1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 1992 obz under the linux copyright
5 * Dynamic diacritical handling - aeb@cwi.nl - Dec 1993
6 * Dynamic keymap and string allocation - aeb@cwi.nl - May 1994
7 * Restrict VT switching via ioctl() - grif@cs.ucr.edu - Dec 1995
8 * Some code moved for less code duplication - Andi Kleen - Mar 1997
9 * Check put/get_user, cleanups - acme@conectiva.com.br - Jun 2001
12 #include <linux/types.h>
13 #include <linux/errno.h>
14 #include <linux/sched/signal.h>
15 #include <linux/tty.h>
16 #include <linux/timer.h>
17 #include <linux/kernel.h>
18 #include <linux/compat.h>
19 #include <linux/module.h>
22 #include <linux/string.h>
23 #include <linux/slab.h>
24 #include <linux/major.h>
26 #include <linux/console.h>
27 #include <linux/consolemap.h>
28 #include <linux/signal.h>
29 #include <linux/suspend.h>
30 #include <linux/timex.h>
33 #include <linux/uaccess.h>
35 #include <linux/nospec.h>
37 #include <linux/kbd_kern.h>
38 #include <linux/vt_kern.h>
39 #include <linux/kbd_diacr.h>
40 #include <linux/selection.h>
44 static inline bool vt_in_use(unsigned int i)
46 const struct vc_data *vc = vc_cons[i].d;
49 * console_lock must be held to prevent the vc from being deallocated
50 * while we're checking whether it's in-use.
52 WARN_CONSOLE_UNLOCKED();
54 return vc && kref_read(&vc->port.kref) > 1;
57 static inline bool vt_busy(int i)
63 if (vc_is_sel(vc_cons[i].d))
70 * Console (vt and kd) routines, as defined by USL SVR4 manual, and by
71 * experimentation and study of X386 SYSV handling.
73 * One point of difference: SYSV vt's are /dev/vtX, which X >= 0, and
74 * /dev/console is a separate ttyp. Under Linux, /dev/tty0 is /dev/console,
75 * and the vc start at /dev/ttyX, X >= 1. We maintain that here, so we will
76 * always treat our set of vt as numbered 1..MAX_NR_CONSOLES (corresponding to
77 * ttys 0..MAX_NR_CONSOLES-1). Explicitly naming VT 0 is illegal, but using
78 * /dev/tty0 (fg_console) as a target is legal, since an implicit aliasing
79 * to the current console is done by the main ioctl code.
83 #include <asm/syscalls.h>
86 static void complete_change_console(struct vc_data *vc);
89 * User space VT_EVENT handlers
92 struct vt_event_wait {
93 struct list_head list;
94 struct vt_event event;
98 static LIST_HEAD(vt_events);
99 static DEFINE_SPINLOCK(vt_event_lock);
100 static DECLARE_WAIT_QUEUE_HEAD(vt_event_waitqueue);
104 * @event: the event that occurred
108 * Post an VT event to interested VT handlers
111 void vt_event_post(unsigned int event, unsigned int old, unsigned int new)
113 struct list_head *pos, *head;
117 spin_lock_irqsave(&vt_event_lock, flags);
120 list_for_each(pos, head) {
121 struct vt_event_wait *ve = list_entry(pos,
122 struct vt_event_wait, list);
123 if (!(ve->event.event & event))
125 ve->event.event = event;
126 /* kernel view is consoles 0..n-1, user space view is
127 console 1..n with 0 meaning current, so we must bias */
128 ve->event.oldev = old + 1;
129 ve->event.newev = new + 1;
133 spin_unlock_irqrestore(&vt_event_lock, flags);
135 wake_up_interruptible(&vt_event_waitqueue);
138 static void __vt_event_queue(struct vt_event_wait *vw)
141 /* Prepare the event */
142 INIT_LIST_HEAD(&vw->list);
144 /* Queue our event */
145 spin_lock_irqsave(&vt_event_lock, flags);
146 list_add(&vw->list, &vt_events);
147 spin_unlock_irqrestore(&vt_event_lock, flags);
150 static void __vt_event_wait(struct vt_event_wait *vw)
152 /* Wait for it to pass */
153 wait_event_interruptible(vt_event_waitqueue, vw->done);
156 static void __vt_event_dequeue(struct vt_event_wait *vw)
161 spin_lock_irqsave(&vt_event_lock, flags);
163 spin_unlock_irqrestore(&vt_event_lock, flags);
167 * vt_event_wait - wait for an event
170 * Waits for an event to occur which completes our vt_event_wait
171 * structure. On return the structure has wv->done set to 1 for success
172 * or 0 if some event such as a signal ended the wait.
