int mkfifo(FAR const char *pathname, mode_t mode)
{
struct pipe_dev_s *dev;
int ret;
/* Allocate and initialize a new device structure instance */
dev = pipecommon_allocdev();
if (!dev)
{
return -ENOMEM;
}
ret = register_driver(pathname, &fifo_fops, mode, (void*)dev);
if (ret != 0)
{
pipecommon_freedev(dev);
}
return ret;
}
int pipe(int fd[2])
{
FAR struct pipe_dev_s *dev = NULL;
char devname[16];
int pipeno;
int err;
int ret;
/* Get exclusive access to the pipe allocation data */
ret = sem_wait(&g_pipesem);
if (ret < 0)
{
/* sem_wait() will have already set errno */
return ERROR;
}
/* Allocate a minor number for the pipe device */
pipeno = pipe_allocate();
if (pipeno < 0)
{
(void)sem_post(&g_pipesem);
err = -pipeno;
goto errout;
}
/* Create a pathname to the pipe device */
sprintf(devname, "/dev/pipe%d", pipeno);
/* Check if the pipe device has already been created */
if ((g_pipecreated & (1 << pipeno)) == 0)
{
/* No.. Allocate and initialize a new device structure instance */
dev = pipecommon_allocdev();
if (!dev)
{
(void)sem_post(&g_pipesem);
err = ENOMEM;
goto errout_with_pipe;
}
dev->d_pipeno = pipeno;
/* Register the pipe device */
ret = register_driver(devname, &pipe_fops, 0666, (FAR void *)dev);
if (ret != 0)
{
(void)sem_post(&g_pipesem);
err = -ret;
goto errout_with_dev;
}
/* Remember that we created this device */
g_pipecreated |= (1 << pipeno);
}
(void)sem_post(&g_pipesem);
/* Get a write file descriptor */
fd[1] = open(devname, O_WRONLY);
if (fd[1] < 0)
{
err = -fd[1];
goto errout_with_driver;
}
/* Get a read file descriptor */
fd[0] = open(devname, O_RDONLY);
if (fd[0] < 0)
{
err = -fd[0];
goto errout_with_wrfd;
}
return OK;
errout_with_wrfd:
close(fd[1]);
errout_with_driver:
unregister_driver(devname);
errout_with_dev:
if (dev)
{
pipecommon_freedev(dev);
}
errout_with_pipe:
pipe_free(pipeno);
errout:
set_errno(err);
return ERROR;
}