intl/relocatable.c - rust-lang/gcc - Git at Google

 /* Provide relocatable packages.
    Copyright (C) 2003 Free Software Foundation, Inc.
    Written by Bruno Haible <bruno@clisp.org>, 2003.

    This program is free software; you can redistribute it and/or modify it
    under the terms of the GNU Library General Public License as published
    by the Free Software Foundation; either version 2, or (at your option)
    any later version.

    This program 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
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public
    License along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301,
    USA.  */


 /* Tell glibc's <stdio.h> to provide a prototype for getline().
    This must come before <config.h> because <config.h> may include
    <features.h>, and once <features.h> has been included, it's too late.  */
 #ifndef _GNU_SOURCE
 # define _GNU_SOURCE	1
 #endif

 #ifdef HAVE_CONFIG_H
 # include "config.h"
 #endif

 /* Specification.  */
 #include "relocatable.h"

 #if ENABLE_RELOCATABLE

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

 #ifdef NO_XMALLOC
 # define xmalloc malloc
 #else
 # include "xmalloc.h"
 #endif

 #if DEPENDS_ON_LIBCHARSET
 # include <libcharset.h>
 #endif
 #if DEPENDS_ON_LIBICONV && HAVE_ICONV
 # include <iconv.h>
 #endif
 #if DEPENDS_ON_LIBINTL && ENABLE_NLS
 # include <libintl.h>
 #endif

 /* Faked cheap 'bool'.  */
 #undef bool
 #undef false
 #undef true
 #define bool int
 #define false 0
 #define true 1

 /* Pathname support.
    ISSLASH(C)           tests whether C is a directory separator character.
    IS_PATH_WITH_DIR(P)  tests whether P contains a directory specification.
  */
 #if defined _WIN32 || defined __WIN32__ || defined __EMX__ || defined __DJGPP__
   /* Win32, OS/2, DOS */
 # define ISSLASH(C) ((C) == '/' || (C) == '\\')
 # define HAS_DEVICE(P) \
     ((((P)[0] >= 'A' && (P)[0] <= 'Z') || ((P)[0] >= 'a' && (P)[0] <= 'z')) \
      && (P)[1] == ':')
 # define IS_PATH_WITH_DIR(P) \
     (strchr (P, '/') != NULL || strchr (P, '\\') != NULL || HAS_DEVICE (P))
 # define FILESYSTEM_PREFIX_LEN(P) (HAS_DEVICE (P) ? 2 : 0)
 #else
   /* Unix */
 # define ISSLASH(C) ((C) == '/')
 # define IS_PATH_WITH_DIR(P) (strchr (P, '/') != NULL)
 # define FILESYSTEM_PREFIX_LEN(P) 0
 #endif

 /* Original installation prefix.  */
 static char *orig_prefix;
 static size_t orig_prefix_len;
 /* Current installation prefix.  */
 static char *curr_prefix;
 static size_t curr_prefix_len;
 /* These prefixes do not end in a slash.  Anything that will be concatenated
    to them must start with a slash.  */

 /* Sets the original and the current installation prefix of this module.
    Relocation simply replaces a pathname starting with the original prefix
    by the corresponding pathname with the current prefix instead.  Both
    prefixes should be directory names without trailing slash (i.e. use ""
    instead of "/").  */
 static void
 set_this_relocation_prefix (const char *orig_prefix_arg,
 			    const char *curr_prefix_arg)
 {
   if (orig_prefix_arg != NULL && curr_prefix_arg != NULL
       /* Optimization: if orig_prefix and curr_prefix are equal, the
 	 relocation is a nop.  */
       && strcmp (orig_prefix_arg, curr_prefix_arg) != 0)
     {
       /* Duplicate the argument strings.  */
       char *memory;

       orig_prefix_len = strlen (orig_prefix_arg);
       curr_prefix_len = strlen (curr_prefix_arg);
       memory = (char *) xmalloc (orig_prefix_len + 1 + curr_prefix_len + 1);
 #ifdef NO_XMALLOC
       if (memory != NULL)
 #endif
 	{
 	  memcpy (memory, orig_prefix_arg, orig_prefix_len + 1);
 	  orig_prefix = memory;
 	  memory += orig_prefix_len + 1;
 	  memcpy (memory, curr_prefix_arg, curr_prefix_len + 1);
 	  curr_prefix = memory;
 	  return;
 	}
     }
   orig_prefix = NULL;
   curr_prefix = NULL;
   /* Don't worry about wasted memory here - this function is usually only
      called once.  */
 }

