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 = (struct vc_data *)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;
377 console = vc->vc_num;
379 if (!vc_cons_allocated(console)) /* impossible? */
383 * To have permissions to do most of the vt ioctls, we either have
384 * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
387 if (current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG))
390 kbd = kbd_table + console;
396 arg = CLOCK_TICK_RATE / arg;
404 unsigned int ticks, count;
407 * Generate the tone for the appropriate number of ticks.
408 * If the time is zero, turn off sound ourselves.
410 ticks = HZ * ((arg >> 16) & 0xffff) / 1000;
411 count = ticks ? (arg & 0xffff) : 0;
413 count = CLOCK_TICK_RATE / count;
414 kd_mksound(count, ticks);
426 * These cannot be implemented on any machine that implements
427 * ioperm() in user level (such as Alpha PCs) or not at all.
429 * XXX: you should never use these, just call ioperm directly..
435 * KDADDIO and KDDELIO may be able to add ports beyond what
436 * we reject here, but to be safe...
438 if (arg < GPFIRST || arg > GPLAST)
440 return sys_ioperm(arg, 1, (cmd == KDADDIO)) ? -ENXIO : 0;
444 return sys_ioperm(GPFIRST, GPNUM,
445 (cmd == KDENABIO)) ? -ENXIO : 0;
448 /* Linux m68k/i386 interface for setting the keyboard delay/repeat rate */
452 struct kbd_repeat kbrep;
455 if (!capable(CAP_SYS_TTY_CONFIG))
458 if (copy_from_user(&kbrep, up, sizeof(struct kbd_repeat)))
460 err = kbd_rate(&kbrep);
463 if (copy_to_user(up, &kbrep, sizeof(struct kbd_repeat)))
470 * currently, setting the mode from KD_TEXT to KD_GRAPHICS
471 * doesn't do a whole lot. i'm not sure if it should do any
472 * restoration of modes or what...
474 * XXX It should at least call into the driver, fbdev's definitely
475 * need to restore their engine state. --BenH
490 if (vc->vc_mode == (unsigned char) arg)
492 vc->vc_mode = (unsigned char) arg;
493 if (console != fg_console)
496 * explicitly blank/unblank the screen if switching modes
498 acquire_console_sem();
500 do_unblank_screen(1);
503 release_console_sem();
513 * these work like a combination of mmap and KDENABIO.
514 * this could be easily finished.
523 kbd->kbdmode = VC_RAW;
526 kbd->kbdmode = VC_MEDIUMRAW;
529 kbd->kbdmode = VC_XLATE;
530 compute_shiftstate();
533 kbd->kbdmode = VC_UNICODE;
534 compute_shiftstate();
539 tty_ldisc_flush(tty);
543 ucval = ((kbd->kbdmode == VC_RAW) ? K_RAW :
544 (kbd->kbdmode == VC_MEDIUMRAW) ? K_MEDIUMRAW :
545 (kbd->kbdmode == VC_UNICODE) ? K_UNICODE :
549 /* this could be folded into KDSKBMODE, but for compatibility
550 reasons it is not so easy to fold KDGKBMETA into KDGKBMODE */
554 clr_vc_kbd_mode(kbd, VC_META);
557 set_vc_kbd_mode(kbd, VC_META);
565 ucval = (vc_kbd_mode(kbd, VC_META) ? K_ESCPREFIX : K_METABIT);
567 return put_user(ucval, (int __user *)arg);
571 if(!capable(CAP_SYS_TTY_CONFIG))
573 return do_kbkeycode_ioctl(cmd, up, perm);
577 return do_kdsk_ioctl(cmd, up, perm, kbd);
581 return do_kdgkb_ioctl(cmd, up, perm);
585 struct kbdiacrs __user *a = up;
586 struct kbdiacr diacr;
589 if (put_user(accent_table_size, &a->kb_cnt))
591 for (i = 0; i < accent_table_size; i++) {
