2 * Copyright (C) 1992 obz under the linux copyright
4 * Dynamic diacritical handling - aeb@cwi.nl - Dec 1993
5 * Dynamic keymap and string allocation - aeb@cwi.nl - May 1994
6 * Restrict VT switching via ioctl() - grif@cs.ucr.edu - Dec 1995
7 * Some code moved for less code duplication - Andi Kleen - Mar 1997
8 * Check put/get_user, cleanups - acme@conectiva.com.br - Jun 2001
11 #include <linux/types.h>
12 #include <linux/errno.h>
13 #include <linux/sched.h>
14 #include <linux/tty.h>
15 #include <linux/timer.h>
16 #include <linux/kernel.h>
17 #include <linux/compat.h>
18 #include <linux/module.h>
21 #include <linux/string.h>
22 #include <linux/slab.h>
23 #include <linux/major.h>
25 #include <linux/console.h>
26 #include <linux/consolemap.h>
27 #include <linux/signal.h>
28 #include <linux/timex.h>
31 #include <asm/uaccess.h>
33 #include <linux/kbd_kern.h>
34 #include <linux/vt_kern.h>
35 #include <linux/kbd_diacr.h>
36 #include <linux/selection.h>
39 extern struct tty_driver *console_driver;
41 #define VT_IS_IN_USE(i) (console_driver->ttys[i] && console_driver->ttys[i]->count)
42 #define VT_BUSY(i) (VT_IS_IN_USE(i) || i == fg_console || vc_cons[i].d == sel_cons)
45 * Console (vt and kd) routines, as defined by USL SVR4 manual, and by
46 * experimentation and study of X386 SYSV handling.
48 * One point of difference: SYSV vt's are /dev/vtX, which X >= 0, and
49 * /dev/console is a separate ttyp. Under Linux, /dev/tty0 is /dev/console,
50 * and the vc start at /dev/ttyX, X >= 1. We maintain that here, so we will
51 * always treat our set of vt as numbered 1..MAX_NR_CONSOLES (corresponding to
52 * ttys 0..MAX_NR_CONSOLES-1). Explicitly naming VT 0 is illegal, but using
53 * /dev/tty0 (fg_console) as a target is legal, since an implicit aliasing
54 * to the current console is done by the main ioctl code.
58 #include <linux/syscalls.h>
61 static void complete_change_console(struct vc_data *vc);
64 * User space VT_EVENT handlers
67 struct vt_event_wait {
68 struct list_head list;
69 struct vt_event event;
73 static LIST_HEAD(vt_events);
74 static DEFINE_SPINLOCK(vt_event_lock);
75 static DECLARE_WAIT_QUEUE_HEAD(vt_event_waitqueue);
79 * @event: the event that occurred
83 * Post an VT event to interested VT handlers
86 void vt_event_post(unsigned int event, unsigned int old, unsigned int new)
88 struct list_head *pos, *head;
92 spin_lock_irqsave(&vt_event_lock, flags);
95 list_for_each(pos, head) {
96 struct vt_event_wait *ve = list_entry(pos,
97 struct vt_event_wait, list);
98 if (!(ve->event.event & event))
100 ve->event.event = event;
101 /* kernel view is consoles 0..n-1, user space view is
102 console 1..n with 0 meaning current, so we must bias */
103 ve->event.oldev = old + 1;
104 ve->event.newev = new + 1;
108 spin_unlock_irqrestore(&vt_event_lock, flags);
110 wake_up_interruptible(&vt_event_waitqueue);
114 * vt_event_wait - wait for an event
117 * Waits for an event to occur which completes our vt_event_wait
118 * structure. On return the structure has wv->done set to 1 for success
119 * or 0 if some event such as a signal ended the wait.
