[linux-block.git] / arch / um / drivers / port_kern.c

/*
 * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{linux.intel,addtoit}.com)
 * Licensed under the GPL
 */

#include <linux/completion.h>
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include <asm/atomic.h>
#include <init.h>
#include <irq_kern.h>
#include <os.h>
#include "port.h"

struct port_list {
	struct list_head list;
	atomic_t wait_count;
	int has_connection;
	struct completion done;
	int port;
	int fd;
	spinlock_t lock;
	struct list_head pending;
	struct list_head connections;
};

struct port_dev {
	struct port_list *port;
	int helper_pid;
	int telnetd_pid;
};

struct connection {
	struct list_head list;
	int fd;
	int helper_pid;
	int socket[2];
	int telnetd_pid;
	struct port_list *port;
};

static irqreturn_t pipe_interrupt(int irq, void *data)
{
	struct connection *conn = data;
	int fd;

	fd = os_rcv_fd(conn->socket[0], &conn->helper_pid);
	if (fd < 0) {
		if (fd == -EAGAIN)
			return IRQ_NONE;

		printk(KERN_ERR "pipe_interrupt : os_rcv_fd returned %d\n",
		       -fd);
		os_close_file(conn->fd);
	}

	list_del(&conn->list);

	conn->fd = fd;
	list_add(&conn->list, &conn->port->connections);

	complete(&conn->port->done);
	return IRQ_HANDLED;
}

#define NO_WAITER_MSG \
    "****\n" \
    "There are currently no UML consoles waiting for port connections.\n" \
    "Either disconnect from one to make it available or activate some more\n" \
    "by enabling more consoles in the UML /etc/inittab.\n" \
    "****\n"

static int port_accept(struct port_list *port)
{
	struct connection *conn;
	int fd, socket[2], pid;

	fd = port_connection(port->fd, socket, &pid);
	if (fd < 0) {
		if (fd != -EAGAIN)
			printk(KERN_ERR "port_accept : port_connection "
			       "returned %d\n", -fd);
		goto out;
	}

	conn = kmalloc(sizeof(*conn), GFP_ATOMIC);
	if (conn == NULL) {
		printk(KERN_ERR "port_accept : failed to allocate "
		       "connection\n");
		goto out_close;
	}
	*conn = ((struct connection)
		{ .list 	= LIST_HEAD_INIT(conn->list),
		  .fd 		= fd,
		  .socket  	= { socket[0], socket[1] },
		  .telnetd_pid 	= pid,
		  .port 	= port });

	if (um_request_irq(TELNETD_IRQ, socket[0], IRQ_READ, pipe_interrupt,
			  IRQF_SHARED, "telnetd", conn)) {
		printk(KERN_ERR "port_accept : failed to get IRQ for "
		       "telnetd\n");
		goto out_free;
	}

	if (atomic_read(&port->wait_count) == 0) {
		os_write_file(fd, NO_WAITER_MSG, sizeof(NO_WAITER_MSG));
		printk(KERN_ERR "No one waiting for port\n");
	}
	list_add(&conn->list, &port->pending);
	return 1;

 out_free:
	kfree(conn);
 out_close:
	os_close_file(fd);
	os_kill_process(pid, 1);
 out:
	return 0;
}

static DEFINE_MUTEX(ports_mutex);
static LIST_HEAD(ports);

static void port_work_proc(struct work_struct *unused)
{
	struct port_list *port;
	struct list_head *ele;
	unsigned long flags;

	local_irq_save(flags);
	list_for_each(ele, &ports) {
		port = list_entry(ele, struct port_list, list);
		if (!port->has_connection)
			continue;

		while (port_accept(port))
			;
		port->has_connection = 0;
	}
	local_irq_restore(flags);
}

