NetBSD-5.0.2/regress/sys/kern/sysvsem/semtest.c
/* $NetBSD: semtest.c,v 1.6 2008/04/28 20:23:07 martin Exp $ */
/*-
* Copyright (c) 1999 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
* NASA Ames Research Center.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Test the SVID-compatible Semaphore facility.
*/
#include <sys/param.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <sys/wait.h>
#include <err.h>
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
int main(int, char *[]);
void print_semid_ds(struct semid_ds *, mode_t);
void sigsys_handler(int);
void sigchld_handler(int);
void cleanup(void);
void waiter(void);
void usage(void);
int sender_semid = -1;
pid_t child_pid;
int child_count;
int signal_was_sigchld;
key_t semkey;
union semun {
int val; /* value for SETVAL */
struct semid_ds *buf; /* buffer for IPC_{STAT,SET} */
u_short *array; /* array for GETALL & SETALL */
};
int
main(argc, argv)
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");
}
void
sigsys_handler(signo)
int signo;
{
errx(1, "System V Semaphore support is not present in the kernel");
}
void
sigchld_handler(signo)
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);
}
void
cleanup()
{
/*
* If we're the sender, and it exists, remove the message queue.
*/
if (child_pid != 0 && sender_semid != -1) {
if (semctl(sender_semid, 0, IPC_RMID) == -1)
warn("semctl IPC_RMID");
}
}
void
print_semid_ds(sp, mode)
struct semid_ds *sp;
mode_t mode;
{
uid_t uid = geteuid();
gid_t gid = getegid();
printf("PERM: uid %d, gid %d, cuid %d, cgid %d, mode 0%o\n",
sp->sem_perm.uid, sp->sem_perm.gid,
sp->sem_perm.cuid, sp->sem_perm.cgid,
sp->sem_perm.mode & 0777);
printf("nsems %u\n", sp->sem_nsems);
printf("otime: %s", ctime(&sp->sem_otime));
printf("ctime: %s", ctime(&sp->sem_ctime));
/*
* Sanity check a few things.
*/
if (sp->sem_perm.uid != uid || sp->sem_perm.cuid != uid)
errx(1, "uid mismatch");
if (sp->sem_perm.gid != gid || sp->sem_perm.cgid != gid)
errx(1, "gid mismatch");
if ((sp->sem_perm.mode & 0777) != mode)
errx(1, "mode mismatch %o != %o",
(sp->sem_perm.mode & 0777), mode);
}
void
usage()
{
fprintf(stderr, "usage: %s keypath\n", getprogname());
exit(1);
}
void
waiter()
{
struct sembuf s;
int semid;
if ((semid = semget(semkey, 1, 0)) == -1)
err(1, "waiter: semget");
/*
* Attempt to acquire the semaphore.
*/
s.sem_num = 0;
s.sem_op = -1;
s.sem_flg = SEM_UNDO;
if (semop(semid, &s, 1) == -1)
err(1, "waiter: semop -1");
printf("WOO! GOT THE SEMAPHORE!\n");
sleep(1);
/*
* Release the semaphore and exit.
*/
s.sem_num = 0;
s.sem_op = 1;
s.sem_flg = SEM_UNDO;
if (semop(semid, &s, 1) == -1)
err(1, "waiter: semop +1");
exit(0);
}