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GitHub Repository: att/ast
 Path: blob/master/src/lib/libast/path/pathcd.c
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/***********************************************************************

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*                                                                      *

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*               This software is part of the ast package               *

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*          Copyright (c) 1985-2011 AT&T Intellectual Property          *

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*                      and is licensed under the                       *

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*                 Eclipse Public License, Version 1.0                  *

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*                    by AT&T Intellectual Property                     *

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*                                                                      *

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*                A copy of the License is available at                 *

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*          http://www.eclipse.org/org/documents/epl-v10.html           *

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*         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *

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*                                                                      *

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*              Information and Software Systems Research               *

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*                            AT&T Research                             *

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*                           Florham Park NJ                            *

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*                                                                      *

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*                 Glenn Fowler <[email protected]>                  *

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*                  David Korn <[email protected]>                   *

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*                   Phong Vo <[email protected]>                    *

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*                                                                      *

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***********************************************************************/

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#pragma prototyped

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/*

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 * K. P. Vo

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 * G. S. Fowler

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 * AT&T Research

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 */

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#include <ast.h>

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#include <error.h>

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#include <stk.h>

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#if DEBUG

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#undef	PATH_MAX

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#define PATH_MAX	16

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static int

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vchdir(const char* path)

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{

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	int	n;

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	if (strlen(path) >= PATH_MAX)

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	{

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		errno = ENAMETOOLONG;

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		n = -1;

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	}

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	else n = chdir(path);

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	return n;

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}

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#define chdir(p)	vchdir(p)

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#endif

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/*

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 * set the current directory to path

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 * if path is long and home!=0 then pathcd(home,0)

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 * is called on intermediate chdir errors

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 */

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int

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pathcd(const char* path, const char* home)

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{

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	register char*	p = (char*)path;

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	register char*	s;

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	register int	n;

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	int		i;

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	int		r;

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	r = 0;

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	for (;;)

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	{

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		/*

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		 * this should work 99% of the time

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		 */

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		if (!chdir(p))

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			return r;

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		/*

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		 * chdir failed

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		 */

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		if ((n = strlen(p)) < PATH_MAX)

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			return -1;

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#ifdef ENAMETOOLONG

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		if (errno != ENAMETOOLONG)

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			return -1;

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#endif

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		/*

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		 * path is too long -- copy so it can be modified in place

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		 */

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		i = stktell(stkstd);

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		sfputr(stkstd, p, 0);

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		stkseek(stkstd, i);

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		p = stkptr(stkstd, i);

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		for (;;)

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		{

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			/*

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			 * get a short prefix component

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			 */

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			s = p + PATH_MAX;

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			while (--s >= p && *s != '/');

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			if (s <= p)

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				break;

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			/*

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			 * chdir to the prefix

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			 */

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			*s++ = 0;

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			if (chdir(p))

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				break;

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			/*

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			 * do the remainder

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			 */

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			if ((n -= s - p) < PATH_MAX)

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			{

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				if (chdir(s))

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					break;

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				return r;

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			}

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			p = s;

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		}

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		/*

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		 * try to recover back to home

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		 */

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		if (!(p = (char*)home))

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			return -1;

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		home = 0;

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		r = -1;

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	}

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}

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