tools/testing/selftests/sched/cs_prctl_test.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Use the core scheduling prctl() to test core scheduling cookies control.
  *
  * Copyright (c) 2021 Oracle and/or its affiliates.
  * Author: Chris Hyser <chris.hyser@oracle.com>
  *
  *
  * This library is free software; you can redistribute it and/or modify it
  * under the terms of version 2.1 of the GNU Lesser General Public License as
  * published by the Free Software Foundation.
  *
  * This library is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
  * for more details.
  *
  * You should have received a copy of the GNU Lesser General Public License
  * along with this library; if not, see <http://www.gnu.org/licenses>.
  */

 #define _GNU_SOURCE
 #include <sys/eventfd.h>
 #include <sys/wait.h>
 #include <sys/types.h>
 #include <sched.h>
 #include <sys/prctl.h>
 #include <unistd.h>
 #include <time.h>
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>

 #if __GLIBC_PREREQ(2, 30) == 0
 #include <sys/syscall.h>
 static pid_t gettid(void)
 {
 	return syscall(SYS_gettid);
 }
 #endif

 #ifndef PR_SCHED_CORE
 #define PR_SCHED_CORE			62
 # define PR_SCHED_CORE_GET		0
 # define PR_SCHED_CORE_CREATE		1 /* create unique core_sched cookie */
 # define PR_SCHED_CORE_SHARE_TO		2 /* push core_sched cookie to pid */
 # define PR_SCHED_CORE_SHARE_FROM	3 /* pull core_sched cookie to pid */
 # define PR_SCHED_CORE_MAX		4
 #endif

 #define MAX_PROCESSES 128
 #define MAX_THREADS   128

 static const char USAGE[] = "cs_prctl_test [options]\n"
 "    options:\n"
 "	-P  : number of processes to create.\n"
 "	-T  : number of threads per process to create.\n"
 "	-d  : delay time to keep tasks alive.\n"
 "	-k  : keep tasks alive until keypress.\n";

 enum pid_type {PIDTYPE_PID = 0, PIDTYPE_TGID, PIDTYPE_PGID};

 const int THREAD_CLONE_FLAGS = CLONE_THREAD | CLONE_SIGHAND | CLONE_FS | CLONE_VM | CLONE_FILES;

 struct child_args {
 	int num_threads;
 	int pfd[2];
 	int cpid;
 	int thr_tids[MAX_THREADS];
 };

 static struct child_args procs[MAX_PROCESSES];
 static int num_processes = 2;
 static int need_cleanup;

 static int _prctl(int option, unsigned long arg2, unsigned long arg3, unsigned long arg4,
 		  unsigned long arg5)
 {
 	int res;

 	res = prctl(option, arg2, arg3, arg4, arg5);
 	printf("%d = prctl(%d, %ld, %ld, %ld, %lx)\n", res, option, (long)arg2, (long)arg3,
 	       (long)arg4, arg5);
 	return res;
 }

 #define STACK_SIZE (1024 * 1024)

 #define handle_error(msg) __handle_error(__FILE__, __LINE__, msg)
 static void __handle_error(char *fn, int ln, char *msg)
 {
 	int pidx;
 	printf("(%s:%d) - ", fn, ln);
 	perror(msg);
 	if (need_cleanup) {
 		for (pidx = 0; pidx < num_processes; ++pidx)
 			kill(procs[pidx].cpid, 15);
 		need_cleanup = 0;
 	}
 	exit(EXIT_FAILURE);
 }

 static void handle_usage(int rc, char *msg)
 {
 	puts(USAGE);
 	puts(msg);
 	putchar('\n');
 	exit(rc);
 }

 static unsigned long get_cs_cookie(int pid)
 {
 	unsigned long long cookie;
 	int ret;

 	ret = prctl(PR_SCHED_CORE, PR_SCHED_CORE_GET, pid, PIDTYPE_PID,
 		    (unsigned long)&cookie);
 	if (ret) {
 		printf("Not a core sched system\n");
 		return -1UL;
 	}

 	return cookie;
 }

 static int child_func_thread(void __attribute__((unused))*arg)
 {
 	while (1)
 		usleep(20000);
 	return 0;
 }

