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 "linux/signal.h"
   9 #include "linux/interrupt.h"
  10 #include "asm/semaphore.h"
  11 #include "asm/irq.h"
  12 #include "irq_user.h"
  13 #include "irq_kern.h"
  14 #include "kern_util.h"
  15 #include "os.h"
  16 #include "xterm.h"
  17
  18 struct xterm_wait {
  19         struct completion ready;
  20         int fd;
  21         int pid;
  22         int new_fd;
  23 };
  24
  25 static irqreturn_t xterm_interrupt(int irq, void *data, struct pt_regs *regs)
  26 {
  27         struct xterm_wait *xterm = data;
  28         int fd;
  29
  30         fd = os_rcv_fd(xterm->fd, &xterm->pid);
  31         if(fd == -EAGAIN)
  32                 return(IRQ_NONE);
  33
  34         xterm->new_fd = fd;
  35         complete(&xterm->ready);
  36         return(IRQ_HANDLED);
  37 }
  38
  39 int xterm_fd(int socket, int *pid_out)
  40 {
  41         struct xterm_wait *data;
  42         int err, ret;
  43
  44         data = kmalloc(sizeof(*data), GFP_KERNEL);
  45         if(data == NULL){
  46                 printk(KERN_ERR "xterm_fd : failed to allocate xterm_wait\n");
  47                 return(-ENOMEM);
  48         }
  49
  50         /* This is a locked semaphore... */
  51         *data = ((struct xterm_wait)
  52                 { .fd           = socket,
  53                   .pid          = -1,
  54                   .new_fd       = -1 });
  55         init_completion(&data->ready);
  56
  57         err = um_request_irq(XTERM_IRQ, socket, IRQ_READ, xterm_interrupt,
  58                              SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM,
  59                              "xterm", data);
  60         if (err){
  61                 printk(KERN_ERR "xterm_fd : failed to get IRQ for xterm, "
  62                        "err = %d\n",  err);
  63                 ret = err;
  64                 goto out;
  65         }
  66
  67         /* ... so here we wait for an xterm interrupt.
  68          *
  69          * XXX Note, if the xterm doesn't work for some reason (eg. DISPLAY
  70          * isn't set) this will hang... */
  71         wait_for_completion(&data->ready);
  72
  73         free_irq_by_irq_and_dev(XTERM_IRQ, data);
  74         free_irq(XTERM_IRQ, data);
  75
  76         ret = data->new_fd;
  77         *pid_out = data->pid;
  78  out:
  79         kfree(data);
  80
  81         return(ret);
  82 }
  83
  84 /*
  85  * Overrides for Emacs so that we follow Linus's tabbing style.
  86  * Emacs will notice this stuff at the end of the file and automatically
  87  * adjust the settings for this buffer only.  This must remain at the end
  88  * of the file.
  89  * ---------------------------------------------------------------------------
  90  * Local variables:
  91  * c-file-style: "linux"
  92  * End:
  93  */