122 static void vt_event_wait(struct vt_event_wait *vw)
125 /* Prepare the event */
126 INIT_LIST_HEAD(&vw->list);
128 /* Queue our event */
129 spin_lock_irqsave(&vt_event_lock, flags);
130 list_add(&vw->list, &vt_events);
131 spin_unlock_irqrestore(&vt_event_lock, flags);
132 /* Wait for it to pass */
133 wait_event_interruptible(vt_event_waitqueue, vw->done);
135 spin_lock_irqsave(&vt_event_lock, flags);
137 spin_unlock_irqrestore(&vt_event_lock, flags);
141 * vt_event_wait_ioctl - event ioctl handler
142 * @arg: argument to ioctl
144 * Implement the VT_WAITEVENT ioctl using the VT event interface
147 static int vt_event_wait_ioctl(struct vt_event __user *event)
149 struct vt_event_wait vw;
151 if (copy_from_user(&vw.event, event, sizeof(struct vt_event)))
153 /* Highest supported event for now */
154 if (vw.event.event & ~VT_MAX_EVENT)
158 /* If it occurred report it */
160 if (copy_to_user(event, &vw.event, sizeof(struct vt_event)))
168 * vt_waitactive - active console wait
172 * Helper for event waits. Used to implement the legacy
173 * event waiting ioctls in terms of events
176 int vt_waitactive(int n)
178 struct vt_event_wait vw;
180 if (n == fg_console + 1)
182 vw.event.event = VT_EVENT_SWITCH;
186 } while (vw.event.newev != n);
191 * these are the valid i/o ports we're allowed to change. they map all the
194 #define GPFIRST 0x3b4
196 #define GPNUM (GPLAST - GPFIRST + 1)
201 do_fontx_ioctl(int cmd, struct consolefontdesc __user *user_cfd, int perm, struct console_font_op *op)
203 struct consolefontdesc cfdarg;
206 if (copy_from_user(&cfdarg, user_cfd, sizeof(struct consolefontdesc)))
213 op->op = KD_FONT_OP_SET;
214 op->flags = KD_FONT_FLAG_OLD;
216 op->height = cfdarg.charheight;
217 op->charcount = cfdarg.charcount;
218 op->data = cfdarg.chardata;
219 return con_font_op(vc_cons[fg_console].d, op);
221 op->op = KD_FONT_OP_GET;
222 op->flags = KD_FONT_FLAG_OLD;
224 op->height = cfdarg.charheight;
225 op->charcount = cfdarg.charcount;
226 op->data = cfdarg.chardata;
227 i = con_font_op(vc_cons[fg_console].d, op);
230 cfdarg.charheight = op->height;
231 cfdarg.charcount = op->charcount;
232 if (copy_to_user(user_cfd, &cfdarg, sizeof(struct consolefontdesc)))
241 do_unimap_ioctl(int cmd, struct unimapdesc __user *user_ud, int perm, struct vc_data *vc)
243 struct unimapdesc tmp;
245 if (copy_from_user(&tmp, user_ud, sizeof tmp))
248 if (!access_ok(VERIFY_WRITE, tmp.entries,
249 tmp.entry_ct*sizeof(struct unipair)))
255 return con_set_unimap(vc, tmp.entry_ct, tmp.entries);
257 if (!perm && fg_console != vc->vc_num)
259 return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct), tmp.entries);
267 * We handle the console-specific ioctl's here. We allow the
268 * capability to modify any console, not just the fg_console.
270 int vt_ioctl(struct tty_struct *tty,
271 unsigned int cmd, unsigned long arg)
273 struct vc_data *vc = tty->driver_data;
274 struct console_font_op op; /* used in multiple places here */
275 unsigned int console;
278 void __user *up = (void __user *)arg;
282 console = vc->vc_num;
285 if (!vc_cons_allocated(console)) { /* impossible? */
292 * To have permissions to do most of the vt ioctls, we either have
293 * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
296 if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
301 ret = tioclinux(tty, arg);
307 * The use of PIT_TICK_RATE is historic, it used to be
308 * the platform-dependent CLOCK_TICK_RATE between 2.6.12
309 * and 2.6.36, which was a minor but unfortunate ABI
310 * change. kd_mksound is locked by the input layer.
313 arg = PIT_TICK_RATE / arg;
321 unsigned int ticks, count;
324 * Generate the tone for the appropriate number of ticks.
325 * If the time is zero, turn off sound ourselves.
327 ticks = HZ * ((arg >> 16) & 0xffff) / 1000;
328 count = ticks ? (arg & 0xffff) : 0;
330 count = PIT_TICK_RATE / count;
331 kd_mksound(count, ticks);
340 ret = put_user(ucval, (char __user *)arg);
344 * These cannot be implemented on any machine that implements
345 * ioperm() in user level (such as Alpha PCs) or not at all.
347 * XXX: you should never use these, just call ioperm directly..
353 * KDADDIO and KDDELIO may be able to add ports beyond what
354 * we reject here, but to be safe...