DECLARE_WORK(port_work, port_work_proc);

static irqreturn_t port_interrupt(int irq, void *data)
{
	struct port_list *port = data;

	port->has_connection = 1;
	schedule_work(&port_work);
	return IRQ_HANDLED;
}

void *port_data(int port_num)
{
	struct list_head *ele;
	struct port_list *port;
	struct port_dev *dev = NULL;
	int fd;

	mutex_lock(&ports_mutex);
	list_for_each(ele, &ports) {
		port = list_entry(ele, struct port_list, list);
		if (port->port == port_num)
			goto found;
	}
	port = kmalloc(sizeof(struct port_list), GFP_KERNEL);
	if (port == NULL) {
		printk(KERN_ERR "Allocation of port list failed\n");
		goto out;
	}

	fd = port_listen_fd(port_num);
	if (fd < 0) {
		printk(KERN_ERR "binding to port %d failed, errno = %d\n",
		       port_num, -fd);
		goto out_free;
	}

	if (um_request_irq(ACCEPT_IRQ, fd, IRQ_READ, port_interrupt,
			  IRQF_SHARED, "port", port)) {
		printk(KERN_ERR "Failed to get IRQ for port %d\n", port_num);
		goto out_close;
	}

	*port = ((struct port_list)
		{ .list 	 	= LIST_HEAD_INIT(port->list),
		  .wait_count		= ATOMIC_INIT(0),
		  .has_connection 	= 0,
		  .port 	 	= port_num,
		  .fd  			= fd,
		  .pending 		= LIST_HEAD_INIT(port->pending),
		  .connections 		= LIST_HEAD_INIT(port->connections) });
	spin_lock_init(&port->lock);
	init_completion(&port->done);
	list_add(&port->list, &ports);

 found:
	dev = kmalloc(sizeof(struct port_dev), GFP_KERNEL);
	if (dev == NULL) {
		printk(KERN_ERR "Allocation of port device entry failed\n");
		goto out;
	}

	*dev = ((struct port_dev) { .port  		= port,
				    .helper_pid  	= -1,
				    .telnetd_pid  	= -1 });
	goto out;

 out_close:
	os_close_file(fd);
 out_free:
	kfree(port);
 out:
	mutex_unlock(&ports_mutex);
	return dev;
}

int port_wait(void *data)
{
	struct port_dev *dev = data;
	struct connection *conn;
	struct port_list *port = dev->port;
	int fd;

	atomic_inc(&port->wait_count);
	while (1) {
		fd = -ERESTARTSYS;
		if (wait_for_completion_interruptible(&port->done))
			goto out;

		spin_lock(&port->lock);

		conn = list_entry(port->connections.next, struct connection,
				  list);
		list_del(&conn->list);
		spin_unlock(&port->lock);

		os_shutdown_socket(conn->socket[0], 1, 1);
		os_close_file(conn->socket[0]);
		os_shutdown_socket(conn->socket[1], 1, 1);
		os_close_file(conn->socket[1]);

		/* This is done here because freeing an IRQ can't be done
		 * within the IRQ handler.  So, pipe_interrupt always ups
		 * the semaphore regardless of whether it got a successful
		 * connection.  Then we loop here throwing out failed
		 * connections until a good one is found.
		 */
		um_free_irq(TELNETD_IRQ, conn);

		if (conn->fd >= 0)
			break;
		os_close_file(conn->fd);
		kfree(conn);
	}

	fd = conn->fd;
	dev->helper_pid = conn->helper_pid;
	dev->telnetd_pid = conn->telnetd_pid;
	kfree(conn);
 out:
	atomic_dec(&port->wait_count);
	return fd;
}

void port_remove_dev(void *d)
{
	struct port_dev *dev = d;

	if (dev->helper_pid != -1)
		os_kill_process(dev->helper_pid, 0);
	if (dev->telnetd_pid != -1)
		os_kill_process(dev->telnetd_pid, 1);
	dev->helper_pid = -1;
	dev->telnetd_pid = -1;
}

void port_kern_free(void *d)
{
	struct port_dev *dev = d;

	port_remove_dev(dev);
	kfree(dev);
}

static void free_port(void)
{
	struct list_head *ele;
	struct port_list *port;

	list_for_each(ele, &ports) {
		port = list_entry(ele, struct port_list, list);
		free_irq_by_fd(port->fd);
		os_close_file(port->fd);
	}
}

