ltdl.c

这是 关于FTP最新版本的PROFTP的 源码

											| NSLOOKUPSYMBOLINIMAGE_OPTION_RETURN_ON_ERROR
											);
					if (retSym) break;
				}
			}
			offset += lc->cmdsize;
		}
	}
	return retSym;
}

static int
sys_dyld_init()
{
	int retCode = 0;
	int err = 0;
	if (!_dyld_present()) {
		retCode=1;
	}
	else {
      err = _dyld_func_lookup("__dyld_NSAddImage",(unsigned long*)&ltdl_NSAddImage);
      err = _dyld_func_lookup("__dyld_NSLookupSymbolInImage",(unsigned long*)&ltdl_NSLookupSymbolInImage);
      err = _dyld_func_lookup("__dyld_NSIsSymbolNameDefinedInImage",(unsigned long*)&ltdl_NSIsSymbolNameDefinedInImage);
      err = _dyld_func_lookup("__dyld_NSMakePrivateModulePublic",(unsigned long*)&ltdl_NSMakePrivateModulePublic);
    }
 return retCode;
}

static lt_module
sys_dyld_open (loader_data, filename)
     lt_user_data loader_data;
     const char *filename;
{
	lt_module   module   = 0;
	NSObjectFileImage ofi = 0;
	NSObjectFileImageReturnCode ofirc;

  	if (!filename)
  		return (lt_module)-1;
	ofirc = NSCreateObjectFileImageFromFile(filename, &ofi);
	switch (ofirc)
	{
		case NSObjectFileImageSuccess:
			module = NSLinkModule(ofi, filename,
						NSLINKMODULE_OPTION_RETURN_ON_ERROR
						 | NSLINKMODULE_OPTION_PRIVATE
						 | NSLINKMODULE_OPTION_BINDNOW);
			NSDestroyObjectFileImage(ofi);
			if (module)
				ltdl_NSMakePrivateModulePublic(module);
			break;
		case NSObjectFileImageInappropriateFile:
		    if (ltdl_NSIsSymbolNameDefinedInImage && ltdl_NSLookupSymbolInImage)
		    {
				module = (lt_module)ltdl_NSAddImage(filename, NSADDIMAGE_OPTION_RETURN_ON_ERROR);
				break;
			}
		default:
			LT_DLMUTEX_SETERROR (lt_int_dyld_error(LT_DLSTRERROR(CANNOT_OPEN)));
			return 0;
	}
	if (!module) LT_DLMUTEX_SETERROR (lt_int_dyld_error(LT_DLSTRERROR(CANNOT_OPEN)));
  return module;
}

static int
sys_dyld_close (loader_data, module)
     lt_user_data loader_data;
     lt_module module;
{
	int retCode = 0;
	int flags = 0;
	if (module == (lt_module)-1) return 0;
#ifdef __BIG_ENDIAN__
  	if (((struct mach_header *)module)->magic == MH_MAGIC)
#else
    if (((struct mach_header *)module)->magic == MH_CIGAM)
#endif
	{
	  LT_DLMUTEX_SETERROR("Can not close a dylib");
	  retCode = 1;
	}
	else
	{
#if 1
/* Currently, if a module contains c++ static destructors and it is unloaded, we
   get a segfault in atexit(), due to compiler and dynamic loader differences of
   opinion, this works around that.
*/
		if ((const struct section *)NULL !=
		   getsectbynamefromheader(lt_int_dyld_get_mach_header_from_nsmodule(module),
		   "__DATA","__mod_term_func"))
		{
			flags += NSUNLINKMODULE_OPTION_KEEP_MEMORY_MAPPED;
		}
#endif
#ifdef __ppc__
			flags += NSUNLINKMODULE_OPTION_RESET_LAZY_REFERENCES;
#endif
		if (!NSUnLinkModule(module,flags))
		{
			retCode=1;
			LT_DLMUTEX_SETERROR (lt_int_dyld_error(LT_DLSTRERROR(CANNOT_CLOSE)));
		}
	}

 return retCode;
}

static lt_ptr
sys_dyld_sym (loader_data, module, symbol)
     lt_user_data loader_data;
     lt_module module;
     const char *symbol;
{
	lt_ptr address = 0;
  	NSSymbol *nssym = 0;
  	void *unused;
  	const struct mach_header *mh=NULL;
  	char saveError[256] = "Symbol not found";
  	if (module == (lt_module)-1)
  	{
  		_dyld_lookup_and_bind(symbol,(unsigned long*)&address,&unused);
  		return address;
  	}
#ifdef __BIG_ENDIAN__
  	if (((struct mach_header *)module)->magic == MH_MAGIC)
#else
    if (((struct mach_header *)module)->magic == MH_CIGAM)
#endif
  	{
  	    if (ltdl_NSIsSymbolNameDefinedInImage && ltdl_NSLookupSymbolInImage)
  	    {
  	    	mh=module;
			if (ltdl_NSIsSymbolNameDefinedInImage((struct mach_header*)module,symbol))
			{
				nssym = ltdl_NSLookupSymbolInImage((struct mach_header*)module,
											symbol,
											NSLOOKUPSYMBOLINIMAGE_OPTION_BIND_NOW
											| NSLOOKUPSYMBOLINIMAGE_OPTION_RETURN_ON_ERROR
											);
			}
	    }

