2 * linux/drivers/char/vt_ioctl.c
4 * Copyright (C) 1992 obz under the linux copyright
6 * Dynamic diacritical handling - aeb@cwi.nl - Dec 1993
7 * Dynamic keymap and string allocation - aeb@cwi.nl - May 1994
8 * Restrict VT switching via ioctl() - grif@cs.ucr.edu - Dec 1995
9 * Some code moved for less code duplication - Andi Kleen - Mar 1997
10 * Check put/get_user, cleanups - acme@conectiva.com.br - Jun 2001
13 #include <linux/types.h>
14 #include <linux/errno.h>
15 #include <linux/sched.h>
16 #include <linux/tty.h>
17 #include <linux/timer.h>
18 #include <linux/kernel.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 * these are the valid i/o ports we're allowed to change. they map all the
69 #define GPNUM (GPLAST - GPFIRST + 1)
71 #define i (tmp.kb_index)
72 #define s (tmp.kb_table)
73 #define v (tmp.kb_value)
75 do_kdsk_ioctl(int cmd, struct kbentry __user *user_kbe, int perm, struct kbd_struct *kbd)
78 ushort *key_map, val, ov;
80 if (copy_from_user(&tmp, user_kbe, sizeof(struct kbentry)))
83 if (!capable(CAP_SYS_TTY_CONFIG))
88 key_map = key_maps[s];
91 if (kbd->kbdmode != VC_UNICODE && KTYP(val) >= NR_TYPES)
94 val = (i ? K_HOLE : K_NOSUCHMAP);
95 return put_user(val, &user_kbe->kb_value);
99 if (!i && v == K_NOSUCHMAP) {
101 key_map = key_maps[s];
104 if (key_map[0] == U(K_ALLOCATED)) {
112 if (KTYP(v) < NR_TYPES) {
113 if (KVAL(v) > max_vals[KTYP(v)])
116 if (kbd->kbdmode != VC_UNICODE)
119 /* ++Geert: non-PC keyboards may generate keycode zero */
120 #if !defined(__mc68000__) && !defined(__powerpc__)
121 /* assignment to entry 0 only tests validity of args */
126 if (!(key_map = key_maps[s])) {
129 if (keymap_count >= MAX_NR_OF_USER_KEYMAPS &&
130 !capable(CAP_SYS_RESOURCE))
133 key_map = kmalloc(sizeof(plain_map),
137 key_maps[s] = key_map;
138 key_map[0] = U(K_ALLOCATED);
139 for (j = 1; j < NR_KEYS; j++)
140 key_map[j] = U(K_HOLE);
145 break; /* nothing to do */
149 if (((ov == K_SAK) || (v == K_SAK)) && !capable(CAP_SYS_ADMIN))
152 if (!s && (KTYP(ov) == KT_SHIFT || KTYP(v) == KT_SHIFT))
153 compute_shiftstate();
163 do_kbkeycode_ioctl(int cmd, struct kbkeycode __user *user_kbkc, int perm)
165 struct kbkeycode tmp;
168 if (copy_from_user(&tmp, user_kbkc, sizeof(struct kbkeycode)))
172 kc = getkeycode(tmp.scancode);
174 kc = put_user(kc, &user_kbkc->keycode);
179 kc = setkeycode(tmp.scancode, tmp.keycode);
186 do_kdgkb_ioctl(int cmd, struct kbsentry __user *user_kdgkb, int perm)
188 struct kbsentry *kbs;
194 char *first_free, *fj, *fnw;
198 if (!capable(CAP_SYS_TTY_CONFIG))
201 kbs = kmalloc(sizeof(*kbs), GFP_KERNEL);
207 /* we mostly copy too much here (512bytes), but who cares ;) */
208 if (copy_from_user(kbs, user_kdgkb, sizeof(struct kbsentry))) {
212 kbs->kb_string[sizeof(kbs->kb_string)-1] = '\0';
217 sz = sizeof(kbs->kb_string) - 1; /* sz should have been
219 up = user_kdgkb->kb_string;
222 for ( ; *p && sz; p++, sz--)
223 if (put_user(*p, up++)) {
227 if (put_user('\0', up)) {
232 return ((p && *p) ? -EOVERFLOW : 0);
240 first_free = funcbufptr + (funcbufsize - funcbufleft);
