1 files changed, 210 insertions, 0 deletions
diff --git a/arch/um/drivers/chan_user.c b/arch/um/drivers/chan_user.c
new file mode 100644
index 000000000000..583b8e137c33
--- /dev/null
+++ b/arch/um/drivers/chan_user.c
@@ -0,0 +1,210 @@
+/* 
+ * Copyright (C) 2000 - 2003 Jeff Dike (jdike@addtoit.com)
+ * Licensed under the GPL
+ */
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <termios.h>
+#include <string.h>
+#include <signal.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include "kern_util.h"
+#include "user_util.h"
+#include "chan_user.h"
+#include "user.h"
+#include "helper.h"
+#include "os.h"
+#include "choose-mode.h"
+#include "mode.h"
+
+int generic_console_write(int fd, const char *buf, int n, void *unused)
+{
+	struct termios save, new;
+	int err;
+
+	if(isatty(fd)){
+		CATCH_EINTR(err = tcgetattr(fd, &save));
+		if (err)
+			goto error;
+		new = save;
+		/* The terminal becomes a bit less raw, to handle \n also as
+		 * "Carriage Return", not only as "New Line". Otherwise, the new
+		 * line won't start at the first column.*/
+		new.c_oflag |= OPOST;
+		CATCH_EINTR(err = tcsetattr(fd, TCSAFLUSH, &new));
+		if (err)
+			goto error;
+	}
+	err = generic_write(fd, buf, n, NULL);
+	/* Restore raw mode, in any case; we *must* ignore any error apart
+	 * EINTR, except for debug.*/
+	if(isatty(fd))
+		CATCH_EINTR(tcsetattr(fd, TCSAFLUSH, &save));
+	return(err);
+error:
+	return(-errno);
+}
+
+/*
+ * UML SIGWINCH handling
+ *
+ * The point of this is to handle SIGWINCH on consoles which have host ttys and
+ * relay them inside UML to whatever might be running on the console and cares
+ * about the window size (since SIGWINCH notifies about terminal size changes).
+ *
+ * So, we have a separate thread for each host tty attached to a UML device
+ * (side-issue - I'm annoyed that one thread can't have multiple controlling
+ * ttys for purposed of handling SIGWINCH, but I imagine there are other reasons
+ * that doesn't make any sense).
+ *
+ * SIGWINCH can't be received synchronously, so you have to set up to receive it
+ * as a signal.  That being the case, if you are going to wait for it, it is
+ * convenient to sit in a pause() and wait for the signal to bounce you out of
+ * it (see below for how we make sure to exit only on SIGWINCH).
+ */
+
+static void winch_handler(int sig)
+{
+}
+
+struct winch_data {
+	int pty_fd;
+	int pipe_fd;
+	int close_me;
+};
+
+static int winch_thread(void *arg)
+{
+	struct winch_data *data = arg;
+	sigset_t sigs;
+	int pty_fd, pipe_fd;
+	int count, err;
+	char c = 1;
+
+	os_close_file(data->close_me);
+	pty_fd = data->pty_fd;
+	pipe_fd = data->pipe_fd;
+	count = os_write_file(pipe_fd, &c, sizeof(c));
+	if(count != sizeof(c))
+		printk("winch_thread : failed to write synchronization "
+		       "byte, err = %d\n", -count);
+
+	/* We are not using SIG_IGN on purpose, so don't fix it as I thought to
+	 * do! If using SIG_IGN, the pause() call below would not stop on
+	 * SIGWINCH. */
+
+	signal(SIGWINCH, winch_handler);
+	sigfillset(&sigs);
+	sigdelset(&sigs, SIGWINCH);
+	/* Block anything else than SIGWINCH. */
+	if(sigprocmask(SIG_SETMASK, &sigs, NULL) < 0){
+		printk("winch_thread : sigprocmask failed, errno = %d\n", 
+		       errno);
+		exit(1);
+	}
+
+	if(setsid() < 0){
+		printk("winch_thread : setsid failed, errno = %d\n", errno);
+		exit(1);
+	}
+
+	err = os_new_tty_pgrp(pty_fd, os_getpid());
+	if(err < 0){
+		printk("winch_thread : new_tty_pgrp failed, err = %d\n", -err);
+		exit(1);
+	}
+
+	/* These are synchronization calls between various UML threads on the
+	 * host - since they are not different kernel threads, we cannot use
+	 * kernel semaphores. We don't use SysV semaphores because they are
+	 * persistant. */
+	count = os_read_file(pipe_fd, &c, sizeof(c));
+	if(count != sizeof(c))
+		printk("winch_thread : failed to read synchronization byte, "
+		       "err = %d\n", -count);
+
+	while(1){
+		/* This will be interrupted by SIGWINCH only, since other signals
+		 * are blocked.*/
+		pause();
+
+		count = os_write_file(pipe_fd, &c, sizeof(c));
+		if(count != sizeof(c))
+			printk("winch_thread : write failed, err = %d\n",
+			       -count);
+	}
+}
+
+static int winch_tramp(int fd, struct tty_struct *tty, int *fd_out)
+{
+	struct winch_data data;
+	unsigned long stack;
+	int fds[2], pid, n, err;
+	char c;
+
+	err = os_pipe(fds, 1, 1);
+	if(err < 0){
+		printk("winch_tramp : os_pipe failed, err = %d\n", -err);
+		return(err);
+	}
+
+	data = ((struct winch_data) { .pty_fd 		= fd,
+				      .pipe_fd 		= fds[1],
+				      .close_me 	= fds[0] } );
+	pid = run_helper_thread(winch_thread, &data, 0, &stack, 0);
+	if(pid < 0){
+		printk("fork of winch_thread failed - errno = %d\n", errno);
+		return(pid);
+	}
+
+	os_close_file(fds[1]);
+	*fd_out = fds[0];
+	n = os_read_file(fds[0], &c, sizeof(c));
+	if(n != sizeof(c)){
+		printk("winch_tramp : failed to read synchronization byte\n");
+		printk("read failed, err = %d\n", -n);
+		printk("fd %d will not support SIGWINCH\n", fd);
+		*fd_out = -1;
+	}
+	return(pid);
+}
+
+void register_winch(int fd, struct tty_struct *tty)
+{
+	int pid, thread, thread_fd;
+	int count;
+	char c = 1;
+
+	if(!isatty(fd))
+		return;
+
+	pid = tcgetpgrp(fd);
+	if(!CHOOSE_MODE_PROC(is_tracer_winch, is_skas_winch, pid, fd,
+			     tty) && (pid == -1)){
+		thread = winch_tramp(fd, tty, &thread_fd);
+		if(fd != -1){
+			register_winch_irq(thread_fd, fd, thread, tty);
+
+			count = os_write_file(thread_fd, &c, sizeof(c));
+			if(count != sizeof(c))
+				printk("register_winch : failed to write "
+				       "synchronization byte, err = %d\n",
+					-count);
+		}
+	}
+}
+
+/*
+ * Overrides for Emacs so that we follow Linus's tabbing style.
+ * Emacs will notice this stuff at the end of the file and automatically
+ * adjust the settings for this buffer only.  This must remain at the end
+ * of the file.
+ * ---------------------------------------------------------------------------
+ * Local variables:
+ * c-file-style: "linux"
+ * End:
+ */