#include <termios.h>
#include <string.h>
#include <signal.h>
+#include <sched.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/socket.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)
+int generic_console_write(int fd, const char *buf, int n)
{
struct termios save, new;
int err;
if(isatty(fd)){
- tcgetattr(fd, &save);
+ 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;
- tcsetattr(fd, TCSAFLUSH, &new);
+ CATCH_EINTR(err = tcsetattr(fd, TCSAFLUSH, &new));
+ if (err)
+ goto error;
}
err = generic_write(fd, buf, n, NULL);
- if(isatty(fd)) tcsetattr(fd, TCSAFLUSH, &save);
+ /* 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 sigsuspend() 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)
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));
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 sigsuspend() call below would not stop on
+ * SIGWINCH. */
+
signal(SIGWINCH, winch_handler);
sigfillset(&sigs);
- sigdelset(&sigs, SIGWINCH);
+ /* Block all signals possible. */
if(sigprocmask(SIG_SETMASK, &sigs, NULL) < 0){
printk("winch_thread : sigprocmask failed, errno = %d\n",
errno);
exit(1);
}
+ /* In sigsuspend(), block anything else than SIGWINCH. */
+ sigdelset(&sigs, SIGWINCH);
if(setsid() < 0){
printk("winch_thread : setsid failed, errno = %d\n", errno);
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
+ * persistent. */
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){
- pause();
+ /* This will be interrupted by SIGWINCH only, since other signals
+ * are blocked.*/
+ sigsuspend(&sigs);
count = os_write_file(pipe_fd, &c, sizeof(c));
if(count != sizeof(c))
}
}
-static int winch_tramp(int fd, void *device_data, int *fd_out)
+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;
+ int fds[2], 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);
+ goto out;
}
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){
+ .pipe_fd = fds[1] } );
+ /* CLONE_FILES so this thread doesn't hold open files which are open
+ * now, but later closed. This is a problem with /dev/net/tun.
+ */
+ err = run_helper_thread(winch_thread, &data, CLONE_FILES, &stack, 0);
+ if(err < 0){
printk("fork of winch_thread failed - errno = %d\n", errno);
- return(pid);
+ goto out_close;
}
- 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;
+ err = -EINVAL;
+ goto out_close;
}
- return(pid);
+ return err ;
+
+ out_close:
+ os_close_file(fds[1]);
+ os_close_file(fds[0]);
+ out:
+ return err;
}
-void register_winch(int fd, void *device_data)
+void register_winch(int fd, struct tty_struct *tty)
{
- int pid, thread, thread_fd;
+ int pid, thread, thread_fd = -1;
int count;
char c = 1;
pid = tcgetpgrp(fd);
if(!CHOOSE_MODE_PROC(is_tracer_winch, is_skas_winch, pid, fd,
- device_data) && (pid == -1)){
- thread = winch_tramp(fd, device_data, &thread_fd);
- if(fd != -1){
- register_winch_irq(thread_fd, fd, thread, device_data);
+ tty) && (pid == -1)){
+ thread = winch_tramp(fd, tty, &thread_fd);
+ if(thread > 0){
+ register_winch_irq(thread_fd, fd, thread, tty);
count = os_write_file(thread_fd, &c, sizeof(c));
if(count != sizeof(c))
git://git.onelab.eu / linux-2.6.git / blobdiff