void
sigchld_handler(int signo)
{
union semun sun;
struct semid_ds s_ds;
int cstatus;
/*
* Reap the child; if it exited successfully, then we're on the
* right track!
*/
if (wait(&cstatus) == -1)
err(1, "wait");
if (WIFEXITED(cstatus) == 0)
errx(1, "receiver exited abnormally");
if (WEXITSTATUS(cstatus) != 0)
errx(1, "receiver exited with status %d",
WEXITSTATUS(cstatus));
/*
* If we get here, the child has exited normally, and we should
* decrement the child count. If the child_count reaches 0, we
* should exit.
*/
sun.buf = &s_ds;
if (semctl(sender_semid, 0, IPC_STAT, sun) == -1)
err(1, "semctl IPC_STAT");
print_semid_ds(&s_ds, 0600);
if (--child_count != 0) {
signal_was_sigchld = 1;
return;
}
exit(0);
}
int
main(int argc, char *argv[])
{
struct sigaction sa;
union semun sun;
struct semid_ds s_ds;
sigset_t sigmask;
int i;
if (argc != 2)
usage();
/*
* Install a SIGSYS handler so that we can exit gracefully if
* System V Semaphore support isn't in the kernel.
*/
sa.sa_handler = sigsys_handler;
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
if (sigaction(SIGSYS, &sa, NULL) == -1)
err(1, "sigaction SIGSYS");
/*
* Install and SIGCHLD handler to deal with all possible exit
* conditions of the receiver.
*/
sa.sa_handler = sigchld_handler;
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
if (sigaction(SIGCHLD, &sa, NULL) == -1)
err(1, "sigaction SIGCHLD");
semkey = ftok(argv[1], 4160);
/*
* Initialize child_pid to ourselves to that the cleanup function
* works before we create the receiver.
*/
child_pid = getpid();
/*
* Make sure that when the sender exits, the message queue is
* removed.
*/
if (atexit(cleanup) == -1)
err(1, "atexit");
if ((sender_semid = semget(semkey, 1, IPC_CREAT | 0640)) == -1)
err(1, "semget");
sun.buf = &s_ds;
if (semctl(sender_semid, 0, IPC_STAT, sun) == -1)
err(1, "semctl IPC_STAT");
print_semid_ds(&s_ds, 0640);
s_ds.sem_perm.mode = (s_ds.sem_perm.mode & ~0777) | 0600;
sun.buf = &s_ds;
if (semctl(sender_semid, 0, IPC_SET, sun) == -1)
err(1, "semctl IPC_SET");
memset(&s_ds, 0, sizeof(s_ds));
sun.buf = &s_ds;
if (semctl(sender_semid, 0, IPC_STAT, sun) == -1)
err(1, "semctl IPC_STAT");
if ((s_ds.sem_perm.mode & 0777) != 0600)
err(1, "IPC_SET of mode didn't hold");
print_semid_ds(&s_ds, 0600);
for (child_count = 0; child_count < 5; child_count++) {
switch ((child_pid = fork())) {
case -1:
err(1, "fork");
/* NOTREACHED */
case 0:
waiter();
break;
default:
break;
}
}
/*
* Wait for all of the waiters to be attempting to acquire the
* semaphore.
*/
for (;;) {
i = semctl(sender_semid, 0, GETNCNT);
if (i == -1)
err(1, "semctl GETNCNT");
if (i == 5)
break;
}
/*
* Now set the thundering herd in motion by initializing the
* semaphore to the value 1.
*/
sun.val = 1;
if (semctl(sender_semid, 0, SETVAL, sun) == -1)
err(1, "sender: semctl SETVAL to 1");
/*
* Suspend forever; when we get SIGCHLD, the handler will exit.
*/
sigemptyset(&sigmask);
for (;;) {
(void) sigsuspend(&sigmask);
if (signal_was_sigchld)
signal_was_sigchld = 0;
else
break;
}
/*
* ...and any other signal is an unexpected error.
