arch/um/drivers/xterm_kern.c

   1 /*
   2  * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include "linux/errno.h"
   7 #include "linux/slab.h"
   8 #include "asm/semaphore.h"
   9 #include "asm/irq.h"
  10 #include "irq_user.h"
  11 #include "kern_util.h"
  12 #include "os.h"
  13 #include "xterm.h"
  14
  15 struct xterm_wait {
  16         struct semaphore sem;
  17         int fd;
  18         int pid;
  19         int new_fd;
  20 };
  21
  22 static void xterm_interrupt(int irq, void *data, struct pt_regs *regs)
  23 {
  24         struct xterm_wait *xterm = data;
  25
  26         xterm->new_fd = os_rcv_fd(xterm->fd, &xterm->pid);
  27         if(xterm->new_fd == -EAGAIN)
  28                 return;
  29
  30         up(&xterm->sem);
  31 }
  32
  33 int xterm_fd(int socket, int *pid_out)
  34 {
  35         struct xterm_wait *data;
  36         int err, ret;
  37
  38         data = kmalloc(sizeof(*data), GFP_KERNEL);
  39         if(data == NULL){
  40                 printk(KERN_ERR "xterm_fd - failed to allocate semaphore\n");
  41                 return(-ENOMEM);
  42         }
  43         *data = ((struct xterm_wait)
  44                 { sem :         __SEMAPHORE_INITIALIZER(data->sem, 0),
  45                   fd :          socket,
  46                   pid :         -1,
  47                   new_fd :      -1 });
  48
  49         err = um_request_irq(XTERM_IRQ, socket, IRQ_READ, xterm_interrupt,
  50                              SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM,
  51                              "xterm", data);
  52         if(err){
  53                 printk(KERN_ERR "Failed to get IRQ for xterm, err = %d\n",
  54                        err);
  55                 return(err);
  56         }
  57         down(&data->sem);
  58
  59         free_irq(XTERM_IRQ, data);
  60
  61         ret = data->new_fd;
  62         *pid_out = data->pid;
  63         kfree(data);
  64
  65         return(ret);
  66 }
  67
  68 /*
  69  * Overrides for Emacs so that we follow Linus's tabbing style.
  70  * Emacs will notice this stuff at the end of the file and automatically
  71  * adjust the settings for this buffer only.  This must remain at the end
  72  * of the file.
  73  * ---------------------------------------------------------------------------
  74  * Local variables:
  75  * c-file-style: "linux"
  76  * End:
  77  */