linux/arch/um/drivers/xterm_kern.c
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   1/* 
   2 * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3 * Licensed under the GPL
   4 */
   5
   6#include <linux/slab.h>
   7#include <linux/completion.h>
   8#include <linux/irqreturn.h>
   9#include <asm/irq.h>
  10#include "irq_kern.h"
  11#include "os.h"
  12
  13struct xterm_wait {
  14        struct completion ready;
  15        int fd;
  16        int pid;
  17        int new_fd;
  18};
  19
  20static irqreturn_t xterm_interrupt(int irq, void *data)
  21{
  22        struct xterm_wait *xterm = data;
  23        int fd;
  24
  25        fd = os_rcv_fd(xterm->fd, &xterm->pid);
  26        if (fd == -EAGAIN)
  27                return IRQ_NONE;
  28
  29        xterm->new_fd = fd;
  30        complete(&xterm->ready);
  31
  32        return IRQ_HANDLED;
  33}
  34
  35int 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
  46        /* This is a locked semaphore... */
  47        *data = ((struct xterm_wait) { .fd              = socket,
  48                                       .pid             = -1,
  49                                       .new_fd          = -1 });
  50        init_completion(&data->ready);
  51
  52        err = um_request_irq(XTERM_IRQ, socket, IRQ_READ, xterm_interrupt,
  53                             IRQF_SHARED | IRQF_SAMPLE_RANDOM,
  54                             "xterm", data);
  55        if (err) {
  56                printk(KERN_ERR "xterm_fd : failed to get IRQ for xterm, "
  57                       "err = %d\n",  err);
  58                ret = err;
  59                goto out;
  60        }
  61
  62        /* ... so here we wait for an xterm interrupt.
  63         *
  64         * XXX Note, if the xterm doesn't work for some reason (eg. DISPLAY
  65         * isn't set) this will hang... */
  66        wait_for_completion(&data->ready);
  67
  68        free_irq(XTERM_IRQ, data);
  69
  70        ret = data->new_fd;
  71        *pid_out = data->pid;
  72 out:
  73        kfree(data);
  74
  75        return ret;
  76}
  77
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