// SPDX-License-Identifier: GPL-2.0
/*
 *    ebcdic keycode functions for s390 console drivers
 *
 *  S390 version
 *    Copyright IBM Corp. 2003
 *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
 */

#include <linux/export.h>
#include <linux/module.h>
#include <linux/sched/signal.h>
#include <linux/slab.h>
#include <linux/sysrq.h>

#include <linux/consolemap.h>
#include <linux/kbd_kern.h>
#include <linux/kbd_diacr.h>
#include <linux/uaccess.h>

#include "keyboard.h"

/*
 * Handler Tables.
 */
#define K_HANDLERS\
        k_self,         k_fn,           k_spec,         k_ignore,\
        k_dead,         k_ignore,       k_ignore,       k_ignore,\
        k_ignore,       k_ignore,       k_ignore,       k_ignore,\
        k_ignore,       k_ignore,       k_ignore,       k_ignore

typedef void (k_handler_fn)(struct kbd_data *, unsigned char);
static k_handler_fn K_HANDLERS;
static k_handler_fn *k_handler[16] = { K_HANDLERS };

/* maximum values each key_handler can handle */
static const int kbd_max_vals[] = {
        255, ARRAY_SIZE(func_table) - 1, NR_FN_HANDLER - 1, 0,
        NR_DEAD - 1, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
static const int KBD_NR_TYPES = ARRAY_SIZE(kbd_max_vals);

static const unsigned char ret_diacr[NR_DEAD] = {
        '`',    /* dead_grave */
        '\'',   /* dead_acute */
        '^',    /* dead_circumflex */
        '~',    /* dead_tilda */
        '"',    /* dead_diaeresis */
        ',',    /* dead_cedilla */
        '_',    /* dead_macron */
        'U',    /* dead_breve */
        '.',    /* dead_abovedot */
        '*',    /* dead_abovering */
        '=',    /* dead_doubleacute */
        'c',    /* dead_caron */
        'k',    /* dead_ogonek */
        'i',    /* dead_iota */
        '#',    /* dead_voiced_sound */
        'o',    /* dead_semivoiced_sound */
        '!',    /* dead_belowdot */
        '?',    /* dead_hook */
        '+',    /* dead_horn */
        '-',    /* dead_stroke */
        ')',    /* dead_abovecomma */
        '(',    /* dead_abovereversedcomma */
        ':',    /* dead_doublegrave */
        'n',    /* dead_invertedbreve */
        ';',    /* dead_belowcomma */
        '$',    /* dead_currency */
        '@',    /* dead_greek */
};

/*
 * Alloc/free of kbd_data structures.
 */
struct kbd_data *
kbd_alloc(void) {
        struct kbd_data *kbd;
        int i;

        kbd = kzalloc_obj(struct kbd_data);
        if (!kbd)
                goto out;
        kbd->key_maps = kzalloc(sizeof(ebc_key_maps), GFP_KERNEL);
        if (!kbd->key_maps)
                goto out_kbd;
        for (i = 0; i < ARRAY_SIZE(ebc_key_maps); i++) {
                if (ebc_key_maps[i]) {
                        kbd->key_maps[i] = kmemdup(ebc_key_maps[i],
                                                   sizeof(u_short) * NR_KEYS,
                                                   GFP_KERNEL);
                        if (!kbd->key_maps[i])
                                goto out_maps;
                }
        }
        kbd->func_table = kzalloc(sizeof(ebc_func_table), GFP_KERNEL);
        if (!kbd->func_table)
                goto out_maps;
        for (i = 0; i < ARRAY_SIZE(ebc_func_table); i++) {
                if (ebc_func_table[i]) {
                        kbd->func_table[i] = kstrdup(ebc_func_table[i],
                                                     GFP_KERNEL);
                        if (!kbd->func_table[i])
                                goto out_func;
                }
        }
        kbd->fn_handler =
                kzalloc_objs(fn_handler_fn *, NR_FN_HANDLER);
        if (!kbd->fn_handler)
                goto out_func;
        kbd->accent_table = kmemdup(ebc_accent_table,
                                    sizeof(struct kbdiacruc) * MAX_DIACR,
                                    GFP_KERNEL);
        if (!kbd->accent_table)
                goto out_fn_handler;
        kbd->accent_table_size = ebc_accent_table_size;
        return kbd;

out_fn_handler:
        kfree(kbd->fn_handler);
out_func:
        for (i = 0; i < ARRAY_SIZE(ebc_func_table); i++)
                kfree(kbd->func_table[i]);
        kfree(kbd->func_table);
out_maps:
        for (i = 0; i < ARRAY_SIZE(ebc_key_maps); i++)
                kfree(kbd->key_maps[i]);
        kfree(kbd->key_maps);
out_kbd:
        kfree(kbd);
out:
        return NULL;
}

void
kbd_free(struct kbd_data *kbd)
{
        int i;

        kfree(kbd->accent_table);
        kfree(kbd->fn_handler);
        for (i = 0; i < ARRAY_SIZE(ebc_func_table); i++)
                kfree(kbd->func_table[i]);
        kfree(kbd->func_table);
        for (i = 0; i < ARRAY_SIZE(ebc_key_maps); i++)
                kfree(kbd->key_maps[i]);
        kfree(kbd->key_maps);
        kfree(kbd);
}

