/*      $NetBSD: ctype_.c,v 1.24 2025/09/15 00:11:54 riastradh Exp $    */

/*
 * Copyright (c) 1989 The Regents of the University of California.
 * All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
/*static char *sccsid = "from: @(#)ctype_.c     5.6 (Berkeley) 6/1/90";*/
#else
__RCSID("$NetBSD: ctype_.c,v 1.24 2025/09/15 00:11:54 riastradh Exp $");
#endif
#endif /* LIBC_SCCS and not lint */

#include <sys/ctype_bits.h>
#include <sys/mman.h>

#include <stdio.h>
#include <string.h>

#include "ctype_guard.h"
#include "ctype_local.h"

#if EOF != -1
#error "EOF != -1"
#endif

#ifdef __BUILD_LEGACY
#define _C      _COMPAT_C
#define _S      _COMPAT_S
#define _U      _COMPAT_U
#define _X      _COMPAT_X
#define _L      _COMPAT_L
#define _P      _COMPAT_P
#define _B      _COMPAT_B
#define _N      _COMPAT_N

__ctype_table
static
const unsigned char _C_compat_bsdctype_guarded[_C_COMPAT_BSDCTYPE_GUARD +
    1 + _CTYPE_NUM_CHARS] = {
        _CTYPE_GUARD_INIT(_C_COMPAT_BSDCTYPE_GUARD, -1)
        [_C_COMPAT_BSDCTYPE_GUARD] = 0,
        _C,     _C,     _C,     _C,     _C,     _C,     _C,     _C,
        _C,     _C|_S,  _C|_S,  _C|_S,  _C|_S,  _C|_S,  _C,     _C,
        _C,     _C,     _C,     _C,     _C,     _C,     _C,     _C,
        _C,     _C,     _C,     _C,     _C,     _C,     _C,     _C,
        _S|_B,  _P,     _P,     _P,     _P,     _P,     _P,     _P,
        _P,     _P,     _P,     _P,     _P,     _P,     _P,     _P,
        _N,     _N,     _N,     _N,     _N,     _N,     _N,     _N,
        _N,     _N,     _P,     _P,     _P,     _P,     _P,     _P,
        _P,     _U|_X,  _U|_X,  _U|_X,  _U|_X,  _U|_X,  _U|_X,  _U,
        _U,     _U,     _U,     _U,     _U,     _U,     _U,     _U,
        _U,     _U,     _U,     _U,     _U,     _U,     _U,     _U,
        _U,     _U,     _U,     _P,     _P,     _P,     _P,     _P,
        _P,     _L|_X,  _L|_X,  _L|_X,  _L|_X,  _L|_X,  _L|_X,  _L,
        _L,     _L,     _L,     _L,     _L,     _L,     _L,     _L,
        _L,     _L,     _L,     _L,     _L,     _L,     _L,     _L,
        _L,     _L,     _L,     _P,     _P,     _P,     _P,     _C
};
__ctype_table_guarded(_C_compat_bsdctype, _C_compat_bsdctype_guarded,
    1 + _CTYPE_NUM_CHARS, /*sizeof(unsigned char)*/1);

#undef _C
#undef _S
#undef _U
#undef _X
#undef _L
#undef _P
#undef _B
#undef _N

#ifdef __weak_alias
__weak_alias(_C_ctype_, _C_compat_bsdctype)
#endif

const unsigned char *_ctype_ = &_C_compat_bsdctype[0];
#endif /* __BUILD_LEGACY */

#define _A      _CTYPE_A
#define _BL     _CTYPE_BL
#define _C      _CTYPE_C
#define _D      _CTYPE_D
#define _G      _CTYPE_G
#define _L      _CTYPE_L
#define _P      _CTYPE_P
#define _R      _CTYPE_R
#define _S      _CTYPE_S
#define _U      _CTYPE_U
#define _X      _CTYPE_X

