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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 22:20:36 (GMT) |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 22:20:36 (GMT) |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/um/drivers/chan_user.c | |
download | linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/um/drivers/chan_user.c')
-rw-r--r-- | arch/um/drivers/chan_user.c | 210 |
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: + */ |