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 * @event: argument to ioctl (the event)
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
213 * Helper for event waits. Used to implement the legacy
214 * event waiting ioctls in terms of events
217 int vt_waitactive(int n)
219 struct vt_event_wait vw;
221 vw.event.event = VT_EVENT_SWITCH;
222 __vt_event_queue(&vw);
223 if (n == fg_console + 1) {
224 __vt_event_dequeue(&vw);
227 __vt_event_wait(&vw);
228 __vt_event_dequeue(&vw);
231 } while (vw.event.newev != n);
236 * these are the valid i/o ports we're allowed to change. they map all the
239 #define GPFIRST 0x3b4
241 #define GPNUM (GPLAST - GPFIRST + 1)
244 * currently, setting the mode from KD_TEXT to KD_GRAPHICS doesn't do a whole
245 * lot. i'm not sure if it should do any restoration of modes or what...
247 * XXX It should at least call into the driver, fbdev's definitely need to
248 * restore their engine state. --BenH
250 static int vt_kdsetmode(struct vc_data *vc, unsigned long mode)
265 /* FIXME: this needs the console lock extending */
266 if (vc->vc_mode == mode)
270 if (vc->vc_num != fg_console)
273 /* explicitly blank/unblank the screen if switching modes */
276 do_unblank_screen(1);
284 static int vt_k_ioctl(struct tty_struct *tty, unsigned int cmd,
285 unsigned long arg, bool perm)
287 struct vc_data *vc = tty->driver_data;
288 void __user *up = (void __user *)arg;
289 unsigned int console = vc->vc_num;
297 * The use of PIT_TICK_RATE is historic, it used to be
298 * the platform-dependent CLOCK_TICK_RATE between 2.6.12
299 * and 2.6.36, which was a minor but unfortunate ABI
300 * change. kd_mksound is locked by the input layer.
303 arg = PIT_TICK_RATE / arg;
311 unsigned int ticks, count;
314 * Generate the tone for the appropriate number of ticks.
315 * If the time is zero, turn off sound ourselves.
317 ticks = msecs_to_jiffies((arg >> 16) & 0xffff);
318 count = ticks ? (arg & 0xffff) : 0;
320 count = PIT_TICK_RATE / count;
321 kd_mksound(count, ticks);
329 return put_user(KB_101, (char __user *)arg);
332 * These cannot be implemented on any machine that implements
333 * ioperm() in user level (such as Alpha PCs) or not at all.
335 * XXX: you should never use these, just call ioperm directly..
341 * KDADDIO and KDDELIO may be able to add ports beyond what
342 * we reject here, but to be safe...
344 * These are locked internally via sys_ioperm
346 if (arg < GPFIRST || arg > GPLAST)
349 return ksys_ioperm(arg, 1, (cmd == KDADDIO)) ? -ENXIO : 0;
353 return ksys_ioperm(GPFIRST, GPNUM,
354 (cmd == KDENABIO)) ? -ENXIO : 0;
357 /* Linux m68k/i386 interface for setting the keyboard delay/repeat rate */
361 struct kbd_repeat kbrep;
363 if (!capable(CAP_SYS_TTY_CONFIG))
366 if (copy_from_user(&kbrep, up, sizeof(struct kbd_repeat)))
369 ret = kbd_rate(&kbrep);
372 if (copy_to_user(up, &kbrep, sizeof(struct kbd_repeat)))
381 return vt_kdsetmode(vc, arg);
384 return put_user(vc->vc_mode, (int __user *)arg);
389 * these work like a combination of mmap and KDENABIO.
390 * this could be easily finished.
397 ret = vt_do_kdskbmode(console, arg);
400 tty_ldisc_flush(tty);
404 return put_user(vt_do_kdgkbmode(console), (int __user *)arg);
406 /* this could be folded into KDSKBMODE, but for compatibility
407 reasons it is not so easy to fold KDGKBMETA into KDGKBMODE */
409 return vt_do_kdskbmeta(console, arg);
412 /* FIXME: should review whether this is worth locking */
413 return put_user(vt_do_kdgkbmeta(console), (int __user *)arg);
417 if(!capable(CAP_SYS_TTY_CONFIG))
419 return vt_do_kbkeycode_ioctl(cmd, up, perm);
423 return vt_do_kdsk_ioctl(cmd, up, perm, console);
427 return vt_do_kdgkb_ioctl(cmd, up, perm);
429 /* Diacritical processing. Handled in keyboard.c as it has
430 to operate on the keyboard locks and structures */
435 return vt_do_diacrit(cmd, up, perm);
437 /* the ioctls below read/set the flags usually shown in the leds */
438 /* don't use them - they will go away without warning */
443 return vt_do_kdskled(console, cmd, arg, perm);
446 * A process can indicate its willingness to accept signals
447 * generated by pressing an appropriate key combination.