592 diacr.diacr = conv_uni_to_8bit(accent_table[i].diacr);
593 diacr.base = conv_uni_to_8bit(accent_table[i].base);
594 diacr.result = conv_uni_to_8bit(accent_table[i].result);
595 if (copy_to_user(a->kbdiacr + i, &diacr, sizeof(struct kbdiacr)))
602 struct kbdiacrsuc __user *a = up;
604 if (put_user(accent_table_size, &a->kb_cnt))
606 if (copy_to_user(a->kbdiacruc, accent_table, accent_table_size*sizeof(struct kbdiacruc)))
613 struct kbdiacrs __user *a = up;
614 struct kbdiacr diacr;
620 if (get_user(ct,&a->kb_cnt))
624 accent_table_size = ct;
625 for (i = 0; i < ct; i++) {
626 if (copy_from_user(&diacr, a->kbdiacr + i, sizeof(struct kbdiacr)))
628 accent_table[i].diacr = conv_8bit_to_uni(diacr.diacr);
629 accent_table[i].base = conv_8bit_to_uni(diacr.base);
630 accent_table[i].result = conv_8bit_to_uni(diacr.result);
637 struct kbdiacrsuc __user *a = up;
642 if (get_user(ct,&a->kb_cnt))
646 accent_table_size = ct;
647 if (copy_from_user(accent_table, a->kbdiacruc, ct*sizeof(struct kbdiacruc)))
652 /* the ioctls below read/set the flags usually shown in the leds */
653 /* don't use them - they will go away without warning */
655 ucval = kbd->ledflagstate | (kbd->default_ledflagstate << 4);
663 kbd->ledflagstate = (arg & 7);
664 kbd->default_ledflagstate = ((arg >> 4) & 7);
668 /* the ioctls below only set the lights, not the functions */
669 /* for those, see KDGKBLED and KDSKBLED above */
671 ucval = getledstate();
673 return put_user(ucval, (char __user *)arg);
678 setledstate(kbd, arg);
682 * A process can indicate its willingness to accept signals
683 * generated by pressing an appropriate key combination.
684 * Thus, one can have a daemon that e.g. spawns a new console
685 * upon a keypress and then changes to it.
686 * See also the kbrequest field of inittab(5).
690 if (!perm || !capable(CAP_KILL))
692 if (!valid_signal(arg) || arg < 1 || arg == SIGKILL)
695 spin_lock_irq(&vt_spawn_con.lock);
696 put_pid(vt_spawn_con.pid);
697 vt_spawn_con.pid = get_pid(task_pid(current));
698 vt_spawn_con.sig = arg;
699 spin_unlock_irq(&vt_spawn_con.lock);
709 if (copy_from_user(&tmp, up, sizeof(struct vt_mode)))
711 if (tmp.mode != VT_AUTO && tmp.mode != VT_PROCESS)
713 acquire_console_sem();
715 /* the frsig is ignored, so we set it to 0 */
716 vc->vt_mode.frsig = 0;
718 vc->vt_pid = get_pid(task_pid(current));
719 /* no switch is required -- saw@shade.msu.ru */
721 release_console_sem();
730 acquire_console_sem();
731 memcpy(&tmp, &vc->vt_mode, sizeof(struct vt_mode));
732 release_console_sem();
734 rc = copy_to_user(up, &tmp, sizeof(struct vt_mode));
735 return rc ? -EFAULT : 0;
739 * Returns global vt state. Note that VT 0 is always open, since
740 * it's an alias for the current VT, and people can't use it here.
741 * We cannot return state for more than 16 VTs, since v_state is short.
745 struct vt_stat __user *vtstat = up;
746 unsigned short state, mask;
748 if (put_user(fg_console + 1, &vtstat->v_active))
750 state = 1; /* /dev/tty0 is always open */
751 for (i = 0, mask = 2; i < MAX_NR_CONSOLES && mask; ++i, mask <<= 1)
754 return put_user(state, &vtstat->v_state);
758 * Returns the first available (non-opened) console.