__uml_exitcall(free_port);
Commit	Line	Data
67608e0c	1	/*
e99525f9	2	* Copyright (C) 2001 - 2007 Jeff Dike (jdike@{linux.intel,addtoit}.com)
1da177e4 LT	3	* Licensed under the GPL
	4	*/
	5
37185b33 AV	6	#include <linux/completion.h>
	7	#include <linux/interrupt.h>
	8	#include <linux/list.h>
	9	#include <linux/mutex.h>
	10	#include <linux/slab.h>
	11	#include <linux/workqueue.h>
	12	#include <asm/atomic.h>
	13	#include <init.h>
	14	#include <irq_kern.h>
	15	#include <os.h>
e99525f9	16	#include "port.h"
1da177e4 LT	17
	18	struct port_list {
	19	struct list_head list;
	20	atomic_t wait_count;
	21	int has_connection;
	22	struct completion done;
	23	int port;
	24	int fd;
	25	spinlock_t lock;
	26	struct list_head pending;
	27	struct list_head connections;
	28	};
	29
	30	struct port_dev {
	31	struct port_list *port;
	32	int helper_pid;
	33	int telnetd_pid;
	34	};
	35
	36	struct connection {
	37	struct list_head list;
	38	int fd;
	39	int helper_pid;
	40	int socket[2];
	41	int telnetd_pid;
	42	struct port_list *port;
	43	};
	44
7bea96fd	45	static irqreturn_t pipe_interrupt(int irq, void *data)
1da177e4 LT	46	{
	47	struct connection *conn = data;
	48	int fd;
	49
	50	fd = os_rcv_fd(conn->socket[0], &conn->helper_pid);
e99525f9 JD	51	if (fd < 0) {
e99525f9 JD	52	if (fd == -EAGAIN)
67608e0c	53	return IRQ_NONE;
1da177e4	54
67608e0c	55	printk(KERN_ERR "pipe_interrupt : os_rcv_fd returned %d\n",
1da177e4 LT	56	-fd);
	57	os_close_file(conn->fd);
	58	}
	59
	60	list_del(&conn->list);
	61
	62	conn->fd = fd;
	63	list_add(&conn->list, &conn->port->connections);
	64
	65	complete(&conn->port->done);
67608e0c	66	return IRQ_HANDLED;
1da177e4 LT	67	}
	68
	69	#define NO_WAITER_MSG \
	70	"****\n" \
	71	"There are currently no UML consoles waiting for port connections.\n" \
	72	"Either disconnect from one to make it available or activate some more\n" \
	73	"by enabling more consoles in the UML /etc/inittab.\n" \
	74	"****\n"
	75
	76	static int port_accept(struct port_list *port)
	77	{
	78	struct connection *conn;
e99525f9	79	int fd, socket[2], pid;
1da177e4 LT	80
1da177e4 LT	81	fd = port_connection(port->fd, socket, &pid);
e99525f9 JD	82	if (fd < 0) {
e99525f9 JD	83	if (fd != -EAGAIN)
1da177e4 LT	84	printk(KERN_ERR "port_accept : port_connection "
	85	"returned %d\n", -fd);
	86	goto out;
	87	}
	88
	89	conn = kmalloc(sizeof(*conn), GFP_ATOMIC);
e99525f9	90	if (conn == NULL) {
1da177e4 LT	91	printk(KERN_ERR "port_accept : failed to allocate "
	92	"connection\n");
	93	goto out_close;
	94	}
67608e0c	95	*conn = ((struct connection)
1da177e4 LT	96	{ .list = LIST_HEAD_INIT(conn->list),
	97	.fd = fd,
	98	.socket = { socket[0], socket[1] },
	99	.telnetd_pid = pid,
	100	.port = port });
	101
e99525f9	102	if (um_request_irq(TELNETD_IRQ, socket[0], IRQ_READ, pipe_interrupt,
aab94460	103	IRQF_SHARED, "telnetd", conn)) {
1da177e4 LT	104	printk(KERN_ERR "port_accept : failed to get IRQ for "