 static void create_threads(int num_threads, int thr_tids[])
 {
 	void *child_stack;
 	pid_t tid;
 	int i;

 	for (i = 0; i < num_threads; ++i) {
 		child_stack = malloc(STACK_SIZE);
 		if (!child_stack)
 			handle_error("child stack allocate");

 		tid = clone(child_func_thread, child_stack + STACK_SIZE, THREAD_CLONE_FLAGS, NULL);
 		if (tid == -1)
 			handle_error("clone thread");
 		thr_tids[i] = tid;
 	}
 }

 static int child_func_process(void *arg)
 {
 	struct child_args *ca = (struct child_args *)arg;
 	int ret;

 	close(ca->pfd[0]);

 	create_threads(ca->num_threads, ca->thr_tids);

 	ret = write(ca->pfd[1], &ca->thr_tids, sizeof(int) * ca->num_threads);
 	if (ret == -1)
 		printf("write failed on pfd[%d] - error (%s)\n",
 			ca->pfd[1], strerror(errno));

 	close(ca->pfd[1]);

 	while (1)
 		usleep(20000);
 	return 0;
 }

 static unsigned char child_func_process_stack[STACK_SIZE];

 void create_processes(int num_processes, int num_threads, struct child_args proc[])
 {
 	pid_t cpid;
 	int i, ret;

 	for (i = 0; i < num_processes; ++i) {
 		proc[i].num_threads = num_threads;

 		if (pipe(proc[i].pfd) == -1)
 			handle_error("pipe() failed");

 		cpid = clone(child_func_process, child_func_process_stack + STACK_SIZE,
 			     SIGCHLD, &proc[i]);
 		proc[i].cpid = cpid;
 		close(proc[i].pfd[1]);
 	}

 	for (i = 0; i < num_processes; ++i) {
 		ret = read(proc[i].pfd[0], &proc[i].thr_tids, sizeof(int) * proc[i].num_threads);
 		if (ret == -1)
 			printf("read failed on proc[%d].pfd[0] error (%s)\n",
 				i, strerror(errno));
 		close(proc[i].pfd[0]);
 	}
 }

 void disp_processes(int num_processes, struct child_args proc[])
 {
 	int i, j;

 	printf("tid=%d, / tgid=%d / pgid=%d: %lx\n", gettid(), getpid(), getpgid(0),
 	       get_cs_cookie(getpid()));

 	for (i = 0; i < num_processes; ++i) {
 		printf("    tid=%d, / tgid=%d / pgid=%d: %lx\n", proc[i].cpid, proc[i].cpid,
 		       getpgid(proc[i].cpid), get_cs_cookie(proc[i].cpid));
 		for (j = 0; j < proc[i].num_threads; ++j) {
 			printf("        tid=%d, / tgid=%d / pgid=%d: %lx\n", proc[i].thr_tids[j],
 			       proc[i].cpid, getpgid(0), get_cs_cookie(proc[i].thr_tids[j]));
 		}
 	}
 	puts("\n");
 }

 static int errors;

 #define validate(v) _validate(__LINE__, v, #v)
 void _validate(int line, int val, char *msg)
 {
 	if (!val) {
 		++errors;
 		printf("(%d) FAILED: %s\n", line, msg);
 	} else {
 		printf("(%d) PASSED: %s\n", line, msg);
 	}
 }

 int main(int argc, char *argv[])
 {
 	int keypress = 0;
 	int num_threads = 3;
 	int delay = 0;
 	int res = 0;
 	int pidx;
 	int pid;
 	int opt;

 	while ((opt = getopt(argc, argv, ":hkT:P:d:")) != -1) {
 		switch (opt) {
 		case 'P':
 			num_processes = (int)strtol(optarg, NULL, 10);
 			break;
 		case 'T':
 			num_threads = (int)strtoul(optarg, NULL, 10);
 			break;
 		case 'd':
 			delay = (int)strtol(optarg, NULL, 10);
 			break;
 		case 'k':
 			keypress = 1;
 			break;
 		case 'h':
 			printf(USAGE);
 			exit(EXIT_SUCCESS);
 		default:
 			handle_usage(20, "unknown option");
 		}
 	}

 	if (num_processes < 1 || num_processes > MAX_PROCESSES)
 		handle_usage(1, "Bad processes value");

 	if (num_threads < 1 || num_threads > MAX_THREADS)
 		handle_usage(2, "Bad thread value");

 	if (keypress)
 		delay = -1;

 	srand(time(NULL));