356 * These are locked internally via sys_ioperm
358 if (arg < GPFIRST || arg > GPLAST) {
362 ret = sys_ioperm(arg, 1, (cmd == KDADDIO)) ? -ENXIO : 0;
367 ret = sys_ioperm(GPFIRST, GPNUM,
368 (cmd == KDENABIO)) ? -ENXIO : 0;
372 /* Linux m68k/i386 interface for setting the keyboard delay/repeat rate */
376 struct kbd_repeat kbrep;
378 if (!capable(CAP_SYS_TTY_CONFIG))
381 if (copy_from_user(&kbrep, up, sizeof(struct kbd_repeat))) {
385 ret = kbd_rate(&kbrep);
388 if (copy_to_user(up, &kbrep, sizeof(struct kbd_repeat)))
395 * currently, setting the mode from KD_TEXT to KD_GRAPHICS
396 * doesn't do a whole lot. i'm not sure if it should do any
397 * restoration of modes or what...
399 * XXX It should at least call into the driver, fbdev's definitely
400 * need to restore their engine state. --BenH
416 /* FIXME: this needs the console lock extending */
417 if (vc->vc_mode == (unsigned char) arg)
419 vc->vc_mode = (unsigned char) arg;
420 if (console != fg_console)
423 * explicitly blank/unblank the screen if switching modes
427 do_unblank_screen(1);
440 * these work like a combination of mmap and KDENABIO.
441 * this could be easily finished.
449 ret = vt_do_kdskbmode(console, arg);
451 tty_ldisc_flush(tty);
455 uival = vt_do_kdgkbmode(console);
456 ret = put_user(uival, (int __user *)arg);
459 /* this could be folded into KDSKBMODE, but for compatibility
460 reasons it is not so easy to fold KDGKBMETA into KDGKBMODE */
462 ret = vt_do_kdskbmeta(console, arg);
466 /* FIXME: should review whether this is worth locking */
467 uival = vt_do_kdgkbmeta(console);
469 ret = put_user(uival, (int __user *)arg);
474 if(!capable(CAP_SYS_TTY_CONFIG))
476 ret = vt_do_kbkeycode_ioctl(cmd, up, perm);
481 ret = vt_do_kdsk_ioctl(cmd, up, perm, console);
486 ret = vt_do_kdgkb_ioctl(cmd, up, perm);
489 /* Diacritical processing. Handled in keyboard.c as it has
490 to operate on the keyboard locks and structures */
495 ret = vt_do_diacrit(cmd, up, perm);
498 /* the ioctls below read/set the flags usually shown in the leds */
499 /* don't use them - they will go away without warning */
504 ret = vt_do_kdskled(console, cmd, arg, perm);
508 * A process can indicate its willingness to accept signals
509 * generated by pressing an appropriate key combination.
510 * Thus, one can have a daemon that e.g. spawns a new console
511 * upon a keypress and then changes to it.
512 * See also the kbrequest field of inittab(5).
516 if (!perm || !capable(CAP_KILL))
518 if (!valid_signal(arg) || arg < 1 || arg == SIGKILL)
521 spin_lock_irq(&vt_spawn_con.lock);
522 put_pid(vt_spawn_con.pid);
523 vt_spawn_con.pid = get_pid(task_pid(current));
524 vt_spawn_con.sig = arg;
525 spin_unlock_irq(&vt_spawn_con.lock);
536 if (copy_from_user(&tmp, up, sizeof(struct vt_mode))) {
540 if (tmp.mode != VT_AUTO && tmp.mode != VT_PROCESS) {
546 /* the frsig is ignored, so we set it to 0 */
547 vc->vt_mode.frsig = 0;
549 vc->vt_pid = get_pid(task_pid(current));
550 /* no switch is required -- saw@shade.msu.ru */
562 memcpy(&tmp, &vc->vt_mode, sizeof(struct vt_mode));
565 rc = copy_to_user(up, &tmp, sizeof(struct vt_mode));
572 * Returns global vt state. Note that VT 0 is always open, since
573 * it's an alias for the current VT, and people can't use it here.
574 * We cannot return state for more than 16 VTs, since v_state is short.