__ctype_table
static const unsigned short _C_ctype_tab_guarded_[_C_CTYPE_TAB_GUARD +
    1 + _CTYPE_NUM_CHARS] = {
        _CTYPE_GUARD_INIT(_C_CTYPE_TAB_GUARD, -1)
        [_C_CTYPE_TAB_GUARD] = 0,
        _C,             _C,             _C,             _C,
        _C,             _C,             _C,             _C,
        _C,             _BL|_C|_S,      _C|_S,          _C|_S,
        _C|_S,          _C|_S,          _C,             _C,
        _C,             _C,             _C,             _C,
        _C,             _C,             _C,             _C,
        _C,             _C,             _C,             _C,
        _C,             _C,             _C,             _C,
        _BL|_R|_S,      _G|_R|_P,       _G|_R|_P,       _G|_R|_P,
        _G|_R|_P,       _G|_R|_P,       _G|_R|_P,       _G|_R|_P,
        _G|_R|_P,       _G|_R|_P,       _G|_R|_P,       _G|_R|_P,
        _G|_R|_P,       _G|_R|_P,       _G|_R|_P,       _G|_R|_P,
        _D|_G|_R|_X,    _D|_G|_R|_X,    _D|_G|_R|_X,    _D|_G|_R|_X,
        _D|_G|_R|_X,    _D|_G|_R|_X,    _D|_G|_R|_X,    _D|_G|_R|_X,
        _D|_G|_R|_X,    _D|_G|_R|_X,    _G|_R|_P,       _G|_R|_P,
        _G|_R|_P,       _G|_R|_P,       _G|_R|_P,       _G|_R|_P,
        _G|_R|_P,       _A|_G|_R|_U|_X, _A|_G|_R|_U|_X, _A|_G|_R|_U|_X,
        _A|_G|_R|_U|_X, _A|_G|_R|_U|_X, _A|_G|_R|_U|_X, _A|_G|_R|_U,
        _A|_G|_R|_U,    _A|_G|_R|_U,    _A|_G|_R|_U,    _A|_G|_R|_U,
        _A|_G|_R|_U,    _A|_G|_R|_U,    _A|_G|_R|_U,    _A|_G|_R|_U,
        _A|_G|_R|_U,    _A|_G|_R|_U,    _A|_G|_R|_U,    _A|_G|_R|_U,
        _A|_G|_R|_U,    _A|_G|_R|_U,    _A|_G|_R|_U,    _A|_G|_R|_U,
        _A|_G|_R|_U,    _A|_G|_R|_U,    _A|_G|_R|_U,    _G|_R|_P,
        _G|_R|_P,       _G|_R|_P,       _G|_R|_P,       _G|_R|_P,
        _G|_R|_P,       _A|_G|_L|_R|_X, _A|_G|_L|_R|_X, _A|_G|_L|_R|_X,
        _A|_G|_L|_R|_X, _A|_G|_L|_R|_X, _A|_G|_L|_R|_X, _A|_G|_L|_R,
        _A|_G|_L|_R,    _A|_G|_L|_R,    _A|_G|_L|_R,    _A|_G|_L|_R,
        _A|_G|_L|_R,    _A|_G|_L|_R,    _A|_G|_L|_R,    _A|_G|_L|_R,
        _A|_G|_L|_R,    _A|_G|_L|_R,    _A|_G|_L|_R,    _A|_G|_L|_R,
        _A|_G|_L|_R,    _A|_G|_L|_R,    _A|_G|_L|_R,    _A|_G|_L|_R,
        _A|_G|_L|_R,    _A|_G|_L|_R,    _A|_G|_L|_R,    _G|_R|_P,
        _G|_R|_P,       _G|_R|_P,       _G|_R|_P,       _C,
};
__ctype_table_guarded(_C_ctype_tab_, _C_ctype_tab_guarded_,
    1 + _CTYPE_NUM_CHARS, __SIZEOF_SHORT__);