 	/* put into separate process group */
 	if (setpgid(0, 0) != 0)
 		handle_error("process group");

 	printf("\n## Create a thread/process/process group hierarchy\n");
 	create_processes(num_processes, num_threads, procs);
 	need_cleanup = 1;
 	disp_processes(num_processes, procs);
 	validate(get_cs_cookie(0) == 0);

 	printf("\n## Set a cookie on entire process group\n");
 	if (_prctl(PR_SCHED_CORE, PR_SCHED_CORE_CREATE, 0, PIDTYPE_PGID, 0) < 0)
 		handle_error("core_sched create failed -- PGID");
 	disp_processes(num_processes, procs);

 	validate(get_cs_cookie(0) != 0);

 	/* get a random process pid */
 	pidx = rand() % num_processes;
 	pid = procs[pidx].cpid;

 	validate(get_cs_cookie(0) == get_cs_cookie(pid));
 	validate(get_cs_cookie(0) == get_cs_cookie(procs[pidx].thr_tids[0]));

 	printf("\n## Set a new cookie on entire process/TGID [%d]\n", pid);
 	if (_prctl(PR_SCHED_CORE, PR_SCHED_CORE_CREATE, pid, PIDTYPE_TGID, 0) < 0)
 		handle_error("core_sched create failed -- TGID");
 	disp_processes(num_processes, procs);

 	validate(get_cs_cookie(0) != get_cs_cookie(pid));
 	validate(get_cs_cookie(pid) != 0);
 	validate(get_cs_cookie(pid) == get_cs_cookie(procs[pidx].thr_tids[0]));

 	printf("\n## Copy the cookie of current/PGID[%d], to pid [%d] as PIDTYPE_PID\n",
 	       getpid(), pid);
 	if (_prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_TO, pid, PIDTYPE_PID, 0) < 0)
 		handle_error("core_sched share to itself failed -- PID");
 	disp_processes(num_processes, procs);

 	validate(get_cs_cookie(0) == get_cs_cookie(pid));
 	validate(get_cs_cookie(pid) != 0);
 	validate(get_cs_cookie(pid) != get_cs_cookie(procs[pidx].thr_tids[0]));

 	printf("\n## Copy cookie from a thread [%d] to current/PGID [%d] as PIDTYPE_PID\n",
 	       procs[pidx].thr_tids[0], getpid());
 	if (_prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_FROM, procs[pidx].thr_tids[0],
 		   PIDTYPE_PID, 0) < 0)
 		handle_error("core_sched share from thread failed -- PID");
 	disp_processes(num_processes, procs);

 	validate(get_cs_cookie(0) == get_cs_cookie(procs[pidx].thr_tids[0]));
 	validate(get_cs_cookie(pid) != get_cs_cookie(procs[pidx].thr_tids[0]));

 	printf("\n## Copy cookie from current [%d] to current as pidtype PGID\n", getpid());
 	if (_prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_TO, 0, PIDTYPE_PGID, 0) < 0)
 		handle_error("core_sched share to self failed -- PGID");
 	disp_processes(num_processes, procs);

 	validate(get_cs_cookie(0) == get_cs_cookie(pid));
 	validate(get_cs_cookie(pid) != 0);
 	validate(get_cs_cookie(pid) == get_cs_cookie(procs[pidx].thr_tids[0]));

 	validate(_prctl(PR_SCHED_CORE, PR_SCHED_CORE_MAX, 0, PIDTYPE_PGID, 0) < 0
 		&& errno == EINVAL);

 	validate(_prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_TO, 0, PIDTYPE_PGID, 1) < 0
 		&& errno == EINVAL);

 	if (errors) {
 		printf("TESTS FAILED. errors: %d\n", errors);
 		res = 10;
 	} else {
 		printf("SUCCESS !!!\n");
 	}

