-static void add_device_fd(int fd)
-{
- FD_SET(fd, &devices.infds);
- if (fd > devices.max_infd)
- devices.max_infd = fd;
-}
-
-/*L:200
- * The Waker.
- *
- * With console, block and network devices, we can have lots of input which we
- * need to process. We could try to tell the kernel what file descriptors to
- * watch, but handing a file descriptor mask through to the kernel is fairly
- * icky.
- *
- * Instead, we clone off a thread which watches the file descriptors and writes
- * the LHREQ_BREAK command to the /dev/lguest file descriptor to tell the Host
- * stop running the Guest. This causes the Launcher to return from the
- * /dev/lguest read with -EAGAIN, where it will write to /dev/lguest to reset
- * the LHREQ_BREAK and wake us up again.
- *
- * This, of course, is merely a different *kind* of icky.
- *
- * Given my well-known antipathy to threads, I'd prefer to use processes. But
- * it's easier to share Guest memory with threads, and trivial to share the
- * devices.infds as the Launcher changes it.
- */
-static int waker(void *unused)
-{
- /* Close the write end of the pipe: only the Launcher has it open. */
- close(waker_fds.pipe[1]);
-
- for (;;) {
- fd_set rfds = devices.infds;
- unsigned long args[] = { LHREQ_BREAK, 1 };
- unsigned int maxfd = devices.max_infd;
-
- /* We also listen to the pipe from the Launcher. */
- FD_SET(waker_fds.pipe[0], &rfds);
- if (waker_fds.pipe[0] > maxfd)
- maxfd = waker_fds.pipe[0];
-
- /* Wait until input is ready from one of the devices. */
- select(maxfd+1, &rfds, NULL, NULL, NULL);
-
- /* Message from Launcher? */
- if (FD_ISSET(waker_fds.pipe[0], &rfds)) {
- char c;
- /* If this fails, then assume Launcher has exited.
- * Don't do anything on exit: we're just a thread! */
- if (read(waker_fds.pipe[0], &c, 1) != 1)
- _exit(0);
- continue;
- }
-
- /* Send LHREQ_BREAK command to snap the Launcher out of it. */
- pwrite(lguest_fd, args, sizeof(args), cpu_id);
- }
- return 0;
-}
-
-/* This routine just sets up a pipe to the Waker process. */
-static void setup_waker(void)
-{
- /* This pipe is closed when Launcher dies, telling Waker. */
- if (pipe(waker_fds.pipe) != 0)
- err(1, "Creating pipe for Waker");
-
- if (clone(waker, malloc(4096) + 4096, CLONE_VM | SIGCHLD, NULL) == -1)
- err(1, "Creating Waker");
-}
-