175 static void vt_event_wait(struct vt_event_wait *vw)
177 __vt_event_queue(vw);
179 __vt_event_dequeue(vw);
183 * vt_event_wait_ioctl - event ioctl handler
184 * @arg: argument to ioctl
186 * Implement the VT_WAITEVENT ioctl using the VT event interface
189 static int vt_event_wait_ioctl(struct vt_event __user *event)
191 struct vt_event_wait vw;
193 if (copy_from_user(&vw.event, event, sizeof(struct vt_event)))
195 /* Highest supported event for now */
196 if (vw.event.event & ~VT_MAX_EVENT)
200 /* If it occurred report it */
202 if (copy_to_user(event, &vw.event, sizeof(struct vt_event)))
210 * vt_waitactive - active console wait
214 * Helper for event waits. Used to implement the legacy
215 * event waiting ioctls in terms of events
218 int vt_waitactive(int n)
220 struct vt_event_wait vw;
222 vw.event.event = VT_EVENT_SWITCH;
223 __vt_event_queue(&vw);
224 if (n == fg_console + 1) {
225 __vt_event_dequeue(&vw);
228 __vt_event_wait(&vw);
229 __vt_event_dequeue(&vw);
232 } while (vw.event.newev != n);
237 * these are the valid i/o ports we're allowed to change. they map all the
240 #define GPFIRST 0x3b4
242 #define GPNUM (GPLAST - GPFIRST + 1)
247 do_fontx_ioctl(struct vc_data *vc, int cmd, struct consolefontdesc __user *user_cfd, int perm, struct console_font_op *op)
249 struct consolefontdesc cfdarg;
252 if (copy_from_user(&cfdarg, user_cfd, sizeof(struct consolefontdesc)))
259 op->op = KD_FONT_OP_SET;
260 op->flags = KD_FONT_FLAG_OLD;
262 op->height = cfdarg.charheight;
263 op->charcount = cfdarg.charcount;
264 op->data = cfdarg.chardata;
265 return con_font_op(vc, op);
268 op->op = KD_FONT_OP_GET;
269 op->flags = KD_FONT_FLAG_OLD;
271 op->height = cfdarg.charheight;
272 op->charcount = cfdarg.charcount;
273 op->data = cfdarg.chardata;
274 i = con_font_op(vc, op);
277 cfdarg.charheight = op->height;
278 cfdarg.charcount = op->charcount;
279 if (copy_to_user(user_cfd, &cfdarg, sizeof(struct consolefontdesc)))
287 do_unimap_ioctl(int cmd, struct unimapdesc __user *user_ud, int perm, struct vc_data *vc)
289 struct unimapdesc tmp;
291 if (copy_from_user(&tmp, user_ud, sizeof tmp))
297 return con_set_unimap(vc, tmp.entry_ct, tmp.entries);
299 if (!perm && fg_console != vc->vc_num)
301 return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct), tmp.entries);
306 /* deallocate a single console, if possible (leave 0) */
307 static int vt_disallocate(unsigned int vc_num)
309 struct vc_data *vc = NULL;
316 vc = vc_deallocate(vc_num);
319 if (vc && vc_num >= MIN_NR_CONSOLES)
320 tty_port_put(&vc->port);
325 /* deallocate all unused consoles, but leave 0 */
326 static void vt_disallocate_all(void)
328 struct vc_data *vc[MAX_NR_CONSOLES];
332 for (i = 1; i < MAX_NR_CONSOLES; i++)
334 vc[i] = vc_deallocate(i);
339 for (i = 1; i < MAX_NR_CONSOLES; i++) {
340 if (vc[i] && i >= MIN_NR_CONSOLES)
341 tty_port_put(&vc[i]->port);
347 * We handle the console-specific ioctl's here. We allow the
348 * capability to modify any console, not just the fg_console.
