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         int fd;
  26
  27         fd = os_rcv_fd(xterm->fd, &xterm->pid);
  28         if(fd == -EAGAIN)
  29                 return;
  30
  31         xterm->new_fd = fd;
  32         up(&xterm->sem);
  33 }
  34
  35 int xterm_fd(int socket, int *pid_out)
  36 {
  37         struct xterm_wait *data;
  38         int err, ret;
  39
  40         data = kmalloc(sizeof(*data), GFP_KERNEL);
  41         if(data == NULL){
  42                 printk(KERN_ERR "xterm_fd : failed to allocate xterm_wait\n");
  43                 return(-ENOMEM);
  44         }
  45         *data = ((struct xterm_wait)
  46                 { .sem          = __SEMAPHORE_INITIALIZER(data->sem, 0),
  47                   .fd           = socket,
  48                   .pid          = -1,
  49                   .new_fd       = -1 });
  50
  51         err = um_request_irq(XTERM_IRQ, socket, IRQ_READ, xterm_interrupt,
  52                              SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM,
  53                              "xterm", data);
  54         if(err){
  55                 printk(KERN_ERR "xterm_fd : failed to get IRQ for xterm, "
  56                        "err = %d\n",  err);
  57                 return(err);
  58         }
  59         down(&data->sem);
  60
  61         free_irq(XTERM_IRQ, data);
  62
  63         ret = data->new_fd;
  64         *pid_out = data->pid;
  65         kfree(data);
  66
  67         return(ret);
  68 }
  69
  70 /*
  71  * Overrides for Emacs so that we follow Linus's tabbing style.
  72  * Emacs will notice this stuff at the end of the file and automatically
  73  * adjust the settings for this buffer only.  This must remain at the end
  74  * of the file.
  75  * ---------------------------------------------------------------------------
  76  * Local variables:
  77  * c-file-style: "linux"
  78  * End:
  79  */