/*
 * Generate ascii -> ebcdic translation table from kbd_data.
 */
void
kbd_ascebc(struct kbd_data *kbd, unsigned char *ascebc)
{
        unsigned short *keymap, keysym;
        int i, j, k;

        memset(ascebc, 0x40, 256);
        for (i = 0; i < ARRAY_SIZE(ebc_key_maps); i++) {
                keymap = kbd->key_maps[i];
                if (!keymap)
                        continue;
                for (j = 0; j < NR_KEYS; j++) {
                        k = ((i & 1) << 7) + j;
                        keysym = keymap[j];
                        if (KTYP(keysym) == (KT_LATIN | 0xf0) ||
                            KTYP(keysym) == (KT_LETTER | 0xf0))
                                ascebc[KVAL(keysym)] = k;
                        else if (KTYP(keysym) == (KT_DEAD | 0xf0))
                                ascebc[ret_diacr[KVAL(keysym)]] = k;
                }
        }
}

#if 0
/*
 * Generate ebcdic -> ascii translation table from kbd_data.
 */
void
kbd_ebcasc(struct kbd_data *kbd, unsigned char *ebcasc)
{
        unsigned short *keymap, keysym;
        int i, j, k;

        memset(ebcasc, ' ', 256);
        for (i = 0; i < ARRAY_SIZE(ebc_key_maps); i++) {
                keymap = kbd->key_maps[i];
                if (!keymap)
                        continue;
                for (j = 0; j < NR_KEYS; j++) {
                        keysym = keymap[j];
                        k = ((i & 1) << 7) + j;
                        if (KTYP(keysym) == (KT_LATIN | 0xf0) ||
                            KTYP(keysym) == (KT_LETTER | 0xf0))
                                ebcasc[k] = KVAL(keysym);
                        else if (KTYP(keysym) == (KT_DEAD | 0xf0))
                                ebcasc[k] = ret_diacr[KVAL(keysym)];
                }
        }
}
#endif

/*
 * We have a combining character DIACR here, followed by the character CH.
 * If the combination occurs in the table, return the corresponding value.
 * Otherwise, if CH is a space or equals DIACR, return DIACR.
 * Otherwise, conclude that DIACR was not combining after all,
 * queue it and return CH.
 */
static unsigned int
handle_diacr(struct kbd_data *kbd, unsigned int ch)
{
        int i, d;

        d = kbd->diacr;
        kbd->diacr = 0;

        for (i = 0; i < kbd->accent_table_size; i++) {
                if (kbd->accent_table[i].diacr == d &&
                    kbd->accent_table[i].base == ch)
                        return kbd->accent_table[i].result;
        }

        if (ch == ' ' || ch == d)
                return d;

        kbd_put_queue(kbd->port, d);
        return ch;
}

/*
 * Handle dead key.
 */
static void
k_dead(struct kbd_data *kbd, unsigned char value)
{
        value = ret_diacr[value];
        kbd->diacr = (kbd->diacr ? handle_diacr(kbd, value) : value);
}

/*
 * Normal character handler.
 */
static void
k_self(struct kbd_data *kbd, unsigned char value)
{
        if (kbd->diacr)
                value = handle_diacr(kbd, value);
        kbd_put_queue(kbd->port, value);
}

/*
 * Special key handlers
 */
static void
k_ignore(struct kbd_data *kbd, unsigned char value)
{
}

/*
 * Function key handler.
 */
static void
k_fn(struct kbd_data *kbd, unsigned char value)
{
        if (kbd->func_table[value])
                kbd_puts_queue(kbd->port, kbd->func_table[value]);
}

static void
k_spec(struct kbd_data *kbd, unsigned char value)
{
        if (value >= NR_FN_HANDLER)
                return;
        if (kbd->fn_handler[value])
                kbd->fn_handler[value](kbd);
}

/*
 * Put utf8 character to tty flip buffer.
 * UTF-8 is defined for words of up to 31 bits,
 * but we need only 16 bits here
 */
static void
to_utf8(struct tty_port *port, ushort c)
{
        if (c < 0x80)
                /*  0******* */
                kbd_put_queue(port, c);
        else if (c < 0x800) {
                /* 110***** 10****** */
                kbd_put_queue(port, 0xc0 | (c >> 6));
                kbd_put_queue(port, 0x80 | (c & 0x3f));
        } else {
                /* 1110**** 10****** 10****** */
                kbd_put_queue(port, 0xe0 | (c >> 12));
                kbd_put_queue(port, 0x80 | ((c >> 6) & 0x3f));
                kbd_put_queue(port, 0x80 | (c & 0x3f));
        }
}