350 int vt_ioctl(struct tty_struct *tty,
351 unsigned int cmd, unsigned long arg)
353 struct vc_data *vc = tty->driver_data;
354 struct console_font_op op; /* used in multiple places here */
355 unsigned int console = vc->vc_num;
358 void __user *up = (void __user *)arg;
363 * To have permissions to do most of the vt ioctls, we either have
364 * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
367 if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
372 ret = tioclinux(tty, arg);
378 * The use of PIT_TICK_RATE is historic, it used to be
379 * the platform-dependent CLOCK_TICK_RATE between 2.6.12
380 * and 2.6.36, which was a minor but unfortunate ABI
381 * change. kd_mksound is locked by the input layer.
384 arg = PIT_TICK_RATE / arg;
392 unsigned int ticks, count;
395 * Generate the tone for the appropriate number of ticks.
396 * If the time is zero, turn off sound ourselves.
398 ticks = msecs_to_jiffies((arg >> 16) & 0xffff);
399 count = ticks ? (arg & 0xffff) : 0;
401 count = PIT_TICK_RATE / count;
402 kd_mksound(count, ticks);
411 ret = put_user(ucval, (char __user *)arg);
415 * These cannot be implemented on any machine that implements
416 * ioperm() in user level (such as Alpha PCs) or not at all.
418 * XXX: you should never use these, just call ioperm directly..
424 * KDADDIO and KDDELIO may be able to add ports beyond what
425 * we reject here, but to be safe...
427 * These are locked internally via sys_ioperm
429 if (arg < GPFIRST || arg > GPLAST) {
433 ret = ksys_ioperm(arg, 1, (cmd == KDADDIO)) ? -ENXIO : 0;
438 ret = ksys_ioperm(GPFIRST, GPNUM,
439 (cmd == KDENABIO)) ? -ENXIO : 0;
443 /* Linux m68k/i386 interface for setting the keyboard delay/repeat rate */
447 struct kbd_repeat kbrep;
449 if (!capable(CAP_SYS_TTY_CONFIG))
452 if (copy_from_user(&kbrep, up, sizeof(struct kbd_repeat))) {
456 ret = kbd_rate(&kbrep);
459 if (copy_to_user(up, &kbrep, sizeof(struct kbd_repeat)))
466 * currently, setting the mode from KD_TEXT to KD_GRAPHICS
467 * doesn't do a whole lot. i'm not sure if it should do any
468 * restoration of modes or what...
470 * XXX It should at least call into the driver, fbdev's definitely
471 * need to restore their engine state. --BenH
488 if (vc->vc_mode == (unsigned char) arg) {
492 vc->vc_mode = (unsigned char) arg;
493 if (console != fg_console) {
498 * explicitly blank/unblank the screen if switching modes
501 do_unblank_screen(1);
514 * these work like a combination of mmap and KDENABIO.
515 * this could be easily finished.
