2 * Copyright (C) 2000 - 2003 Jeff Dike (jdike@addtoit.com)
3 * Licensed under the GPL
14 #include <sys/ioctl.h>
15 #include <sys/socket.h>
16 #include "kern_util.h"
17 #include "chan_user.h"
20 #include "choose-mode.h"
22 #include "um_malloc.h"
24 void generic_close(int fd, void *unused)
29 int generic_read(int fd, char *c_out, void *unused)
33 n = os_read_file(fd, c_out, sizeof(*c_out));
42 /* XXX Trivial wrapper around os_write_file */
44 int generic_write(int fd, const char *buf, int n, void *unused)
46 return os_write_file(fd, buf, n);
49 int generic_window_size(int fd, void *unused, unsigned short *rows_out,
50 unsigned short *cols_out)
55 ret = os_window_size(fd, &rows, &cols);
59 ret = ((*rows_out != rows) || (*cols_out != cols));
67 void generic_free(void *data)
72 int generic_console_write(int fd, const char *buf, int n)
74 struct termios save, new;
78 CATCH_EINTR(err = tcgetattr(fd, &save));
82 /* The terminal becomes a bit less raw, to handle \n also as
83 * "Carriage Return", not only as "New Line". Otherwise, the new
84 * line won't start at the first column.*/
86 CATCH_EINTR(err = tcsetattr(fd, TCSAFLUSH, &new));
90 err = generic_write(fd, buf, n, NULL);
91 /* Restore raw mode, in any case; we *must* ignore any error apart
92 * EINTR, except for debug.*/
94 CATCH_EINTR(tcsetattr(fd, TCSAFLUSH, &save));
101 * UML SIGWINCH handling
103 * The point of this is to handle SIGWINCH on consoles which have host
104 * ttys and relay them inside UML to whatever might be running on the
105 * console and cares about the window size (since SIGWINCH notifies
106 * about terminal size changes).
108 * So, we have a separate thread for each host tty attached to a UML
109 * device (side-issue - I'm annoyed that one thread can't have
110 * multiple controlling ttys for the purpose of handling SIGWINCH, but
111 * I imagine there are other reasons that doesn't make any sense).
113 * SIGWINCH can't be received synchronously, so you have to set up to
114 * receive it as a signal. That being the case, if you are going to
115 * wait for it, it is convenient to sit in sigsuspend() and wait for
116 * the signal to bounce you out of it (see below for how we make sure
117 * to exit only on SIGWINCH).
120 static void winch_handler(int sig)
129 static int winch_thread(void *arg)
131 struct winch_data *data = arg;
137 pty_fd = data->pty_fd;
138 pipe_fd = data->pipe_fd;
139 count = os_write_file(pipe_fd, &c, sizeof(c));
140 if(count != sizeof(c))
141 printk("winch_thread : failed to write synchronization "
142 "byte, err = %d\n", -count);
144 /* We are not using SIG_IGN on purpose, so don't fix it as I thought to
145 * do! If using SIG_IGN, the sigsuspend() call below would not stop on
148 signal(SIGWINCH, winch_handler);
150 /* Block all signals possible. */
151 if(sigprocmask(SIG_SETMASK, &sigs, NULL) < 0){
152 printk("winch_thread : sigprocmask failed, errno = %d\n",
156 /* In sigsuspend(), block anything else than SIGWINCH. */
157 sigdelset(&sigs, SIGWINCH);
160 printk("winch_thread : setsid failed, errno = %d\n", errno);
164 err = os_new_tty_pgrp(pty_fd, os_getpid());
166 printk("winch_thread : new_tty_pgrp failed on fd %d, "
167 "err = %d\n", pty_fd, -err);
171 /* These are synchronization calls between various UML threads on the
172 * host - since they are not different kernel threads, we cannot use
173 * kernel semaphores. We don't use SysV semaphores because they are
175 count = os_read_file(pipe_fd, &c, sizeof(c));
176 if(count != sizeof(c))
177 printk("winch_thread : failed to read synchronization byte, "
178 "err = %d\n", -count);
181 /* This will be interrupted by SIGWINCH only, since
182 * other signals are blocked.
186 count = os_write_file(pipe_fd, &c, sizeof(c));
187 if(count != sizeof(c))
188 printk("winch_thread : write failed, err = %d\n",
193 static int winch_tramp(int fd, struct tty_struct *tty, int *fd_out,
194 unsigned long *stack_out)
196 struct winch_data data;
200 err = os_pipe(fds, 1, 1);
202 printk("winch_tramp : os_pipe failed, err = %d\n", -err);
206 data = ((struct winch_data) { .pty_fd = fd,
207 .pipe_fd = fds[1] } );
208 /* CLONE_FILES so this thread doesn't hold open files which are open
209 * now, but later closed in a different thread. This is a
210 * problem with /dev/net/tun, which if held open by this
211 * thread, prevents the TUN/TAP device from being reused.
213 err = run_helper_thread(winch_thread, &data, CLONE_FILES, stack_out);
215 printk("fork of winch_thread failed - errno = %d\n", -err);
220 n = os_read_file(fds[0], &c, sizeof(c));
222 printk("winch_tramp : failed to read synchronization byte\n");
223 printk("read failed, err = %d\n", -n);
224 printk("fd %d will not support SIGWINCH\n", fd);
229 if (os_set_fd_block(*fd_out, 0)) {
230 printk("winch_tramp: failed to set thread_fd non-blocking.\n");
237 os_close_file(fds[1]);
238 os_close_file(fds[0]);
243 void register_winch(int fd, struct tty_struct *tty)
246 int pid, thread, count, thread_fd = -1;
253 if (!CHOOSE_MODE_PROC(is_tracer_winch, is_skas_winch, pid, fd, tty) &&
255 thread = winch_tramp(fd, tty, &thread_fd, &stack);
259 register_winch_irq(thread_fd, fd, thread, tty, stack);
261 count = os_write_file(thread_fd, &c, sizeof(c));
262 if(count != sizeof(c))
263 printk("register_winch : failed to write "
264 "synchronization byte, err = %d\n", -count);