 /* Sets the original and the current installation prefix of the package.
    Relocation simply replaces a pathname starting with the original prefix
    by the corresponding pathname with the current prefix instead.  Both
    prefixes should be directory names without trailing slash (i.e. use ""
    instead of "/").  */
 void
 set_relocation_prefix (const char *orig_prefix_arg, const char *curr_prefix_arg)
 {
   set_this_relocation_prefix (orig_prefix_arg, curr_prefix_arg);

   /* Now notify all dependent libraries.  */
 #if DEPENDS_ON_LIBCHARSET
   libcharset_set_relocation_prefix (orig_prefix_arg, curr_prefix_arg);
 #endif
 #if DEPENDS_ON_LIBICONV && HAVE_ICONV && _LIBICONV_VERSION >= 0x0109
   libiconv_set_relocation_prefix (orig_prefix_arg, curr_prefix_arg);
 #endif
 #if DEPENDS_ON_LIBINTL && ENABLE_NLS && defined libintl_set_relocation_prefix
   libintl_set_relocation_prefix (orig_prefix_arg, curr_prefix_arg);
 #endif
 }

 /* Convenience function:
    Computes the current installation prefix, based on the original
    installation prefix, the original installation directory of a particular
    file, and the current pathname of this file.  Returns NULL upon failure.  */
 #ifdef IN_LIBRARY
 #define compute_curr_prefix local_compute_curr_prefix
 static
 #endif
 const char *
 compute_curr_prefix (const char *orig_installprefix,
 		     const char *orig_installdir,
 		     const char *curr_pathname)
 {
   const char *curr_installdir;
   const char *rel_installdir;

   if (curr_pathname == NULL)
     return NULL;

   /* Determine the relative installation directory, relative to the prefix.
      This is simply the difference between orig_installprefix and
      orig_installdir.  */
   if (strncmp (orig_installprefix, orig_installdir, strlen (orig_installprefix))
       != 0)
     /* Shouldn't happen - nothing should be installed outside $(prefix).  */
     return NULL;
   rel_installdir = orig_installdir + strlen (orig_installprefix);

   /* Determine the current installation directory.  */
   {
     const char *p_base = curr_pathname + FILESYSTEM_PREFIX_LEN (curr_pathname);
     const char *p = curr_pathname + strlen (curr_pathname);
     char *q;

     while (p > p_base)
       {
 	p--;
 	if (ISSLASH (*p))
 	  break;
       }

     q = (char *) xmalloc (p - curr_pathname + 1);
 #ifdef NO_XMALLOC
     if (q == NULL)
       return NULL;
 #endif
     memcpy (q, curr_pathname, p - curr_pathname);
     q[p - curr_pathname] = '\0';
     curr_installdir = q;
   }

   /* Compute the current installation prefix by removing the trailing
      rel_installdir from it.  */
   {
     const char *rp = rel_installdir + strlen (rel_installdir);
     const char *cp = curr_installdir + strlen (curr_installdir);
     const char *cp_base =
       curr_installdir + FILESYSTEM_PREFIX_LEN (curr_installdir);

     while (rp > rel_installdir && cp > cp_base)
       {
 	bool same = false;
 	const char *rpi = rp;
 	const char *cpi = cp;

