unpv13e/server/lock_pthread.c

/* include my_lock_init */
#include	"unpthread.h"
#include	<sys/mman.h>

static pthread_mutex_t	*mptr;	/* actual mutex will be in shared memory */

void
my_lock_init(char *pathname)
{
	int		fd;
	pthread_mutexattr_t	mattr;

	fd = Open("/dev/zero", O_RDWR, 0);

	mptr = Mmap(0, sizeof(pthread_mutex_t), PROT_READ | PROT_WRITE,
				MAP_SHARED, fd, 0);
	Close(fd);

	Pthread_mutexattr_init(&mattr);
	Pthread_mutexattr_setpshared(&mattr, PTHREAD_PROCESS_SHARED);
	Pthread_mutex_init(mptr, &mattr);
}
/* end my_lock_init */

/* include my_lock_wait */
void
my_lock_wait()
{
	Pthread_mutex_lock(mptr);
}

void
my_lock_release()
{
	Pthread_mutex_unlock(mptr);
}
/* end my_lock_wait */