	105	"telnetd\n");
	106	goto out_free;
	107	}
	108
e99525f9	109	if (atomic_read(&port->wait_count) == 0) {
a6ea4cce	110	os_write_file(fd, NO_WAITER_MSG, sizeof(NO_WAITER_MSG));
e99525f9	111	printk(KERN_ERR "No one waiting for port\n");
1da177e4 LT	112	}
1da177e4 LT	113	list_add(&conn->list, &port->pending);
67608e0c	114	return 1;
1da177e4 LT	115
	116	out_free:
	117	kfree(conn);
	118	out_close:
	119	os_close_file(fd);
e99525f9	120	os_kill_process(pid, 1);
1da177e4	121	out:
e99525f9	122	return 0;
67608e0c	123	}
1da177e4	124
2aa9c5db	125	static DEFINE_MUTEX(ports_mutex);
c59bce62	126	static LIST_HEAD(ports);
1da177e4	127
e99525f9	128	static void port_work_proc(struct work_struct *unused)
1da177e4 LT	129	{
	130	struct port_list *port;
	131	struct list_head *ele;
	132	unsigned long flags;
	133
	134	local_irq_save(flags);
e99525f9	135	list_for_each(ele, &ports) {
1da177e4	136	port = list_entry(ele, struct port_list, list);
e99525f9	137	if (!port->has_connection)
1da177e4	138	continue;
e99525f9	139
e99525f9 JD	140	while (port_accept(port))
e99525f9 JD	141	;
1da177e4 LT	142	port->has_connection = 0;
	143	}
	144	local_irq_restore(flags);
	145	}
	146
6d5aefb8	147	DECLARE_WORK(port_work, port_work_proc);
1da177e4	148
7bea96fd	149	static irqreturn_t port_interrupt(int irq, void *data)
1da177e4 LT	150	{
	151	struct port_list *port = data;
	152
	153	port->has_connection = 1;
	154	schedule_work(&port_work);
67608e0c JD	155	return IRQ_HANDLED;
67608e0c JD	156	}
1da177e4 LT	157
	158	void *port_data(int port_num)
	159	{
	160	struct list_head *ele;
	161	struct port_list *port;
	162	struct port_dev *dev = NULL;
	163	int fd;
	164
2aa9c5db	165	mutex_lock(&ports_mutex);
e99525f9	166	list_for_each(ele, &ports) {
1da177e4	167	port = list_entry(ele, struct port_list, list);
e99525f9 JD	168	if (port->port == port_num)
e99525f9 JD	169	goto found;
1da177e4 LT	170	}
1da177e4 LT	171	port = kmalloc(sizeof(struct port_list), GFP_KERNEL);
e99525f9	172	if (port == NULL) {
1da177e4 LT	173	printk(KERN_ERR "Allocation of port list failed\n");
	174	goto out;
	175	}
	176
	177	fd = port_listen_fd(port_num);
e99525f9	178	if (fd < 0) {
1da177e4 LT	179	printk(KERN_ERR "binding to port %d failed, errno = %d\n",
	180	port_num, -fd);
	181	goto out_free;
	182	}
e99525f9 JD	183
e99525f9 JD	184	if (um_request_irq(ACCEPT_IRQ, fd, IRQ_READ, port_interrupt,
aab94460	185	IRQF_SHARED, "port", port)) {
1da177e4 LT	186	printk(KERN_ERR "Failed to get IRQ for port %d\n", port_num);
	187	goto out_close;
	188	}
	189
67608e0c	190	*port = ((struct port_list)
1da177e4 LT	191	{ .list = LIST_HEAD_INIT(port->list),
	192	.wait_count = ATOMIC_INIT(0),
	193	.has_connection = 0,
	194	.port = port_num,
	195	.fd = fd,
	196	.pending = LIST_HEAD_INIT(port->pending),
	197	.connections = LIST_HEAD_INIT(port->connections) });
	198	spin_lock_init(&port->lock);