523 ret = vt_do_kdskbmode(console, arg);
525 tty_ldisc_flush(tty);
529 uival = vt_do_kdgkbmode(console);
530 ret = put_user(uival, (int __user *)arg);
533 /* this could be folded into KDSKBMODE, but for compatibility
534 reasons it is not so easy to fold KDGKBMETA into KDGKBMODE */
536 ret = vt_do_kdskbmeta(console, arg);
540 /* FIXME: should review whether this is worth locking */
541 uival = vt_do_kdgkbmeta(console);
543 ret = put_user(uival, (int __user *)arg);
548 if(!capable(CAP_SYS_TTY_CONFIG))
550 ret = vt_do_kbkeycode_ioctl(cmd, up, perm);
555 ret = vt_do_kdsk_ioctl(cmd, up, perm, console);
560 ret = vt_do_kdgkb_ioctl(cmd, up, perm);
563 /* Diacritical processing. Handled in keyboard.c as it has
564 to operate on the keyboard locks and structures */
569 ret = vt_do_diacrit(cmd, up, perm);
572 /* the ioctls below read/set the flags usually shown in the leds */
573 /* don't use them - they will go away without warning */
578 ret = vt_do_kdskled(console, cmd, arg, perm);
582 * A process can indicate its willingness to accept signals
583 * generated by pressing an appropriate key combination.
584 * Thus, one can have a daemon that e.g. spawns a new console
585 * upon a keypress and then changes to it.
586 * See also the kbrequest field of inittab(5).
590 if (!perm || !capable(CAP_KILL))
592 if (!valid_signal(arg) || arg < 1 || arg == SIGKILL)
595 spin_lock_irq(&vt_spawn_con.lock);
596 put_pid(vt_spawn_con.pid);
597 vt_spawn_con.pid = get_pid(task_pid(current));
598 vt_spawn_con.sig = arg;
599 spin_unlock_irq(&vt_spawn_con.lock);
610 if (copy_from_user(&tmp, up, sizeof(struct vt_mode))) {
614 if (tmp.mode != VT_AUTO && tmp.mode != VT_PROCESS) {
620 /* the frsig is ignored, so we set it to 0 */
621 vc->vt_mode.frsig = 0;
623 vc->vt_pid = get_pid(task_pid(current));
624 /* no switch is required -- saw@shade.msu.ru */
636 memcpy(&tmp, &vc->vt_mode, sizeof(struct vt_mode));
639 rc = copy_to_user(up, &tmp, sizeof(struct vt_mode));
646 * Returns global vt state. Note that VT 0 is always open, since
647 * it's an alias for the current VT, and people can't use it here.
648 * We cannot return state for more than 16 VTs, since v_state is short.
652 struct vt_stat __user *vtstat = up;
653 unsigned short state, mask;
655 if (put_user(fg_console + 1, &vtstat->v_active))
658 state = 1; /* /dev/tty0 is always open */
659 console_lock(); /* required by vt_in_use() */
660 for (i = 0, mask = 2; i < MAX_NR_CONSOLES && mask;
665 ret = put_user(state, &vtstat->v_state);
671 * Returns the first available (non-opened) console.
674 console_lock(); /* required by vt_in_use() */
675 for (i = 0; i < MAX_NR_CONSOLES; ++i)
679 uival = i < MAX_NR_CONSOLES ? (i+1) : -1;
683 * ioctl(fd, VT_ACTIVATE, num) will cause us to switch to vt # num,
684 * with num >= 1 (switches to vt 0, our console, are not allowed, just
685 * to preserve sanity).