761 for (i = 0; i < MAX_NR_CONSOLES; ++i)
762 if (! VT_IS_IN_USE(i))
764 ucval = i < MAX_NR_CONSOLES ? (i+1) : -1;
768 * ioctl(fd, VT_ACTIVATE, num) will cause us to switch to vt # num,
769 * with num >= 1 (switches to vt 0, our console, are not allowed, just
770 * to preserve sanity).
775 if (arg == 0 || arg > MAX_NR_CONSOLES)
778 acquire_console_sem();
779 i = vc_allocate(arg);
780 release_console_sem();
787 * wait until the specified VT has been activated
792 if (arg == 0 || arg > MAX_NR_CONSOLES)
794 return vt_waitactive(arg-1);
797 * If a vt is under process control, the kernel will not switch to it
798 * immediately, but postpone the operation until the process calls this
799 * ioctl, allowing the switch to complete.
801 * According to the X sources this is the behavior:
802 * 0: pending switch-from not OK
803 * 1: pending switch-from OK
804 * 2: completed switch-to OK
809 if (vc->vt_mode.mode != VT_PROCESS)
813 * Switching-from response
815 acquire_console_sem();
816 if (vc->vt_newvt >= 0) {
819 * Switch disallowed, so forget we were trying
826 * The current vt has been released, so
827 * complete the switch.
830 newvt = vc->vt_newvt;
832 i = vc_allocate(newvt);
834 release_console_sem();
838 * When we actually do the console switch,
839 * make sure we are atomic with respect to
840 * other console switches..
842 complete_change_console(vc_cons[newvt].d);
847 * Switched-to response
852 * If it's just an ACK, ignore it
854 if (arg != VT_ACKACQ) {
855 release_console_sem();
859 release_console_sem();
864 * Disallocate memory associated to VT (but leave VT1)
867 if (arg > MAX_NR_CONSOLES)
870 /* deallocate all unused consoles, but leave 0 */
871 acquire_console_sem();
872 for (i=1; i<MAX_NR_CONSOLES; i++)
875 release_console_sem();
877 /* deallocate a single console, if possible */
881 if (arg) { /* leave 0 */
882 acquire_console_sem();
884 release_console_sem();
891 struct vt_sizes __user *vtsizes = up;
897 if (get_user(ll, &vtsizes->v_rows) ||
898 get_user(cc, &vtsizes->v_cols))
901 for (i = 0; i < MAX_NR_CONSOLES; i++) {
905 vc->vc_resize_user = 1;
906 vc_lock_resize(vc_cons[i].d, cc, ll);
915 struct vt_consize __user *vtconsize = up;
916 ushort ll,cc,vlin,clin,vcol,ccol;
919 if (!access_ok(VERIFY_READ, vtconsize,
920 sizeof(struct vt_consize)))
922 __get_user(ll, &vtconsize->v_rows);
923 __get_user(cc, &vtconsize->v_cols);
924 __get_user(vlin, &vtconsize->v_vlin);
925 __get_user(clin, &vtconsize->v_clin);
926 __get_user(vcol, &vtconsize->v_vcol);
927 __get_user(ccol, &vtconsize->v_ccol);
928 vlin = vlin ? vlin : vc->vc_scan_lines;
932 return -EINVAL; /* Parameters don't add up */
947 for (i = 0; i < MAX_NR_CONSOLES; i++) {
950 acquire_console_sem();
952 vc_cons[i].d->vc_scan_lines = vlin;
954 vc_cons[i].d->vc_font.height = clin;
955 vc_cons[i].d->vc_resize_user = 1;
956 vc_resize(vc_cons[i].d, cc, ll);
957 release_console_sem();
965 op.op = KD_FONT_OP_SET;
966 op.flags = KD_FONT_FLAG_OLD | KD_FONT_FLAG_DONT_RECALC; /* Compatibility */
971 return con_font_op(vc_cons[fg_console].d, &op);
975 op.op = KD_FONT_OP_GET;
976 op.flags = KD_FONT_FLAG_OLD;
981 return con_font_op(vc_cons[fg_console].d, &op);
987 return con_set_cmap(up);
990 return con_get_cmap(up);
994 return do_fontx_ioctl(cmd, up, perm, &op);
1001 #ifdef BROKEN_GRAPHICS_PROGRAMS