 	while (rpi > rel_installdir && cpi > cp_base)
 	  {
 	    rpi--;
 	    cpi--;
 	    if (ISSLASH (*rpi) || ISSLASH (*cpi))
 	      {
 		if (ISSLASH (*rpi) && ISSLASH (*cpi))
 		  same = true;
 		break;
 	      }
 #if defined _WIN32 || defined __WIN32__ || defined __EMX__ || defined __DJGPP__
 	    /* Win32, OS/2, DOS - case insignificant filesystem */
 	    if ((*rpi >= 'a' && *rpi <= 'z' ? *rpi - 'a' + 'A' : *rpi)
 		!= (*cpi >= 'a' && *cpi <= 'z' ? *cpi - 'a' + 'A' : *cpi))
 	      break;
 #else
 	    if (*rpi != *cpi)
 	      break;
 #endif
 	  }
 	if (!same)
 	  break;
 	/* The last pathname component was the same.  opi and cpi now point
 	   to the slash before it.  */
 	rp = rpi;
 	cp = cpi;
       }

     if (rp > rel_installdir)
       /* Unexpected: The curr_installdir does not end with rel_installdir.  */
       return NULL;

     {
       size_t curr_prefix_len = cp - curr_installdir;
       char *curr_prefix;

       curr_prefix = (char *) xmalloc (curr_prefix_len + 1);
 #ifdef NO_XMALLOC
       if (curr_prefix == NULL)
 	return NULL;
 #endif
       memcpy (curr_prefix, curr_installdir, curr_prefix_len);
       curr_prefix[curr_prefix_len] = '\0';

       return curr_prefix;
     }
   }
 }

 #if defined PIC && defined INSTALLDIR

 /* Full pathname of shared library, or NULL.  */
 static char *shared_library_fullname;

 #if defined _WIN32 || defined __WIN32__

 /* Determine the full pathname of the shared library when it is loaded.  */

 BOOL WINAPI
 DllMain (HINSTANCE module_handle, DWORD event, LPVOID reserved)
 {
   (void) reserved;

   if (event == DLL_PROCESS_ATTACH)
     {
       /* The DLL is being loaded into an application's address range.  */
       static char location[MAX_PATH];

       if (!GetModuleFileName (module_handle, location, sizeof (location)))
 	/* Shouldn't happen.  */
 	return FALSE;

       if (!IS_PATH_WITH_DIR (location))
 	/* Shouldn't happen.  */
 	return FALSE;

       shared_library_fullname = strdup (location);
     }

   return TRUE;
 }

 #else /* Unix */

 static void
 find_shared_library_fullname ()
 {
 #ifdef __linux__
   FILE *fp;

   /* Open the current process' maps file.  It describes one VMA per line.  */
   fp = fopen ("/proc/self/maps", "r");
   if (fp)
     {
       unsigned long address = (unsigned long) &find_shared_library_fullname;
       for (;;)
 	{
 	  unsigned long start, end;
 	  int c;

 	  if (fscanf (fp, "%lx-%lx", &start, &end) != 2)
 	    break;
 	  if (address >= start && address <= end - 1)
 	    {
 	      /* Found it.  Now see if this line contains a filename.  */
 	      while (c = getc (fp), c != EOF && c != '\n' && c != '/')
 		continue;
 	      if (c == '/')
 		{
 		  size_t size;
 		  int len;

 		  ungetc (c, fp);
 		  shared_library_fullname = NULL; size = 0;
 		  len = getline (&shared_library_fullname, &size, fp);
 		  if (len >= 0)
 		    {
 		      /* Success: filled shared_library_fullname.  */
 		      if (len > 0 && shared_library_fullname[len - 1] == '\n')
 			shared_library_fullname[len - 1] = '\0';
 		    }
 		}
 	      break;
 	    }
 	  while (c = getc (fp), c != EOF && c != '\n')
 	    continue;
 	}
       fclose (fp);
     }
 #endif
 }

 #endif /* WIN32 / Unix */

 /* Return the full pathname of the current shared library.
    Return NULL if unknown.
    Guaranteed to work only on Linux and Woe32.  */
 static char *
 get_shared_library_fullname ()
 {
 #if !(defined _WIN32 || defined __WIN32__)
   static bool tried_find_shared_library_fullname;
   if (!tried_find_shared_library_fullname)
     {
       find_shared_library_fullname ();
       tried_find_shared_library_fullname = true;
     }
 #endif
   return shared_library_fullname;
 }

 #endif /* PIC */

 /* Returns the pathname, relocated according to the current installation
    directory.  */
 const char *
 relocate (const char *pathname)
 {
 #if defined PIC && defined INSTALLDIR
   static int initialized;