578 struct vt_stat __user *vtstat = up;
579 unsigned short state, mask;
581 /* Review: FIXME: Console lock ? */
582 if (put_user(fg_console + 1, &vtstat->v_active))
585 state = 1; /* /dev/tty0 is always open */
586 for (i = 0, mask = 2; i < MAX_NR_CONSOLES && mask;
590 ret = put_user(state, &vtstat->v_state);
596 * Returns the first available (non-opened) console.
599 /* FIXME: locking ? - but then this is a stupid API */
600 for (i = 0; i < MAX_NR_CONSOLES; ++i)
601 if (! VT_IS_IN_USE(i))
603 uival = i < MAX_NR_CONSOLES ? (i+1) : -1;
607 * ioctl(fd, VT_ACTIVATE, num) will cause us to switch to vt # num,
608 * with num >= 1 (switches to vt 0, our console, are not allowed, just
609 * to preserve sanity).
614 if (arg == 0 || arg > MAX_NR_CONSOLES)
619 ret = vc_allocate(arg);
629 struct vt_setactivate vsa;
634 if (copy_from_user(&vsa, (struct vt_setactivate __user *)arg,
635 sizeof(struct vt_setactivate))) {
639 if (vsa.console == 0 || vsa.console > MAX_NR_CONSOLES)
644 ret = vc_allocate(vsa.console);
647 /* This is safe providing we don't drop the
648 console sem between vc_allocate and
649 finishing referencing nvc */
650 nvc = vc_cons[vsa.console].d;
651 nvc->vt_mode = vsa.mode;
652 nvc->vt_mode.frsig = 0;
653 put_pid(nvc->vt_pid);
654 nvc->vt_pid = get_pid(task_pid(current));
659 /* Commence switch and lock */
660 /* Review set_console locks */
661 set_console(vsa.console);
667 * wait until the specified VT has been activated
672 if (arg == 0 || arg > MAX_NR_CONSOLES)
675 ret = vt_waitactive(arg);
679 * If a vt is under process control, the kernel will not switch to it
680 * immediately, but postpone the operation until the process calls this
681 * ioctl, allowing the switch to complete.
683 * According to the X sources this is the behavior:
684 * 0: pending switch-from not OK
685 * 1: pending switch-from OK
686 * 2: completed switch-to OK
693 if (vc->vt_mode.mode != VT_PROCESS) {
699 * Switching-from response
701 if (vc->vt_newvt >= 0) {
704 * Switch disallowed, so forget we were trying
711 * The current vt has been released, so
712 * complete the switch.
715 newvt = vc->vt_newvt;
717 ret = vc_allocate(newvt);
723 * When we actually do the console switch,
724 * make sure we are atomic with respect to
725 * other console switches..
727 complete_change_console(vc_cons[newvt].d);
731 * Switched-to response
734 * If it's just an ACK, ignore it
736 if (arg != VT_ACKACQ)
743 * Disallocate memory associated to VT (but leave VT1)
746 if (arg > MAX_NR_CONSOLES) {
751 /* deallocate all unused consoles, but leave 0 */
753 for (i=1; i<MAX_NR_CONSOLES; i++)
758 /* deallocate a single console, if possible */
762 else if (arg) { /* leave 0 */
772 struct vt_sizes __user *vtsizes = up;
778 if (get_user(ll, &vtsizes->v_rows) ||
779 get_user(cc, &vtsizes->v_cols))
783 for (i = 0; i < MAX_NR_CONSOLES; i++) {
787 vc->vc_resize_user = 1;
788 /* FIXME: review v tty lock */
789 vc_resize(vc_cons[i].d, cc, ll);
799 struct vt_consize __user *vtconsize = up;
800 ushort ll,cc,vlin,clin,vcol,ccol;
803 if (!access_ok(VERIFY_READ, vtconsize,
804 sizeof(struct vt_consize))) {
808 /* FIXME: Should check the copies properly */
809 __get_user(ll, &vtconsize->v_rows);
810 __get_user(cc, &vtconsize->v_cols);
811 __get_user(vlin, &vtconsize->v_vlin);
812 __get_user(clin, &vtconsize->v_clin);
813 __get_user(vcol, &vtconsize->v_vcol);
814 __get_user(ccol, &vtconsize->v_ccol);