690 if (arg == 0 || arg > MAX_NR_CONSOLES)
694 arg = array_index_nospec(arg, MAX_NR_CONSOLES);
696 ret = vc_allocate(arg);
706 struct vt_setactivate vsa;
711 if (copy_from_user(&vsa, (struct vt_setactivate __user *)arg,
712 sizeof(struct vt_setactivate))) {
716 if (vsa.console == 0 || vsa.console > MAX_NR_CONSOLES)
720 vsa.console = array_index_nospec(vsa.console,
723 ret = vc_allocate(vsa.console);
726 /* This is safe providing we don't drop the
727 console sem between vc_allocate and
728 finishing referencing nvc */
729 nvc = vc_cons[vsa.console].d;
730 nvc->vt_mode = vsa.mode;
731 nvc->vt_mode.frsig = 0;
732 put_pid(nvc->vt_pid);
733 nvc->vt_pid = get_pid(task_pid(current));
738 /* Commence switch and lock */
739 /* Review set_console locks */
740 set_console(vsa.console);
746 * wait until the specified VT has been activated
751 if (arg == 0 || arg > MAX_NR_CONSOLES)
754 ret = vt_waitactive(arg);
758 * If a vt is under process control, the kernel will not switch to it
759 * immediately, but postpone the operation until the process calls this
760 * ioctl, allowing the switch to complete.
762 * According to the X sources this is the behavior:
763 * 0: pending switch-from not OK
764 * 1: pending switch-from OK
765 * 2: completed switch-to OK
772 if (vc->vt_mode.mode != VT_PROCESS) {
778 * Switching-from response
780 if (vc->vt_newvt >= 0) {
783 * Switch disallowed, so forget we were trying
790 * The current vt has been released, so
791 * complete the switch.
794 newvt = vc->vt_newvt;
796 ret = vc_allocate(newvt);
802 * When we actually do the console switch,
803 * make sure we are atomic with respect to
804 * other console switches..
806 complete_change_console(vc_cons[newvt].d);
810 * Switched-to response
813 * If it's just an ACK, ignore it
815 if (arg != VT_ACKACQ)
822 * Disallocate memory associated to VT (but leave VT1)
825 if (arg > MAX_NR_CONSOLES) {
830 vt_disallocate_all();
832 ret = vt_disallocate(--arg);
837 struct vt_sizes __user *vtsizes = up;
843 if (get_user(ll, &vtsizes->v_rows) ||
844 get_user(cc, &vtsizes->v_cols))
848 for (i = 0; i < MAX_NR_CONSOLES; i++) {
852 vc->vc_resize_user = 1;
853 /* FIXME: review v tty lock */
854 vc_resize(vc_cons[i].d, cc, ll);
867 if (copy_from_user(&v, up, sizeof(struct vt_consize)))
869 /* FIXME: Should check the copies properly */
871 v.v_vlin = vc->vc_scan_lines;
873 int rows = v.v_vlin/v.v_clin;
874 if (v.v_rows != rows) {
875 if (v.v_rows) /* Parameters don't add up */
880 if (v.v_vcol && v.v_ccol) {
881 int cols = v.v_vcol/v.v_ccol;
882 if (v.v_cols != cols) {
892 for (i = 0; i < MAX_NR_CONSOLES; i++) {
901 int save_scan_lines = vcp->vc_scan_lines;
902 int save_cell_height = vcp->vc_cell_height;
905 vcp->vc_scan_lines = v.v_vlin;
907 vcp->vc_cell_height = v.v_clin;
908 vcp->vc_resize_user = 1;
909 ret = vc_resize(vcp, v.v_cols, v.v_rows);
911 vcp->vc_scan_lines = save_scan_lines;
912 vcp->vc_cell_height = save_cell_height;
925 op.op = KD_FONT_OP_SET;
926 op.flags = KD_FONT_FLAG_OLD | KD_FONT_FLAG_DONT_RECALC; /* Compatibility */
931 ret = con_font_op(vc, &op);
936 op.op = KD_FONT_OP_GET;
937 op.flags = KD_FONT_FLAG_OLD;
942 ret = con_font_op(vc, &op);
950 ret = con_set_cmap(up);
954 ret = con_get_cmap(up);
959 ret = do_fontx_ioctl(vc, cmd, up, perm, &op);
967 #ifdef BROKEN_GRAPHICS_PROGRAMS
968 /* With BROKEN_GRAPHICS_PROGRAMS defined, the default