/*
 * Process keycode.
 */
void
kbd_keycode(struct kbd_data *kbd, unsigned int keycode)
{
        unsigned short keysym;
        unsigned char type, value;

        if (!kbd)
                return;

        if (keycode >= 384)
                keysym = kbd->key_maps[5][keycode - 384];
        else if (keycode >= 256)
                keysym = kbd->key_maps[4][keycode - 256];
        else if (keycode >= 128)
                keysym = kbd->key_maps[1][keycode - 128];
        else
                keysym = kbd->key_maps[0][keycode];

        type = KTYP(keysym);
        if (type >= 0xf0) {
                type -= 0xf0;
                if (type == KT_LETTER)
                        type = KT_LATIN;
                value = KVAL(keysym);
#ifdef CONFIG_MAGIC_SYSRQ              /* Handle the SysRq Hack */
                if (kbd->sysrq) {
                        if (kbd->sysrq == K(KT_LATIN, '-')) {
                                kbd->sysrq = 0;
                                handle_sysrq(value);
                                return;
                        }
                        if (value == '-') {
                                kbd->sysrq = K(KT_LATIN, '-');
                                return;
                        }
                        /* Incomplete sysrq sequence. */
                        (*k_handler[KTYP(kbd->sysrq)])(kbd, KVAL(kbd->sysrq));
                        kbd->sysrq = 0;
                } else if ((type == KT_LATIN && value == '^') ||
                           (type == KT_DEAD && ret_diacr[value] == '^')) {
                        kbd->sysrq = K(type, value);
                        return;
                }
#endif
                (*k_handler[type])(kbd, value);
        } else
                to_utf8(kbd->port, keysym);
}

/*
 * Ioctl stuff.
 */
static int
do_kdsk_ioctl(struct kbd_data *kbd, struct kbentry __user *user_kbe,
              int cmd, int perm)
{
        struct kbentry tmp;
        unsigned long kb_index, kb_table;
        ushort *key_map, val, ov;

        if (copy_from_user(&tmp, user_kbe, sizeof(struct kbentry)))
                return -EFAULT;
        kb_index = (unsigned long) tmp.kb_index;
#if NR_KEYS < 256
        if (kb_index >= NR_KEYS)
                return -EINVAL;
#endif
        kb_table = (unsigned long) tmp.kb_table;
#if MAX_NR_KEYMAPS < 256
        if (kb_table >= MAX_NR_KEYMAPS)
                return -EINVAL; 
        kb_table = array_index_nospec(kb_table , MAX_NR_KEYMAPS);
#endif

        switch (cmd) {
        case KDGKBENT:
                key_map = kbd->key_maps[kb_table];
                if (key_map) {
                    val = U(key_map[kb_index]);
                    if (KTYP(val) >= KBD_NR_TYPES)
                        val = K_HOLE;
                } else
                    val = (kb_index ? K_HOLE : K_NOSUCHMAP);
                return put_user(val, &user_kbe->kb_value);
        case KDSKBENT:
                if (!perm)
                        return -EPERM;
                if (!kb_index && tmp.kb_value == K_NOSUCHMAP) {
                        /* disallocate map */
                        key_map = kbd->key_maps[kb_table];
                        if (key_map) {
                            kbd->key_maps[kb_table] = NULL;
                            kfree(key_map);
                        }
                        break;
                }

                if (KTYP(tmp.kb_value) >= KBD_NR_TYPES)
                        return -EINVAL;
                if (KVAL(tmp.kb_value) > kbd_max_vals[KTYP(tmp.kb_value)])
                        return -EINVAL;

                if (!(key_map = kbd->key_maps[kb_table])) {
                        int j;

                        key_map = kmalloc(sizeof(plain_map),
                                                     GFP_KERNEL);
                        if (!key_map)
                                return -ENOMEM;
                        kbd->key_maps[kb_table] = key_map;
                        for (j = 0; j < NR_KEYS; j++)
                                key_map[j] = U(K_HOLE);
                }
                ov = U(key_map[kb_index]);
                if (tmp.kb_value == ov)
                        break;  /* nothing to do */
                /*
                 * Attention Key.
                 */
                if (((ov == K_SAK) || (tmp.kb_value == K_SAK)) &&
                    !capable(CAP_SYS_ADMIN))
                        return -EPERM;
                key_map[kb_index] = U(tmp.kb_value);
                break;
        }
        return 0;
}

static int
do_kdgkb_ioctl(struct kbd_data *kbd, struct kbsentry __user *u_kbs,
               int cmd, int perm)
{
        unsigned char kb_func;
        char *p;
        int len;