   /* Initialization code for a shared library.  */
   if (!initialized)
     {
       /* At this point, orig_prefix and curr_prefix likely have already been
 	 set through the main program's set_program_name_and_installdir
 	 function.  This is sufficient in the case that the library has
 	 initially been installed in the same orig_prefix.  But we can do
 	 better, to also cover the cases that 1. it has been installed
 	 in a different prefix before being moved to orig_prefix and (later)
 	 to curr_prefix, 2. unlike the program, it has not moved away from
 	 orig_prefix.  */
       const char *orig_installprefix = INSTALLPREFIX;
       const char *orig_installdir = INSTALLDIR;
       const char *curr_prefix_better;

       curr_prefix_better =
 	compute_curr_prefix (orig_installprefix, orig_installdir,
 			     get_shared_library_fullname ());
       if (curr_prefix_better == NULL)
 	curr_prefix_better = curr_prefix;

       set_relocation_prefix (orig_installprefix, curr_prefix_better);

       initialized = 1;
     }
 #endif

   /* Note: It is not necessary to perform case insensitive comparison here,
      even for DOS-like filesystems, because the pathname argument was
      typically created from the same Makefile variable as orig_prefix came
      from.  */
   if (orig_prefix != NULL && curr_prefix != NULL
       && strncmp (pathname, orig_prefix, orig_prefix_len) == 0)
     {
       if (pathname[orig_prefix_len] == '\0')
 	/* pathname equals orig_prefix.  */
 	return curr_prefix;
       if (ISSLASH (pathname[orig_prefix_len]))
 	{
 	  /* pathname starts with orig_prefix.  */
 	  const char *pathname_tail = &pathname[orig_prefix_len];
 	  char *result =
 	    (char *) xmalloc (curr_prefix_len + strlen (pathname_tail) + 1);

 #ifdef NO_XMALLOC
 	  if (result != NULL)
 #endif
 	    {
 	      memcpy (result, curr_prefix, curr_prefix_len);
 	      strcpy (result + curr_prefix_len, pathname_tail);
 	      return result;
 	    }
 	}
     }
   /* Nothing to relocate.  */
   return pathname;
 }

 #endif
	/* Provide relocatable packages.
	Copyright (C) 2003 Free Software Foundation, Inc.
	Written by Bruno Haible <bruno@clisp.org>, 2003.

	This program is free software; you can redistribute it and/or modify it
	under the terms of the GNU Library General Public License as published
	by the Free Software Foundation; either version 2, or (at your option)
	any later version.

	This program 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
	Library General Public License for more details.

	You should have received a copy of the GNU Library General Public
	License along with this program; if not, write to the Free Software
	Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301,
	USA. */


	/* Tell glibc's <stdio.h> to provide a prototype for getline().
	This must come before <config.h> because <config.h> may include
	<features.h>, and once <features.h> has been included, it's too late. */
	#ifndef _GNU_SOURCE
	# define _GNU_SOURCE 1
	#endif

	#ifdef HAVE_CONFIG_H
	# include "config.h"
	#endif

	/* Specification. */
	#include "relocatable.h"

	#if ENABLE_RELOCATABLE

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

	#ifdef NO_XMALLOC
	# define xmalloc malloc
	#else
	# include "xmalloc.h"
	#endif

	#if DEPENDS_ON_LIBCHARSET
	# include <libcharset.h>
	#endif
	#if DEPENDS_ON_LIBICONV && HAVE_ICONV
	# include <iconv.h>
	#endif
	#if DEPENDS_ON_LIBINTL && ENABLE_NLS
	# include <libintl.h>
	#endif

	/* Faked cheap 'bool'. */
	#undef bool
	#undef false
	#undef true
	#define bool int
	#define false 0
	#define true 1