448 * Thus, one can have a daemon that e.g. spawns a new console
449 * upon a keypress and then changes to it.
450 * See also the kbrequest field of inittab(5).
453 if (!perm || !capable(CAP_KILL))
455 if (!valid_signal(arg) || arg < 1 || arg == SIGKILL)
458 spin_lock_irq(&vt_spawn_con.lock);
459 put_pid(vt_spawn_con.pid);
460 vt_spawn_con.pid = get_pid(task_pid(current));
461 vt_spawn_con.sig = arg;
462 spin_unlock_irq(&vt_spawn_con.lock);
466 struct console_font_op op;
468 if (copy_from_user(&op, up, sizeof(op)))
470 if (!perm && op.op != KD_FONT_OP_GET)
472 ret = con_font_op(vc, &op);
475 if (copy_to_user(up, &op, sizeof(op)))
487 static inline int do_fontx_ioctl(int cmd,
488 struct consolefontdesc __user *user_cfd,
489 struct console_font_op *op)
491 struct consolefontdesc cfdarg;
494 if (copy_from_user(&cfdarg, user_cfd, sizeof(struct consolefontdesc)))
499 op->op = KD_FONT_OP_SET;
500 op->flags = KD_FONT_FLAG_OLD;
502 op->height = cfdarg.charheight;
503 op->charcount = cfdarg.charcount;
504 op->data = cfdarg.chardata;
505 return con_font_op(vc_cons[fg_console].d, op);
507 op->op = KD_FONT_OP_GET;
508 op->flags = KD_FONT_FLAG_OLD;
510 op->height = cfdarg.charheight;
511 op->charcount = cfdarg.charcount;
512 op->data = cfdarg.chardata;
513 i = con_font_op(vc_cons[fg_console].d, op);
516 cfdarg.charheight = op->height;
517 cfdarg.charcount = op->charcount;
518 if (copy_to_user(user_cfd, &cfdarg, sizeof(struct consolefontdesc)))
526 static int vt_io_fontreset(struct console_font_op *op)
530 if (__is_defined(BROKEN_GRAPHICS_PROGRAMS)) {
532 * With BROKEN_GRAPHICS_PROGRAMS defined, the default font is
538 op->op = KD_FONT_OP_SET_DEFAULT;
540 ret = con_font_op(vc_cons[fg_console].d, op);
545 con_set_default_unimap(vc_cons[fg_console].d);
551 static inline int do_unimap_ioctl(int cmd, struct unimapdesc __user *user_ud,
554 struct unimapdesc tmp;
556 if (copy_from_user(&tmp, user_ud, sizeof tmp))
560 return con_set_unimap(vc, tmp.entry_ct, tmp.entries);
562 if (fg_console != vc->vc_num)
564 return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct),
570 static int vt_io_ioctl(struct vc_data *vc, unsigned int cmd, void __user *up,
573 struct console_font_op op; /* used in multiple places here */
579 op.op = KD_FONT_OP_SET;
580 op.flags = KD_FONT_FLAG_OLD | KD_FONT_FLAG_DONT_RECALC; /* Compatibility */
585 return con_font_op(vc_cons[fg_console].d, &op);
588 op.op = KD_FONT_OP_GET;
589 op.flags = KD_FONT_FLAG_OLD;
594 return con_font_op(vc_cons[fg_console].d, &op);
599 return con_set_cmap(up);
602 return con_get_cmap(up);
610 return do_fontx_ioctl(cmd, up, &op);
616 return vt_io_fontreset(&op);
621 return con_set_trans_old(up);
624 return con_get_trans_old(up);
629 return con_set_trans_new(up);
632 return con_get_trans_new(up);
637 con_clear_unimap(vc);
645 return do_unimap_ioctl(cmd, up, vc);
654 static int vt_reldisp(struct vc_data *vc, unsigned int swtch)
658 if (vc->vt_mode.mode != VT_PROCESS)
661 /* Switched-to response */
662 if (vc->vt_newvt < 0) {
663 /* If it's just an ACK, ignore it */
664 return swtch == VT_ACKACQ ? 0 : -EINVAL;
667 /* Switching-from response */
669 /* Switch disallowed, so forget we were trying to do it. */
674 /* The current vt has been released, so complete the switch. */
675 newvt = vc->vt_newvt;
677 ret = vc_allocate(newvt);
682 * When we actually do the console switch, make sure we are atomic with
683 * respect to other console switches..
