summaryrefslogtreecommitdiffstats
path: root/arch/um/drivers/chan_user.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/um/drivers/chan_user.c')
-rw-r--r--arch/um/drivers/chan_user.c210
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 0000000..583b8e1
--- /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:
+ */
OpenPOWER on IntegriCloud