always
support CLOCK_MONOTONIC as well as CLOCK_REALTIME; there are several
places where we are using CLOCK_REALTIME where _MONOTONIC would be
more appropriate, and/or trying to use _MONOTONIC and then falling
back to _REALTIME.  But the Hurd doesn't support CLOCK_MONOTONIC yet,
and it looks like adding it would involve substantial changes to
gnumach's internals and API.  Oh well.)

A few Hurd-specific files were changed to use __host_get_time instead
of __clock_gettime, as this seemed tidier.  We also assume this cannot
fail.  Skimming the code in gnumach leads me to believe the only way
it could fail is if __mach_host_self also failed, and our
Hurd-specific code consistently assumes that can't happen, so I'm
going with that.

With the exception of support/support_test_main.c, test cases are not
modified, mainly because I didn't want to have to figure out which
test cases were testing gettimeofday specifically.

The definition of GETTIME in sysdeps/generic/memusage.h had a typo and
was not reading tv_sec at all.  I fixed this.  It appears nobody has been
generating malloc traces on a machine that doesn't have a superseding
definition.

There are a whole bunch of places where the code could be simplified
by factoring out timespec subtraction and/or comparison logic, but I
want to keep this patch as mechanical as possible.

Checked on x86_64-linux-gnu, i686-linux-gnu, powerpc64le-linux-gnu,
powerpc64-linux-gnu, powerpc-linux-gnu, and aarch64-linux-gnu.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: Lukasz Majewski <lukma@denx.de>

1 files changed, 11 insertions, 12 deletions

diff --git a/support/support_test_main.c b/support/support_test_main.c
index 0be1bd3..1df6e4f 100644
--- a/support/support_test_main.c
+++ b/support/support_test_main.c
@@ -91,16 +91,18 @@ static pid_t test_pid;
 static void (*cleanup_function) (void);
 
 static void
-print_timestamp (const char *what, struct timeval tv)
+print_timestamp (const char *what, struct timespec tv)
 {
   struct tm tm;
+  /* Casts of tv.tv_nsec below are necessary because the type of
+     tv_nsec is not literally long int on all supported platforms.  */
   if (gmtime_r (&tv.tv_sec, &tm) == NULL)
-    printf ("%s: %lld.%06d\n",
-            what, (long long int) tv.tv_sec, (int) tv.tv_usec);
+    printf ("%s: %lld.%09ld\n",
+            what, (long long int) tv.tv_sec, (long int) tv.tv_nsec);
   else
-    printf ("%s: %04d-%02d-%02dT%02d:%02d:%02d.%06d\n",
+    printf ("%s: %04d-%02d-%02dT%02d:%02d:%02d.%09ld\n",
             what, 1900 + tm.tm_year, tm.tm_mon + 1, tm.tm_mday,
-            tm.tm_hour, tm.tm_min, tm.tm_sec, (int) tv.tv_usec);
+            tm.tm_hour, tm.tm_min, tm.tm_sec, (long int) tv.tv_nsec);
 }
 
 /* Timeout handler.  We kill the child and exit with an error.  */
@@ -113,8 +115,8 @@ signal_handler (int sig)
 
   /* Do this first to avoid further interference from the
      subprocess.  */
-  struct timeval now;
-  bool now_available = gettimeofday (&now, NULL) == 0;
+  struct timespec now;
+  clock_gettime (CLOCK_REALTIME, &now);
   struct stat64 st;
   bool st_available = fstat64 (STDOUT_FILENO, &st) == 0 && st.st_mtime != 0;
 
@@ -168,12 +170,9 @@ signal_handler (int sig)
     printf ("Timed out: killed the child process but it exited %d\n",
             WEXITSTATUS (status));
 
-  if (now_available)
-    print_timestamp ("Termination time", now);
+  print_timestamp ("Termination time", now);
   if (st_available)
-    print_timestamp ("Last write to standard output",
-                     (struct timeval) { st.st_mtim.tv_sec,
-                         st.st_mtim.tv_nsec / 1000 });
+    print_timestamp ("Last write to standard output", st.st_mtim);
 
   /* Exit with an error.  */
   exit (1);