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