text: /* Return the canonical absolute name of a given file.
     Copyright (C) 1996-2003 Free Software Foundation, Inc.
     This file is part of the GNU C Library.
  
     The GNU C Library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Lesser General Public
     License as published by the Free Software Foundation; either
     version 2.1 of the License, or (at your option) any later version.
  
     The GNU C Library is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     Lesser General Public License for more details.
  
     You should have received a copy of the GNU Lesser General Public
     License along with the GNU C Library; if not, write to the Free
     Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
     02111-1307 USA.  */
  
  #if HAVE_CONFIG_H
  # include <config.h>
  #endif
  
  #if !HAVE_CANONICALIZE_FILE_NAME || defined _LIBC
  
  #include <alloca.h>
  
  /* Specification.  */
  #include "canonicalize.h"
  
  #include <stddef.h>
  #include <stdlib.h>
  #include <string.h>
  
  #if HAVE_UNISTD_H || defined _LIBC
  # include <unistd.h>
  #endif
  
  #include <limits.h>
  
  #if HAVE_SYS_PARAM_H || defined _LIBC
  # include <sys/param.h>
  #endif
  #ifndef MAXSYMLINKS
  # define MAXSYMLINKS 20
  #endif
  
  #include <sys/stat.h>
  
  #include <errno.h>
  #ifndef _LIBC
  # define __set_errno(e) errno = (e)
  # ifndef ENAMETOOLONG
  #  define ENAMETOOLONG EINVAL
  # endif
  #endif
  
  #ifdef _LIBC
  # include <shlib-compat.h>
  #else
  # define SHLIB_COMPAT(lib, introduced, obsoleted) 0
  # define versioned_symbol(lib, local, symbol, version)
  # define compat_symbol(lib, local, symbol, version)
  # define weak_alias(local, symbol)
  # define __canonicalize_file_name canonicalize_file_name
  # define __realpath rpl_realpath
  # include "pathmax.h"
  # define __alloca alloca
  # if HAVE_GETCWD
  #  define __getcwd getcwd
  # else
  #  define __getcwd(buf, max) getwd (buf)
  # endif
  # define __readlink readlink
  #endif
  
  /* Return the canonical absolute name of file NAME.  A canonical name
     does not contain any `.', `..' components nor any repeated path
     separators ('/') or symlinks.  All path components must exist.  If
     RESOLVED is null, the result is malloc'd; otherwise, if the
     canonical name is PATH_MAX chars or more, returns null with `errno'
     set to ENAMETOOLONG; if the name fits in fewer than PATH_MAX chars,
     returns the name in RESOLVED.  If the name cannot be resolved and
     RESOLVED is non-NULL, it contains the path of the first component
     that cannot be resolved.  If the path can be resolved, RESOLVED
     holds the same value as the value returned.  */
  
  char *
  __realpath (const char *name, char *resolved)
  {
    char *rpath, *dest, *extra_buf = NULL;
    const char *start, *end, *rpath_limit;
    long int path_max;
    int num_links = 0;
  
    if (name == NULL)
      {
        /* As per Single Unix Specification V2 we must return an error if
  	 either parameter is a null pointer.  We extend this to allow
  	 the RESOLVED parameter to be NULL in case the we are expected to
  	 allocate the room for the return value.  */
        __set_errno (EINVAL);
        return NULL;
      }
  
    if (name[0] == '\0')
      {
        /* As per Single Unix Specification V2 we must return an error if
  	 the name argument points to an empty string.  */
        __set_errno (ENOENT);
        return NULL;
      }
  
  #ifdef PATH_MAX
    path_max = PATH_MAX;
  #else
    path_max = pathconf (name, _PC_PATH_MAX);
    if (path_max <= 0)
      path_max = 1024;
  #endif
  
    if (resolved == NULL)
      {
        rpath = malloc (path_max);
        if (rpath == NULL)
  	return NULL;
      }
    else
      rpath = resolved;
    rpath_limit = rpath + path_max;
  
    if (name[0] != '/')
      {
        if (!__getcwd (rpath, path_max))
  	{
  	  rpath[0] = '\0';
  	  goto error;
  	}
        dest = strchr (rpath, '\0');
      }
    else
      {
        rpath[0] = '/';
        dest = rpath + 1;
      }
  
    for (start = end = name; *start; start = end)
      {
  #ifdef _LIBC
        struct stat64 st;
  #else
        struct stat st;
  #endif
        int n;
  
