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 semaphore sem;
  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         up(&xterm->sem);
  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         *data = ((struct xterm_wait)
  50                 { .sem          = __SEMAPHORE_INITIALIZER(data->sem, 0),
  51                   .fd           = socket,
  52                   .pid          = -1,
  53                   .new_fd       = -1 });
  54
  55         err = um_request_irq(XTERM_IRQ, socket, IRQ_READ, xterm_interrupt,
  56                              SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM,
  57                              "xterm", data);
  58         if(err){
  59                 printk(KERN_ERR "xterm_fd : failed to get IRQ for xterm, "
  60                        "err = %d\n",  err);
  61                 ret = err;
  62                 goto out;
  63         }
  64         down(&data->sem);
  65
  66         free_irq(XTERM_IRQ, data);
  67
  68         ret = data->new_fd;
  69         *pid_out = data->pid;
  70  out:
  71         kfree(data);
  72
  73         return(ret);
  74 }
  75
  76 /*
  77  * Overrides for Emacs so that we follow Linus's tabbing style.
  78  * Emacs will notice this stuff at the end of the file and automatically
  79  * adjust the settings for this buffer only.  This must remain at the end
  80  * of the file.
  81  * ---------------------------------------------------------------------------
  82  * Local variables:
  83  * c-file-style: "linux"
  84  * End:
  85  */