1002 /* With BROKEN_GRAPHICS_PROGRAMS defined, the default
1003 font is not saved. */
1007 op.op = KD_FONT_OP_SET_DEFAULT;
1009 i = con_font_op(vc_cons[fg_console].d, &op);
1012 con_set_default_unimap(vc_cons[fg_console].d);
1019 if (copy_from_user(&op, up, sizeof(op)))
1021 if (!perm && op.op != KD_FONT_OP_GET)
1023 i = con_font_op(vc, &op);
1025 if (copy_to_user(up, &op, sizeof(op)))
1033 return con_set_trans_old(up);
1036 return con_get_trans_old(up);
1038 case PIO_UNISCRNMAP:
1041 return con_set_trans_new(up);
1043 case GIO_UNISCRNMAP:
1044 return con_get_trans_new(up);
1047 { struct unimapinit ui;
1050 i = copy_from_user(&ui, up, sizeof(struct unimapinit));
1051 if (i) return -EFAULT;
1052 con_clear_unimap(vc, &ui);
1058 return do_unimap_ioctl(cmd, up, perm, vc);
1061 if (!capable(CAP_SYS_TTY_CONFIG))
1065 case VT_UNLOCKSWITCH:
1066 if (!capable(CAP_SYS_TTY_CONFIG))
1070 case VT_GETHIFONTMASK:
1071 return put_user(vc->vc_hi_font_mask, (unsigned short __user *)arg);
1073 return -ENOIOCTLCMD;
1078 * Sometimes we want to wait until a particular VT has been activated. We
1079 * do it in a very simple manner. Everybody waits on a single queue and
1080 * get woken up at once. Those that are satisfied go on with their business,
1081 * while those not ready go back to sleep. Seems overkill to add a wait
1082 * to each vt just for this - usually this does nothing!
1084 static DECLARE_WAIT_QUEUE_HEAD(vt_activate_queue);
1087 * Sleeps until a vt is activated, or the task is interrupted. Returns
1088 * 0 if activation, -EINTR if interrupted by a signal handler.
1090 int vt_waitactive(int vt)
1093 DECLARE_WAITQUEUE(wait, current);
1095 add_wait_queue(&vt_activate_queue, &wait);
1100 * Synchronize with redraw_screen(). By acquiring the console
1101 * semaphore we make sure that the console switch is completed
1102 * before we return. If we didn't wait for the semaphore, we
1103 * could return at a point where fg_console has already been
1104 * updated, but the console switch hasn't been completed.
1106 acquire_console_sem();
1107 set_current_state(TASK_INTERRUPTIBLE);
1108 if (vt == fg_console) {
1109 release_console_sem();
1112 release_console_sem();
1113 retval = -ERESTARTNOHAND;
1114 if (signal_pending(current))
1118 remove_wait_queue(&vt_activate_queue, &wait);
1119 __set_current_state(TASK_RUNNING);
1123 #define vt_wake_waitactive() wake_up(&vt_activate_queue)
1125 void reset_vc(struct vc_data *vc)
1127 vc->vc_mode = KD_TEXT;
1128 kbd_table[vc->vc_num].kbdmode = default_utf8 ? VC_UNICODE : VC_XLATE;
1129 vc->vt_mode.mode = VT_AUTO;
1130 vc->vt_mode.waitv = 0;
1131 vc->vt_mode.relsig = 0;
1132 vc->vt_mode.acqsig = 0;
1133 vc->vt_mode.frsig = 0;
1134 put_pid(vc->vt_pid);
1137 if (!in_interrupt()) /* Via keyboard.c:SAK() - akpm */
1141 void vc_SAK(struct work_struct *work)
1144 container_of(work, struct vc, SAK_work);
1146 struct tty_struct *tty;
1148 acquire_console_sem();
1153 * SAK should also work in all raw modes and reset
1160 release_console_sem();
1164 * Performs the back end of a vt switch
1166 static void complete_change_console(struct vc_data *vc)
1168 unsigned char old_vc_mode;
1170 last_console = fg_console;
1173 * If we're switching, we could be going from KD_GRAPHICS to
1174 * KD_TEXT mode or vice versa, which means we need to blank or
1175 * unblank the screen later.
