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/interrupt.h"
  10 #include "linux/irq.h"
  11 #include "linux/spinlock.h"
  12 #include "linux/errno.h"
  13 #include "asm/semaphore.h"
  14 #include "asm/errno.h"
  15 #include "kern_util.h"
  16 #include "kern.h"
  17 #include "irq_user.h"
  18 #include "irq_kern.h"
  19 #include "port.h"
  20 #include "init.h"
  21 #include "os.h"
  22
  23 struct port_list {
  24         struct list_head list;
  25         int has_connection;
  26         struct semaphore sem;
  27         int port;
  28         int fd;
  29         spinlock_t lock;
  30         struct list_head pending;
  31         struct list_head connections;
  32 };
  33
  34 struct port_dev {
  35         struct port_list *port;
  36         int helper_pid;
  37         int telnetd_pid;
  38 };
  39
  40 struct connection {
  41         struct list_head list;
  42         int fd;
  43         int helper_pid;
  44         int socket[2];
  45         int telnetd_pid;
  46         struct port_list *port;
  47 };
  48
  49 static irqreturn_t pipe_interrupt(int irq, void *data, struct pt_regs *regs)
  50 {
  51         struct connection *conn = data;
  52         int fd;
  53
  54         fd = os_rcv_fd(conn->socket[0], &conn->helper_pid);
  55         if(fd < 0){
  56                 if(fd == -EAGAIN)
  57                         return(IRQ_NONE);
  58
  59                 printk(KERN_ERR "pipe_interrupt : os_rcv_fd returned %d\n",
  60                        -fd);
  61                 os_close_file(conn->fd);
  62         }
  63
  64         list_del(&conn->list);
  65
  66         conn->fd = fd;
  67         list_add(&conn->list, &conn->port->connections);
  68
  69         up(&conn->port->sem);
  70         return(IRQ_HANDLED);
  71 }
  72
  73 static int port_accept(struct port_list *port)
  74 {
  75         struct connection *conn;
  76         int fd, socket[2], pid, ret = 0;
  77
  78         fd = port_connection(port->fd, socket, &pid);
  79         if(fd < 0){
  80                 if(fd != -EAGAIN)
  81                         printk(KERN_ERR "port_accept : port_connection "
  82                                "returned %d\n", -fd);
  83                 goto out;
  84         }
  85
  86         conn = kmalloc(sizeof(*conn), GFP_ATOMIC);
  87         if(conn == NULL){
  88                 printk(KERN_ERR "port_accept : failed to allocate "
  89                        "connection\n");
  90                 goto out_close;
  91         }
  92         *conn = ((struct connection)
  93                 { .list         = LIST_HEAD_INIT(conn->list),
  94                   .fd           = fd,
  95                   .socket       = { socket[0], socket[1] },
  96                   .telnetd_pid  = pid,
  97                   .port         = port });
  98
  99         if(um_request_irq(TELNETD_IRQ, socket[0], IRQ_READ, pipe_interrupt,
 100                           SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM,
 101                           "telnetd", conn)){
 102                 printk(KERN_ERR "port_accept : failed to get IRQ for "
 103                        "telnetd\n");
 104                 goto out_free;
 105         }
 106
 107         list_add(&conn->list, &port->pending);
 108         return(1);
 109
 110  out_free:
 111         kfree(conn);
 112  out_close:
 113         os_close_file(fd);
 114         if(pid != -1)
 115                 os_kill_process(pid, 1);
 116  out:
 117         return(ret);
 118 }
 119
 120 DECLARE_MUTEX(ports_sem);
 121 struct list_head ports = LIST_HEAD_INIT(ports);
 122
 123 void port_work_proc(void *unused)
 124 {
 125         struct port_list *port;
 126         struct list_head *ele;
 127         unsigned long flags;
 128
 129         local_irq_save(flags);
 130         list_for_each(ele, &ports){
 131                 port = list_entry(ele, struct port_list, list);
 132                 if(!port->has_connection)
 133                         continue;
 134                 reactivate_fd(port->fd, ACCEPT_IRQ);
 135                 while(port_accept(port)) ;
 136                 port->has_connection = 0;
 137         }
 138         local_irq_restore(flags);
 139 }
 140
 141 DECLARE_WORK(port_work, port_work_proc, NULL);
 142
 143 static irqreturn_t port_interrupt(int irq, void *data, struct pt_regs *regs)
 144 {
 145         struct port_list *port = data;
 146
 147         port->has_connection = 1;
 148         schedule_work(&port_work);
 149         return(IRQ_HANDLED);
 150 }
 151
 152 void *port_data(int port_num)
 153 {
 154         struct list_head *ele;
 155         struct port_list *port;
 156         struct port_dev *dev = NULL;
 157         int fd;
 158
 159         down(&ports_sem);
 160         list_for_each(ele, &ports){
 161                 port = list_entry(ele, struct port_list, list);
 162                 if(port->port == port_num) goto found;
 163         }
 164         port = kmalloc(sizeof(struct port_list), GFP_KERNEL);
 165         if(port == NULL){
 166                 printk(KERN_ERR "Allocation of port list failed\n");
