tstsem.c

PostgreSQL7.4.6 for Linux

/*-------------------------------------------------------------------------
 *
 * tstsem.c
 *	  Test of System V Semaphore Emulation
 *
 * Copyright (c) 1999, repas AEG Automation GmbH
 *
 *
 * IDENTIFICATION
 *	  $Header: /cvsroot/pgsql/src/backend/port/qnx4/tstsem.c,v 1.9 2002/11/08 20:23:56 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */

#include "postgres.h"

#include <signal.h>
#include <unistd.h>
#include "storage/ipc.h"
#include <sys/mman.h>
#include <sys/sem.h>


#define SEMMAX	16
#define OPSMAX	1

int			MaxBackends = SEMMAX;

static int	semid;

static void
sig_handler(int sig_no)
{
	union semun arg;
	int			i = semctl(semid, 0, GETNCNT, arg);

	if (i == -1)
		perror("semctl");
	else
		printf("semval = %d\n", i);
}

void		on_proc_exit(void (*function) (), Datum arg)
{
	atexit(function);
}
int
main(int argc, char **argv)
{
	int			c,
				errflg = 0;
	char		s[80];
	key_t		key = IPC_PRIVATE;
	int			nsems = SEMMAX;
	int			semflg = 0;
	int			unlink = 0;
	int			i;
	struct sembuf sops[OPSMAX];
	u_short		array[SEMMAX];
	union semun arg;

	optarg = NULL;
	while (!errflg && (c = getopt(argc, argv, "k:n:cxu")) != -1)
	{
		switch (c)
		{
			case 'k':
				key = atoi(optarg);
				break;
			case 'n':
				nsems = atoi(optarg);
				break;
			case 'c':
				semflg |= IPC_CREAT;
				break;
			case 'x':
				semflg |= IPC_EXCL;
				break;
			case 'u':
				unlink = 1;
				break;
			default:
				errflg++;
		}
	}
	if (errflg)
	{
		printf("usage: tstsem [-k key] [-n nsems] [-cxu]\n");
		exit(1);
	}

	if (unlink)
	{
		i = shm_unlink("SysV_Sem_Info");
		if (i == -1)
			perror("shm_unlink");
		exit(i);
	}

	semid = semget(key, nsems, semflg);
	if (semid == -1)
	{
		perror("semget");
		exit(semid);
	}

	/* test signal interrupts */
	signal(SIGTERM, sig_handler);

	do
	{
		printf("(-)sem_op, (+)sem_op, (G)ETVAL, (S)ETVAL, GET(P)ID, GET(A)LL, SETA(L)L, GET(N)CNT, GET(Z)CNT, e(x)it: ");
		scanf("%s", s);
		switch (s[0])
		{
			case '-':
			case '+':
				sops[0].sem_num = 0;
				sops[0].sem_op = atoi(s);
				if (sops[0].sem_op == 0)
					sops[0].sem_op = s[0] == '+' ? +1 : -1;
				sops[0].sem_flg = 0;
				if (semop(semid, sops, 1) == -1)
					perror("semop");
				break;

			case 'G':
			case 'g':
				i = semctl(semid, 0, GETVAL, arg);
				if (i == -1)
					perror("semctl");
				else
					printf("semval = %d\n", i);
				break;

			case 'S':
			case 's':
				printf("semval = ");
				scanf("%d", &arg.val);
				if (semctl(semid, 0, SETVAL, arg) == -1)
					perror("semctl");
				break;

			case 'P':
			case 'p':
				i = semctl(semid, 0, GETPID, arg);
				if (i == -1)
					perror("semctl");
				else
					printf("PID = %d\n", i);
				break;

			case 'A':
			case 'a':
				arg.array = array;
				i = semctl(semid, 0, GETALL, arg);
				if (i == -1)
					perror("semctl");
				else
				{
					for (i = 0; i < nsems; i++)
						printf("semval[%d] = %hu\n", i, arg.array[i]);
				}
				break;

			case 'L':
			case 'l':
				arg.array = array;
				for (i = 0; i < nsems; i++)
				{
					printf("semval[%d] = ", i);
					scanf("%hu", &arg.array[i]);
				}
				if (semctl(semid, 0, SETALL, arg) == -1)
					perror("semctl");
				break;

			case 'N':
			case 'n':
				i = semctl(semid, 0, GETNCNT, arg);
				if (i == -1)
					perror("semctl");
				else
					printf("semval = %d\n", i);
				break;

			case 'Z':
			case 'z':
				i = semctl(semid, 0, GETZCNT, arg);
				if (i == -1)
					perror("semctl");
				else
					printf("semval = %d\n", i);
				break;
		}
	}
	while (s[0] != 'x');

	if (semctl(semid, 0, IPC_RMID, arg) == -1)
	{
		perror("semctl");
		exit(-1);
	}

	exit(0);
}