read_entry.c   [plain text]

/****************************************************************************
 * Copyright (c) 1998,1999,2000 Free Software Foundation, Inc.              *
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 * copy of this software and associated documentation files (the            *
 * "Software"), to deal in the Software without restriction, including      *
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 * distribute, distribute with modifications, sublicense, and/or sell       *
 * copies of the Software, and to permit persons to whom the Software is    *
 * furnished to do so, subject to the following conditions:                 *
 *                                                                          *
 * The above copyright notice and this permission notice shall be included  *
 * in all copies or substantial portions of the Software.                   *
 *                                                                          *
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 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
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/****************************************************************************
 *  Author: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995               *
 *     and: Eric S. Raymond <esr@snark.thyrsus.com>                         *
 ****************************************************************************/

/*
 *	read_entry.c -- Routine for reading in a compiled terminfo file
 *
 */

#include <curses.priv.h>

#include <tic.h>
#include <term_entry.h>

MODULE_ID("$Id: read_entry.c,v 1.2 2002/02/19 02:01:07 jevans Exp $")

#if !HAVE_TELL
#define tell(fd) 0		/* lseek() is POSIX, but not tell() - odd... */
#endif

/*
 *	int
 *	_nc_read_file_entry(filename, ptr)
 *
 *	Read the compiled terminfo entry in the given file into the
 *	structure pointed to by ptr, allocating space for the string
 *	table.
 */

#undef  BYTE
#define BYTE(p,n)	(unsigned char)((p)[n])

#define IS_NEG1(p)	((BYTE(p,0) == 0377) && (BYTE(p,1) == 0377))
#define IS_NEG2(p)	((BYTE(p,0) == 0376) && (BYTE(p,1) == 0377))
#define LOW_MSB(p)	(BYTE(p,0) + 256*BYTE(p,1))

static bool have_tic_directory = FALSE;
static bool keep_tic_directory = FALSE;

/*
 * Record the "official" location of the terminfo directory, according to
 * the place where we're writing to, or the normal default, if not.
 */
NCURSES_EXPORT(const char *)
_nc_tic_dir(const char *path)
{
    static const char *result = TERMINFO;

    if (!keep_tic_directory) {
	if (path != 0) {
	    result = path;
	    have_tic_directory = TRUE;
	} else if (!have_tic_directory && use_terminfo_vars()) {
	    char *envp;
	    if ((envp = getenv("TERMINFO")) != 0)
		return _nc_tic_dir(envp);
	}
    }
    return result;
}

/*
 * Special fix to prevent the terminfo directory from being moved after tic
 * has chdir'd to it.  If we let it be changed, then if $TERMINFO has a
 * relative path, we'll lose track of the actual directory.
 */
NCURSES_EXPORT(void)
_nc_keep_tic_dir(const char *path)
{
    _nc_tic_dir(path);
    keep_tic_directory = TRUE;
}

static void
convert_shorts(char *buf, short *Numbers, int count)
{
    int i;
    for (i = 0; i < count; i++) {
	if (IS_NEG1(buf + 2 * i))
	    Numbers[i] = ABSENT_NUMERIC;
	else if (IS_NEG2(buf + 2 * i))
	    Numbers[i] = CANCELLED_NUMERIC;
	else
	    Numbers[i] = LOW_MSB(buf + 2 * i);
	TR(TRACE_DATABASE, ("get Numbers[%d]=%d", i, Numbers[i]));
    }
}

static void
convert_strings(char *buf, char **Strings, int count, int size, char *table)
{
    int i;
    char *p;

    for (i = 0; i < count; i++) {
	if (IS_NEG1(buf + 2 * i)) {
	    Strings[i] = ABSENT_STRING;
	} else if (IS_NEG2(buf + 2 * i)) {
	    Strings[i] = CANCELLED_STRING;
	} else if (LOW_MSB(buf + 2 * i) > size) {
	    Strings[i] = ABSENT_STRING;
	} else {
	    Strings[i] = (LOW_MSB(buf + 2 * i) + table);
	    TR(TRACE_DATABASE, ("Strings[%d] = %s", i, _nc_visbuf(Strings[i])));
	}

	/* make sure all strings are NUL terminated */
	if (VALID_STRING(Strings[i])) {
	    for (p = Strings[i]; p <= table + size; p++)
		if (*p == '\0')
		    break;
	    /* if there is no NUL, ignore the string */
	    if (p > table + size)
		Strings[i] = ABSENT_STRING;
	}
    }
}

#define read_shorts(fd, buf, count) (read(fd, buf, (count)*2) == (count)*2)