	/* Pathname support.
	ISSLASH(C) tests whether C is a directory separator character.
	IS_PATH_WITH_DIR(P) tests whether P contains a directory specification.
	*/
	#if defined _WIN32 \|\| defined __WIN32__ \|\| defined __EMX__ \|\| defined __DJGPP__
	/* Win32, OS/2, DOS */
	# define ISSLASH(C) ((C) == '/' \|\| (C) == '\\')
	# define HAS_DEVICE(P) \
	((((P)[0] >= 'A' && (P)[0] <= 'Z') \|\| ((P)[0] >= 'a' && (P)[0] <= 'z')) \
	&& (P)[1] == ':')
	# define IS_PATH_WITH_DIR(P) \
	(strchr (P, '/') != NULL \|\| strchr (P, '\\') != NULL \|\| HAS_DEVICE (P))
	# define FILESYSTEM_PREFIX_LEN(P) (HAS_DEVICE (P) ? 2 : 0)
	#else
	/* Unix */
	# define ISSLASH(C) ((C) == '/')
	# define IS_PATH_WITH_DIR(P) (strchr (P, '/') != NULL)
	# define FILESYSTEM_PREFIX_LEN(P) 0
	#endif

	/* Original installation prefix. */
	static char *orig_prefix;
	static size_t orig_prefix_len;
	/* Current installation prefix. */
	static char *curr_prefix;
	static size_t curr_prefix_len;
	/* These prefixes do not end in a slash. Anything that will be concatenated
	to them must start with a slash. */

	/* Sets the original and the current installation prefix of this module.
	Relocation simply replaces a pathname starting with the original prefix
	by the corresponding pathname with the current prefix instead. Both
	prefixes should be directory names without trailing slash (i.e. use ""
	instead of "/"). */
	static void
	set_this_relocation_prefix (const char *orig_prefix_arg,
	const char *curr_prefix_arg)
	{
	if (orig_prefix_arg != NULL && curr_prefix_arg != NULL
	/* Optimization: if orig_prefix and curr_prefix are equal, the
	relocation is a nop. */
	&& strcmp (orig_prefix_arg, curr_prefix_arg) != 0)
	{
	/* Duplicate the argument strings. */
	char *memory;

	orig_prefix_len = strlen (orig_prefix_arg);
	curr_prefix_len = strlen (curr_prefix_arg);
	memory = (char *) xmalloc (orig_prefix_len + 1 + curr_prefix_len + 1);
	#ifdef NO_XMALLOC
	if (memory != NULL)
	#endif
	{
	memcpy (memory, orig_prefix_arg, orig_prefix_len + 1);
	orig_prefix = memory;
	memory += orig_prefix_len + 1;
	memcpy (memory, curr_prefix_arg, curr_prefix_len + 1);
	curr_prefix = memory;
	return;
	}
	}
	orig_prefix = NULL;
	curr_prefix = NULL;
	/* Don't worry about wasted memory here - this function is usually only
	called once. */
	}

	/* Sets the original and the current installation prefix of the package.
	Relocation simply replaces a pathname starting with the original prefix
	by the corresponding pathname with the current prefix instead. Both
	prefixes should be directory names without trailing slash (i.e. use ""
	instead of "/"). */
	void
	set_relocation_prefix (const char orig_prefix_arg, const char curr_prefix_arg)
	{
	set_this_relocation_prefix (orig_prefix_arg, curr_prefix_arg);

	/* Now notify all dependent libraries. */
	#if DEPENDS_ON_LIBCHARSET
	libcharset_set_relocation_prefix (orig_prefix_arg, curr_prefix_arg);
	#endif
	#if DEPENDS_ON_LIBICONV && HAVE_ICONV && _LIBICONV_VERSION >= 0x0109
	libiconv_set_relocation_prefix (orig_prefix_arg, curr_prefix_arg);
	#endif
	#if DEPENDS_ON_LIBINTL && ENABLE_NLS && defined libintl_set_relocation_prefix
	libintl_set_relocation_prefix (orig_prefix_arg, curr_prefix_arg);
	#endif
	}

	/* Convenience function:
	Computes the current installation prefix, based on the original
	installation prefix, the original installation directory of a particular
	file, and the current pathname of this file. Returns NULL upon failure. */
	#ifdef IN_LIBRARY
	#define compute_curr_prefix local_compute_curr_prefix
	static
	#endif
	const char *
	compute_curr_prefix (const char *orig_installprefix,
	const char *orig_installdir,
	const char *curr_pathname)
	{
	const char *curr_installdir;
	const char *rel_installdir;

	if (curr_pathname == NULL)
	return NULL;