	199	init_completion(&port->done);
	200	list_add(&port->list, &ports);
	201
	202	found:
	203	dev = kmalloc(sizeof(struct port_dev), GFP_KERNEL);
e99525f9	204	if (dev == NULL) {
1da177e4 LT	205	printk(KERN_ERR "Allocation of port device entry failed\n");
	206	goto out;
	207	}
	208
	209	*dev = ((struct port_dev) { .port = port,
	210	.helper_pid = -1,
	211	.telnetd_pid = -1 });
	212	goto out;
	213
1da177e4 LT	214	out_close:
1da177e4 LT	215	os_close_file(fd);
79f66233 JD	216	out_free:
79f66233 JD	217	kfree(port);
1da177e4	218	out:
2aa9c5db	219	mutex_unlock(&ports_mutex);
67608e0c	220	return dev;
1da177e4 LT	221	}
	222
	223	int port_wait(void *data)
	224	{
	225	struct port_dev *dev = data;
	226	struct connection *conn;
	227	struct port_list *port = dev->port;
	228	int fd;
	229
67608e0c	230	atomic_inc(&port->wait_count);
e99525f9	231	while (1) {
1da177e4	232	fd = -ERESTARTSYS;
e99525f9	233	if (wait_for_completion_interruptible(&port->done))
67608e0c	234	goto out;
1da177e4 LT	235
	236	spin_lock(&port->lock);
	237
67608e0c	238	conn = list_entry(port->connections.next, struct connection,
1da177e4 LT	239	list);
	240	list_del(&conn->list);
	241	spin_unlock(&port->lock);
	242
	243	os_shutdown_socket(conn->socket[0], 1, 1);
	244	os_close_file(conn->socket[0]);
	245	os_shutdown_socket(conn->socket[1], 1, 1);
67608e0c	246	os_close_file(conn->socket[1]);
1da177e4 LT	247
	248	/* This is done here because freeing an IRQ can't be done
	249	* within the IRQ handler. So, pipe_interrupt always ups
	250	* the semaphore regardless of whether it got a successful
67608e0c	251	* connection. Then we loop here throwing out failed
1da177e4 LT	252	* connections until a good one is found.
1da177e4 LT	253	*/
fa7a0449	254	um_free_irq(TELNETD_IRQ, conn);
1da177e4	255
e99525f9 JD	256	if (conn->fd >= 0)
e99525f9 JD	257	break;
1da177e4 LT	258	os_close_file(conn->fd);
	259	kfree(conn);
	260	}
	261
	262	fd = conn->fd;
	263	dev->helper_pid = conn->helper_pid;
	264	dev->telnetd_pid = conn->telnetd_pid;
	265	kfree(conn);
	266	out:
	267	atomic_dec(&port->wait_count);
	268	return fd;
	269	}
	270
	271	void port_remove_dev(void *d)
	272	{
	273	struct port_dev *dev = d;
	274
e99525f9	275	if (dev->helper_pid != -1)
1da177e4	276	os_kill_process(dev->helper_pid, 0);
e99525f9	277	if (dev->telnetd_pid != -1)
1da177e4 LT	278	os_kill_process(dev->telnetd_pid, 1);
	279	dev->helper_pid = -1;
	280	dev->telnetd_pid = -1;
	281	}
	282
	283	void port_kern_free(void *d)
	284	{
	285	struct port_dev *dev = d;
	286
	287	port_remove_dev(dev);
	288	kfree(dev);
	289	}
	290
	291	static void free_port(void)
	292	{
	293	struct list_head *ele;
	294	struct port_list *port;
	295
e99525f9	296	list_for_each(ele, &ports) {
1da177e4 LT	297	port = list_entry(ele, struct port_list, list);
	298	free_irq_by_fd(port->fd);
	299	os_close_file(port->fd);
	300	}
	301	}
	302
	303	__uml_exitcall(free_port);