arch/um/drivers/pty.c

Source file repositories/reference/linux-study-clean/arch/um/drivers/pty.c

File Facts

System
Linux kernel
Corpus path
arch/um/drivers/pty.c
Extension
.c
Size
3192 bytes
Lines
166
Domain
Architecture Layer
Bucket
arch/um
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

struct pty_chan {
	void (*announce)(char *dev_name, int dev);
	int dev;
	int raw;
	struct termios tt;
	char dev_name[sizeof("/dev/pts/0123456\0")];
};

static void *pty_chan_init(char *str, int device, const struct chan_opts *opts)
{
	struct pty_chan *data;

	data = uml_kmalloc(sizeof(*data), UM_GFP_KERNEL);
	if (data == NULL)
		return NULL;

	*data = ((struct pty_chan) { .announce  	= opts->announce,
				     .dev  		= device,
				     .raw  		= opts->raw });
	return data;
}

static int pts_open(int input, int output, int primary, void *d,
		    char **dev_out)
{
	struct pty_chan *data = d;
	char *dev;
	int fd, err;

	fd = get_pty();
	if (fd < 0) {
		err = -errno;
		printk(UM_KERN_ERR "open_pts : Failed to open pts\n");
		return err;
	}

	if (data->raw) {
		CATCH_EINTR(err = tcgetattr(fd, &data->tt));
		if (err)
			goto out_close;

		err = raw(fd);
		if (err)
			goto out_close;
	}

	dev = ptsname(fd);
	sprintf(data->dev_name, "%s", dev);
	*dev_out = data->dev_name;

	if (data->announce)
		(*data->announce)(dev, data->dev);

	return fd;

out_close:
	close(fd);
	return err;
}

static int getmaster(char *line)
{
	struct stat buf;
	char *pty, *bank, *cp;
	int master, err;

	pty = &line[strlen("/dev/ptyp")];
	for (bank = "pqrs"; *bank; bank++) {
		line[strlen("/dev/pty")] = *bank;
		*pty = '0';
		/* Did we hit the end ? */
		if ((stat(line, &buf) < 0) && (errno == ENOENT))
			break;

		for (cp = "0123456789abcdef"; *cp; cp++) {
			*pty = *cp;
			master = open(line, O_RDWR);
			if (master >= 0) {
				char *tp = &line[strlen("/dev/")];

				/* verify slave side is usable */
				*tp = 't';
				err = access(line, R_OK | W_OK);
				*tp = 'p';
				if (!err)
					return master;
				close(master);
			}
		}
	}

Annotation

Implementation Notes