 	if (keypress)
 		getchar();
 	else
 		sleep(delay);

 	for (pidx = 0; pidx < num_processes; ++pidx)
 		kill(procs[pidx].cpid, 15);

 	return res;
 }
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Use the core scheduling prctl() to test core scheduling cookies control.
	*
	* Copyright (c) 2021 Oracle and/or its affiliates.
	* Author: Chris Hyser <chris.hyser@oracle.com>
	*
	*
	* This library is free software; you can redistribute it and/or modify it
	* under the terms of version 2.1 of the GNU Lesser General Public License as
	* published by the Free Software Foundation.
	*
	* This library is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
	* for more details.
	*
	* You should have received a copy of the GNU Lesser General Public License
	* along with this library; if not, see <http://www.gnu.org/licenses>.
	*/

	#define _GNU_SOURCE
	#include <sys/eventfd.h>
	#include <sys/wait.h>
	#include <sys/types.h>
	#include <sched.h>
	#include <sys/prctl.h>
	#include <unistd.h>
	#include <time.h>
	#include <errno.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>

	#if __GLIBC_PREREQ(2, 30) == 0
	#include <sys/syscall.h>
	static pid_t gettid(void)
	{
	return syscall(SYS_gettid);
	}
	#endif

	#ifndef PR_SCHED_CORE
	#define PR_SCHED_CORE 62
	# define PR_SCHED_CORE_GET 0
	# define PR_SCHED_CORE_CREATE 1 /* create unique core_sched cookie */
	# define PR_SCHED_CORE_SHARE_TO 2 /* push core_sched cookie to pid */
	# define PR_SCHED_CORE_SHARE_FROM 3 /* pull core_sched cookie to pid */
	# define PR_SCHED_CORE_MAX 4
	#endif

	#define MAX_PROCESSES 128
	#define MAX_THREADS 128

	static const char USAGE[] = "cs_prctl_test [options]\n"
	" options:\n"
	" -P : number of processes to create.\n"
	" -T : number of threads per process to create.\n"
	" -d : delay time to keep tasks alive.\n"
	" -k : keep tasks alive until keypress.\n";

	enum pid_type {PIDTYPE_PID = 0, PIDTYPE_TGID, PIDTYPE_PGID};

	const int THREAD_CLONE_FLAGS = CLONE_THREAD \| CLONE_SIGHAND \| CLONE_FS \| CLONE_VM \| CLONE_FILES;

	struct child_args {
	int num_threads;
	int pfd[2];
	int cpid;
	int thr_tids[MAX_THREADS];
	};

	static struct child_args procs[MAX_PROCESSES];
	static int num_processes = 2;
	static int need_cleanup;

	static int _prctl(int option, unsigned long arg2, unsigned long arg3, unsigned long arg4,
	unsigned long arg5)
	{
	int res;

	res = prctl(option, arg2, arg3, arg4, arg5);
	printf("%d = prctl(%d, %ld, %ld, %ld, %lx)\n", res, option, (long)arg2, (long)arg3,
	(long)arg4, arg5);
	return res;
	}

	#define STACK_SIZE (1024 * 1024)

	#define handle_error(msg) __handle_error(__FILE__, __LINE__, msg)
	static void __handle_error(char fn, int ln, char msg)
	{
	int pidx;
	printf("(%s:%d) - ", fn, ln);
	perror(msg);
	if (need_cleanup) {
	for (pidx = 0; pidx < num_processes; ++pidx)
	kill(procs[pidx].cpid, 15);
	need_cleanup = 0;
	}
	exit(EXIT_FAILURE);
	}

	static void handle_usage(int rc, char *msg)
	{
	puts(USAGE);
	puts(msg);
	putchar('\n');
	exit(rc);
	}

	static unsigned long get_cs_cookie(int pid)
	{
	unsigned long long cookie;
	int ret;

	ret = prctl(PR_SCHED_CORE, PR_SCHED_CORE_GET, pid, PIDTYPE_PID,
	(unsigned long)&cookie);
	if (ret) {
	printf("Not a core sched system\n");
	return -1UL;
	}