815 vlin = vlin ? vlin : vc->vc_scan_lines;
818 if (ll != vlin/clin) {
819 /* Parameters don't add up */
828 if (cc != vcol/ccol) {
841 for (i = 0; i < MAX_NR_CONSOLES; i++) {
846 vc_cons[i].d->vc_scan_lines = vlin;
848 vc_cons[i].d->vc_font.height = clin;
849 vc_cons[i].d->vc_resize_user = 1;
850 vc_resize(vc_cons[i].d, cc, ll);
859 op.op = KD_FONT_OP_SET;
860 op.flags = KD_FONT_FLAG_OLD | KD_FONT_FLAG_DONT_RECALC; /* Compatibility */
865 ret = con_font_op(vc_cons[fg_console].d, &op);
870 op.op = KD_FONT_OP_GET;
871 op.flags = KD_FONT_FLAG_OLD;
876 ret = con_font_op(vc_cons[fg_console].d, &op);
884 ret = con_set_cmap(up);
888 ret = con_get_cmap(up);
893 ret = do_fontx_ioctl(cmd, up, perm, &op);
901 #ifdef BROKEN_GRAPHICS_PROGRAMS
902 /* With BROKEN_GRAPHICS_PROGRAMS defined, the default
903 font is not saved. */
908 op.op = KD_FONT_OP_SET_DEFAULT;
910 ret = con_font_op(vc_cons[fg_console].d, &op);
914 con_set_default_unimap(vc_cons[fg_console].d);
922 if (copy_from_user(&op, up, sizeof(op))) {
926 if (!perm && op.op != KD_FONT_OP_GET)
928 ret = con_font_op(vc, &op);
931 if (copy_to_user(up, &op, sizeof(op)))
940 ret = con_set_trans_old(up);
944 ret = con_get_trans_old(up);
951 ret = con_set_trans_new(up);
955 ret = con_get_trans_new(up);
959 { struct unimapinit ui;
962 ret = copy_from_user(&ui, up, sizeof(struct unimapinit));
966 con_clear_unimap(vc, &ui);
972 ret = do_unimap_ioctl(cmd, up, perm, vc);
976 if (!capable(CAP_SYS_TTY_CONFIG))
980 case VT_UNLOCKSWITCH:
981 if (!capable(CAP_SYS_TTY_CONFIG))
985 case VT_GETHIFONTMASK:
986 ret = put_user(vc->vc_hi_font_mask,
987 (unsigned short __user *)arg);
990 ret = vt_event_wait_ioctl((struct vt_event __user *)arg);
999 void reset_vc(struct vc_data *vc)
1001 vc->vc_mode = KD_TEXT;
1002 vt_reset_unicode(vc->vc_num);
1003 vc->vt_mode.mode = VT_AUTO;
1004 vc->vt_mode.waitv = 0;
1005 vc->vt_mode.relsig = 0;
1006 vc->vt_mode.acqsig = 0;
1007 vc->vt_mode.frsig = 0;
1008 put_pid(vc->vt_pid);
1011 if (!in_interrupt()) /* Via keyboard.c:SAK() - akpm */
1015 void vc_SAK(struct work_struct *work)
1018 container_of(work, struct vc, SAK_work);
1020 struct tty_struct *tty;
1025 /* FIXME: review tty ref counting */
1028 * SAK should also work in all raw modes and reset
1038 #ifdef CONFIG_COMPAT
1040 struct compat_consolefontdesc {
1041 unsigned short charcount; /* characters in font (256 or 512) */
1042 unsigned short charheight; /* scan lines per character (1-32) */
1043 compat_caddr_t chardata; /* font data in expanded form */
1047 compat_fontx_ioctl(int cmd, struct compat_consolefontdesc __user *user_cfd,
1048 int perm, struct console_font_op *op)
1050 struct compat_consolefontdesc cfdarg;
1053 if (copy_from_user(&cfdarg, user_cfd, sizeof(struct compat_consolefontdesc)))
1060 op->op = KD_FONT_OP_SET;
1061 op->flags = KD_FONT_FLAG_OLD;
1063 op->height = cfdarg.charheight;
1064 op->charcount = cfdarg.charcount;
1065 op->data = compat_ptr(cfdarg.chardata);
1066 return con_font_op(vc_cons[fg_console].d, op);
1068 op->op = KD_FONT_OP_GET;
1069 op->flags = KD_FONT_FLAG_OLD;
1071 op->height = cfdarg.charheight;
1072 op->charcount = cfdarg.charcount;
1073 op->data = compat_ptr(cfdarg.chardata);
1074 i = con_font_op(vc_cons[fg_console].d, op);
1077 cfdarg.charheight = op->height;
1078 cfdarg.charcount = op->charcount;
1079 if (copy_to_user(user_cfd, &cfdarg, sizeof(struct compat_consolefontdesc)))
