[glibc] time: Fix overflow itimer tests on 32-bit systems

[Stafford Horne <shorne@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=6e8a0aac2f883a23efb1683b120499138f9e6021

commit 6e8a0aac2f883a23efb1683b120499138f9e6021
Author: Stafford Horne <shorne@gmail.com>
Date:   Mon Jun 7 22:10:19 2021 +0900

    time: Fix overflow itimer tests on 32-bit systems
    
    On the port of OpenRISC I am working on and it appears the rv32 port
    we have sets __TIMESIZE == 64 && __WORDSIZE == 32.  This causes the
    size of time_t to be 8 bytes, but the tv_sec in the kernel is still 32-bit
    causing truncation.
    
    The truncations are unavoidable on these systems so skip the
    testing/failures by guarding with __KERNEL_OLD_TIMEVAL_MATCHES_TIMEVAL64.
    
    Also, futher in the tests and in other parts of code checking for time_t
    overflow does not work on 32-bit systems when time_t is 64-bit.  As
    suggested by Adhemerval, update the in_time_t_range function to assume
    32-bits by using int32_t.
    
    This also brings in the header for stdint.h so we can update other
    usages of __int32_t to int32_t as suggested by Adhemerval.
    
    Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

Diff:
---
 include/time.h    | 10 ++++++----
 time/tst-itimer.c |  4 ++--
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/include/time.h b/include/time.h
index 22b29ca583..127347eb90 100644
--- a/include/time.h
+++ b/include/time.h
@@ -11,6 +11,7 @@
 # include <sys/time.h>
 # include <time-clockid.h>
 # include <sys/time.h>
+# include <stdint.h>
 
 extern __typeof (strftime_l) __strftime_l;
 libc_hidden_proto (__strftime_l)
@@ -342,11 +343,12 @@ libc_hidden_proto (__time64)
    actual clock ID.  */
 #define CLOCK_IDFIELD_SIZE	3
 
-/* Check whether T fits in time_t.  */
+/* Check whether T fits in int32_t, assume all usages are for
+   sizeof(time_t) == 32.  */
 static inline bool
 in_time_t_range (__time64_t t)
 {
-  time_t s = t;
+  int32_t s = t;
   return s == t;
 }
 
@@ -453,8 +455,8 @@ timespec64_to_timeval64 (const struct __timespec64 ts64)
    and suseconds_t.  */
 struct __timeval32
 {
-  __int32_t tv_sec;         /* Seconds.  */
-  __int32_t tv_usec;        /* Microseconds.  */
+  int32_t tv_sec;         /* Seconds.  */
+  int32_t tv_usec;        /* Microseconds.  */
 };
 
 /* Conversion functions for converting to/from __timeval32  */
diff --git a/time/tst-itimer.c b/time/tst-itimer.c
index 929c2b74c7..bd7d7afe83 100644
--- a/time/tst-itimer.c
+++ b/time/tst-itimer.c
@@ -100,7 +100,7 @@ do_test (void)
 
       /* Linux does not provide 64 bit time_t support for getitimer and
 	 setitimer on architectures with 32 bit time_t support.  */
-      if (sizeof (__time_t) == 8)
+      if (__KERNEL_OLD_TIMEVAL_MATCHES_TIMEVAL64)
 	{
 	  TEST_COMPARE (setitimer (timers[i], &it, NULL), 0);
 	  TEST_COMPARE (setitimer (timers[i], &(struct itimerval) { 0 },
@@ -131,7 +131,7 @@ do_test (void)
       it.it_interval.tv_usec = 20;
       it.it_value.tv_sec = 30;
       it.it_value.tv_usec = 40;
-      if (sizeof (__time_t) == 8)
+      if (__KERNEL_OLD_TIMEVAL_MATCHES_TIMEVAL64)
 	{
 	  TEST_COMPARE (setitimer (timers[i], &it, NULL), 0);