1 /*
2 * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{linux.intel,addtoit}.com)
3 * Licensed under the GPL
4 */
5
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>
16 #include "port.h"
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
pipe_interrupt(int irq,void * data)45 static irqreturn_t pipe_interrupt(int irq, void *data)
46 {
47 struct connection *conn = data;
48 int fd;
49
50 fd = os_rcv_fd(conn->socket[0], &conn->helper_pid);
51 if (fd < 0) {
52 if (fd == -EAGAIN)
53 return IRQ_NONE;
54
55 printk(KERN_ERR "pipe_interrupt : os_rcv_fd returned %d\n",
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);
66 return IRQ_HANDLED;
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
port_accept(struct port_list * port)76 static int port_accept(struct port_list *port)
77 {
78 struct connection *conn;
79 int fd, socket[2], pid;
80
81 fd = port_connection(port->fd, socket, &pid);
82 if (fd < 0) {
83 if (fd != -EAGAIN)
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);
90 if (conn == NULL) {
91 printk(KERN_ERR "port_accept : failed to allocate "
92 "connection\n");
93 goto out_close;
94 }
95 *conn = ((struct connection)
96 { .list = LIST_HEAD_INIT(conn->list),
97 .fd = fd,
98 .socket = { socket[0], socket[1] },
99 .telnetd_pid = pid,
100 .port = port });
101
102 if (um_request_irq(TELNETD_IRQ, socket[0], IRQ_READ, pipe_interrupt,
103 IRQF_SHARED, "telnetd", conn)) {
104 printk(KERN_ERR "port_accept : failed to get IRQ for "
105 "telnetd\n");
106 goto out_free;
107 }
108
109 if (atomic_read(&port->wait_count) == 0) {
110 os_write_file(fd, NO_WAITER_MSG, sizeof(NO_WAITER_MSG));
111 printk(KERN_ERR "No one waiting for port\n");
112 }
113 list_add(&conn->list, &port->pending);
114 return 1;
115
116 out_free:
117 kfree(conn);
118 out_close:
119 os_close_file(fd);
120 os_kill_process(pid, 1);
121 out:
122 return 0;
123 }
124
125 static DEFINE_MUTEX(ports_mutex);
126 static LIST_HEAD(ports);
127
port_work_proc(struct work_struct * unused)128 static void port_work_proc(struct work_struct *unused)
129 {
130 struct port_list *port;
131 struct list_head *ele;
132 unsigned long flags;
133
134 local_irq_save(flags);
135 list_for_each(ele, &ports) {
136 port = list_entry(ele, struct port_list, list);
137 if (!port->has_connection)
138 continue;
139
140 reactivate_fd(port->fd, ACCEPT_IRQ);
141 while (port_accept(port))
142 ;
143 port->has_connection = 0;
144 }
145 local_irq_restore(flags);
146 }
147
148 DECLARE_WORK(port_work, port_work_proc);
149
port_interrupt(int irq,void * data)150 static irqreturn_t port_interrupt(int irq, void *data)
151 {
152 struct port_list *port = data;
153
154 port->has_connection = 1;
155 schedule_work(&port_work);
156 return IRQ_HANDLED;
157 }
158
port_data(int port_num)159 void *port_data(int port_num)
160 {
161 struct list_head *ele;
162 struct port_list *port;
163 struct port_dev *dev = NULL;
164 int fd;
165
166 mutex_lock(&ports_mutex);
167 list_for_each(ele, &ports) {
168 port = list_entry(ele, struct port_list, list);
169 if (port->port == port_num)
170 goto found;
171 }
172 port = kmalloc(sizeof(struct port_list), GFP_KERNEL);
173 if (port == NULL) {
174 printk(KERN_ERR "Allocation of port list failed\n");
175 goto out;
