129 lines
3.7 KiB
C
129 lines
3.7 KiB
C
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/* Libiberty realpath. Like realpath, but more consistent behavior.
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Based on gdb_realpath from GDB.
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Copyright 2003 Free Software Foundation, Inc.
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This file is part of the libiberty library.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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/*
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@deftypefn Replacement {const char*} lrealpath (const char *@var{name})
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Given a pointer to a string containing a pathname, returns a canonical
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version of the filename. Symlinks will be resolved, and ``.'' and ``..''
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components will be simplified. The returned value will be allocated using
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@code{malloc}, or @code{NULL} will be returned on a memory allocation error.
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@end deftypefn
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*/
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#include "config.h"
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#include "ansidecl.h"
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#include "libiberty.h"
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#ifdef HAVE_LIMITS_H
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#include <limits.h>
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#endif
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#ifdef HAVE_STDLIB_H
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#include <stdlib.h>
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#endif
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#ifdef HAVE_STRING_H
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#include <string.h>
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#endif
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/* On GNU libc systems the declaration is only visible with _GNU_SOURCE. */
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#if defined(HAVE_CANONICALIZE_FILE_NAME) \
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&& defined(NEED_DECLARATION_CANONICALIZE_FILE_NAME)
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extern char *canonicalize_file_name (const char *);
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#endif
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#if defined(HAVE_REALPATH)
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# if defined (PATH_MAX)
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# define REALPATH_LIMIT PATH_MAX
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# else
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# if defined (MAXPATHLEN)
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# define REALPATH_LIMIT MAXPATHLEN
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# endif
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# endif
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#endif
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char *
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lrealpath (filename)
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const char *filename;
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{
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/* Method 1: The system has a compile time upper bound on a filename
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path. Use that and realpath() to canonicalize the name. This is
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the most common case. Note that, if there isn't a compile time
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upper bound, you want to avoid realpath() at all costs. */
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#if defined(REALPATH_LIMIT)
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{
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char buf[REALPATH_LIMIT];
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const char *rp = realpath (filename, buf);
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if (rp == NULL)
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rp = filename;
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return strdup (rp);
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}
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#endif /* REALPATH_LIMIT */
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/* Method 2: The host system (i.e., GNU) has the function
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canonicalize_file_name() which malloc's a chunk of memory and
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returns that, use that. */
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#if defined(HAVE_CANONICALIZE_FILE_NAME)
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{
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char *rp = canonicalize_file_name (filename);
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if (rp == NULL)
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return strdup (filename);
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else
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return rp;
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}
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#endif
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/* Method 3: Now we're getting desperate! The system doesn't have a
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compile time buffer size and no alternative function. Query the
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OS, using pathconf(), for the buffer limit. Care is needed
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though, some systems do not limit PATH_MAX (return -1 for
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pathconf()) making it impossible to pass a correctly sized buffer
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to realpath() (it could always overflow). On those systems, we
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skip this. */
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#if defined (HAVE_REALPATH) && defined (HAVE_UNISTD_H)
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{
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/* Find out the max path size. */
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long path_max = pathconf ("/", _PC_PATH_MAX);
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if (path_max > 0)
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{
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/* PATH_MAX is bounded. */
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char *buf, *rp, *ret;
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buf = malloc (path_max);
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if (buf == NULL)
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return NULL;
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rp = realpath (filename, buf);
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ret = strdup (rp ? rp : filename);
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free (buf);
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return ret;
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}
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}
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#endif
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/* This system is a lost cause, just duplicate the filename. */
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return strdup (filename);
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}
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