1086 struct compat_console_font_op {
1087 compat_uint_t op; /* operation code KD_FONT_OP_* */
1088 compat_uint_t flags; /* KD_FONT_FLAG_* */
1089 compat_uint_t width, height; /* font size */
1090 compat_uint_t charcount;
1091 compat_caddr_t data; /* font data with height fixed to 32 */
1095 compat_kdfontop_ioctl(struct compat_console_font_op __user *fontop,
1096 int perm, struct console_font_op *op, struct vc_data *vc)
1100 if (copy_from_user(op, fontop, sizeof(struct compat_console_font_op)))
1102 if (!perm && op->op != KD_FONT_OP_GET)
1104 op->data = compat_ptr(((struct compat_console_font_op *)op)->data);
1105 i = con_font_op(vc, op);
1108 ((struct compat_console_font_op *)op)->data = (unsigned long)op->data;
1109 if (copy_to_user(fontop, op, sizeof(struct compat_console_font_op)))
1114 struct compat_unimapdesc {
1115 unsigned short entry_ct;
1116 compat_caddr_t entries;
1120 compat_unimap_ioctl(unsigned int cmd, struct compat_unimapdesc __user *user_ud,
1121 int perm, struct vc_data *vc)
1123 struct compat_unimapdesc tmp;
1124 struct unipair __user *tmp_entries;
1126 if (copy_from_user(&tmp, user_ud, sizeof tmp))
1128 tmp_entries = compat_ptr(tmp.entries);
1130 if (!access_ok(VERIFY_WRITE, tmp_entries,
1131 tmp.entry_ct*sizeof(struct unipair)))
1137 return con_set_unimap(vc, tmp.entry_ct, tmp_entries);
1139 if (!perm && fg_console != vc->vc_num)
1141 return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct), tmp_entries);
1146 long vt_compat_ioctl(struct tty_struct *tty,
1147 unsigned int cmd, unsigned long arg)
1149 struct vc_data *vc = tty->driver_data;
1150 struct console_font_op op; /* used in multiple places here */
1151 unsigned int console;
1152 void __user *up = (void __user *)arg;
1156 console = vc->vc_num;
1158 if (!vc_cons_allocated(console)) { /* impossible? */
1164 * To have permissions to do most of the vt ioctls, we either have
1165 * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
1168 if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
1173 * these need special handlers for incompatible data structures
1177 ret = compat_fontx_ioctl(cmd, up, perm, &op);
1181 ret = compat_kdfontop_ioctl(up, perm, &op, vc);
1186 ret = compat_unimap_ioctl(cmd, up, perm, vc);
1190 * all these treat 'arg' as an integer
1209 case VT_DISALLOCATE:
1215 * the rest has a compatible data structure behind arg,
1216 * but we have to convert it to a proper 64 bit pointer.
1219 arg = (unsigned long)compat_ptr(arg);
1226 return vt_ioctl(tty, cmd, arg);
1230 #endif /* CONFIG_COMPAT */
1234 * Performs the back end of a vt switch. Called under the console
1237 static void complete_change_console(struct vc_data *vc)
1239 unsigned char old_vc_mode;
1240 int old = fg_console;
1242 last_console = fg_console;
1245 * If we're switching, we could be going from KD_GRAPHICS to
1246 * KD_TEXT mode or vice versa, which means we need to blank or
1247 * unblank the screen later.
1249 old_vc_mode = vc_cons[fg_console].d->vc_mode;
1253 * This can't appear below a successful kill_pid(). If it did,
1254 * then the *blank_screen operation could occur while X, having
1255 * received acqsig, is waking up on another processor. This
1256 * condition can lead to overlapping accesses to the VGA range
1257 * and the framebuffer (causing system lockups).
1259 * To account for this we duplicate this code below only if the
1260 * controlling process is gone and we've called reset_vc.