#define even_boundary(value) \
    if ((value) % 2 != 0) read(fd, buf, 1)

static int
read_termtype(int fd, TERMTYPE * ptr)
/* return 1 if read, 0 if not found or garbled */
{
    int name_size, bool_count, num_count, str_count, str_size;
    int i;
    char buf[MAX_ENTRY_SIZE];

    TR(TRACE_DATABASE, ("READ termtype header @%d", tell(fd)));

    memset(ptr, 0, sizeof(*ptr));

    /* grab the header */
    if (!read_shorts(fd, buf, 6)
	|| LOW_MSB(buf) != MAGIC) {
	return (0);
    }

    _nc_free_termtype(ptr);
    name_size = LOW_MSB(buf + 2);
    bool_count = LOW_MSB(buf + 4);
    num_count = LOW_MSB(buf + 6);
    str_count = LOW_MSB(buf + 8);
    str_size = LOW_MSB(buf + 10);

    TR(TRACE_DATABASE,
       ("TERMTYPE name_size=%d, bool=%d/%d, num=%d/%d str=%d/%d(%d)",
	name_size, bool_count, BOOLCOUNT, num_count, NUMCOUNT,
	str_count, STRCOUNT, str_size));
    if (name_size < 0
	|| bool_count < 0
	|| num_count < 0
	|| str_count < 0
	|| str_size < 0) {
	return (0);
    }

    if (str_size) {
	/* try to allocate space for the string table */
	if (str_count * 2 >= (int) sizeof(buf)
	    || (ptr->str_table = typeMalloc(char, (unsigned) str_size)) == 0) {
	    return (0);
	}
    } else {
	str_count = 0;
    }

    /* grab the name (a null-terminate string) */
    read(fd, buf, min(MAX_NAME_SIZE, (unsigned) name_size));
    buf[MAX_NAME_SIZE] = '\0';
    ptr->term_names = typeCalloc(char, strlen(buf) + 1);
    if (ptr->term_names == NULL) {
	return (0);
    }
    (void) strcpy(ptr->term_names, buf);
    if (name_size > MAX_NAME_SIZE)
	lseek(fd, (off_t) (name_size - MAX_NAME_SIZE), 1);

    /* grab the booleans */
    if ((ptr->Booleans = typeCalloc(char, max(BOOLCOUNT, bool_count))) == 0
	|| read(fd, ptr->Booleans, (unsigned) bool_count) < bool_count) {
	return (0);
    }

    /*
     * If booleans end on an odd byte, skip it.  The machine they
     * originally wrote terminfo on must have been a 16-bit
     * word-oriented machine that would trap out if you tried a
     * word access off a 2-byte boundary.
     */
    even_boundary(name_size + bool_count);

    /* grab the numbers */
    if ((ptr->Numbers = typeCalloc(short, max(NUMCOUNT, num_count))) == 0
	|| !read_shorts(fd, buf, num_count)) {
	return (0);
    }
    convert_shorts(buf, ptr->Numbers, num_count);

    if ((ptr->Strings = typeCalloc(char *, max(STRCOUNT, str_count))) == 0)
	  return (0);

    if (str_count) {
	/* grab the string offsets */
	if (!read_shorts(fd, buf, str_count)) {
	    return (0);
	}
	/* finally, grab the string table itself */
	if (read(fd, ptr->str_table, (unsigned) str_size) != str_size)
	    return (0);
	convert_strings(buf, ptr->Strings, str_count, str_size, ptr->str_table);
    }
#if NCURSES_XNAMES

    ptr->num_Booleans = BOOLCOUNT;
    ptr->num_Numbers = NUMCOUNT;
    ptr->num_Strings = STRCOUNT;

    /*
     * Read extended entries, if any, after the normal end of terminfo data.
     */
    even_boundary(str_size);
    TR(TRACE_DATABASE, ("READ extended_header @%d", tell(fd)));
    if (_nc_user_definable && read_shorts(fd, buf, 5)) {
	int ext_bool_count = LOW_MSB(buf + 0);
	int ext_num_count = LOW_MSB(buf + 2);
	int ext_str_count = LOW_MSB(buf + 4);
	int ext_str_size = LOW_MSB(buf + 6);
	int ext_str_limit = LOW_MSB(buf + 8);
	int need = (ext_bool_count + ext_num_count + ext_str_count);
	int base = 0;

	if (need >= (int) sizeof(buf)
	    || ext_str_size >= (int) sizeof(buf)
	    || ext_str_limit >= (int) sizeof(buf)
	    || ext_bool_count < 0
	    || ext_num_count < 0
	    || ext_str_count < 0
	    || ext_str_size < 0
	    || ext_str_limit < 0)
	    return (0);

	ptr->num_Booleans = BOOLCOUNT + ext_bool_count;
	ptr->num_Numbers = NUMCOUNT + ext_num_count;
	ptr->num_Strings = STRCOUNT + ext_str_count;

	ptr->Booleans = typeRealloc(char, ptr->num_Booleans, ptr->Booleans);
	ptr->Numbers = typeRealloc(short, ptr->num_Numbers, ptr->Numbers);
	ptr->Strings = typeRealloc(char *, ptr->num_Strings, ptr->Strings);