685 complete_change_console(vc_cons[newvt].d);
690 static int vt_setactivate(struct vt_setactivate __user *sa)
692 struct vt_setactivate vsa;
696 if (copy_from_user(&vsa, sa, sizeof(vsa)))
698 if (vsa.console == 0 || vsa.console > MAX_NR_CONSOLES)
701 vsa.console = array_index_nospec(vsa.console, MAX_NR_CONSOLES + 1);
704 ret = vc_allocate(vsa.console);
711 * This is safe providing we don't drop the console sem between
712 * vc_allocate and finishing referencing nvc.
714 nvc = vc_cons[vsa.console].d;
715 nvc->vt_mode = vsa.mode;
716 nvc->vt_mode.frsig = 0;
717 put_pid(nvc->vt_pid);
718 nvc->vt_pid = get_pid(task_pid(current));
721 /* Commence switch and lock */
722 /* Review set_console locks */
723 set_console(vsa.console);
728 /* deallocate a single console, if possible (leave 0) */
729 static int vt_disallocate(unsigned int vc_num)
731 struct vc_data *vc = NULL;
738 vc = vc_deallocate(vc_num);
741 if (vc && vc_num >= MIN_NR_CONSOLES)
742 tty_port_put(&vc->port);
747 /* deallocate all unused consoles, but leave 0 */
748 static void vt_disallocate_all(void)
750 struct vc_data *vc[MAX_NR_CONSOLES];
754 for (i = 1; i < MAX_NR_CONSOLES; i++)
756 vc[i] = vc_deallocate(i);
761 for (i = 1; i < MAX_NR_CONSOLES; i++) {
762 if (vc[i] && i >= MIN_NR_CONSOLES)
763 tty_port_put(&vc[i]->port);
767 static int vt_resizex(struct vc_data *vc, struct vt_consize __user *cs)
772 if (copy_from_user(&v, cs, sizeof(struct vt_consize)))
776 pr_info_once("\"struct vt_consize\"->v_vlin is ignored. Please report if you need this.\n");
778 pr_info_once("\"struct vt_consize\"->v_clin is ignored. Please report if you need this.\n");
781 for (i = 0; i < MAX_NR_CONSOLES; i++) {
785 vc->vc_resize_user = 1;
786 vc_resize(vc, v.v_cols, v.v_rows);
795 * We handle the console-specific ioctl's here. We allow the
796 * capability to modify any console, not just the fg_console.
798 int vt_ioctl(struct tty_struct *tty,
799 unsigned int cmd, unsigned long arg)
801 struct vc_data *vc = tty->driver_data;
802 void __user *up = (void __user *)arg;
807 * To have permissions to do most of the vt ioctls, we either have
808 * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
811 if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
814 ret = vt_k_ioctl(tty, cmd, arg, perm);
815 if (ret != -ENOIOCTLCMD)
818 ret = vt_io_ioctl(vc, cmd, up, perm);
819 if (ret != -ENOIOCTLCMD)
824 return tioclinux(tty, arg);
831 if (copy_from_user(&tmp, up, sizeof(struct vt_mode)))
833 if (tmp.mode != VT_AUTO && tmp.mode != VT_PROCESS)
838 /* the frsig is ignored, so we set it to 0 */
839 vc->vt_mode.frsig = 0;
841 vc->vt_pid = get_pid(task_pid(current));
842 /* no switch is required -- saw@shade.msu.ru */
854 memcpy(&tmp, &vc->vt_mode, sizeof(struct vt_mode));
857 rc = copy_to_user(up, &tmp, sizeof(struct vt_mode));
864 * Returns global vt state. Note that VT 0 is always open, since
865 * it's an alias for the current VT, and people can't use it here.
866 * We cannot return state for more than 16 VTs, since v_state is short.