1262 if (old_vc_mode != vc->vc_mode) {
1263 if (vc->vc_mode == KD_TEXT)
1264 do_unblank_screen(1);
1270 * If this new console is under process control, send it a signal
1271 * telling it that it has acquired. Also check if it has died and
1272 * clean up (similar to logic employed in change_console())
1274 if (vc->vt_mode.mode == VT_PROCESS) {
1276 * Send the signal as privileged - kill_pid() will
1277 * tell us if the process has gone or something else
1280 if (kill_pid(vc->vt_pid, vc->vt_mode.acqsig, 1) != 0) {
1282 * The controlling process has died, so we revert back to
1283 * normal operation. In this case, we'll also change back
1284 * to KD_TEXT mode. I'm not sure if this is strictly correct
1285 * but it saves the agony when the X server dies and the screen
1286 * remains blanked due to KD_GRAPHICS! It would be nice to do
1287 * this outside of VT_PROCESS but there is no single process
1288 * to account for and tracking tty count may be undesirable.
1292 if (old_vc_mode != vc->vc_mode) {
1293 if (vc->vc_mode == KD_TEXT)
1294 do_unblank_screen(1);
1302 * Wake anyone waiting for their VT to activate
1304 vt_event_post(VT_EVENT_SWITCH, old, vc->vc_num);
1309 * Performs the front-end of a vt switch
1311 void change_console(struct vc_data *new_vc)
1315 if (!new_vc || new_vc->vc_num == fg_console || vt_dont_switch)
1319 * If this vt is in process mode, then we need to handshake with
1320 * that process before switching. Essentially, we store where that
1321 * vt wants to switch to and wait for it to tell us when it's done
1322 * (via VT_RELDISP ioctl).
1324 * We also check to see if the controlling process still exists.
1325 * If it doesn't, we reset this vt to auto mode and continue.
1326 * This is a cheap way to track process control. The worst thing
1327 * that can happen is: we send a signal to a process, it dies, and
1328 * the switch gets "lost" waiting for a response; hopefully, the
1329 * user will try again, we'll detect the process is gone (unless
1330 * the user waits just the right amount of time :-) and revert the
1331 * vt to auto control.
1333 vc = vc_cons[fg_console].d;
1334 if (vc->vt_mode.mode == VT_PROCESS) {
1336 * Send the signal as privileged - kill_pid() will
1337 * tell us if the process has gone or something else
1340 * We need to set vt_newvt *before* sending the signal or we
1343 vc->vt_newvt = new_vc->vc_num;
1344 if (kill_pid(vc->vt_pid, vc->vt_mode.relsig, 1) == 0) {
1346 * It worked. Mark the vt to switch to and
1347 * return. The process needs to send us a
1348 * VT_RELDISP ioctl to complete the switch.
1354 * The controlling process has died, so we revert back to
1355 * normal operation. In this case, we'll also change back
1356 * to KD_TEXT mode. I'm not sure if this is strictly correct
1357 * but it saves the agony when the X server dies and the screen
1358 * remains blanked due to KD_GRAPHICS! It would be nice to do
1359 * this outside of VT_PROCESS but there is no single process
1360 * to account for and tracking tty count may be undesirable.
1365 * Fall through to normal (VT_AUTO) handling of the switch...
1370 * Ignore all switches in KD_GRAPHICS+VT_AUTO mode
1372 if (vc->vc_mode == KD_GRAPHICS)
1375 complete_change_console(new_vc);
1378 /* Perform a kernel triggered VT switch for suspend/resume */
1380 static int disable_vt_switch;
1382 int vt_move_to_console(unsigned int vt, int alloc)
1387 /* Graphics mode - up to X */
1388 if (disable_vt_switch) {
1394 if (alloc && vc_allocate(vt)) {
1395 /* we can't have a free VC for now. Too bad,
1396 * we don't want to mess the screen for now. */
1401 if (set_console(vt)) {
1403 * We're unable to switch to the SUSPEND_CONSOLE.
1404 * Let the calling function know so it can decide
1411 if (vt_waitactive(vt + 1)) {
1412 pr_debug("Suspend: Can't switch VCs.");
1419 * Normally during a suspend, we allocate a new console and switch to it.
1420 * When we resume, we switch back to the original console. This switch
1421 * can be slow, so on systems where the framebuffer can handle restoration
1422 * of video registers anyways, there's little point in doing the console
1423 * switch. This function allows you to disable it by passing it '0'.
1425 void pm_set_vt_switch(int do_switch)
1428 disable_vt_switch = !do_switch;
1431 EXPORT_SYMBOL(pm_set_vt_switch);