176 }
177
178 fd = port_listen_fd(port_num);
179 if (fd < 0) {
180 printk(KERN_ERR "binding to port %d failed, errno = %d\n",
181 port_num, -fd);
182 goto out_free;
183 }
184
185 if (um_request_irq(ACCEPT_IRQ, fd, IRQ_READ, port_interrupt,
186 IRQF_SHARED, "port", port)) {
187 printk(KERN_ERR "Failed to get IRQ for port %d\n", port_num);
188 goto out_close;
189 }
190
191 *port = ((struct port_list)
192 { .list = LIST_HEAD_INIT(port->list),
193 .wait_count = ATOMIC_INIT(0),
194 .has_connection = 0,
195 .port = port_num,
196 .fd = fd,
197 .pending = LIST_HEAD_INIT(port->pending),
198 .connections = LIST_HEAD_INIT(port->connections) });
199 spin_lock_init(&port->lock);
200 init_completion(&port->done);
201 list_add(&port->list, &ports);
202
203 found:
204 dev = kmalloc(sizeof(struct port_dev), GFP_KERNEL);
205 if (dev == NULL) {
206 printk(KERN_ERR "Allocation of port device entry failed\n");
207 goto out;
208 }
209
210 *dev = ((struct port_dev) { .port = port,
211 .helper_pid = -1,
212 .telnetd_pid = -1 });
213 goto out;
214
215 out_close:
216 os_close_file(fd);
217 out_free:
218 kfree(port);
219 out:
220 mutex_unlock(&ports_mutex);
221 return dev;
222 }
223
port_wait(void * data)224 int port_wait(void *data)
225 {
226 struct port_dev *dev = data;
227 struct connection *conn;
228 struct port_list *port = dev->port;
229 int fd;
230
231 atomic_inc(&port->wait_count);
232 while (1) {
233 fd = -ERESTARTSYS;
234 if (wait_for_completion_interruptible(&port->done))
235 goto out;
236
237 spin_lock(&port->lock);
238
239 conn = list_entry(port->connections.next, struct connection,
240 list);
241 list_del(&conn->list);
242 spin_unlock(&port->lock);
243
244 os_shutdown_socket(conn->socket[0], 1, 1);
245 os_close_file(conn->socket[0]);
246 os_shutdown_socket(conn->socket[1], 1, 1);
247 os_close_file(conn->socket[1]);
248
249 /* This is done here because freeing an IRQ can't be done
250 * within the IRQ handler. So, pipe_interrupt always ups
251 * the semaphore regardless of whether it got a successful
252 * connection. Then we loop here throwing out failed
253 * connections until a good one is found.
254 */
255 um_free_irq(TELNETD_IRQ, conn);
256
257 if (conn->fd >= 0)
258 break;
259 os_close_file(conn->fd);
260 kfree(conn);
261 }
262
263 fd = conn->fd;
264 dev->helper_pid = conn->helper_pid;
265 dev->telnetd_pid = conn->telnetd_pid;
266 kfree(conn);
267 out:
268 atomic_dec(&port->wait_count);
269 return fd;
270 }
271
port_remove_dev(void * d)272 void port_remove_dev(void *d)
273 {
274 struct port_dev *dev = d;
275
276 if (dev->helper_pid != -1)
277 os_kill_process(dev->helper_pid, 0);
278 if (dev->telnetd_pid != -1)
279 os_kill_process(dev->telnetd_pid, 1);
280 dev->helper_pid = -1;
281 dev->telnetd_pid = -1;
282 }
283
port_kern_free(void * d)284 void port_kern_free(void *d)
285 {
286 struct port_dev *dev = d;
287
288 port_remove_dev(dev);
289 kfree(dev);
290 }
291
free_port(void)292 static void free_port(void)
293 {
294 struct list_head *ele;
295 struct port_list *port;
296
297 list_for_each(ele, &ports) {
298 port = list_entry(ele, struct port_list, list);
299 free_irq_by_fd(port->fd);
300 os_close_file(port->fd);
301 }
302 }
303
304 __uml_exitcall(free_port);
305