870 struct vt_stat __user *vtstat = up;
871 unsigned short state, mask;
873 if (put_user(fg_console + 1, &vtstat->v_active))
876 state = 1; /* /dev/tty0 is always open */
877 console_lock(); /* required by vt_in_use() */
878 for (i = 0, mask = 2; i < MAX_NR_CONSOLES && mask;
883 return put_user(state, &vtstat->v_state);
887 * Returns the first available (non-opened) console.
890 console_lock(); /* required by vt_in_use() */
891 for (i = 0; i < MAX_NR_CONSOLES; ++i)
895 i = i < MAX_NR_CONSOLES ? (i+1) : -1;
896 return put_user(i, (int __user *)arg);
899 * ioctl(fd, VT_ACTIVATE, num) will cause us to switch to vt # num,
900 * with num >= 1 (switches to vt 0, our console, are not allowed, just
901 * to preserve sanity).
906 if (arg == 0 || arg > MAX_NR_CONSOLES)
911 ret = vc_allocate(arg);
922 return vt_setactivate(up);
925 * wait until the specified VT has been activated
930 if (arg == 0 || arg > MAX_NR_CONSOLES)
932 return vt_waitactive(arg);
935 * If a vt is under process control, the kernel will not switch to it
936 * immediately, but postpone the operation until the process calls this
937 * ioctl, allowing the switch to complete.
939 * According to the X sources this is the behavior:
940 * 0: pending switch-from not OK
941 * 1: pending switch-from OK
942 * 2: completed switch-to OK
949 ret = vt_reldisp(vc, arg);
956 * Disallocate memory associated to VT (but leave VT1)
959 if (arg > MAX_NR_CONSOLES)
963 vt_disallocate_all();
965 return vt_disallocate(--arg);
970 struct vt_sizes __user *vtsizes = up;
976 if (get_user(ll, &vtsizes->v_rows) ||
977 get_user(cc, &vtsizes->v_cols))
981 for (i = 0; i < MAX_NR_CONSOLES; i++) {
985 vc->vc_resize_user = 1;
986 /* FIXME: review v tty lock */
987 vc_resize(vc_cons[i].d, cc, ll);
998 return vt_resizex(vc, up);
1001 if (!capable(CAP_SYS_TTY_CONFIG))
1003 vt_dont_switch = true;
1005 case VT_UNLOCKSWITCH:
1006 if (!capable(CAP_SYS_TTY_CONFIG))
1008 vt_dont_switch = false;
1010 case VT_GETHIFONTMASK:
1011 return put_user(vc->vc_hi_font_mask,
1012 (unsigned short __user *)arg);
1014 return vt_event_wait_ioctl((struct vt_event __user *)arg);
1016 return -ENOIOCTLCMD;
1022 void reset_vc(struct vc_data *vc)
1024 vc->vc_mode = KD_TEXT;
1025 vt_reset_unicode(vc->vc_num);
1026 vc->vt_mode.mode = VT_AUTO;
1027 vc->vt_mode.waitv = 0;
1028 vc->vt_mode.relsig = 0;
1029 vc->vt_mode.acqsig = 0;
1030 vc->vt_mode.frsig = 0;
1031 put_pid(vc->vt_pid);
1034 if (!in_interrupt()) /* Via keyboard.c:SAK() - akpm */
1038 void vc_SAK(struct work_struct *work)
1041 container_of(work, struct vc, SAK_work);
1043 struct tty_struct *tty;
1048 /* FIXME: review tty ref counting */
1051 * SAK should also work in all raw modes and reset
1061 #ifdef CONFIG_COMPAT
1063 struct compat_consolefontdesc {
1064 unsigned short charcount; /* characters in font (256 or 512) */
1065 unsigned short charheight; /* scan lines per character (1-32) */
1066 compat_caddr_t chardata; /* font data in expanded form */
1070 compat_fontx_ioctl(int cmd, struct compat_consolefontdesc __user *user_cfd,
1071 int perm, struct console_font_op *op)
1073 struct compat_consolefontdesc cfdarg;
1076 if (copy_from_user(&cfdarg, user_cfd, sizeof(struct compat_consolefontdesc)))
1083 op->op = KD_FONT_OP_SET;
1084 op->flags = KD_FONT_FLAG_OLD;
1086 op->height = cfdarg.charheight;
1087 op->charcount = cfdarg.charcount;
1088 op->data = compat_ptr(cfdarg.chardata);
1089 return con_font_op(vc_cons[fg_console].d, op);
1091 op->op = KD_FONT_OP_GET;
1092 op->flags = KD_FONT_FLAG_OLD;
1094 op->height = cfdarg.charheight;
