diff options
Diffstat (limited to 'drivers/char/vt.c')
| -rw-r--r-- | drivers/char/vt.c | 43 |
1 files changed, 37 insertions, 6 deletions
diff --git a/drivers/char/vt.c b/drivers/char/vt.c index 1e3d728dbf7..e43fbc66aef 100644 --- a/drivers/char/vt.c +++ b/drivers/char/vt.c @@ -184,12 +184,10 @@ static DECLARE_WORK(console_work, console_callback); * fg_console is the current virtual console, * last_console is the last used one, * want_console is the console we want to switch to, - * kmsg_redirect is the console for kernel messages, */ int fg_console; int last_console; int want_console = -1; -int kmsg_redirect; /* * For each existing display, we have a pointer to console currently visible @@ -2434,6 +2432,37 @@ struct tty_driver *console_driver; #ifdef CONFIG_VT_CONSOLE +/** + * vt_kmsg_redirect() - Sets/gets the kernel message console + * @new: The new virtual terminal number or -1 if the console should stay + * unchanged + * + * By default, the kernel messages are always printed on the current virtual + * console. However, the user may modify that default with the + * TIOCL_SETKMSGREDIRECT ioctl call. + * + * This function sets the kernel message console to be @new. It returns the old + * virtual console number. The virtual terminal number 0 (both as parameter and + * return value) means no redirection (i.e. always printed on the currently + * active console). + * + * The parameter -1 means that only the current console is returned, but the + * value is not modified. You may use the macro vt_get_kmsg_redirect() in that + * case to make the code more understandable. + * + * When the kernel is compiled without CONFIG_VT_CONSOLE, this function ignores + * the parameter and always returns 0. + */ +int vt_kmsg_redirect(int new) +{ + static int kmsg_con; + + if (new != -1) + return xchg(&kmsg_con, new); + else + return kmsg_con; +} + /* * Console on virtual terminal * @@ -2448,6 +2477,7 @@ static void vt_console_print(struct console *co, const char *b, unsigned count) const ushort *start; ushort cnt = 0; ushort myx; + int kmsg_console; /* console busy or not yet initialized */ if (!printable) @@ -2455,8 +2485,9 @@ static void vt_console_print(struct console *co, const char *b, unsigned count) if (!spin_trylock(&printing_lock)) return; - if (kmsg_redirect && vc_cons_allocated(kmsg_redirect - 1)) - vc = vc_cons[kmsg_redirect - 1].d; + kmsg_console = vt_get_kmsg_redirect(); + if (kmsg_console && vc_cons_allocated(kmsg_console - 1)) + vc = vc_cons[kmsg_console - 1].d; /* read `x' only after setting currcons properly (otherwise the `x' macro will read the x of the foreground console). */ @@ -2613,7 +2644,7 @@ int tioclinux(struct tty_struct *tty, unsigned long arg) ret = set_vesa_blanking(p); break; case TIOCL_GETKMSGREDIRECT: - data = kmsg_redirect; + data = vt_get_kmsg_redirect(); ret = __put_user(data, p); break; case TIOCL_SETKMSGREDIRECT: @@ -2623,7 +2654,7 @@ int tioclinux(struct tty_struct *tty, unsigned long arg) if (get_user(data, p+1)) ret = -EFAULT; else - kmsg_redirect = data; + vt_kmsg_redirect(data); } break; case TIOCL_GETFGCONSOLE: |