969 font is not saved. */
974 op.op = KD_FONT_OP_SET_DEFAULT;
976 ret = con_font_op(vc, &op);
980 con_set_default_unimap(vc);
988 if (copy_from_user(&op, up, sizeof(op))) {
992 if (!perm && op.op != KD_FONT_OP_GET)
994 ret = con_font_op(vc, &op);
997 if (copy_to_user(up, &op, sizeof(op)))
1006 ret = con_set_trans_old(up);
1010 ret = con_get_trans_old(up);
1013 case PIO_UNISCRNMAP:
1017 ret = con_set_trans_new(up);
1020 case GIO_UNISCRNMAP:
1021 ret = con_get_trans_new(up);
1027 con_clear_unimap(vc);
1032 ret = do_unimap_ioctl(cmd, up, perm, vc);
1036 if (!capable(CAP_SYS_TTY_CONFIG))
1038 vt_dont_switch = true;
1040 case VT_UNLOCKSWITCH:
1041 if (!capable(CAP_SYS_TTY_CONFIG))
1043 vt_dont_switch = false;
1045 case VT_GETHIFONTMASK:
1046 ret = put_user(vc->vc_hi_font_mask,
1047 (unsigned short __user *)arg);
1050 ret = vt_event_wait_ioctl((struct vt_event __user *)arg);
1059 void reset_vc(struct vc_data *vc)
1061 vc->vc_mode = KD_TEXT;
1062 vt_reset_unicode(vc->vc_num);
1063 vc->vt_mode.mode = VT_AUTO;
1064 vc->vt_mode.waitv = 0;
1065 vc->vt_mode.relsig = 0;
1066 vc->vt_mode.acqsig = 0;
1067 vc->vt_mode.frsig = 0;
1068 put_pid(vc->vt_pid);
1071 if (!in_interrupt()) /* Via keyboard.c:SAK() - akpm */
1075 void vc_SAK(struct work_struct *work)
1078 container_of(work, struct vc, SAK_work);
1080 struct tty_struct *tty;
1085 /* FIXME: review tty ref counting */
1088 * SAK should also work in all raw modes and reset
1098 #ifdef CONFIG_COMPAT
1100 struct compat_consolefontdesc {
1101 unsigned short charcount; /* characters in font (256 or 512) */
1102 unsigned short charheight; /* scan lines per character (1-32) */
1103 compat_caddr_t chardata; /* font data in expanded form */
1107 compat_fontx_ioctl(struct vc_data *vc, int cmd,
1108 struct compat_consolefontdesc __user *user_cfd,
1109 int perm, struct console_font_op *op)
1111 struct compat_consolefontdesc cfdarg;
1114 if (copy_from_user(&cfdarg, user_cfd, sizeof(struct compat_consolefontdesc)))
1121 op->op = KD_FONT_OP_SET;
1122 op->flags = KD_FONT_FLAG_OLD;
1124 op->height = cfdarg.charheight;
1125 op->charcount = cfdarg.charcount;
1126 op->data = compat_ptr(cfdarg.chardata);
1127 return con_font_op(vc, op);
1130 op->op = KD_FONT_OP_GET;
1131 op->flags = KD_FONT_FLAG_OLD;
1133 op->height = cfdarg.charheight;
1134 op->charcount = cfdarg.charcount;
1135 op->data = compat_ptr(cfdarg.chardata);
1136 i = con_font_op(vc, op);
1139 cfdarg.charheight = op->height;
1140 cfdarg.charcount = op->charcount;
1141 if (copy_to_user(user_cfd, &cfdarg, sizeof(struct compat_consolefontdesc)))
1148 struct compat_console_font_op {
1149 compat_uint_t op; /* operation code KD_FONT_OP_* */
1150 compat_uint_t flags; /* KD_FONT_FLAG_* */
1151 compat_uint_t width, height; /* font size */
1152 compat_uint_t charcount;
1153 compat_caddr_t data; /* font data with height fixed to 32 */
1157 compat_kdfontop_ioctl(struct compat_console_font_op __user *fontop,
1158 int perm, struct console_font_op *op, struct vc_data *vc)
1162 if (copy_from_user(op, fontop, sizeof(struct compat_console_font_op)))
1164 if (!perm && op->op != KD_FONT_OP_GET)
1166 op->data = compat_ptr(((struct compat_console_font_op *)op)->data);
1167 i = con_font_op(vc, op);
1170 ((struct compat_console_font_op *)op)->data = (unsigned long)op->data;
1171 if (copy_to_user(fontop, op, sizeof(struct compat_console_font_op)))
1176 struct compat_unimapdesc {