241 for (j = i+1; j < MAX_NR_FUNC && !func_table[j]; j++)
248 delta = (q ? -strlen(q) : 1) + strlen(kbs->kb_string);
249 if (delta <= funcbufleft) { /* it fits in current buf */
250 if (j < MAX_NR_FUNC) {
251 memmove(fj + delta, fj, first_free - fj);
252 for (k = j; k < MAX_NR_FUNC; k++)
254 func_table[k] += delta;
258 funcbufleft -= delta;
259 } else { /* allocate a larger buffer */
261 while (sz < funcbufsize - funcbufleft + delta)
263 fnw = kmalloc(sz, GFP_KERNEL);
272 memmove(fnw, funcbufptr, fj - funcbufptr);
273 for (k = 0; k < j; k++)
275 func_table[k] = fnw + (func_table[k] - funcbufptr);
277 if (first_free > fj) {
278 memmove(fnw + (fj - funcbufptr) + delta, fj, first_free - fj);
279 for (k = j; k < MAX_NR_FUNC; k++)
281 func_table[k] = fnw + (func_table[k] - funcbufptr) + delta;
283 if (funcbufptr != func_buf)
286 funcbufleft = funcbufleft - delta + sz - funcbufsize;
289 strcpy(func_table[i], kbs->kb_string);
299 do_fontx_ioctl(int cmd, struct consolefontdesc __user *user_cfd, int perm, struct console_font_op *op)
301 struct consolefontdesc cfdarg;
304 if (copy_from_user(&cfdarg, user_cfd, sizeof(struct consolefontdesc)))
311 op->op = KD_FONT_OP_SET;
312 op->flags = KD_FONT_FLAG_OLD;
314 op->height = cfdarg.charheight;
315 op->charcount = cfdarg.charcount;
316 op->data = cfdarg.chardata;
317 return con_font_op(vc_cons[fg_console].d, op);
319 op->op = KD_FONT_OP_GET;
320 op->flags = KD_FONT_FLAG_OLD;
322 op->height = cfdarg.charheight;
323 op->charcount = cfdarg.charcount;
324 op->data = cfdarg.chardata;
325 i = con_font_op(vc_cons[fg_console].d, op);
328 cfdarg.charheight = op->height;
329 cfdarg.charcount = op->charcount;
330 if (copy_to_user(user_cfd, &cfdarg, sizeof(struct consolefontdesc)))
339 do_unimap_ioctl(int cmd, struct unimapdesc __user *user_ud, int perm, struct vc_data *vc)
341 struct unimapdesc tmp;
343 if (copy_from_user(&tmp, user_ud, sizeof tmp))
346 if (!access_ok(VERIFY_WRITE, tmp.entries,
347 tmp.entry_ct*sizeof(struct unipair)))
353 return con_set_unimap(vc, tmp.entry_ct, tmp.entries);
355 if (!perm && fg_console != vc->vc_num)
357 return con_get_unimap(vc, tmp.entry_ct, &(user_ud->entry_ct), tmp.entries);
363 * We handle the console-specific ioctl's here. We allow the
364 * capability to modify any console, not just the fg_console.
366 int vt_ioctl(struct tty_struct *tty, struct file * file,
367 unsigned int cmd, unsigned long arg)
369 struct vc_data *vc = tty->driver_data;
370 struct console_font_op op; /* used in multiple places here */
371 struct kbd_struct * kbd;
372 unsigned int console;
374 void __user *up = (void __user *)arg;
378 console = vc->vc_num;
382 if (!vc_cons_allocated(console)) { /* impossible? */
389 * To have permissions to do most of the vt ioctls, we either have
390 * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
393 if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
396 kbd = kbd_table + console;
399 return tioclinux(tty, arg);
404 arg = CLOCK_TICK_RATE / arg;
412 unsigned int ticks, count;
415 * Generate the tone for the appropriate number of ticks.