1095 op->charcount = cfdarg.charcount;
1096 op->data = compat_ptr(cfdarg.chardata);
1097 i = con_font_op(vc_cons[fg_console].d, op);
1100 cfdarg.charheight = op->height;
1101 cfdarg.charcount = op->charcount;
1102 if (copy_to_user(user_cfd, &cfdarg, sizeof(struct compat_consolefontdesc)))
1109 struct compat_console_font_op {
1110 compat_uint_t op; /* operation code KD_FONT_OP_* */
1111 compat_uint_t flags; /* KD_FONT_FLAG_* */
1112 compat_uint_t width, height; /* font size */
1113 compat_uint_t charcount;
1114 compat_caddr_t data; /* font data with height fixed to 32 */
1118 compat_kdfontop_ioctl(struct compat_console_font_op __user *fontop,
1119 int perm, struct console_font_op *op, struct vc_data *vc)
1123 if (copy_from_user(op, fontop, sizeof(struct compat_console_font_op)))
1125 if (!perm && op->op != KD_FONT_OP_GET)
1127 op->data = compat_ptr(((struct compat_console_font_op *)op)->data);
1128 i = con_font_op(vc, op);
1131 ((struct compat_console_font_op *)op)->data = (unsigned long)op->data;
1132 if (copy_to_user(fontop, op, sizeof(struct compat_console_font_op)))
1137 struct compat_unimapdesc {
1138 unsigned short entry_ct;
1139 compat_caddr_t entries;
1143 compat_unimap_ioctl(unsigned int cmd, struct compat_unimapdesc __user *user_ud,
1144 int perm, struct vc_data *vc)
1146 struct compat_unimapdesc tmp;
1147 struct unipair __user *tmp_entries;
1149 if (copy_from_user(&tmp, user_ud, sizeof tmp))
1151 tmp_entries = compat_ptr(tmp.entries);
1156 return con_set_unimap(vc, tmp.entry_ct, tmp_entries);
1158 if (!perm && fg_console != vc->vc_num)
1160 return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct), tmp_entries);
1165 long vt_compat_ioctl(struct tty_struct *tty,
1166 unsigned int cmd, unsigned long arg)
1168 struct vc_data *vc = tty->driver_data;
1169 struct console_font_op op; /* used in multiple places here */
1170 void __user *up = compat_ptr(arg);
1174 * To have permissions to do most of the vt ioctls, we either have
1175 * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
1178 if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
1183 * these need special handlers for incompatible data structures
1187 return compat_fontx_ioctl(cmd, up, perm, &op);
1190 return compat_kdfontop_ioctl(up, perm, &op, vc);
1194 return compat_unimap_ioctl(cmd, up, perm, vc);
1197 * all these treat 'arg' as an integer
1216 case VT_DISALLOCATE:
1219 return vt_ioctl(tty, cmd, arg);
1222 * the rest has a compatible data structure behind arg,
1223 * but we have to convert it to a proper 64 bit pointer.
1226 return vt_ioctl(tty, cmd, (unsigned long)up);
1231 #endif /* CONFIG_COMPAT */
1235 * Performs the back end of a vt switch. Called under the console
1238 static void complete_change_console(struct vc_data *vc)
1240 unsigned char old_vc_mode;
1241 int old = fg_console;
1243 last_console = fg_console;
1246 * If we're switching, we could be going from KD_GRAPHICS to
1247 * KD_TEXT mode or vice versa, which means we need to blank or
1248 * unblank the screen later.
1250 old_vc_mode = vc_cons[fg_console].d->vc_mode;
1254 * This can't appear below a successful kill_pid(). If it did,
1255 * then the *blank_screen operation could occur while X, having
1256 * received acqsig, is waking up on another processor. This
1257 * condition can lead to overlapping accesses to the VGA range
1258 * and the framebuffer (causing system lockups).
1260 * To account for this we duplicate this code below only if the
1261 * controlling process is gone and we've called reset_vc.