1177 old_vc_mode = vc_cons[fg_console].d->vc_mode;
1181 * This can't appear below a successful kill_pid(). If it did,
1182 * then the *blank_screen operation could occur while X, having
1183 * received acqsig, is waking up on another processor. This
1184 * condition can lead to overlapping accesses to the VGA range
1185 * and the framebuffer (causing system lockups).
1187 * To account for this we duplicate this code below only if the
1188 * controlling process is gone and we've called reset_vc.
1190 if (old_vc_mode != vc->vc_mode) {
1191 if (vc->vc_mode == KD_TEXT)
1192 do_unblank_screen(1);
1198 * If this new console is under process control, send it a signal
1199 * telling it that it has acquired. Also check if it has died and
1200 * clean up (similar to logic employed in change_console())
1202 if (vc->vt_mode.mode == VT_PROCESS) {
1204 * Send the signal as privileged - kill_pid() will
1205 * tell us if the process has gone or something else
1208 if (kill_pid(vc->vt_pid, vc->vt_mode.acqsig, 1) != 0) {
1210 * The controlling process has died, so we revert back to
1211 * normal operation. In this case, we'll also change back
1212 * to KD_TEXT mode. I'm not sure if this is strictly correct
1213 * but it saves the agony when the X server dies and the screen
1214 * remains blanked due to KD_GRAPHICS! It would be nice to do
1215 * this outside of VT_PROCESS but there is no single process
1216 * to account for and tracking tty count may be undesirable.
1220 if (old_vc_mode != vc->vc_mode) {
1221 if (vc->vc_mode == KD_TEXT)
1222 do_unblank_screen(1);
1230 * Wake anyone waiting for their VT to activate
1232 vt_wake_waitactive();
1237 * Performs the front-end of a vt switch
1239 void change_console(struct vc_data *new_vc)
1243 if (!new_vc || new_vc->vc_num == fg_console || vt_dont_switch)
1247 * If this vt is in process mode, then we need to handshake with
1248 * that process before switching. Essentially, we store where that
1249 * vt wants to switch to and wait for it to tell us when it's done
1250 * (via VT_RELDISP ioctl).
1252 * We also check to see if the controlling process still exists.
1253 * If it doesn't, we reset this vt to auto mode and continue.
1254 * This is a cheap way to track process control. The worst thing
1255 * that can happen is: we send a signal to a process, it dies, and
1256 * the switch gets "lost" waiting for a response; hopefully, the
1257 * user will try again, we'll detect the process is gone (unless
1258 * the user waits just the right amount of time :-) and revert the
1259 * vt to auto control.
1261 vc = vc_cons[fg_console].d;
1262 if (vc->vt_mode.mode == VT_PROCESS) {
1264 * Send the signal as privileged - kill_pid() will
1265 * tell us if the process has gone or something else
1268 * We need to set vt_newvt *before* sending the signal or we
1271 vc->vt_newvt = new_vc->vc_num;
1272 if (kill_pid(vc->vt_pid, vc->vt_mode.relsig, 1) == 0) {
1274 * It worked. Mark the vt to switch to and
1275 * return. The process needs to send us a
1276 * VT_RELDISP ioctl to complete the switch.
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.
1293 * Fall through to normal (VT_AUTO) handling of the switch...
1298 * Ignore all switches in KD_GRAPHICS+VT_AUTO mode
1300 if (vc->vc_mode == KD_GRAPHICS)
1303 complete_change_console(new_vc);