416 * If the time is zero, turn off sound ourselves.
418 ticks = HZ * ((arg >> 16) & 0xffff) / 1000;
419 count = ticks ? (arg & 0xffff) : 0;
421 count = CLOCK_TICK_RATE / count;
422 kd_mksound(count, ticks);
434 * These cannot be implemented on any machine that implements
435 * ioperm() in user level (such as Alpha PCs) or not at all.
437 * XXX: you should never use these, just call ioperm directly..
443 * KDADDIO and KDDELIO may be able to add ports beyond what
444 * we reject here, but to be safe...
446 if (arg < GPFIRST || arg > GPLAST) {
450 ret = sys_ioperm(arg, 1, (cmd == KDADDIO)) ? -ENXIO : 0;
455 ret = sys_ioperm(GPFIRST, GPNUM,
456 (cmd == KDENABIO)) ? -ENXIO : 0;
460 /* Linux m68k/i386 interface for setting the keyboard delay/repeat rate */
464 struct kbd_repeat kbrep;
466 if (!capable(CAP_SYS_TTY_CONFIG))
469 if (copy_from_user(&kbrep, up, sizeof(struct kbd_repeat))) {
473 ret = kbd_rate(&kbrep);
476 if (copy_to_user(up, &kbrep, sizeof(struct kbd_repeat)))
483 * currently, setting the mode from KD_TEXT to KD_GRAPHICS
484 * doesn't do a whole lot. i'm not sure if it should do any
485 * restoration of modes or what...
487 * XXX It should at least call into the driver, fbdev's definitely
488 * need to restore their engine state. --BenH
504 if (vc->vc_mode == (unsigned char) arg)
506 vc->vc_mode = (unsigned char) arg;
507 if (console != fg_console)
510 * explicitly blank/unblank the screen if switching modes
512 acquire_console_sem();
514 do_unblank_screen(1);
517 release_console_sem();
527 * these work like a combination of mmap and KDENABIO.
528 * this could be easily finished.
538 kbd->kbdmode = VC_RAW;
541 kbd->kbdmode = VC_MEDIUMRAW;
544 kbd->kbdmode = VC_XLATE;
545 compute_shiftstate();
548 kbd->kbdmode = VC_UNICODE;
549 compute_shiftstate();
555 tty_ldisc_flush(tty);
559 ucval = ((kbd->kbdmode == VC_RAW) ? K_RAW :
560 (kbd->kbdmode == VC_MEDIUMRAW) ? K_MEDIUMRAW :
561 (kbd->kbdmode == VC_UNICODE) ? K_UNICODE :
565 /* this could be folded into KDSKBMODE, but for compatibility
566 reasons it is not so easy to fold KDGKBMETA into KDGKBMODE */
570 clr_vc_kbd_mode(kbd, VC_META);
573 set_vc_kbd_mode(kbd, VC_META);
581 ucval = (vc_kbd_mode(kbd, VC_META) ? K_ESCPREFIX : K_METABIT);
583 ret = put_user(ucval, (int __user *)arg);
588 if(!capable(CAP_SYS_TTY_CONFIG))
590 ret = do_kbkeycode_ioctl(cmd, up, perm);
595 ret = do_kdsk_ioctl(cmd, up, perm, kbd);
600 ret = do_kdgkb_ioctl(cmd, up, perm);
605 struct kbdiacrs __user *a = up;
606 struct kbdiacr diacr;
609 if (put_user(accent_table_size, &a->kb_cnt)) {
613 for (i = 0; i < accent_table_size; i++) {
614 diacr.diacr = conv_uni_to_8bit(accent_table[i].diacr);
615 diacr.base = conv_uni_to_8bit(accent_table[i].base);
616 diacr.result = conv_uni_to_8bit(accent_table[i].result);
617 if (copy_to_user(a->kbdiacr + i, &diacr, sizeof(struct kbdiacr))) {
626 struct kbdiacrsuc __user *a = up;
628 if (put_user(accent_table_size, &a->kb_cnt))
630 else if (copy_to_user(a->kbdiacruc, accent_table,
631 accent_table_size*sizeof(struct kbdiacruc)))
