[LTP] [PATCH] open_posix_testsuite: Don't use clock_settime() to reset a CPU-time Clock

[Gui Jianfeng <guijianfeng@cn.fujitsu.com>]

This case is trying to set CPU-time clock(ID is returned by clock_getcpuclockid()) of
a specific process by calling clock_settime(). But Linux kernel doesn't allow to reset
a CPU-time clock of a specific process. Kernel returns -EPERM. So test fails.

In "IEEE Std 1003.1, 2004 Edition", It's said as following:
If _POSIX_CPUTIME is defined, implementations shall support clock ID values obtained by
invoking clock_getcpuclockid(), which represent the CPU-time clock of a given process.
Implementations shall also support the special clockid_t value CLOCK_PROCESS_CPUTIME_ID,
which represents the CPU-time clock of the calling process when invoking one of the 
clock_*() or timer_*() functions. For these clock IDs, the values returned by 
clock_gettime() and specified by clock_settime() represent the amount of execution time
of the process associated with the clock. Changing the value of a CPU-time clock via
clock_settime() shall have no effect on the behavior of the sporadic server scheduling
policy. 

So the behaviour when changing the value of a CPU-time clock via clock_settime() is
operating system specific. 

We may change the test progress to stop using clock_settime(). Now, We just make use
of clock_gettime() instead to achieve the same test purpose.

Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
---
 .../interfaces/clock_getcpuclockid/2-1.c           |   67 ++++++++++----------
 1 files changed, 33 insertions(+), 34 deletions(-)

diff --git a/testcases/open_posix_testsuite/conformance/interfaces/clock_getcpuclockid/2-1.c b/testcases/open_posix_testsuite/conformance/interfaces/clock_getcpuclockid/2-1.c
index edeb397..52240df 100644
--- a/testcases/open_posix_testsuite/conformance/interfaces/clock_getcpuclockid/2-1.c
+++ b/testcases/open_posix_testsuite/conformance/interfaces/clock_getcpuclockid/2-1.c
@@ -23,48 +23,47 @@ int main(int argc, char *argv[])
         printf("_POSIX_CPUTIME unsupported\n");
         return PTS_UNSUPPORTED;
 #else
-	unsigned long time_to_set;	
 	clockid_t clockid_1, clockid_2;
 	struct timespec tp1, tp2;
+	int i;
 
 	if (sysconf(_SC_CPUTIME) == -1) {
 		printf("_POSIX_CPUTIME unsupported\n");
 		return PTS_UNSUPPORTED;
 	}
 
-	if (clock_getcpuclockid(getpid(), &clockid_1) != 0) {
-		printf("clock_getcpuclockid(getpid(), ) failed\n");
-		return PTS_FAIL;
-	}
-	
-	if (clock_getcpuclockid(0, &clockid_2) != 0) {
-		printf("clock_getcpuclockid(0, ) failed\n");
-		return PTS_FAIL;
-	}
+        for (i = 0; i < 10; i++) {
+                if (clock_getcpuclockid(getpid(), &clockid_1) != 0) {
+                        printf("clock_getcpuclockid(getpid(), ) failed\n");
+                        return PTS_FAIL;
+                }
 
-	/* Set clockid_1 as a random value from 1 sec to 10 sec */
-	srand((unsigned long)time(NULL));
-	time_to_set = rand() * 10.0 / RAND_MAX + 1;
-	tp1.tv_sec = time_to_set;
-	tp1.tv_nsec = 0;	 
-	if (clock_settime(clockid_1, &tp1) != 0) {
-		printf("clock_getcpuclockid() returned an invalid clockid_t: "
-			"%d\n", clockid_1);
-		return PTS_FAIL;
-	}
-	/* Get the time of clockid_2, should almost the same as clockid_1 */
-	if (clock_gettime(clockid_2, &tp2) != 0) {
-		printf("clock_getcpuclockid() returned an invalid clockid_t: "
-			"%d\n", clockid_2);
-		return PTS_FAIL;
-	}
-	if (tp1.tv_sec == tp2.tv_sec)	
-	{
-		printf("Test PASSED\n");
-		return PTS_PASS;
-	}
-	printf("Test FAILED\n");
-	return PTS_FAIL;
-	
+                if (clock_getcpuclockid(0, &clockid_2) != 0) {
+                        printf("clock_getcpuclockid(0, ) failed\n");
+                        return PTS_FAIL;
+                }
+
+                /* Get the time of clockid_1 */
+                if (clock_gettime(clockid_1, &tp1) != 0) {
+                        printf("clock_getcpuclockid() returned an invalid clockid_t: "
+                               "%d\n", clockid_1);
+                        return PTS_FAIL;
+                }
+
+                /* Get the time of clockid_2, should almost the same as clockid_1 */
+                if (clock_gettime(clockid_2, &tp2) != 0) {
+                        printf("clock_getcpuclockid() returned an invalid clockid_t: "
+                               "%d\n", clockid_2);
+                        return PTS_FAIL;
+                }
+
+                if (tp1.tv_sec != tp2.tv_sec) {
+                        printf("Test FAILED\n");
+                        return PTS_FAIL;
+                }
+        }
+
+        printf("Test PASSED\n");
+        return PTS_PASS;
 #endif
 }
-- 
1.7.0.4



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