1177 unsigned short entry_ct;
1178 compat_caddr_t entries;
1182 compat_unimap_ioctl(unsigned int cmd, struct compat_unimapdesc __user *user_ud,
1183 int perm, struct vc_data *vc)
1185 struct compat_unimapdesc tmp;
1186 struct unipair __user *tmp_entries;
1188 if (copy_from_user(&tmp, user_ud, sizeof tmp))
1190 tmp_entries = compat_ptr(tmp.entries);
1195 return con_set_unimap(vc, tmp.entry_ct, tmp_entries);
1197 if (!perm && fg_console != vc->vc_num)
1199 return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct), tmp_entries);
1204 long vt_compat_ioctl(struct tty_struct *tty,
1205 unsigned int cmd, unsigned long arg)
1207 struct vc_data *vc = tty->driver_data;
1208 struct console_font_op op; /* used in multiple places here */
1209 void __user *up = (void __user *)arg;
1214 * To have permissions to do most of the vt ioctls, we either have
1215 * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
1218 if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
1223 * these need special handlers for incompatible data structures
1227 ret = compat_fontx_ioctl(vc, cmd, up, perm, &op);
1231 ret = compat_kdfontop_ioctl(up, perm, &op, vc);
1236 ret = compat_unimap_ioctl(cmd, up, perm, vc);
1240 * all these treat 'arg' as an integer
1259 case VT_DISALLOCATE:
1265 * the rest has a compatible data structure behind arg,
1266 * but we have to convert it to a proper 64 bit pointer.
1269 arg = (unsigned long)compat_ptr(arg);
1276 return vt_ioctl(tty, cmd, arg);
1280 #endif /* CONFIG_COMPAT */
1284 * Performs the back end of a vt switch. Called under the console
1287 static void complete_change_console(struct vc_data *vc)
1289 unsigned char old_vc_mode;
1290 int old = fg_console;
1292 last_console = fg_console;
1295 * If we're switching, we could be going from KD_GRAPHICS to
1296 * KD_TEXT mode or vice versa, which means we need to blank or
1297 * unblank the screen later.
1299 old_vc_mode = vc_cons[fg_console].d->vc_mode;
1303 * This can't appear below a successful kill_pid(). If it did,
1304 * then the *blank_screen operation could occur while X, having
1305 * received acqsig, is waking up on another processor. This
1306 * condition can lead to overlapping accesses to the VGA range
1307 * and the framebuffer (causing system lockups).
1309 * To account for this we duplicate this code below only if the
1310 * controlling process is gone and we've called reset_vc.
1312 if (old_vc_mode != vc->vc_mode) {
1313 if (vc->vc_mode == KD_TEXT)
1314 do_unblank_screen(1);
1320 * If this new console is under process control, send it a signal
1321 * telling it that it has acquired. Also check if it has died and
1322 * clean up (similar to logic employed in change_console())
1324 if (vc->vt_mode.mode == VT_PROCESS) {
1326 * Send the signal as privileged - kill_pid() will
1327 * tell us if the process has gone or something else
1330 if (kill_pid(vc->vt_pid, vc->vt_mode.acqsig, 1) != 0) {
1332 * The controlling process has died, so we revert back to
1333 * normal operation. In this case, we'll also change back
1334 * to KD_TEXT mode. I'm not sure if this is strictly correct
1335 * but it saves the agony when the X server dies and the screen
1336 * remains blanked due to KD_GRAPHICS! It would be nice to do
1337 * this outside of VT_PROCESS but there is no single process
1338 * to account for and tracking tty count may be undesirable.