638 struct kbdiacrs __user *a = up;
639 struct kbdiacr diacr;
645 if (get_user(ct,&a->kb_cnt)) {
649 if (ct >= MAX_DIACR) {
653 accent_table_size = ct;
654 for (i = 0; i < ct; i++) {
655 if (copy_from_user(&diacr, a->kbdiacr + i, sizeof(struct kbdiacr))) {
659 accent_table[i].diacr = conv_8bit_to_uni(diacr.diacr);
660 accent_table[i].base = conv_8bit_to_uni(diacr.base);
661 accent_table[i].result = conv_8bit_to_uni(diacr.result);
668 struct kbdiacrsuc __user *a = up;
673 if (get_user(ct,&a->kb_cnt)) {
677 if (ct >= MAX_DIACR) {
681 accent_table_size = ct;
682 if (copy_from_user(accent_table, a->kbdiacruc, ct*sizeof(struct kbdiacruc)))
687 /* the ioctls below read/set the flags usually shown in the leds */
688 /* don't use them - they will go away without warning */
690 ucval = kbd->ledflagstate | (kbd->default_ledflagstate << 4);
700 kbd->ledflagstate = (arg & 7);
701 kbd->default_ledflagstate = ((arg >> 4) & 7);
705 /* the ioctls below only set the lights, not the functions */
706 /* for those, see KDGKBLED and KDSKBLED above */
708 ucval = getledstate();
710 ret = put_user(ucval, (char __user *)arg);
716 setledstate(kbd, arg);
720 * A process can indicate its willingness to accept signals
721 * generated by pressing an appropriate key combination.
722 * Thus, one can have a daemon that e.g. spawns a new console
723 * upon a keypress and then changes to it.
724 * See also the kbrequest field of inittab(5).
728 if (!perm || !capable(CAP_KILL))
730 if (!valid_signal(arg) || arg < 1 || arg == SIGKILL)
733 spin_lock_irq(&vt_spawn_con.lock);
734 put_pid(vt_spawn_con.pid);
735 vt_spawn_con.pid = get_pid(task_pid(current));
736 vt_spawn_con.sig = arg;
737 spin_unlock_irq(&vt_spawn_con.lock);
748 if (copy_from_user(&tmp, up, sizeof(struct vt_mode))) {
752 if (tmp.mode != VT_AUTO && tmp.mode != VT_PROCESS) {
756 acquire_console_sem();
758 /* the frsig is ignored, so we set it to 0 */
759 vc->vt_mode.frsig = 0;
761 vc->vt_pid = get_pid(task_pid(current));
762 /* no switch is required -- saw@shade.msu.ru */
764 release_console_sem();
773 acquire_console_sem();
774 memcpy(&tmp, &vc->vt_mode, sizeof(struct vt_mode));
775 release_console_sem();
777 rc = copy_to_user(up, &tmp, sizeof(struct vt_mode));
784 * Returns global vt state. Note that VT 0 is always open, since
785 * it's an alias for the current VT, and people can't use it here.
786 * We cannot return state for more than 16 VTs, since v_state is short.
790 struct vt_stat __user *vtstat = up;
791 unsigned short state, mask;
793 if (put_user(fg_console + 1, &vtstat->v_active))
796 state = 1; /* /dev/tty0 is always open */
797 for (i = 0, mask = 2; i < MAX_NR_CONSOLES && mask;
801 ret = put_user(state, &vtstat->v_state);
807 * Returns the first available (non-opened) console.
810 for (i = 0; i < MAX_NR_CONSOLES; ++i)
811 if (! VT_IS_IN_USE(i))
813 ucval = i < MAX_NR_CONSOLES ? (i+1) : -1;
817 * ioctl(fd, VT_ACTIVATE, num) will cause us to switch to vt # num,
818 * with num >= 1 (switches to vt 0, our console, are not allowed, just
819 * to preserve sanity).
