arch/um/drivers/port_kern.c

   1 /*
   2  * Copyright (C) 2001, 2002 Jeff Dike (jdike@karaya.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include "linux/list.h"
   7 #include "linux/sched.h"
   8 #include "linux/slab.h"
   9 #include "linux/irq.h"
  10 #include "linux/spinlock.h"
  11 #include "linux/errno.h"
  12 #include "asm/semaphore.h"
  13 #include "asm/errno.h"
  14 #include "kern_util.h"
  15 #include "kern.h"
  16 #include "irq_user.h"
  17 #include "port.h"
  18 #include "init.h"
  19 #include "os.h"
  20
  21 struct port_list {
  22         struct list_head list;
  23         int has_connection;
  24         struct semaphore sem;
  25         int port;
  26         int fd;
  27         spinlock_t lock;
  28         struct list_head pending;
  29         struct list_head connections;
  30 };
  31
  32 struct port_dev {
  33         struct port_list *port;
  34         int helper_pid;
  35         int telnetd_pid;
  36 };
  37
  38 struct connection {
  39         struct list_head list;
  40         int fd;
  41         int helper_pid;
  42         int socket[2];
  43         int telnetd_pid;
  44         struct port_list *port;
  45 };
  46
  47 static void pipe_interrupt(int irq, void *data, struct pt_regs *regs)
  48 {
  49         struct connection *conn = data;
  50         int fd;
  51
  52         fd = os_rcv_fd(conn->socket[0], &conn->helper_pid);
  53         if(fd < 0){
  54                 if(fd == -EAGAIN)
  55                         return;
  56
  57                 printk(KERN_ERR "pipe_interrupt : os_rcv_fd returned %d\n",
  58                        -fd);
  59                 os_close_file(conn->fd);
  60         }
  61
  62         list_del(&conn->list);
  63
  64         conn->fd = fd;
  65         list_add(&conn->list, &conn->port->connections);
  66
  67         up(&conn->port->sem);
  68 }
  69
  70 static int port_accept(struct port_list *port)
  71 {
  72         struct connection *conn;
  73         int fd, socket[2], pid, ret = 0;
  74
  75         fd = port_connection(port->fd, socket, &pid);
  76         if(fd < 0){
  77                 if(fd != -EAGAIN)
  78                         printk(KERN_ERR "port_accept : port_connection "
  79                                "returned %d\n", -fd);
  80                 goto out;
  81         }
  82
  83         conn = kmalloc(sizeof(*conn), GFP_ATOMIC);
  84         if(conn == NULL){
  85                 printk(KERN_ERR "port_accept : failed to allocate "
  86                        "connection\n");
  87                 goto out_close;
  88         }
  89         *conn = ((struct connection)
  90                 { .list         = LIST_HEAD_INIT(conn->list),
  91                   .fd           = fd,
  92                   .socket       = { socket[0], socket[1] },
  93                   .telnetd_pid  = pid,
  94                   .port         = port });
  95
  96         if(um_request_irq(TELNETD_IRQ, socket[0], IRQ_READ, pipe_interrupt,
  97                           SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM,
  98                           "telnetd", conn)){
  99                 printk(KERN_ERR "port_accept : failed to get IRQ for "
 100                        "telnetd\n");
 101                 goto out_free;
 102         }
 103
 104         list_add(&conn->list, &port->pending);
 105         ret = 1;
 106         goto out;
 107
 108  out_free:
 109         kfree(conn);
 110  out_close:
 111         os_close_file(fd);
 112         if(pid != -1)
 113                 os_kill_process(pid, 1);
 114  out:
 115         return(ret);
 116 }
 117
 118 DECLARE_MUTEX(ports_sem);
 119 struct list_head ports = LIST_HEAD_INIT(ports);
 120
 121 void port_work_proc(void *unused)
 122 {
 123         struct port_list *port;
 124         struct list_head *ele;
 125         unsigned long flags;
 126
 127         local_irq_save(flags);
 128         list_for_each(ele, &ports){
 129                 port = list_entry(ele, struct port_list, list);
 130                 if(!port->has_connection)
 131                         continue;
 132                 reactivate_fd(port->fd, ACCEPT_IRQ);
 133                 while(port_accept(port)) ;
 134                 port->has_connection = 0;
 135         }
 136         local_irq_restore(flags);
 137 }
 138
 139 DECLARE_WORK(port_work, port_work_proc, NULL);
 140
 141 static void port_interrupt(int irq, void *data, struct pt_regs *regs)
 142 {
 143         struct port_list *port = data;
 144
 145         port->has_connection = 1;
 146         schedule_work(&port_work);
 147 }
 148
 149 void *port_data(int port_num)
 150 {
 151         struct list_head *ele;
 152         struct port_list *port;
 153         struct port_dev *dev = NULL;
 154         int fd;
 155
 156         down(&ports_sem);
 157         list_for_each(ele, &ports){
 158                 port = list_entry(ele, struct port_list, list);
 159                 if(port->port == port_num) goto found;
 160         }
 161         port = kmalloc(sizeof(struct port_list), GFP_KERNEL);