	return cookie;
	}

	static int child_func_thread(void __attribute__((unused))*arg)
	{
	while (1)
	usleep(20000);
	return 0;
	}

	static void create_threads(int num_threads, int thr_tids[])
	{
	void *child_stack;
	pid_t tid;
	int i;

	for (i = 0; i < num_threads; ++i) {
	child_stack = malloc(STACK_SIZE);
	if (!child_stack)
	handle_error("child stack allocate");

	tid = clone(child_func_thread, child_stack + STACK_SIZE, THREAD_CLONE_FLAGS, NULL);
	if (tid == -1)
	handle_error("clone thread");
	thr_tids[i] = tid;
	}
	}

	static int child_func_process(void *arg)
	{
	struct child_args ca = (struct child_args )arg;
	int ret;

	close(ca->pfd[0]);

	create_threads(ca->num_threads, ca->thr_tids);

	ret = write(ca->pfd[1], &ca->thr_tids, sizeof(int) * ca->num_threads);
	if (ret == -1)
	printf("write failed on pfd[%d] - error (%s)\n",
	ca->pfd[1], strerror(errno));

	close(ca->pfd[1]);

	while (1)
	usleep(20000);
	return 0;
	}

	static unsigned char child_func_process_stack[STACK_SIZE];

	void create_processes(int num_processes, int num_threads, struct child_args proc[])
	{
	pid_t cpid;
	int i, ret;

	for (i = 0; i < num_processes; ++i) {
	proc[i].num_threads = num_threads;

	if (pipe(proc[i].pfd) == -1)
	handle_error("pipe() failed");

	cpid = clone(child_func_process, child_func_process_stack + STACK_SIZE,
	SIGCHLD, &proc[i]);
	proc[i].cpid = cpid;
	close(proc[i].pfd[1]);
	}

	for (i = 0; i < num_processes; ++i) {
	ret = read(proc[i].pfd[0], &proc[i].thr_tids, sizeof(int) * proc[i].num_threads);
	if (ret == -1)
	printf("read failed on proc[%d].pfd[0] error (%s)\n",
	i, strerror(errno));
	close(proc[i].pfd[0]);
	}
	}

	void disp_processes(int num_processes, struct child_args proc[])
	{
	int i, j;

	printf("tid=%d, / tgid=%d / pgid=%d: %lx\n", gettid(), getpid(), getpgid(0),
	get_cs_cookie(getpid()));

	for (i = 0; i < num_processes; ++i) {
	printf(" tid=%d, / tgid=%d / pgid=%d: %lx\n", proc[i].cpid, proc[i].cpid,
	getpgid(proc[i].cpid), get_cs_cookie(proc[i].cpid));
	for (j = 0; j < proc[i].num_threads; ++j) {
	printf(" tid=%d, / tgid=%d / pgid=%d: %lx\n", proc[i].thr_tids[j],
	proc[i].cpid, getpgid(0), get_cs_cookie(proc[i].thr_tids[j]));
	}
	}
	puts("\n");
	}

	static int errors;

	#define validate(v) _validate(__LINE__, v, #v)
	void _validate(int line, int val, char *msg)
	{
	if (!val) {
	++errors;
	printf("(%d) FAILED: %s\n", line, msg);
	} else {
	printf("(%d) PASSED: %s\n", line, msg);
	}
	}

	int main(int argc, char *argv[])
	{
	int keypress = 0;
	int num_threads = 3;
	int delay = 0;
	int res = 0;
	int pidx;
	int pid;
	int opt;

	while ((opt = getopt(argc, argv, ":hkT:P:d:")) != -1) {
	switch (opt) {
	case 'P':
	num_processes = (int)strtol(optarg, NULL, 10);
	break;
	case 'T':
	num_threads = (int)strtoul(optarg, NULL, 10);
	break;
	case 'd':
	delay = (int)strtol(optarg, NULL, 10);
	break;
	case 'k':
	keypress = 1;
	break;
	case 'h':
	printf(USAGE);
	exit(EXIT_SUCCESS);
	default:
	handle_usage(20, "unknown option");
	}
	}

	if (num_processes < 1 \|\| num_processes > MAX_PROCESSES)
	handle_usage(1, "Bad processes value");

	if (num_threads < 1 \|\| num_threads > MAX_THREADS)
	handle_usage(2, "Bad thread value");

	if (keypress)
	delay = -1;

	srand(time(NULL));

