[LTP] [PATCH 2/2] getitimer01: add checking for nonzero timer

[Li Wang]

By default a new process disabled the timer and getitimer()
returned zero value. But we also need to check if the timer
is correct when reset to nonzero.

Signed-off-by: Li Wang <liwang@redhat.com>
---

Notes:
      The reason for using jiffy instead of time_step is that it only
      checks the timer is set expectedly but not really expired. So we
      use a rough value in the macro definition is enough.

 .../kernel/syscalls/getitimer/getitimer01.c   | 84 ++++++++++++++++---
 1 file changed, 71 insertions(+), 13 deletions(-)

diff --git a/testcases/kernel/syscalls/getitimer/getitimer01.c b/testcases/kernel/syscalls/getitimer/getitimer01.c
index 5ecfac55c..a49f63a85 100644
--- a/testcases/kernel/syscalls/getitimer/getitimer01.c
+++ b/testcases/kernel/syscalls/getitimer/getitimer01.c
@@ -12,25 +12,83 @@
  */
 
 #include "tst_test.h"
+#include "tst_safe_clocks.h"
 
-static int itimer_name[] = {
-	ITIMER_REAL,
-	ITIMER_VIRTUAL,
-	ITIMER_PROF,
+#define SEC  100
+#define USEC 10000
+
+static struct itimerval *value;
+static long jiffy;
+
+static struct tcase {
+	int which;
+	char *des;
+} tcases[] = {
+	{ITIMER_REAL,    "ITIMER_REAL"},
+	{ITIMER_VIRTUAL, "ITIMER_VIRTUAL"},
+	{ITIMER_PROF,    "ITIMER_PROF"},
 };
 
-static void run(void)
+static void set_setitimer_value(int sec, int usec)
 {
-	long unsigned int i;
-	struct itimerval value;
+	value->it_value.tv_sec = sec;
+	value->it_value.tv_usec = usec;
+	value->it_interval.tv_sec = sec;
+	value->it_interval.tv_usec = usec;
+}
 
-	for (i = 0; i < ARRAY_SIZE(itimer_name); i++) {
-		TST_EXP_PASS(getitimer(itimer_name[i], &value));
-		TST_EXP_EQ_LI(value.it_value.tv_sec, 0);
-		TST_EXP_EQ_LI(value.it_value.tv_usec, 0);
-	}
+static void verify_getitimer(unsigned int i)
+{
+	struct tcase *tc = &tcases[i];
+
+	tst_res(TINFO, "tc->which = %s", tc->des);
+
+	TST_EXP_PASS(getitimer(tc->which, value));
+	TST_EXP_EQ_LI(value->it_value.tv_sec, 0);
+	TST_EXP_EQ_LI(value->it_value.tv_usec, 0);
+	TST_EXP_EQ_LI(value->it_interval.tv_sec, 0);
+	TST_EXP_EQ_LI(value->it_interval.tv_usec, 0);
+
+	set_setitimer_value(SEC, USEC);
+	TST_EXP_PASS(setitimer(tc->which, value, NULL));
+
+	set_setitimer_value(0, 0);
+	TST_EXP_PASS(getitimer(tc->which, value));
+
+	TST_EXP_EQ_LI(value->it_interval.tv_sec, SEC);
+	TST_EXP_EQ_LI(value->it_interval.tv_usec, USEC);
+
+	tst_res(TINFO, "value->it_value.tv_sec=%ld, value->it_value.tv_usec=%ld",
+			value->it_value.tv_sec, value->it_value.tv_usec);
+
+	/*
+	 * ITIMER_VIRTUAL and ITIMER_PROF timers always expire a
+	 * TICK_NSEC (jiffy) afterward the elapsed time to make
+	 * sure that at least time counters take effect.
+	 */
+	long margin = (tc->which == ITIMER_REAL) ? 0 : jiffy;
+
+	if (value->it_value.tv_sec > SEC ||
+			value->it_value.tv_usec > USEC + margin)
+		tst_res(TFAIL, "timer value is not within the expected range");
+	else
+		tst_res(TPASS, "timer value is within the expected range");
+}
+
+static void setup(void)
+{
+	struct timespec time_res;
+
+	SAFE_CLOCK_GETRES(CLOCK_MONOTONIC_COARSE, &time_res);
+	jiffy = (time_res.tv_nsec + 999) / 1000;
 }
 
 static struct tst_test test = {
-	.test_all = run
+	.tcnt = ARRAY_SIZE(tcases),
+	.setup = setup,
+	.test = verify_getitimer,
+	.bufs = (struct tst_buffers[]) {
+		{&value,  .size = sizeof(struct itimerval)},
+		{}
+	}
 };
-- 
2.35.3