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>
17 void generic_close(int fd
, void *unused
)
22 int generic_read(int fd
, char *c_out
, void *unused
)
26 n
= read(fd
, c_out
, sizeof(*c_out
));
29 else if (errno
== EAGAIN
)
36 /* XXX Trivial wrapper around write */
38 int generic_write(int fd
, const char *buf
, int n
, void *unused
)
42 err
= write(fd
, buf
, n
);
45 else if (errno
== EAGAIN
)
52 int generic_window_size(int fd
, void *unused
, unsigned short *rows_out
,
53 unsigned short *cols_out
)
58 if (ioctl(fd
, TIOCGWINSZ
, &size
) < 0)
61 ret
= ((*rows_out
!= size
.ws_row
) || (*cols_out
!= size
.ws_col
));
63 *rows_out
= size
.ws_row
;
64 *cols_out
= size
.ws_col
;
69 void generic_free(void *data
)
74 int generic_console_write(int fd
, const char *buf
, int n
)
76 sigset_t old
, no_sigio
;
77 struct termios save
, new;
81 sigemptyset(&no_sigio
);
82 sigaddset(&no_sigio
, SIGIO
);
83 if (sigprocmask(SIG_BLOCK
, &no_sigio
, &old
))
86 CATCH_EINTR(err
= tcgetattr(fd
, &save
));
91 * The terminal becomes a bit less raw, to handle \n also as
92 * "Carriage Return", not only as "New Line". Otherwise, the new
93 * line won't start at the first column.
96 CATCH_EINTR(err
= tcsetattr(fd
, TCSAFLUSH
, &new));
100 err
= generic_write(fd
, buf
, n
, NULL
);
102 * Restore raw mode, in any case; we *must* ignore any error apart
103 * EINTR, except for debug.
106 CATCH_EINTR(tcsetattr(fd
, TCSAFLUSH
, &save
));
107 sigprocmask(SIG_SETMASK
, &old
, NULL
);
116 * UML SIGWINCH handling
118 * The point of this is to handle SIGWINCH on consoles which have host
119 * ttys and relay them inside UML to whatever might be running on the
120 * console and cares about the window size (since SIGWINCH notifies
121 * about terminal size changes).
123 * So, we have a separate thread for each host tty attached to a UML
124 * device (side-issue - I'm annoyed that one thread can't have
125 * multiple controlling ttys for the purpose of handling SIGWINCH, but
126 * I imagine there are other reasons that doesn't make any sense).
128 * SIGWINCH can't be received synchronously, so you have to set up to
129 * receive it as a signal. That being the case, if you are going to
130 * wait for it, it is convenient to sit in sigsuspend() and wait for
131 * the signal to bounce you out of it (see below for how we make sure
132 * to exit only on SIGWINCH).
135 static void winch_handler(int sig
)
144 static int winch_thread(void *arg
)
146 struct winch_data
*data
= arg
;
152 pty_fd
= data
->pty_fd
;
153 pipe_fd
= data
->pipe_fd
;
154 count
= write(pipe_fd
, &c
, sizeof(c
));
155 if (count
!= sizeof(c
))
156 printk(UM_KERN_ERR
"winch_thread : failed to write "
157 "synchronization byte, err = %d\n", -count
);
160 * We are not using SIG_IGN on purpose, so don't fix it as I thought to
161 * do! If using SIG_IGN, the sigsuspend() call below would not stop on
165 signal(SIGWINCH
, winch_handler
);
167 /* Block all signals possible. */
168 if (sigprocmask(SIG_SETMASK
, &sigs
, NULL
) < 0) {
169 printk(UM_KERN_ERR
"winch_thread : sigprocmask failed, "
170 "errno = %d\n", errno
);
173 /* In sigsuspend(), block anything else than SIGWINCH. */
174 sigdelset(&sigs
, SIGWINCH
);
177 printk(UM_KERN_ERR
"winch_thread : setsid failed, errno = %d\n",
182 if (ioctl(pty_fd
, TIOCSCTTY
, 0) < 0) {
183 printk(UM_KERN_ERR
"winch_thread : TIOCSCTTY failed on "
184 "fd %d err = %d\n", pty_fd
, errno
);
188 if (tcsetpgrp(pty_fd
, os_getpid()) < 0) {
189 printk(UM_KERN_ERR
"winch_thread : tcsetpgrp failed on "
190 "fd %d err = %d\n", pty_fd
, errno
);
195 * These are synchronization calls between various UML threads on the
196 * host - since they are not different kernel threads, we cannot use
197 * kernel semaphores. We don't use SysV semaphores because they are
200 count
= read(pipe_fd
, &c
, sizeof(c
));
201 if (count
!= sizeof(c
))
202 printk(UM_KERN_ERR
"winch_thread : failed to read "
203 "synchronization byte, err = %d\n", errno
);
207 * This will be interrupted by SIGWINCH only, since
208 * other signals are blocked.
212 count
= write(pipe_fd
, &c
, sizeof(c
));
213 if (count
!= sizeof(c
))
214 printk(UM_KERN_ERR
"winch_thread : write failed, "
215 "err = %d\n", errno
);
219 static int winch_tramp(int fd
, struct tty_struct
*tty
, int *fd_out
,
220 unsigned long *stack_out
)
222 struct winch_data data
;
226 err
= os_pipe(fds
, 1, 1);
228 printk(UM_KERN_ERR
"winch_tramp : os_pipe failed, err = %d\n",
233 data
= ((struct winch_data
) { .pty_fd
= fd
,
234 .pipe_fd
= fds
[1] } );
236 * CLONE_FILES so this thread doesn't hold open files which are open
237 * now, but later closed in a different thread. This is a
238 * problem with /dev/net/tun, which if held open by this
239 * thread, prevents the TUN/TAP device from being reused.
241 err
= run_helper_thread(winch_thread
, &data
, CLONE_FILES
, stack_out
);
243 printk(UM_KERN_ERR
"fork of winch_thread failed - errno = %d\n",
249 n
= read(fds
[0], &c
, sizeof(c
));
250 if (n
!= sizeof(c
)) {
251 printk(UM_KERN_ERR
"winch_tramp : failed to read "
252 "synchronization byte\n");
253 printk(UM_KERN_ERR
"read failed, err = %d\n", errno
);
254 printk(UM_KERN_ERR
"fd %d will not support SIGWINCH\n", fd
);
259 if (os_set_fd_block(*fd_out
, 0)) {
260 printk(UM_KERN_ERR
"winch_tramp: failed to set thread_fd "
274 void register_winch(int fd
, struct tty_struct
*tty
)
277 int pid
, thread
, count
, thread_fd
= -1;
284 if (is_skas_winch(pid
, fd
, tty
)) {
285 register_winch_irq(-1, fd
, -1, tty
, 0);
290 thread
= winch_tramp(fd
, tty
, &thread_fd
, &stack
);
294 register_winch_irq(thread_fd
, fd
, thread
, tty
, stack
);
296 count
= write(thread_fd
, &c
, sizeof(c
));
297 if (count
!= sizeof(c
))
298 printk(UM_KERN_ERR
"register_winch : failed to write "
299 "synchronization byte, err = %d\n", errno
);