	TR(TRACE_DATABASE, ("extended header is %d/%d/%d(%d:%d)",
			    ext_bool_count, ext_num_count, ext_str_count,
			    ext_str_size, ext_str_limit));

	TR(TRACE_DATABASE, ("READ %d extended-booleans @%d",
			    ext_bool_count, tell(fd)));
	if ((ptr->ext_Booleans = ext_bool_count) != 0) {
	    if (read(fd, ptr->Booleans + BOOLCOUNT, (unsigned)
		     ext_bool_count) != ext_bool_count)
		return (0);
	}
	even_boundary(ext_bool_count);

	TR(TRACE_DATABASE, ("READ %d extended-numbers @%d",
			    ext_num_count, tell(fd)));
	if ((ptr->ext_Numbers = ext_num_count) != 0) {
	    if (!read_shorts(fd, buf, ext_num_count))
		return (0);
	    TR(TRACE_DATABASE, ("Before converting extended-numbers"));
	    convert_shorts(buf, ptr->Numbers + NUMCOUNT, ext_num_count);
	}

	TR(TRACE_DATABASE, ("READ extended-offsets @%d", tell(fd)));
	if ((ext_str_count || need)
	    && !read_shorts(fd, buf, ext_str_count + need))
	    return (0);

	TR(TRACE_DATABASE, ("READ %d bytes of extended-strings @%d",
			    ext_str_limit, tell(fd)));

	if (ext_str_limit) {
	    if ((ptr->ext_str_table = typeMalloc(char, ext_str_limit)) == 0)
		  return (0);
	    if (read(fd, ptr->ext_str_table, ext_str_limit) != ext_str_limit)
		return (0);
	    TR(TRACE_DATABASE, ("first extended-string is %s", _nc_visbuf(ptr->ext_str_table)));
	}

	if ((ptr->ext_Strings = ext_str_count) != 0) {
	    TR(TRACE_DATABASE,
	       ("Before computing extended-string capabilities str_count=%d, ext_str_count=%d",
		str_count, ext_str_count));
	    convert_strings(buf, ptr->Strings + str_count, ext_str_count,
			    ext_str_limit, ptr->ext_str_table);
	    for (i = ext_str_count - 1; i >= 0; i--) {
		TR(TRACE_DATABASE, ("MOVE from [%d:%d] %s",
				    i, i + str_count,
				    _nc_visbuf(ptr->Strings[i + str_count])));
		ptr->Strings[i + STRCOUNT] = ptr->Strings[i + str_count];
		if (VALID_STRING(ptr->Strings[i + STRCOUNT]))
		    base += (strlen(ptr->Strings[i + STRCOUNT]) + 1);
		TR(TRACE_DATABASE, ("... to    [%d] %s",
				    i + STRCOUNT,
				    _nc_visbuf(ptr->Strings[i + STRCOUNT])));
	    }
	}

	if (need) {
	    if ((ptr->ext_Names = typeCalloc(char *, need)) == 0)
		  return (0);
	    TR(TRACE_DATABASE,
	       ("ext_NAMES starting @%d in extended_strings, first = %s",
		base, _nc_visbuf(ptr->ext_str_table + base)));
	    convert_strings(buf + (2 * ext_str_count), ptr->ext_Names, need,
			    ext_str_limit, ptr->ext_str_table + base);
	}

	T(("...done reading terminfo bool %d(%d) num %d(%d) str %d(%d)",
	   ptr->num_Booleans, ptr->ext_Booleans,
	   ptr->num_Numbers, ptr->ext_Numbers,
	   ptr->num_Strings, ptr->ext_Strings));