824 if (arg == 0 || arg > MAX_NR_CONSOLES)
828 acquire_console_sem();
829 ret = vc_allocate(arg);
830 release_console_sem();
838 * wait until the specified VT has been activated
843 if (arg == 0 || arg > MAX_NR_CONSOLES)
846 ret = vt_waitactive(arg - 1);
850 * If a vt is under process control, the kernel will not switch to it
851 * immediately, but postpone the operation until the process calls this
852 * ioctl, allowing the switch to complete.
854 * According to the X sources this is the behavior:
855 * 0: pending switch-from not OK
856 * 1: pending switch-from OK
857 * 2: completed switch-to OK
863 if (vc->vt_mode.mode != VT_PROCESS) {
868 * Switching-from response
870 acquire_console_sem();
871 if (vc->vt_newvt >= 0) {
874 * Switch disallowed, so forget we were trying
881 * The current vt has been released, so
882 * complete the switch.
885 newvt = vc->vt_newvt;
887 ret = vc_allocate(newvt);
889 release_console_sem();
893 * When we actually do the console switch,
894 * make sure we are atomic with respect to
895 * other console switches..
897 complete_change_console(vc_cons[newvt].d);
901 * Switched-to response
904 * If it's just an ACK, ignore it
906 if (arg != VT_ACKACQ)
909 release_console_sem();
913 * Disallocate memory associated to VT (but leave VT1)
916 if (arg > MAX_NR_CONSOLES) {
921 /* deallocate all unused consoles, but leave 0 */
922 acquire_console_sem();
923 for (i=1; i<MAX_NR_CONSOLES; i++)
926 release_console_sem();
928 /* deallocate a single console, if possible */
932 else if (arg) { /* leave 0 */
933 acquire_console_sem();
935 release_console_sem();
942 struct vt_sizes __user *vtsizes = up;
948 if (get_user(ll, &vtsizes->v_rows) ||
949 get_user(cc, &vtsizes->v_cols))
952 acquire_console_sem();
953 for (i = 0; i < MAX_NR_CONSOLES; i++) {
957 vc->vc_resize_user = 1;
958 vc_resize(vc_cons[i].d, cc, ll);
961 release_console_sem();
968 struct vt_consize __user *vtconsize = up;
969 ushort ll,cc,vlin,clin,vcol,ccol;
972 if (!access_ok(VERIFY_READ, vtconsize,
973 sizeof(struct vt_consize))) {
977 /* FIXME: Should check the copies properly */
978 __get_user(ll, &vtconsize->v_rows);
979 __get_user(cc, &vtconsize->v_cols);
980 __get_user(vlin, &vtconsize->v_vlin);
981 __get_user(clin, &vtconsize->v_clin);
982 __get_user(vcol, &vtconsize->v_vcol);
983 __get_user(ccol, &vtconsize->v_ccol);
984 vlin = vlin ? vlin : vc->vc_scan_lines;
987 if (ll != vlin/clin) {
988 /* Parameters don't add up */
997 if (cc != vcol/ccol) {
1010 for (i = 0; i < MAX_NR_CONSOLES; i++) {
1013 acquire_console_sem();
1015 vc_cons[i].d->vc_scan_lines = vlin;
1017 vc_cons[i].d->vc_font.height = clin;
1018 vc_cons[i].d->vc_resize_user = 1;
1019 vc_resize(vc_cons[i].d, cc, ll);
1020 release_console_sem();
1028 op.op = KD_FONT_OP_SET;
1029 op.flags = KD_FONT_FLAG_OLD | KD_FONT_FLAG_DONT_RECALC; /* Compatibility */
1034 ret = con_font_op(vc_cons[fg_console].d, &op);
1039 op.op = KD_FONT_OP_GET;
1040 op.flags = KD_FONT_FLAG_OLD;
1045 ret = con_font_op(vc_cons[fg_console].d, &op);
1053 ret = con_set_cmap(up);
1057 ret = con_get_cmap(up);
1062 ret = do_fontx_ioctl(cmd, up, perm, &op);
1070 #ifdef BROKEN_GRAPHICS_PROGRAMS
1071 /* With BROKEN_GRAPHICS_PROGRAMS defined, the default