        /* Skip sequence of multiple path-separators.  */
        while (*start == '/')
  	++start;
  
        /* Find end of path component.  */
        for (end = start; *end && *end != '/'; ++end)
  	/* Nothing.  */;
  
        if (end - start == 0)
  	break;
        else if (end - start == 1 && start[0] == '.')
  	/* nothing */;
        else if (end - start == 2 && start[0] == '.' && start[1] == '.')
  	{
  	  /* Back up to previous component, ignore if at root already.  */
  	  if (dest > rpath + 1)
  	    while ((--dest)[-1] != '/');
  	}
        else
  	{
  	  size_t new_size;
  
  	  if (dest[-1] != '/')
  	    *dest++ = '/';
  
  	  if (dest + (end - start) >= rpath_limit)
  	    {
  	      ptrdiff_t dest_offset = dest - rpath;
  	      char *new_rpath;
  
  	      if (resolved)
  		{
  		  __set_errno (ENAMETOOLONG);
  		  if (dest > rpath + 1)
  		    dest--;
  		  *dest = '\0';
  		  goto error;
  		}
  	      new_size = rpath_limit - rpath;
  	      if (end - start + 1 > path_max)
  		new_size += end - start + 1;
  	      else
  		new_size += path_max;
  	      new_rpath = (char *) realloc (rpath, new_size);
  	      if (new_rpath == NULL)
  		goto error;
  	      rpath = new_rpath;
  	      rpath_limit = rpath + new_size;
  
  	      dest = rpath + dest_offset;
  	    }
  
  #ifdef _LIBC
  	  dest = __mempcpy (dest, start, end - start);
  #else
  	  memcpy (dest, start, end - start);
  	  dest += end - start;
  #endif
  	  *dest = '\0';
  
  #ifdef _LIBC
  	  if (__lxstat64 (_STAT_VER, rpath, &st) < 0)
  #else
  	  if (lstat (rpath, &st) < 0)
  #endif
  	    goto error;
  
  #ifdef S_ISLNK
  	  if (S_ISLNK (st.st_mode))
  	    {
  	      char *buf = __alloca (path_max);
  	      size_t len;
  
  	      if (++num_links > MAXSYMLINKS)
  		{
  		  __set_errno (ELOOP);
  		  goto error;
  		}
  
  	      n = __readlink (rpath, buf, path_max);
  	      if (n < 0)
  		goto error;
  	      buf[n] = '\0';
  
  	      if (!extra_buf)
  		extra_buf = __alloca (path_max);
  
  	      len = strlen (end);
  	      if ((long int) (n + len) >= path_max)
  		{
  		  __set_errno (ENAMETOOLONG);
  		  goto error;
  		}
  
  	      /* Careful here, end may be a pointer into extra_buf... */
  	      memmove (&extra_buf[n], end, len + 1);
  	      name = end = memcpy (extra_buf, buf, n);
  
  	      if (buf[0] == '/')
  		dest = rpath + 1;	/* It's an absolute symlink */
  	      else
  		/* Back up to previous component, ignore if at root already: */
  		if (dest > rpath + 1)
  		  while ((--dest)[-1] != '/');
  	    }
  #endif
  	}
      }
    if (dest > rpath + 1 && dest[-1] == '/')
      --dest;
    *dest = '\0';
  
    return resolved ? memcpy (resolved, rpath, dest - rpath + 1) : rpath;
  
  error:
    if (resolved)
      strcpy (resolved, rpath);
    else
      free (rpath);
    return NULL;
  }
  versioned_symbol (libc, __realpath, realpath, GLIBC_2_3);
  
  
  #if SHLIB_COMPAT(libc, GLIBC_2_0, GLIBC_2_3)
  char *
  __old_realpath (const char *name, char *resolved)
  {
    if (resolved == NULL)
      {
        __set_errno (EINVAL);
        return NULL;
      }
  
    return __realpath (name, resolved);
  }
  compat_symbol (libc, __old_realpath, realpath, GLIBC_2_0);
  #endif
  
  
  char *
  __canonicalize_file_name (const char *name)
  {
    return __realpath (name, NULL);
  }
  weak_alias (__canonicalize_file_name, canonicalize_file_name)
  
  #endif
  