 162         if(port == NULL){
 163                 printk(KERN_ERR "Allocation of port list failed\n");
 164                 goto out;
 165         }
 166
 167         fd = port_listen_fd(port_num);
 168         if(fd < 0){
 169                 printk(KERN_ERR "binding to port %d failed, errno = %d\n",
 170                        port_num, -fd);
 171                 goto out_free;
 172         }
 173         if(um_request_irq(ACCEPT_IRQ, fd, IRQ_READ, port_interrupt,
 174                           SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM, "port",
 175                           port)){
 176                 printk(KERN_ERR "Failed to get IRQ for port %d\n", port_num);
 177                 goto out_close;
 178         }
 179
 180         *port = ((struct port_list)
 181                 { .list                 = LIST_HEAD_INIT(port->list),
 182                   .has_connection       = 0,
 183                   .sem                  = __SEMAPHORE_INITIALIZER(port->sem,
 184                                                                   0),
 185                   .lock                 = SPIN_LOCK_UNLOCKED,
 186                   .port                 = port_num,
 187                   .fd                   = fd,
 188                   .pending              = LIST_HEAD_INIT(port->pending),
 189                   .connections          = LIST_HEAD_INIT(port->connections) });
 190         list_add(&port->list, &ports);
 191
 192  found:
 193         dev = kmalloc(sizeof(struct port_dev), GFP_KERNEL);
 194         if(dev == NULL){
 195                 printk(KERN_ERR "Allocation of port device entry failed\n");
 196                 goto out;
 197         }
 198
 199         *dev = ((struct port_dev) { .port               = port,
 200                                     .helper_pid         = -1,
 201                                     .telnetd_pid        = -1 });
 202         goto out;
 203
 204  out_free:
 205         kfree(port);
 206  out_close:
 207         os_close_file(fd);
 208  out:
 209         up(&ports_sem);
 210         return(dev);
 211 }
 212
 213 int port_wait(void *data)
 214 {
 215         struct port_dev *dev = data;
 216         struct connection *conn;
 217         struct port_list *port = dev->port;
 218         int fd;
 219
 220         while(1){
 221                 if(down_interruptible(&port->sem))
 222                         return(-ERESTARTSYS);
 223
 224                 spin_lock(&port->lock);
 225
 226                 conn = list_entry(port->connections.next, struct connection,
 227                                   list);
 228                 list_del(&conn->list);
 229                 spin_unlock(&port->lock);
 230
 231                 os_shutdown_socket(conn->socket[0], 1, 1);
 232                 os_close_file(conn->socket[0]);
 233                 os_shutdown_socket(conn->socket[1], 1, 1);
 234                 os_close_file(conn->socket[1]);
 235
 236                 /* This is done here because freeing an IRQ can't be done
 237                  * within the IRQ handler.  So, pipe_interrupt always ups
 238                  * the semaphore regardless of whether it got a successful
 239                  * connection.  Then we loop here throwing out failed
 240                  * connections until a good one is found.
 241                  */
 242                 free_irq(TELNETD_IRQ, conn);
 243
 244                 if(conn->fd >= 0) break;
 245                 os_close_file(conn->fd);
 246                 kfree(conn);
 247         }
 248
 249         fd = conn->fd;
 250         dev->helper_pid = conn->helper_pid;
 251         dev->telnetd_pid = conn->telnetd_pid;
 252         kfree(conn);
 253
 254         return(fd);
 255 }
 256
 257 void port_remove_dev(void *d)
 258 {
 259         struct port_dev *dev = d;
 260
 261         if(dev->helper_pid != -1)
 262                 os_kill_process(dev->helper_pid, 0);
 263         if(dev->telnetd_pid != -1)
 264                 os_kill_process(dev->telnetd_pid, 1);
 265         dev->helper_pid = -1;
 266         dev->telnetd_pid = -1;
 267 }
 268
 269 void port_kern_free(void *d)
 270 {
 271         struct port_dev *dev = d;
 272
 273         port_remove_dev(dev);
 274         kfree(dev);
 275 }
 276
 277 static void free_port(void)
 278 {
 279         struct list_head *ele;
 280         struct port_list *port;
 281
 282         list_for_each(ele, &ports){
 283                 port = list_entry(ele, struct port_list, list);
 284                 free_irq_by_fd(port->fd);
 285                 os_close_file(port->fd);
 286         }
 287 }
 288
 289 __uml_exitcall(free_port);
 290
 291 /*
 292  * Overrides for Emacs so that we follow Linus's tabbing style.
 293  * Emacs will notice this stuff at the end of the file and automatically
 294  * adjust the settings for this buffer only.  This must remain at the end
 295  * of the file.
 296  * ---------------------------------------------------------------------------
 297  * Local variables:
 298  * c-file-style: "linux"
 299  * End:
 300  */