1072 font is not saved. */
1077 op.op = KD_FONT_OP_SET_DEFAULT;
1079 ret = con_font_op(vc_cons[fg_console].d, &op);
1082 con_set_default_unimap(vc_cons[fg_console].d);
1089 if (copy_from_user(&op, up, sizeof(op))) {
1093 if (!perm && op.op != KD_FONT_OP_GET)
1095 ret = con_font_op(vc, &op);
1098 if (copy_to_user(up, &op, sizeof(op)))
1107 ret = con_set_trans_old(up);
1111 ret = con_get_trans_old(up);
1114 case PIO_UNISCRNMAP:
1118 ret = con_set_trans_new(up);
1121 case GIO_UNISCRNMAP:
1122 ret = con_get_trans_new(up);
1126 { struct unimapinit ui;
1129 ret = copy_from_user(&ui, up, sizeof(struct unimapinit));
1131 con_clear_unimap(vc, &ui);
1137 ret = do_unimap_ioctl(cmd, up, perm, vc);
1141 if (!capable(CAP_SYS_TTY_CONFIG))
1145 case VT_UNLOCKSWITCH:
1146 if (!capable(CAP_SYS_TTY_CONFIG))
1150 case VT_GETHIFONTMASK:
1151 ret = put_user(vc->vc_hi_font_mask,
1152 (unsigned short __user *)arg);
1166 * Sometimes we want to wait until a particular VT has been activated. We
1167 * do it in a very simple manner. Everybody waits on a single queue and
1168 * get woken up at once. Those that are satisfied go on with their business,
1169 * while those not ready go back to sleep. Seems overkill to add a wait
1170 * to each vt just for this - usually this does nothing!
1172 static DECLARE_WAIT_QUEUE_HEAD(vt_activate_queue);
1175 * Sleeps until a vt is activated, or the task is interrupted. Returns
1176 * 0 if activation, -EINTR if interrupted by a signal handler.
1178 int vt_waitactive(int vt)
1181 DECLARE_WAITQUEUE(wait, current);
1183 add_wait_queue(&vt_activate_queue, &wait);
1188 * Synchronize with redraw_screen(). By acquiring the console
1189 * semaphore we make sure that the console switch is completed
1190 * before we return. If we didn't wait for the semaphore, we
1191 * could return at a point where fg_console has already been
1192 * updated, but the console switch hasn't been completed.
1194 acquire_console_sem();
1195 set_current_state(TASK_INTERRUPTIBLE);
1196 if (vt == fg_console) {
1197 release_console_sem();
1200 release_console_sem();
1201 retval = -ERESTARTNOHAND;
1202 if (signal_pending(current))
1206 remove_wait_queue(&vt_activate_queue, &wait);
1207 __set_current_state(TASK_RUNNING);
1211 #define vt_wake_waitactive() wake_up(&vt_activate_queue)
1213 void reset_vc(struct vc_data *vc)
1215 vc->vc_mode = KD_TEXT;
1216 kbd_table[vc->vc_num].kbdmode = default_utf8 ? VC_UNICODE : VC_XLATE;
1217 vc->vt_mode.mode = VT_AUTO;
1218 vc->vt_mode.waitv = 0;
1219 vc->vt_mode.relsig = 0;
1220 vc->vt_mode.acqsig = 0;
1221 vc->vt_mode.frsig = 0;
1222 put_pid(vc->vt_pid);
1225 if (!in_interrupt()) /* Via keyboard.c:SAK() - akpm */
1229 void vc_SAK(struct work_struct *work)
1232 container_of(work, struct vc, SAK_work);
1234 struct tty_struct *tty;
1236 acquire_console_sem();
1241 * SAK should also work in all raw modes and reset
1248 release_console_sem();
1252 * Performs the back end of a vt switch
1254 static void complete_change_console(struct vc_data *vc)
1256 unsigned char old_vc_mode;
1258 last_console = fg_console;
1261 * If we're switching, we could be going from KD_GRAPHICS to
1262 * KD_TEXT mode or vice versa, which means we need to blank or
1263 * unblank the screen later.
