2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{linux.intel,addtoit}.com)
3 * Licensed under the GPL
12 #include <sys/ioctl.h>
13 #include "chan_user.h"
15 #include "um_malloc.h"
18 void generic_close(int fd, void *unused)
23 int generic_read(int fd, char *c_out, void *unused)
27 n = read(fd, c_out, sizeof(*c_out));
30 else if (errno == EAGAIN)
37 /* XXX Trivial wrapper around write */
39 int generic_write(int fd, const char *buf, int n, void *unused)
43 err = write(fd, buf, n);
46 else if (errno == EAGAIN)
53 int generic_window_size(int fd, void *unused, unsigned short *rows_out,
54 unsigned short *cols_out)
59 if (ioctl(fd, TIOCGWINSZ, &size) < 0)
62 ret = ((*rows_out != size.ws_row) || (*cols_out != size.ws_col));
64 *rows_out = size.ws_row;
65 *cols_out = size.ws_col;
70 void generic_free(void *data)
75 int generic_console_write(int fd, const char *buf, int n)
77 struct termios save, new;
81 CATCH_EINTR(err = tcgetattr(fd, &save));
85 /* The terminal becomes a bit less raw, to handle \n also as
86 * "Carriage Return", not only as "New Line". Otherwise, the new
87 * line won't start at the first column.*/
89 CATCH_EINTR(err = tcsetattr(fd, TCSAFLUSH, &new));
93 err = generic_write(fd, buf, n, NULL);
94 /* Restore raw mode, in any case; we *must* ignore any error apart
95 * EINTR, except for debug.*/
97 CATCH_EINTR(tcsetattr(fd, TCSAFLUSH, &save));
104 * UML SIGWINCH handling
106 * The point of this is to handle SIGWINCH on consoles which have host
107 * ttys and relay them inside UML to whatever might be running on the
108 * console and cares about the window size (since SIGWINCH notifies
109 * about terminal size changes).
111 * So, we have a separate thread for each host tty attached to a UML
112 * device (side-issue - I'm annoyed that one thread can't have
113 * multiple controlling ttys for the purpose of handling SIGWINCH, but
114 * I imagine there are other reasons that doesn't make any sense).
116 * SIGWINCH can't be received synchronously, so you have to set up to
117 * receive it as a signal. That being the case, if you are going to
118 * wait for it, it is convenient to sit in sigsuspend() and wait for
119 * the signal to bounce you out of it (see below for how we make sure
120 * to exit only on SIGWINCH).
123 static void winch_handler(int sig)
132 static int winch_thread(void *arg)
134 struct winch_data *data = arg;
140 pty_fd = data->pty_fd;
141 pipe_fd = data->pipe_fd;
142 count = os_write_file(pipe_fd, &c, sizeof(c));
143 if (count != sizeof(c))
144 printk(UM_KERN_ERR "winch_thread : failed to write "
145 "synchronization byte, err = %d\n", -count);
148 * We are not using SIG_IGN on purpose, so don't fix it as I thought to
149 * do! If using SIG_IGN, the sigsuspend() call below would not stop on
153 signal(SIGWINCH, winch_handler);
155 /* Block all signals possible. */
156 if (sigprocmask(SIG_SETMASK, &sigs, NULL) < 0) {
157 printk(UM_KERN_ERR "winch_thread : sigprocmask failed, "
158 "errno = %d\n", errno);
161 /* In sigsuspend(), block anything else than SIGWINCH. */
162 sigdelset(&sigs, SIGWINCH);
165 printk(UM_KERN_ERR "winch_thread : setsid failed, errno = %d\n",
170 err = os_new_tty_pgrp(pty_fd, os_getpid());
172 printk(UM_KERN_ERR "winch_thread : new_tty_pgrp failed on "
173 "fd %d err = %d\n", pty_fd, -err);
178 * These are synchronization calls between various UML threads on the
179 * host - since they are not different kernel threads, we cannot use
180 * kernel semaphores. We don't use SysV semaphores because they are
183 count = os_read_file(pipe_fd, &c, sizeof(c));
184 if (count != sizeof(c))
185 printk(UM_KERN_ERR "winch_thread : failed to read "
186 "synchronization byte, err = %d\n", -count);
190 * This will be interrupted by SIGWINCH only, since
191 * other signals are blocked.
195 count = os_write_file(pipe_fd, &c, sizeof(c));
196 if (count != sizeof(c))
197 printk(UM_KERN_ERR "winch_thread : write failed, "
198 "err = %d\n", -count);
202 static int winch_tramp(int fd, struct tty_struct *tty, int *fd_out,
203 unsigned long *stack_out)
205 struct winch_data data;
209 err = os_pipe(fds, 1, 1);
211 printk(UM_KERN_ERR "winch_tramp : os_pipe failed, err = %d\n",
216 data = ((struct winch_data) { .pty_fd = fd,
217 .pipe_fd = fds[1] } );
219 * CLONE_FILES so this thread doesn't hold open files which are open
220 * now, but later closed in a different thread. This is a
221 * problem with /dev/net/tun, which if held open by this
222 * thread, prevents the TUN/TAP device from being reused.
224 err = run_helper_thread(winch_thread, &data, CLONE_FILES, stack_out);
226 printk(UM_KERN_ERR "fork of winch_thread failed - errno = %d\n",
232 n = os_read_file(fds[0], &c, sizeof(c));
233 if (n != sizeof(c)) {
234 printk(UM_KERN_ERR "winch_tramp : failed to read "
235 "synchronization byte\n");
236 printk(UM_KERN_ERR "read failed, err = %d\n", -n);
237 printk(UM_KERN_ERR "fd %d will not support SIGWINCH\n", fd);
242 if (os_set_fd_block(*fd_out, 0)) {
243 printk(UM_KERN_ERR "winch_tramp: failed to set thread_fd "
251 os_close_file(fds[1]);
252 os_close_file(fds[0]);
257 void register_winch(int fd, struct tty_struct *tty)
260 int pid, thread, count, thread_fd = -1;
267 if (!CHOOSE_MODE_PROC(is_tracer_winch, is_skas_winch, pid, fd, tty) &&
269 thread = winch_tramp(fd, tty, &thread_fd, &stack);
273 register_winch_irq(thread_fd, fd, thread, tty, stack);
275 count = os_write_file(thread_fd, &c, sizeof(c));
276 if (count != sizeof(c))
277 printk(UM_KERN_ERR "register_winch : failed to write "
278 "synchronization byte, err = %d\n", -count);