[LTP] [PATCH v7] semctl01: look up SEM_STAT index for this test's sem_id

[Stephen Bertram]

Walk 0..max_idx with SEM_STAT until the returned id equals this test's
sem_id.

Test: ./kirk -w 4 -f syscalls_8 -p semctl01 -i 1000

Results summary before:
Total runs:  8000
Runtime:    4m 8s
Passed:     103994
Failed:     0
Skipped:    0
Broken:     3
Warnings:   0

Results summary after:
Total runs:  8000
Runtime:    4m 9s
Passed:     104000
Failed:     0
Skipped:    0
Broken:     0
Warnings:   0

Assisted-by: Cursor

Signed-off-by: Stephen Bertram <sbertram@redhat.com>
---
 testcases/kernel/syscalls/semctl/semctl01.c | 85 +++++++++++++++------
 1 file changed, 62 insertions(+), 23 deletions(-)

diff --git a/testcases/kernel/syscalls/semctl/semctl01.c b/testcases/kernel/syscalls/semctl/semctl01.c
index 5bd675ab6..7b60d5739 100644
--- a/testcases/kernel/syscalls/semctl/semctl01.c
+++ b/testcases/kernel/syscalls/semctl/semctl01.c
@@ -19,7 +19,6 @@
 #define SEMUN_CAST (union semun)
 
 static int sem_id = -1;
-static int sem_index;
 static struct semid_ds buf;
 static struct seminfo ipc_buf;
 static unsigned short array[PSEMS];
@@ -210,13 +209,10 @@ static void func_rmid(void)
 
 static void func_iinfo(int hidx)
 {
-	if (hidx >= 0) {
-		sem_index = hidx;
+	if (hidx >= 0)
 		tst_res(TPASS, "the highest index is correct");
-	} else {
-		sem_index = 0;
+	else
 		tst_res(TFAIL, "the highest index is incorrect");
-	}
 }
 
 static void func_sinfo(void)
@@ -229,35 +225,73 @@ static void func_sinfo(void)
 
 static void func_sstat(int semidx)
 {
-	if (semidx >= 0)
+	if (semidx == sem_id)
 		tst_res(TPASS, "id of the semaphore set is correct");
 	else
-		tst_res(TFAIL, "id of the semaphore set is incorrect");
+		tst_res(TFAIL, "expected sem_id %d, got %d", sem_id, semidx);
 }
 
 static struct tcases {
-	int *semid;
 	int semnum;
 	int cmd;
 	void (*func_test) ();
 	union semun arg;
 	void (*func_setup) ();
 } tests[] = {
-	{&sem_id, 0, IPC_STAT, func_stat, SEMUN_CAST & buf, NULL},
-	{&sem_id, 0, IPC_SET, func_set, SEMUN_CAST & buf, set_setup},
-	{&sem_id, 0, GETALL, func_gall, SEMUN_CAST array, NULL},
-	{&sem_id, 4, GETNCNT, func_cnt, SEMUN_CAST & buf, cnt_setup},
-	{&sem_id, 2, GETPID, func_pid, SEMUN_CAST & buf, pid_setup},
-	{&sem_id, 2, GETVAL, func_gval, SEMUN_CAST & buf, NULL},
-	{&sem_id, 4, GETZCNT, func_cnt, SEMUN_CAST & buf, cnt_setup},
-	{&sem_id, 0, SETALL, func_sall, SEMUN_CAST array, sall_setup},
-	{&sem_id, 4, SETVAL, func_sval, SEMUN_CAST INCVAL, NULL},
-	{&sem_id, 0, IPC_INFO, func_iinfo, SEMUN_CAST & ipc_buf, NULL},
-	{&sem_id, 0, SEM_INFO, func_sinfo, SEMUN_CAST & ipc_buf, NULL},
-	{&sem_index, 0, SEM_STAT, func_sstat, SEMUN_CAST & buf, NULL},
-	{&sem_id, 0, IPC_RMID, func_rmid, SEMUN_CAST & buf, NULL},
+	{0, IPC_STAT, func_stat, SEMUN_CAST & buf, NULL},
+	{0, IPC_SET, func_set, SEMUN_CAST & buf, set_setup},
+	{0, GETALL, func_gall, SEMUN_CAST array, NULL},
+	{4, GETNCNT, func_cnt, SEMUN_CAST & buf, cnt_setup},
+	{2, GETPID, func_pid, SEMUN_CAST & buf, pid_setup},
+	{2, GETVAL, func_gval, SEMUN_CAST & buf, NULL},
+	{4, GETZCNT, func_cnt, SEMUN_CAST & buf, cnt_setup},
+	{0, SETALL, func_sall, SEMUN_CAST array, sall_setup},
+	{4, SETVAL, func_sval, SEMUN_CAST INCVAL, NULL},
+	{0, IPC_INFO, func_iinfo, SEMUN_CAST & ipc_buf, NULL},
+	{0, SEM_INFO, func_sinfo, SEMUN_CAST & ipc_buf, NULL},
+	{0, SEM_STAT, func_sstat, SEMUN_CAST & buf, NULL},
+	{0, IPC_RMID, func_rmid, SEMUN_CAST & buf, NULL},
 };
 
+/*
+ * SEM_STAT takes an idr index. Walk 0..max_idx until SEM_STAT
+ * returns this test's sem_id so parallel IPC tests cannot make us exercise
+ * some other process's set (EIDRM/EINVAL/EACCES on a moving max_idx).
+ * Returns that semid.
+ */
+static int sem_stat_for_id(int id, union semun arg)
+{
+	struct seminfo info;
+	union semun info_arg;
+	int max_idx, i, ret;
+
+	info_arg.__buf = &info;
+	max_idx = SAFE_SEMCTL(id, 0, IPC_INFO, info_arg);
+
+	for (i = 0; i <= max_idx; i++) {
+		ret = semctl(i, 0, SEM_STAT, arg);
+		if (ret == id)
+			return ret;
+		if (ret == -1 && errno != EIDRM && errno != EINVAL &&
+			errno != EACCES)
+			tst_brk(TBROK | TERRNO, "semctl(%d, SEM_STAT)", i);
+	}
+
+	return -1;
+}
+
+static int do_sem_stat(union semun arg)
+{
+	int ret;
+
+	ret = sem_stat_for_id(sem_id, arg);
+	if (ret < 0)
+		tst_brk(TBROK, "Failed to find SEM_STAT for sem_id %d",
+			sem_id);
+
+	return ret;
+}
+
 static void verify_semctl(unsigned int n)
 {
 	struct tcases *tc = &tests[n];
@@ -265,6 +299,7 @@ static void verify_semctl(unsigned int n)
 
 	if (sem_id == -1)
 		sem_id = SAFE_SEMGET(IPC_PRIVATE, PSEMS, IPC_CREAT | IPC_EXCL | SEM_RA);
+
 	if (tc->func_setup) {
 		switch (tc->cmd) {
 		case GETNCNT:
@@ -279,7 +314,11 @@ static void verify_semctl(unsigned int n)
 		}
 	}
 
-	rval = SAFE_SEMCTL(*(tc->semid), tc->semnum, tc->cmd, tc->arg);
+	if (tc->cmd == SEM_STAT)
+		rval = do_sem_stat(tc->arg);
+	else
+		rval = SAFE_SEMCTL(sem_id, tc->semnum, tc->cmd, tc->arg);
+
 	switch (tc->cmd) {
 	case GETNCNT:
 	case GETZCNT:
-- 
2.55.0