1342 if (old_vc_mode != vc->vc_mode) {
1343 if (vc->vc_mode == KD_TEXT)
1344 do_unblank_screen(1);
1352 * Wake anyone waiting for their VT to activate
1354 vt_event_post(VT_EVENT_SWITCH, old, vc->vc_num);
1359 * Performs the front-end of a vt switch
1361 void change_console(struct vc_data *new_vc)
1365 if (!new_vc || new_vc->vc_num == fg_console || vt_dont_switch)
1369 * If this vt is in process mode, then we need to handshake with
1370 * that process before switching. Essentially, we store where that
1371 * vt wants to switch to and wait for it to tell us when it's done
1372 * (via VT_RELDISP ioctl).
1374 * We also check to see if the controlling process still exists.
1375 * If it doesn't, we reset this vt to auto mode and continue.
1376 * This is a cheap way to track process control. The worst thing
1377 * that can happen is: we send a signal to a process, it dies, and
1378 * the switch gets "lost" waiting for a response; hopefully, the
1379 * user will try again, we'll detect the process is gone (unless
1380 * the user waits just the right amount of time :-) and revert the
1381 * vt to auto control.
1383 vc = vc_cons[fg_console].d;
1384 if (vc->vt_mode.mode == VT_PROCESS) {
1386 * Send the signal as privileged - kill_pid() will
1387 * tell us if the process has gone or something else
1390 * We need to set vt_newvt *before* sending the signal or we
1393 vc->vt_newvt = new_vc->vc_num;
1394 if (kill_pid(vc->vt_pid, vc->vt_mode.relsig, 1) == 0) {
1396 * It worked. Mark the vt to switch to and
1397 * return. The process needs to send us a
1398 * VT_RELDISP ioctl to complete the switch.
1404 * The controlling process has died, so we revert back to
1405 * normal operation. In this case, we'll also change back
1406 * to KD_TEXT mode. I'm not sure if this is strictly correct
1407 * but it saves the agony when the X server dies and the screen
1408 * remains blanked due to KD_GRAPHICS! It would be nice to do
1409 * this outside of VT_PROCESS but there is no single process
1410 * to account for and tracking tty count may be undesirable.
1415 * Fall through to normal (VT_AUTO) handling of the switch...
1420 * Ignore all switches in KD_GRAPHICS+VT_AUTO mode
1422 if (vc->vc_mode == KD_GRAPHICS)
1425 complete_change_console(new_vc);
1428 /* Perform a kernel triggered VT switch for suspend/resume */
1430 static int disable_vt_switch;
1432 int vt_move_to_console(unsigned int vt, int alloc)
1437 /* Graphics mode - up to X */
1438 if (disable_vt_switch) {
1444 if (alloc && vc_allocate(vt)) {
1445 /* we can't have a free VC for now. Too bad,
1446 * we don't want to mess the screen for now. */
1451 if (set_console(vt)) {
1453 * We're unable to switch to the SUSPEND_CONSOLE.
1454 * Let the calling function know so it can decide
1461 if (vt_waitactive(vt + 1)) {
1462 pr_debug("Suspend: Can't switch VCs.");
1469 * Normally during a suspend, we allocate a new console and switch to it.
1470 * When we resume, we switch back to the original console. This switch
1471 * can be slow, so on systems where the framebuffer can handle restoration
1472 * of video registers anyways, there's little point in doing the console
1473 * switch. This function allows you to disable it by passing it '0'.
1475 void pm_set_vt_switch(int do_switch)
1478 disable_vt_switch = !do_switch;
1481 EXPORT_SYMBOL(pm_set_vt_switch);