	/* Determine the relative installation directory, relative to the prefix.
	This is simply the difference between orig_installprefix and
	orig_installdir. */
	if (strncmp (orig_installprefix, orig_installdir, strlen (orig_installprefix))
	!= 0)
	/* Shouldn't happen - nothing should be installed outside $(prefix). */
	return NULL;
	rel_installdir = orig_installdir + strlen (orig_installprefix);

	/* Determine the current installation directory. */
	{
	const char *p_base = curr_pathname + FILESYSTEM_PREFIX_LEN (curr_pathname);
	const char *p = curr_pathname + strlen (curr_pathname);
	char *q;

	while (p > p_base)
	{
	p--;
	if (ISSLASH (*p))
	break;
	}

	q = (char *) xmalloc (p - curr_pathname + 1);
	#ifdef NO_XMALLOC
	if (q == NULL)
	return NULL;
	#endif
	memcpy (q, curr_pathname, p - curr_pathname);
	q[p - curr_pathname] = '\0';
	curr_installdir = q;
	}

	/* Compute the current installation prefix by removing the trailing
	rel_installdir from it. */
	{
	const char *rp = rel_installdir + strlen (rel_installdir);
	const char *cp = curr_installdir + strlen (curr_installdir);
	const char *cp_base =
	curr_installdir + FILESYSTEM_PREFIX_LEN (curr_installdir);

	while (rp > rel_installdir && cp > cp_base)
	{
	bool same = false;
	const char *rpi = rp;
	const char *cpi = cp;

	while (rpi > rel_installdir && cpi > cp_base)
	{
	rpi--;
	cpi--;
	if (ISSLASH (rpi) \|\| ISSLASH (cpi))
	{
	if (ISSLASH (rpi) && ISSLASH (cpi))
	same = true;
	break;
	}
	#if defined _WIN32 \|\| defined __WIN32__ \|\| defined __EMX__ \|\| defined __DJGPP__
	/* Win32, OS/2, DOS - case insignificant filesystem */
	if ((rpi >= 'a' && rpi <= 'z' ? rpi - 'a' + 'A' : rpi)
	!= (cpi >= 'a' && cpi <= 'z' ? cpi - 'a' + 'A' : cpi))
	break;
	#else
	if (rpi != cpi)
	break;
	#endif
	}
	if (!same)
	break;
	/* The last pathname component was the same. opi and cpi now point
	to the slash before it. */
	rp = rpi;
	cp = cpi;
	}

	if (rp > rel_installdir)
	/* Unexpected: The curr_installdir does not end with rel_installdir. */
	return NULL;

	{
	size_t curr_prefix_len = cp - curr_installdir;
	char *curr_prefix;

	curr_prefix = (char *) xmalloc (curr_prefix_len + 1);
	#ifdef NO_XMALLOC
	if (curr_prefix == NULL)
	return NULL;
	#endif
	memcpy (curr_prefix, curr_installdir, curr_prefix_len);
	curr_prefix[curr_prefix_len] = '\0';

	return curr_prefix;
	}
	}
	}

	#if defined PIC && defined INSTALLDIR

	/* Full pathname of shared library, or NULL. */
	static char *shared_library_fullname;

	#if defined _WIN32 \|\| defined __WIN32__

	/* Determine the full pathname of the shared library when it is loaded. */

	BOOL WINAPI
	DllMain (HINSTANCE module_handle, DWORD event, LPVOID reserved)
	{
	(void) reserved;

	if (event == DLL_PROCESS_ATTACH)
	{
	/* The DLL is being loaded into an application's address range. */
	static char location[MAX_PATH];

	if (!GetModuleFileName (module_handle, location, sizeof (location)))
	/* Shouldn't happen. */
	return FALSE;

	if (!IS_PATH_WITH_DIR (location))
	/* Shouldn't happen. */
	return FALSE;

	shared_library_fullname = strdup (location);
	}

	return TRUE;
	}

	#else /* Unix */

	static void
	find_shared_library_fullname ()
	{
	#ifdef __linux__
	FILE *fp;

