170 lines
3.6 KiB
C
170 lines
3.6 KiB
C
/* $NetBSD: cnmagic.c,v 1.13 2011/11/19 17:34:41 christos Exp $ */
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/*
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* Copyright (c) 2000 Eduardo Horvath
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: cnmagic.c,v 1.13 2011/11/19 17:34:41 christos Exp $");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#define ENCODE_STATE(c, n) (short)(((c)&0x1ff)|(((n)&0x7f)<<9))
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static unsigned short cn_magic[CNS_LEN];
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/*
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* Initialize a cnm_state_t.
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*/
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void
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cn_init_magic(cnm_state_t *cnm)
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{
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cnm->cnm_state = 0;
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cnm->cnm_magic = cn_magic;
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}
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/*
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* Destroy a cnm_state_t.
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*/
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void
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cn_destroy_magic(cnm_state_t *cnm)
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{
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cnm->cnm_state = 0;
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cnm->cnm_magic = NULL;
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}
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/*
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* Translate a magic string to a state
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* machine table.
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*/
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int
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cn_set_magic(const char *smagic)
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{
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const unsigned char *magic = (const unsigned char *)smagic;
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unsigned short i, c, n;
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unsigned short m[CNS_LEN];
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for (i = 0; i < CNS_LEN; i++) {
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c = *magic++;
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switch (c) {
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case 0:
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/* End of string */
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if (i == 0) {
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/* empty string? */
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#ifdef DEBUG
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printf("cn_set_magic(): empty!\n");
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#endif
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}
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cn_magic[i] = 0;
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while (i--)
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cn_magic[i] = m[i];
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return 0;
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case 0x27:
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/* Escape sequence */
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c = *magic++;
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switch (c) {
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case 0x27:
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break;
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case 0x01:
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/* BREAK */
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c = CNC_BREAK;
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break;
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case 0x02:
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/* NUL */
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c = 0;
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break;
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}
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/* FALLTHROUGH */
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default:
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/* Transition to the next state. */
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n = *magic ? i + 1 : CNS_TERM;
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#ifdef DEBUG
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if (!cold)
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aprint_normal("mag %d %x:%x\n", i, c, n);
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#endif
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m[i] = ENCODE_STATE(c, n);
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break;
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}
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}
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return EINVAL;
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}
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/*
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* Translatea state machine table back to
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* a magic string.
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*/
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int
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cn_get_magic(char *magic, size_t maglen)
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{
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size_t i, n = 0;
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#define ADD_CHAR(x) \
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do \
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if (n < maglen) \
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magic[n++] = (x); \
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else \
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goto error; \
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while (/*CONSTCOND*/0)
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for (i = 0; i < CNS_LEN; /* empty */) {
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unsigned short c = cn_magic[i];
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i = CNS_MAGIC_NEXT(c);
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if (i == 0)
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goto finish;
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/* Translate a character */
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switch (CNS_MAGIC_VAL(c)) {
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case CNC_BREAK:
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ADD_CHAR(0x27);
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ADD_CHAR(0x01);
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break;
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case 0:
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ADD_CHAR(0x27);
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ADD_CHAR(0x02);
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break;
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case 0x27:
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ADD_CHAR(0x27);
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ADD_CHAR(0x27);
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break;
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default:
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ADD_CHAR(c);
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break;
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}
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/* Now go to the next state */
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if (i == CNS_TERM)
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goto finish;
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}
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error:
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return EINVAL;
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finish:
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/* Either termination state or empty machine */
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ADD_CHAR('\0');
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return 0;
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}
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