1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) 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 #include "xterm.h" 13 14 struct xterm_wait { 15 struct completion ready; 16 int fd; 17 int pid; 18 int new_fd; 19 }; 20 21 static irqreturn_t xterm_interrupt(int irq, void *data) 22 { 23 struct xterm_wait *xterm = data; 24 int fd = -1, n_fds = 1; 25 ssize_t ret; 26 27 ret = os_rcv_fd_msg(xterm->fd, &fd, n_fds, 28 &xterm->pid, sizeof(xterm->pid)); 29 if (ret == -EAGAIN) 30 return IRQ_NONE; 31 32 if (ret < 0) 33 fd = ret; 34 else if (ret != sizeof(xterm->pid)) 35 fd = -EMSGSIZE; 36 37 xterm->new_fd = fd; 38 complete(&xterm->ready); 39 40 return IRQ_HANDLED; 41 } 42 43 int xterm_fd(int socket, int *pid_out) 44 { 45 struct xterm_wait *data; 46 int err, ret; 47 48 data = kmalloc(sizeof(*data), GFP_KERNEL); 49 if (data == NULL) { 50 printk(KERN_ERR "xterm_fd : failed to allocate xterm_wait\n"); 51 return -ENOMEM; 52 } 53 54 /* This is a locked semaphore... */ 55 *data = ((struct xterm_wait) { .fd = socket, 56 .pid = -1, 57 .new_fd = -1 }); 58 init_completion(&data->ready); 59 60 err = um_request_irq(XTERM_IRQ, socket, IRQ_READ, xterm_interrupt, 61 IRQF_SHARED, "xterm", data); 62 if (err < 0) { 63 printk(KERN_ERR "xterm_fd : failed to get IRQ for xterm, " 64 "err = %d\n", err); 65 ret = err; 66 goto out; 67 } 68 69 /* ... so here we wait for an xterm interrupt. 70 * 71 * XXX Note, if the xterm doesn't work for some reason (eg. DISPLAY 72 * isn't set) this will hang... */ 73 wait_for_completion(&data->ready); 74 75 um_free_irq(XTERM_IRQ, data); 76 77 ret = data->new_fd; 78 *pid_out = data->pid; 79 out: 80 kfree(data); 81 82 return ret; 83 } 84