1263 if (old_vc_mode != vc->vc_mode) {
1264 if (vc->vc_mode == KD_TEXT)
1265 do_unblank_screen(1);
1271 * If this new console is under process control, send it a signal
1272 * telling it that it has acquired. Also check if it has died and
1273 * clean up (similar to logic employed in change_console())
1275 if (vc->vt_mode.mode == VT_PROCESS) {
1277 * Send the signal as privileged - kill_pid() will
1278 * tell us if the process has gone or something else
1281 if (kill_pid(vc->vt_pid, vc->vt_mode.acqsig, 1) != 0) {
1283 * The controlling process has died, so we revert back to
1284 * normal operation. In this case, we'll also change back
1285 * to KD_TEXT mode. I'm not sure if this is strictly correct
1286 * but it saves the agony when the X server dies and the screen
1287 * remains blanked due to KD_GRAPHICS! It would be nice to do
1288 * this outside of VT_PROCESS but there is no single process
1289 * to account for and tracking tty count may be undesirable.
1293 if (old_vc_mode != vc->vc_mode) {
1294 if (vc->vc_mode == KD_TEXT)
1295 do_unblank_screen(1);
1303 * Wake anyone waiting for their VT to activate
1305 vt_event_post(VT_EVENT_SWITCH, old, vc->vc_num);
1310 * Performs the front-end of a vt switch
1312 void change_console(struct vc_data *new_vc)
1316 if (!new_vc || new_vc->vc_num == fg_console || vt_dont_switch)
1320 * If this vt is in process mode, then we need to handshake with
1321 * that process before switching. Essentially, we store where that
1322 * vt wants to switch to and wait for it to tell us when it's done
1323 * (via VT_RELDISP ioctl).
1325 * We also check to see if the controlling process still exists.
1326 * If it doesn't, we reset this vt to auto mode and continue.
1327 * This is a cheap way to track process control. The worst thing
1328 * that can happen is: we send a signal to a process, it dies, and
1329 * the switch gets "lost" waiting for a response; hopefully, the
1330 * user will try again, we'll detect the process is gone (unless
1331 * the user waits just the right amount of time :-) and revert the
1332 * vt to auto control.
1334 vc = vc_cons[fg_console].d;
1335 if (vc->vt_mode.mode == VT_PROCESS) {
1337 * Send the signal as privileged - kill_pid() will
1338 * tell us if the process has gone or something else
1341 * We need to set vt_newvt *before* sending the signal or we
1344 vc->vt_newvt = new_vc->vc_num;
1345 if (kill_pid(vc->vt_pid, vc->vt_mode.relsig, 1) == 0) {
1347 * It worked. Mark the vt to switch to and
1348 * return. The process needs to send us a
1349 * VT_RELDISP ioctl to complete the switch.
1355 * The controlling process has died, so we revert back to
1356 * normal operation. In this case, we'll also change back
1357 * to KD_TEXT mode. I'm not sure if this is strictly correct
1358 * but it saves the agony when the X server dies and the screen
1359 * remains blanked due to KD_GRAPHICS! It would be nice to do
1360 * this outside of VT_PROCESS but there is no single process
1361 * to account for and tracking tty count may be undesirable.
1366 * Fall through to normal (VT_AUTO) handling of the switch...
1371 * Ignore all switches in KD_GRAPHICS+VT_AUTO mode
1373 if (vc->vc_mode == KD_GRAPHICS)
1376 complete_change_console(new_vc);
1379 /* Perform a kernel triggered VT switch for suspend/resume */
1381 static int disable_vt_switch;
1383 int vt_move_to_console(unsigned int vt, int alloc)
1388 /* Graphics mode - up to X */
1389 if (disable_vt_switch) {
1395 if (alloc && vc_allocate(vt)) {
1396 /* we can't have a free VC for now. Too bad,
1397 * we don't want to mess the screen for now. */
1402 if (set_console(vt)) {
1404 * We're unable to switch to the SUSPEND_CONSOLE.
1405 * Let the calling function know so it can decide
1412 if (vt_waitactive(vt + 1)) {
1413 pr_debug("Suspend: Can't switch VCs.");
1420 * Normally during a suspend, we allocate a new console and switch to it.
1421 * When we resume, we switch back to the original console. This switch
1422 * can be slow, so on systems where the framebuffer can handle restoration
1423 * of video registers anyways, there's little point in doing the console
1424 * switch. This function allows you to disable it by passing it '0'.
1426 void pm_set_vt_switch(int do_switch)
1429 disable_vt_switch = !do_switch;
1432 EXPORT_SYMBOL(pm_set_vt_switch);