	/* put into separate process group */
	if (setpgid(0, 0) != 0)
	handle_error("process group");

	printf("\n## Create a thread/process/process group hierarchy\n");
	create_processes(num_processes, num_threads, procs);
	need_cleanup = 1;
	disp_processes(num_processes, procs);
	validate(get_cs_cookie(0) == 0);

	printf("\n## Set a cookie on entire process group\n");
	if (_prctl(PR_SCHED_CORE, PR_SCHED_CORE_CREATE, 0, PIDTYPE_PGID, 0) < 0)
	handle_error("core_sched create failed -- PGID");
	disp_processes(num_processes, procs);

	validate(get_cs_cookie(0) != 0);

	/* get a random process pid */
	pidx = rand() % num_processes;
	pid = procs[pidx].cpid;

	validate(get_cs_cookie(0) == get_cs_cookie(pid));
	validate(get_cs_cookie(0) == get_cs_cookie(procs[pidx].thr_tids[0]));

	printf("\n## Set a new cookie on entire process/TGID [%d]\n", pid);
	if (_prctl(PR_SCHED_CORE, PR_SCHED_CORE_CREATE, pid, PIDTYPE_TGID, 0) < 0)
	handle_error("core_sched create failed -- TGID");
	disp_processes(num_processes, procs);

	validate(get_cs_cookie(0) != get_cs_cookie(pid));
	validate(get_cs_cookie(pid) != 0);
	validate(get_cs_cookie(pid) == get_cs_cookie(procs[pidx].thr_tids[0]));

	printf("\n## Copy the cookie of current/PGID[%d], to pid [%d] as PIDTYPE_PID\n",
	getpid(), pid);
	if (_prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_TO, pid, PIDTYPE_PID, 0) < 0)
	handle_error("core_sched share to itself failed -- PID");
	disp_processes(num_processes, procs);

	validate(get_cs_cookie(0) == get_cs_cookie(pid));
	validate(get_cs_cookie(pid) != 0);
	validate(get_cs_cookie(pid) != get_cs_cookie(procs[pidx].thr_tids[0]));

	printf("\n## Copy cookie from a thread [%d] to current/PGID [%d] as PIDTYPE_PID\n",
	procs[pidx].thr_tids[0], getpid());
	if (_prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_FROM, procs[pidx].thr_tids[0],
	PIDTYPE_PID, 0) < 0)
	handle_error("core_sched share from thread failed -- PID");
	disp_processes(num_processes, procs);

	validate(get_cs_cookie(0) == get_cs_cookie(procs[pidx].thr_tids[0]));
	validate(get_cs_cookie(pid) != get_cs_cookie(procs[pidx].thr_tids[0]));

	printf("\n## Copy cookie from current [%d] to current as pidtype PGID\n", getpid());
	if (_prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_TO, 0, PIDTYPE_PGID, 0) < 0)
	handle_error("core_sched share to self failed -- PGID");
	disp_processes(num_processes, procs);

	validate(get_cs_cookie(0) == get_cs_cookie(pid));
	validate(get_cs_cookie(pid) != 0);
	validate(get_cs_cookie(pid) == get_cs_cookie(procs[pidx].thr_tids[0]));

	validate(_prctl(PR_SCHED_CORE, PR_SCHED_CORE_MAX, 0, PIDTYPE_PGID, 0) < 0
	&& errno == EINVAL);

	validate(_prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_TO, 0, PIDTYPE_PGID, 1) < 0
	&& errno == EINVAL);

	if (errors) {
	printf("TESTS FAILED. errors: %d\n", errors);
	res = 10;
	} else {
	printf("SUCCESS !!!\n");
	}

	if (keypress)
	getchar();
	else
	sleep(delay);

	for (pidx = 0; pidx < num_processes; ++pidx)
	kill(procs[pidx].cpid, 15);

	return res;
	}