	/* Open the current process' maps file. It describes one VMA per line. */
	fp = fopen ("/proc/self/maps", "r");
	if (fp)
	{
	unsigned long address = (unsigned long) &find_shared_library_fullname;
	for (;;)
	{
	unsigned long start, end;
	int c;

	if (fscanf (fp, "%lx-%lx", &start, &end) != 2)
	break;
	if (address >= start && address <= end - 1)
	{
	/* Found it. Now see if this line contains a filename. */
	while (c = getc (fp), c != EOF && c != '\n' && c != '/')
	continue;
	if (c == '/')
	{
	size_t size;
	int len;

	ungetc (c, fp);
	shared_library_fullname = NULL; size = 0;
	len = getline (&shared_library_fullname, &size, fp);
	if (len >= 0)
	{
	/* Success: filled shared_library_fullname. */
	if (len > 0 && shared_library_fullname[len - 1] == '\n')
	shared_library_fullname[len - 1] = '\0';
	}
	}
	break;
	}
	while (c = getc (fp), c != EOF && c != '\n')
	continue;
	}
	fclose (fp);
	}
	#endif
	}

	#endif /* WIN32 / Unix */

	/* Return the full pathname of the current shared library.
	Return NULL if unknown.
	Guaranteed to work only on Linux and Woe32. */
	static char *
	get_shared_library_fullname ()
	{
	#if !(defined _WIN32 \|\| defined __WIN32__)
	static bool tried_find_shared_library_fullname;
	if (!tried_find_shared_library_fullname)
	{
	find_shared_library_fullname ();
	tried_find_shared_library_fullname = true;
	}
	#endif
	return shared_library_fullname;
	}

	#endif /* PIC */

	/* Returns the pathname, relocated according to the current installation
	directory. */
	const char *
	relocate (const char *pathname)
	{
	#if defined PIC && defined INSTALLDIR
	static int initialized;

	/* Initialization code for a shared library. */
	if (!initialized)
	{
	/* At this point, orig_prefix and curr_prefix likely have already been
	set through the main program's set_program_name_and_installdir
	function. This is sufficient in the case that the library has
	initially been installed in the same orig_prefix. But we can do
	better, to also cover the cases that 1. it has been installed
	in a different prefix before being moved to orig_prefix and (later)
	to curr_prefix, 2. unlike the program, it has not moved away from
	orig_prefix. */
	const char *orig_installprefix = INSTALLPREFIX;
	const char *orig_installdir = INSTALLDIR;
	const char *curr_prefix_better;

	curr_prefix_better =
	compute_curr_prefix (orig_installprefix, orig_installdir,
	get_shared_library_fullname ());
	if (curr_prefix_better == NULL)
	curr_prefix_better = curr_prefix;

	set_relocation_prefix (orig_installprefix, curr_prefix_better);

	initialized = 1;
	}
	#endif

	/* Note: It is not necessary to perform case insensitive comparison here,
	even for DOS-like filesystems, because the pathname argument was
	typically created from the same Makefile variable as orig_prefix came
	from. */
	if (orig_prefix != NULL && curr_prefix != NULL
	&& strncmp (pathname, orig_prefix, orig_prefix_len) == 0)
	{
	if (pathname[orig_prefix_len] == '\0')
	/* pathname equals orig_prefix. */
	return curr_prefix;
	if (ISSLASH (pathname[orig_prefix_len]))
	{
	/* pathname starts with orig_prefix. */
	const char *pathname_tail = &pathname[orig_prefix_len];
	char *result =
	(char *) xmalloc (curr_prefix_len + strlen (pathname_tail) + 1);

	#ifdef NO_XMALLOC
	if (result != NULL)
	#endif
	{
	memcpy (result, curr_prefix, curr_prefix_len);
	strcpy (result + curr_prefix_len, pathname_tail);
	return result;
	}
	}
	}
	/* Nothing to relocate. */
	return pathname;
	}

	#endif