 167                 goto out;
 168         }
 169
 170         fd = port_listen_fd(port_num);
 171         if(fd < 0){
 172                 printk(KERN_ERR "binding to port %d failed, errno = %d\n",
 173                        port_num, -fd);
 174                 goto out_free;
 175         }
 176         if(um_request_irq(ACCEPT_IRQ, fd, IRQ_READ, port_interrupt,
 177                           SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM, "port",
 178                           port)){
 179                 printk(KERN_ERR "Failed to get IRQ for port %d\n", port_num);
 180                 goto out_close;
 181         }
 182
 183         *port = ((struct port_list)
 184                 { .list                 = LIST_HEAD_INIT(port->list),
 185                   .has_connection       = 0,
 186                   .sem                  = __SEMAPHORE_INITIALIZER(port->sem,
 187                                                                   0),
 188                   .lock                 = SPIN_LOCK_UNLOCKED,
 189                   .port                 = port_num,
 190                   .fd                   = fd,
 191                   .pending              = LIST_HEAD_INIT(port->pending),
 192                   .connections          = LIST_HEAD_INIT(port->connections) });
 193         list_add(&port->list, &ports);
 194
 195  found:
 196         dev = kmalloc(sizeof(struct port_dev), GFP_KERNEL);
 197         if(dev == NULL){
 198                 printk(KERN_ERR "Allocation of port device entry failed\n");
 199                 goto out;
 200         }
 201
 202         *dev = ((struct port_dev) { .port               = port,
 203                                     .helper_pid         = -1,
 204                                     .telnetd_pid        = -1 });
 205         goto out;
 206
 207  out_free:
 208         kfree(port);
 209  out_close:
 210         os_close_file(fd);
 211  out:
 212         up(&ports_sem);
 213         return(dev);
 214 }
 215
 216 int port_wait(void *data)
 217 {
 218         struct port_dev *dev = data;
 219         struct connection *conn;
 220         struct port_list *port = dev->port;
 221         int fd;
 222
 223         while(1){
 224                 if(down_interruptible(&port->sem))
 225                         return(-ERESTARTSYS);
 226
 227                 spin_lock(&port->lock);
 228
 229                 conn = list_entry(port->connections.next, struct connection,
 230                                   list);
 231                 list_del(&conn->list);
 232                 spin_unlock(&port->lock);
 233
 234                 os_shutdown_socket(conn->socket[0], 1, 1);
 235                 os_close_file(conn->socket[0]);
 236                 os_shutdown_socket(conn->socket[1], 1, 1);
 237                 os_close_file(conn->socket[1]);
 238
 239                 /* This is done here because freeing an IRQ can't be done
 240                  * within the IRQ handler.  So, pipe_interrupt always ups
 241                  * the semaphore regardless of whether it got a successful
 242                  * connection.  Then we loop here throwing out failed
 243                  * connections until a good one is found.
 244                  */
 245                 free_irq_by_irq_and_dev(TELNETD_IRQ, conn);
 246                 free_irq(TELNETD_IRQ, conn);
 247
 248                 if(conn->fd >= 0) break;
 249                 os_close_file(conn->fd);
 250                 kfree(conn);
 251         }
 252
 253         fd = conn->fd;
 254         dev->helper_pid = conn->helper_pid;
 255         dev->telnetd_pid = conn->telnetd_pid;
 256         kfree(conn);
 257
 258         return(fd);
 259 }
 260
 261 void port_remove_dev(void *d)
 262 {
 263         struct port_dev *dev = d;
 264
 265         if(dev->helper_pid != -1)
 266                 os_kill_process(dev->helper_pid, 0);
 267         if(dev->telnetd_pid != -1)
 268                 os_kill_process(dev->telnetd_pid, 1);
 269         dev->helper_pid = -1;
 270         dev->telnetd_pid = -1;
 271 }
 272
 273 void port_kern_free(void *d)
 274 {
 275         struct port_dev *dev = d;
 276
 277         port_remove_dev(dev);
 278         kfree(dev);
 279 }
 280
 281 static void free_port(void)
 282 {
 283         struct list_head *ele;
 284         struct port_list *port;
 285
 286         list_for_each(ele, &ports){
 287                 port = list_entry(ele, struct port_list, list);
 288                 free_irq_by_fd(port->fd);
 289                 os_close_file(port->fd);
 290         }
 291 }
 292
 293 __uml_exitcall(free_port);
 294
 295 /*
 296  * Overrides for Emacs so that we follow Linus's tabbing style.
 297  * Emacs will notice this stuff at the end of the file and automatically
 298  * adjust the settings for this buffer only.  This must remain at the end
 299  * of the file.
 300  * ---------------------------------------------------------------------------
 301  * Local variables:
 302  * c-file-style: "linux"
 303  * End:
 304  */