	TR(TRACE_DATABASE, ("extend: num_Booleans:%d", ptr->num_Booleans));
    } else
#endif /* NCURSES_XNAMES */
    {
	T(("...done reading terminfo bool %d num %d str %d",
	   bool_count, num_count, str_count));
#if NCURSES_XNAMES
	TR(TRACE_DATABASE, ("normal: num_Booleans:%d", ptr->num_Booleans));
#endif
    }

    for (i = bool_count; i < BOOLCOUNT; i++)
	ptr->Booleans[i] = FALSE;
    for (i = num_count; i < NUMCOUNT; i++)
	ptr->Numbers[i] = ABSENT_NUMERIC;
    for (i = str_count; i < STRCOUNT; i++)
	ptr->Strings[i] = ABSENT_STRING;

    return (1);
}

NCURSES_EXPORT(int)
_nc_read_file_entry
(const char *const filename, TERMTYPE * ptr)
/* return 1 if read, 0 if not found or garbled */
{
    int code, fd = -1;

    if (_nc_access(filename, R_OK) < 0
	|| (fd = open(filename, O_RDONLY | O_BINARY)) < 0) {
	T(("cannot open terminfo %s (errno=%d)", filename, errno));
	return (0);
    }

    T(("read terminfo %s", filename));
    if ((code = read_termtype(fd, ptr)) == 0)
	_nc_free_termtype(ptr);
    close(fd);

    return (code);
}

/*
 * Build a terminfo pathname and try to read the data.  Returns 1 on success,
 * 0 on failure.
 */
static int
_nc_read_tic_entry(char *const filename,
		   const char *const dir, const char *ttn, TERMTYPE * const tp)
{
/* maximum safe length of terminfo root directory name */
#define MAX_TPATH	(PATH_MAX - MAX_ALIAS - 6)

    if (strlen(dir) > MAX_TPATH)
	return 0;
    (void) sprintf(filename, "%s/%s", dir, ttn);
    return _nc_read_file_entry(filename, tp);
}

/*
 * Process the list of :-separated directories, looking for the terminal type.
 * We don't use strtok because it does not show us empty tokens.
 */
static int
_nc_read_terminfo_dirs(const char *dirs, char *const filename, const char *const
		       ttn, TERMTYPE * const tp)
{
    char *list, *a;
    const char *b;
    int code = 0;

    /* we'll modify the argument, so we must copy */
    if ((b = a = list = strdup(dirs)) == NULL)
	return (0);

    for (;;) {
	int c = *a;
	if (c == 0 || c == NCURSES_PATHSEP) {
	    *a = 0;
	    if ((b + 1) >= a)
		b = TERMINFO;
	    if (_nc_read_tic_entry(filename, b, ttn, tp) == 1) {
		code = 1;
		break;
	    }
	    b = a + 1;
	    if (c == 0)
		break;
	}
	a++;
    }

    free(list);
    return (code);
}

/*
 *	_nc_read_entry(char *tn, char *filename, TERMTYPE *tp)
 *
 *	Find and read the compiled entry for a given terminal type,
 *	if it exists.  We take pains here to make sure no combination
 *	of environment variables and terminal type name can be used to
 *	overrun the file buffer.
 */

NCURSES_EXPORT(int)
_nc_read_entry
(const char *const tn, char *const filename, TERMTYPE * const tp)
{
    char *envp;
    char ttn[MAX_ALIAS + 4];

    /* truncate the terminal name to prevent dangerous buffer airline */
    (void) sprintf(ttn, "%02x/%.*s", *tn, MAX_ALIAS, tn);

    /* This is System V behavior, in conjunction with our requirements for
     * writing terminfo entries.
     */
    if (have_tic_directory
	&& _nc_read_tic_entry(filename, _nc_tic_dir(0), ttn, tp) == 1)
	return 1;

    if (use_terminfo_vars()) {
	if ((envp = getenv("TERMINFO")) != 0
	    && _nc_read_tic_entry(filename, _nc_tic_dir(envp), ttn, tp) == 1)
	    return 1;

	/* this is an ncurses extension */
	if ((envp = _nc_home_terminfo()) != 0) {
	    if (_nc_read_tic_entry(filename, envp, ttn, tp) == 1) {
		return (1);
	    }
	}

	/* this is an ncurses extension */
	if ((envp = getenv("TERMINFO_DIRS")) != 0)
	    return _nc_read_terminfo_dirs(envp, filename, ttn, tp);
    }

    /* Try the system directory.  Note that the TERMINFO_DIRS value, if
     * defined by the configure script, begins with a ":", which will be
     * interpreted as TERMINFO.
     */
#ifdef TERMINFO_DIRS
    return _nc_read_terminfo_dirs(TERMINFO_DIRS, filename, ttn, tp);
#else
    return _nc_read_tic_entry(filename, TERMINFO, ttn, tp);
#endif
}