        /* Get u_kbs->kb_func. */
        if (get_user(kb_func, &u_kbs->kb_func))
                return -EFAULT;
#if MAX_NR_FUNC < 256
        if (kb_func >= MAX_NR_FUNC)
                return -EINVAL;
#endif

        switch (cmd) {
        case KDGKBSENT:
                p = kbd->func_table[kb_func];
                if (p) {
                        len = strlen(p);
                        if (len >= sizeof(u_kbs->kb_string))
                                len = sizeof(u_kbs->kb_string) - 1;
                        if (copy_to_user(u_kbs->kb_string, p, len))
                                return -EFAULT;
                } else
                        len = 0;
                if (put_user('\0', u_kbs->kb_string + len))
                        return -EFAULT;
                break;
        case KDSKBSENT:
                if (!perm)
                        return -EPERM;
                p = strndup_user(u_kbs->kb_string, sizeof(u_kbs->kb_string));
                if (IS_ERR(p))
                        return PTR_ERR(p);
                kfree(kbd->func_table[kb_func]);
                kbd->func_table[kb_func] = p;
                break;
        }
        return 0;
}

int kbd_ioctl(struct kbd_data *kbd, unsigned int cmd, unsigned long arg)
{
        struct tty_struct *tty;
        void __user *argp;
        unsigned int ct;
        int perm;

        argp = (void __user *)arg;

        /*
         * To have permissions to do most of the vt ioctls, we either have
         * to be the owner of the tty, or have CAP_SYS_TTY_CONFIG.
         */
        tty = tty_port_tty_get(kbd->port);
        /* FIXME this test is pretty racy */
        perm = current->signal->tty == tty || capable(CAP_SYS_TTY_CONFIG);
        tty_kref_put(tty);
        switch (cmd) {
        case KDGKBTYPE:
                return put_user(KB_101, (char __user *)argp);
        case KDGKBENT:
        case KDSKBENT:
                return do_kdsk_ioctl(kbd, argp, cmd, perm);
        case KDGKBSENT:
        case KDSKBSENT:
                return do_kdgkb_ioctl(kbd, argp, cmd, perm);
        case KDGKBDIACR:
        {
                struct kbdiacrs __user *a = argp;
                struct kbdiacr diacr;
                int i;

                if (put_user(kbd->accent_table_size, &a->kb_cnt))
                        return -EFAULT;
                for (i = 0; i < kbd->accent_table_size; i++) {
                        diacr.diacr = kbd->accent_table[i].diacr;
                        diacr.base = kbd->accent_table[i].base;
                        diacr.result = kbd->accent_table[i].result;
                        if (copy_to_user(a->kbdiacr + i, &diacr, sizeof(struct kbdiacr)))
                        return -EFAULT;
                }
                return 0;
        }
        case KDGKBDIACRUC:
        {
                struct kbdiacrsuc __user *a = argp;

                ct = kbd->accent_table_size;
                if (put_user(ct, &a->kb_cnt))
                        return -EFAULT;
                if (copy_to_user(a->kbdiacruc, kbd->accent_table,
                                 ct * sizeof(struct kbdiacruc)))
                        return -EFAULT;
                return 0;
        }
        case KDSKBDIACR:
        {
                struct kbdiacrs __user *a = argp;
                struct kbdiacr diacr;
                int i;

                if (!perm)
                        return -EPERM;
                if (get_user(ct, &a->kb_cnt))
                        return -EFAULT;
                if (ct >= MAX_DIACR)
                        return -EINVAL;
                kbd->accent_table_size = ct;
                for (i = 0; i < ct; i++) {
                        if (copy_from_user(&diacr, a->kbdiacr + i, sizeof(struct kbdiacr)))
                                return -EFAULT;
                        kbd->accent_table[i].diacr = diacr.diacr;
                        kbd->accent_table[i].base = diacr.base;
                        kbd->accent_table[i].result = diacr.result;
                }
                return 0;
        }
        case KDSKBDIACRUC:
        {
                struct kbdiacrsuc __user *a = argp;

                if (!perm)
                        return -EPERM;
                if (get_user(ct, &a->kb_cnt))
                        return -EFAULT;
                if (ct >= MAX_DIACR)
                        return -EINVAL;
                kbd->accent_table_size = ct;
                if (copy_from_user(kbd->accent_table, a->kbdiacruc,
                                   ct * sizeof(struct kbdiacruc)))
                        return -EFAULT;
                return 0;
        }
        default:
                return -ENOIOCTLCMD;
        }
}

EXPORT_SYMBOL(kbd_ioctl);
EXPORT_SYMBOL(kbd_ascebc);
EXPORT_SYMBOL(kbd_free);
EXPORT_SYMBOL(kbd_alloc);
EXPORT_SYMBOL(kbd_keycode);