linux/arch/um/drivers/port_kern.c

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/*
* Copyright (C) 2001, 2002 Jeff Dike (jdike@karaya.com)
* Licensed under the GPL
*/
#include "linux/list.h"
#include "linux/sched.h"
#include "linux/slab.h"
#include "linux/interrupt.h"
#include "linux/irq.h"
#include "linux/spinlock.h"
#include "linux/errno.h"
#include "asm/atomic.h"
#include "asm/semaphore.h"
#include "asm/errno.h"
#include "kern_util.h"
#include "kern.h"
#include "irq_user.h"
#include "irq_kern.h"
#include "port.h"
#include "init.h"
#include "os.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 pt_regs *regs)
{
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, ret = 0;
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,
SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM,
"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("No one waiting for port\n");
}
list_add(&conn->list, &port->pending);
return(1);
out_free:
kfree(conn);
out_close:
os_close_file(fd);
if(pid != -1)
os_kill_process(pid, 1);
out:
return(ret);
}
DECLARE_MUTEX(ports_sem);
struct list_head ports = LIST_HEAD_INIT(ports);
void port_work_proc(void *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;
reactivate_fd(port->fd, ACCEPT_IRQ);
while(port_accept(port)) ;
port->has_connection = 0;
}
local_irq_restore(flags);
}
DECLARE_WORK(port_work, port_work_proc, NULL);
static irqreturn_t port_interrupt(int irq, void *data, struct pt_regs *regs)
{
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;
down(&ports_sem);
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,
SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM, "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_free:
kfree(port);
out_close:
os_close_file(fd);
out:
up(&ports_sem);
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.
*/
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);