1265 old_vc_mode = vc_cons[fg_console].d->vc_mode;
1269 * This can't appear below a successful kill_pid(). If it did,
1270 * then the *blank_screen operation could occur while X, having
1271 * received acqsig, is waking up on another processor. This
1272 * condition can lead to overlapping accesses to the VGA range
1273 * and the framebuffer (causing system lockups).
1275 * To account for this we duplicate this code below only if the
1276 * controlling process is gone and we've called reset_vc.
1278 if (old_vc_mode != vc->vc_mode) {
1279 if (vc->vc_mode == KD_TEXT)
1280 do_unblank_screen(1);
1286 * If this new console is under process control, send it a signal
1287 * telling it that it has acquired. Also check if it has died and
1288 * clean up (similar to logic employed in change_console())
1290 if (vc->vt_mode.mode == VT_PROCESS) {
1292 * Send the signal as privileged - kill_pid() will
1293 * tell us if the process has gone or something else
1296 if (kill_pid(vc->vt_pid, vc->vt_mode.acqsig, 1) != 0) {
1298 * The controlling process has died, so we revert back to
1299 * normal operation. In this case, we'll also change back
1300 * to KD_TEXT mode. I'm not sure if this is strictly correct
1301 * but it saves the agony when the X server dies and the screen
1302 * remains blanked due to KD_GRAPHICS! It would be nice to do
1303 * this outside of VT_PROCESS but there is no single process
1304 * to account for and tracking tty count may be undesirable.
1308 if (old_vc_mode != vc->vc_mode) {
1309 if (vc->vc_mode == KD_TEXT)
1310 do_unblank_screen(1);
1318 * Wake anyone waiting for their VT to activate
1320 vt_wake_waitactive();
1325 * Performs the front-end of a vt switch
1327 void change_console(struct vc_data *new_vc)
1331 if (!new_vc || new_vc->vc_num == fg_console || vt_dont_switch)
1335 * If this vt is in process mode, then we need to handshake with
1336 * that process before switching. Essentially, we store where that
1337 * vt wants to switch to and wait for it to tell us when it's done
1338 * (via VT_RELDISP ioctl).
1340 * We also check to see if the controlling process still exists.
1341 * If it doesn't, we reset this vt to auto mode and continue.
1342 * This is a cheap way to track process control. The worst thing
1343 * that can happen is: we send a signal to a process, it dies, and
1344 * the switch gets "lost" waiting for a response; hopefully, the
1345 * user will try again, we'll detect the process is gone (unless
1346 * the user waits just the right amount of time :-) and revert the
1347 * vt to auto control.
1349 vc = vc_cons[fg_console].d;
1350 if (vc->vt_mode.mode == VT_PROCESS) {
1352 * Send the signal as privileged - kill_pid() will
1353 * tell us if the process has gone or something else
1356 * We need to set vt_newvt *before* sending the signal or we
1359 vc->vt_newvt = new_vc->vc_num;
1360 if (kill_pid(vc->vt_pid, vc->vt_mode.relsig, 1) == 0) {
1362 * It worked. Mark the vt to switch to and
1363 * return. The process needs to send us a
1364 * VT_RELDISP ioctl to complete the switch.
1370 * The controlling process has died, so we revert back to
1371 * normal operation. In this case, we'll also change back
1372 * to KD_TEXT mode. I'm not sure if this is strictly correct
1373 * but it saves the agony when the X server dies and the screen
1374 * remains blanked due to KD_GRAPHICS! It would be nice to do
1375 * this outside of VT_PROCESS but there is no single process
1376 * to account for and tracking tty count may be undesirable.
1381 * Fall through to normal (VT_AUTO) handling of the switch...
1386 * Ignore all switches in KD_GRAPHICS+VT_AUTO mode
1388 if (vc->vc_mode == KD_GRAPHICS)
1391 complete_change_console(new_vc);