#undef _A
#undef _BL
#undef _C
#undef _D
#undef _G
#undef _L
#undef _P
#undef _R
#undef _S
#undef _U
#undef _X

const unsigned short *_ctype_tab_ = &_C_ctype_tab_[0];

/*
 * _allow_ctype_abuse()
 *
 *      Internal subroutine to interpret environ and return true if
 *      LIBC_ALLOWCTYPEABUSE is defined, false if not.
 *
 *      We use environ and strcmp directly to make sure this works
 *      inside constructors and to avoid pulling in all the
 *      stdlib/_env.c machinery if unnecessary.  We cache it so we only
 *      add one traversal of environ to each process startup for the
 *      ctype, toupper, and tolower tables (not ideal -- rtld already
 *      does another traversal -- but better than adding multiple
 *      traversals).
 *
 *      This query is also used by the out-of-line ctype logic in
 *      isctype.c outside a constructor, where it could use getenv, and
 *      perhaps support finer-grained distinctions -- like
 *      LIBC_ALLOWCTYPEABUSE=silent vs LIBC_ALLOWCTYPEABUSE=noisy.  But
 *      until we feel the need to implement such finer distinctions,
 *      let's keep the logic of interpreting LIBC_ALLOWCTYPEABUSE
 *      together in one place.
 */
#ifndef RTLD_LOADER
#include "extern.h"             /* environ */
static bool
_allow_ctype_abuse(void)
{
        const char vareq[] = "LIBC_ALLOWCTYPEABUSE=";
        char *const *envp;

        for (envp = environ; *envp != NULL; envp++) {
                if (strncmp(*envp, vareq, strlen(vareq)) == 0) {
                        return true;
                }
        }
        return false;
}
#endif

#if _CTYPE_GUARD_PAGE

static enum {
        ABUSE_UNDETERMINED = 0,
        ABUSE_ALLOWED,
        ABUSE_TRAPPED,
} allow_ctype_abuse_cache;

/*
 * allow_ctype_abuse()
 *
 *      True if LIBC_ALLOWCTYPEABUSE is defined in the environment,
 *      false if not.  May reflect the environment any time between
 *      process startup and now.
 */
__dso_hidden
bool
allow_ctype_abuse(void)
{

        if (allow_ctype_abuse_cache != ABUSE_UNDETERMINED)
                return allow_ctype_abuse_cache == ABUSE_ALLOWED;
        return _allow_ctype_abuse();
}

/*
 * constructor_allow_ctype_abuse()
 *
 *      True if LIBC_ALLOWCTYPEABUSE is defined in the environment,
 *      false if not.  May be used only in an ELF constructor.
 */
__dso_hidden
bool
constructor_allow_ctype_abuse(void)
{

        if (allow_ctype_abuse_cache != ABUSE_UNDETERMINED)
                return allow_ctype_abuse_cache == ABUSE_ALLOWED;
        if (_allow_ctype_abuse()) {
                allow_ctype_abuse_cache = ABUSE_ALLOWED;
                return true;
        } else {
                allow_ctype_abuse_cache = ABUSE_TRAPPED;
                return false;
        }
}

__attribute__((constructor))
static void
_C_ctype_tab_guard_init(void)
{

        if (constructor_allow_ctype_abuse())
                return;
#ifdef __BUILD_LEGACY
        (void)mprotect(__UNCONST(_C_compat_bsdctype_guarded),
            _CTYPE_GUARD_SIZE, PROT_NONE);
#endif  /* __BUILD_LEGACY */
        (void)mprotect(__UNCONST(_C_ctype_tab_guarded_),
            _CTYPE_GUARD_SIZE, PROT_NONE);
}

#else

#ifndef RTLD_LOADER
__dso_hidden
bool
allow_ctype_abuse(void)
{

        return _allow_ctype_abuse();
}
#endif

#endif  /* _CTYPE_GUARD_PAGE */