*/
errx(1, "sender: received unexpected signal");
}
ATF_TC_BODY(sem, tc)
{
struct sigaction sa;
union semun sun;
struct semid_ds s_ds;
sigset_t sigmask;
int sender_semid;
int i;
int c_status;
/*
* Install a SIGSYS handler so that we can exit gracefully if
* System V Semaphore support isn't in the kernel.
*/
did_sigsys = 0;
sa.sa_handler = sigsys_handler;
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
ATF_REQUIRE_MSG(sigaction(SIGSYS, &sa, NULL) != -1,
"sigaction SIGSYS: %d", errno);
/*
* Install a SIGCHLD handler to deal with all possible exit
* conditions of the receiver.
*/
did_sigchild = 0;
child_count = 0;
sa.sa_handler = sigchld_handler;
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
ATF_REQUIRE_MSG(sigaction(SIGCHLD, &sa, NULL) != -1,
"sigaction SIGCHLD: %d", errno);
semkey = get_ftok(4160);
ATF_REQUIRE_MSG(semkey != (key_t)-1, "get_ftok failed");
sender_semid = semget(semkey, 1, IPC_CREAT | 0640);
ATF_REQUIRE_MSG(sender_semid != -1, "semget: %d", errno);
write_int("sender_semid", sender_semid);
if (did_sigsys) {
atf_tc_skip("SYSV Semaphore not supported");
return;
}
sun.buf = &s_ds;
ATF_REQUIRE_MSG(semctl(sender_semid, 0, IPC_STAT, sun) != -1,
"semctl IPC_STAT: %d", errno);
print_semid_ds(&s_ds, 0640);
s_ds.sem_perm.mode = (s_ds.sem_perm.mode & ~0777) | 0600;
sun.buf = &s_ds;
ATF_REQUIRE_MSG(semctl(sender_semid, 0, IPC_SET, sun) != -1,
"semctl IPC_SET: %d", errno);
memset(&s_ds, 0, sizeof(s_ds));
sun.buf = &s_ds;
ATF_REQUIRE_MSG(semctl(sender_semid, 0, IPC_STAT, sun) != -1,
"semctl IPC_STAT: %d", errno);
ATF_REQUIRE_MSG((s_ds.sem_perm.mode & 0777) == 0600,
"IPC_SET of mode didn't hold");
print_semid_ds(&s_ds, 0600);
for (child_count = 0; child_count < 5; child_count++) {
switch ((child_pid = fork())) {
case -1:
atf_tc_fail("fork: %d", errno);
return;
case 0:
waiter();
break;
default:
break;
}
}
/*
* Wait for all of the waiters to be attempting to acquire the
* semaphore.
*/
for (;;) {
i = semctl(sender_semid, 0, GETNCNT);
if (i == -1)
atf_tc_fail("semctl GETNCNT: %d", i);
if (i == 5)
break;
}
/*
* Now set the thundering herd in motion by initializing the
* semaphore to the value 1.
*/
sun.val = 1;
ATF_REQUIRE_MSG(semctl(sender_semid, 0, SETVAL, sun) != -1,
"sender: semctl SETVAL to 1: %d", errno);
/*
* Wait for all children to finish
*/
sigemptyset(&sigmask);
for (;;) {
(void) sigsuspend(&sigmask);
if (did_sigchild) {
c_status = child_status;
if (c_status < 0)
atf_tc_fail("waitpid: %d", -c_status);
else if (WIFEXITED(c_status) == 0)
atf_tc_fail("c abnormal exit: %d", c_status);
else if (WEXITSTATUS(c_status) != 0)
atf_tc_fail("c status: %d",
WEXITSTATUS(c_status));
else {
sun.buf = &s_ds;
ATF_REQUIRE_MSG(semctl(sender_semid, 0,
IPC_STAT, sun) != -1,
"semctl IPC_STAT: %d", errno);
print_semid_ds(&s_ds, 0600);
atf_tc_pass();
}
if (child_count <= 0)
break;
did_sigchild = 0;
} else {
atf_tc_fail("sender: received unexpected signal");
break;
}
}
}