  	}
  else {
	nssym = NSLookupSymbolInModule(module, symbol);
	}
	if (!nssym)
	{
		strncpy(saveError, lt_int_dyld_error(LT_DLSTRERROR(SYMBOL_NOT_FOUND)), 255);
		saveError[255] = 0;
		if (!mh) mh=lt_int_dyld_get_mach_header_from_nsmodule(module);
		nssym = lt_int_dyld_NSlookupSymbolInLinkedLibs(symbol,mh);
	}
	if (!nssym)
	{
		LT_DLMUTEX_SETERROR (saveError);
		return NULL;
	}
	return NSAddressOfSymbol(nssym);
}

static struct lt_user_dlloader sys_dyld =
  { "_", sys_dyld_open, sys_dyld_close, sys_dyld_sym, 0, 0 };


#endif /* HAVE_DYLD */


/* --- DLPREOPEN() INTERFACE LOADER --- */


/* emulate dynamic linking using preloaded_symbols */

typedef struct lt_dlsymlists_t
{
  struct lt_dlsymlists_t       *next;
  const lt_dlsymlist	       *syms;
} lt_dlsymlists_t;

static	const lt_dlsymlist     *default_preloaded_symbols	= 0;
static	lt_dlsymlists_t	       *preloaded_symbols		= 0;

static int
presym_init (loader_data)
     lt_user_data loader_data;
{
  int errors = 0;

  LT_DLMUTEX_LOCK ();

  preloaded_symbols = 0;
  if (default_preloaded_symbols)
    {
      errors = lt_dlpreload (default_preloaded_symbols);
    }

  LT_DLMUTEX_UNLOCK ();

  return errors;
}

static int
presym_free_symlists ()
{
  lt_dlsymlists_t *lists;

  LT_DLMUTEX_LOCK ();

  lists = preloaded_symbols;
  while (lists)
    {
      lt_dlsymlists_t	*tmp = lists;

      lists = lists->next;
      LT_DLFREE (tmp);
    }
  preloaded_symbols = 0;

  LT_DLMUTEX_UNLOCK ();

  return 0;
}

static int
presym_exit (loader_data)
     lt_user_data loader_data;
{
  presym_free_symlists ();
  return 0;
}

static int
presym_add_symlist (preloaded)
     const lt_dlsymlist *preloaded;
{
  lt_dlsymlists_t *tmp;
  lt_dlsymlists_t *lists;
  int		   errors   = 0;

  LT_DLMUTEX_LOCK ();

  lists = preloaded_symbols;
  while (lists)
    {
      if (lists->syms == preloaded)
	{
	  goto done;
	}
      lists = lists->next;
    }

  tmp = LT_EMALLOC (lt_dlsymlists_t, 1);
  if (tmp)
    {
      memset (tmp, 0, sizeof(lt_dlsymlists_t));
      tmp->syms = preloaded;
      tmp->next = preloaded_symbols;
      preloaded_symbols = tmp;
    }
  else
    {
      ++errors;
    }

 done:
  LT_DLMUTEX_UNLOCK ();
  return errors;
}

static lt_module
presym_open (loader_data, filename)
     lt_user_data loader_data;
     const char *filename;
{
  lt_dlsymlists_t *lists;
  lt_module	   module = (lt_module) 0;

  LT_DLMUTEX_LOCK ();
  lists = preloaded_symbols;

  if (!lists)
    {
      LT_DLMUTEX_SETERROR (LT_DLSTRERROR (NO_SYMBOLS));
      goto done;
    }

  /* Can't use NULL as the reflective symbol header, as NULL is
     used to mark the end of the entire symbol list.  Self-dlpreopened
     symbols follow this magic number, chosen to be an unlikely
     clash with a real module name.  */
  if (!filename)
    {
      filename = "@PROGRAM@";
    }

  while (lists)
    {
      const lt_dlsymlist *syms = lists->syms;

      while (syms->name)
	{
	  if (!syms->address && strcmp(syms->name, filename) == 0)
	    {
	      module = (lt_module) syms;
	      goto done;
	    }
	  ++syms;
	}

      lists = lists->next;
    }

  LT_DLMUTEX_SETERROR (LT_DLSTRERROR (FILE_NOT_FOUND));

 done:
  LT_DLMUTEX_UNLOCK ();
  return module;
}

static int
presym_close (loader_data, module)
     lt_user_data loader_data;
     lt_module module;
{
  /* Just to silence gcc -Wall */
  module = 0;
  return 0;
}

static lt_ptr
presym_sym (loader_data, module, symbol)
     lt_user_data loader_data;
     lt_module module;
     const char *symbol;
{
  lt_dlsymlist *syms = (lt_dlsymlist*) module;

  ++syms;
  while (syms->address)
    {
      if (strcmp(syms->name, symbol) == 0)
	{
	  return syms->address;
	}

    ++syms;
  }

  LT_DLMUTEX_SETERROR (LT_DLSTRERROR (SYMBOL_NOT_FOUND));

  return 0;
}

static struct lt_user_dlloader presym = {
  0, presym_open, presym_close, presym_sym, presym_exit, 0
};





/* --- DYNAMIC MODULE LOADING --- */


/* The type of a function used at each iteration of  foreach_dirinpath().  */
typedef int	foreach_callback_func LT_PARAMS((char *filename, lt_ptr data1,
						 lt_ptr data2));

static	int	foreach_dirinpath     LT_PARAMS((const char *search_path,
						 const char *base_name,
						 foreach_callback_func *func,
						 lt_ptr data1, lt_ptr data2));

static	int	find_file_callback    LT_PARAMS((char *filename, lt_ptr data,
						 lt_ptr ignored));
static	int	find_handle_callback  LT_PARAMS((char *filename, lt_ptr data,
						 lt_ptr ignored));
static	int	foreachfile_callback  LT_PARAMS((char *filename, lt_ptr data1,
						 lt_ptr data2));


static	int     canonicalize_path     LT_PARAMS((const char *path,
						 char **pcanonical));
static	int	argzize_path 	      LT_PARAMS((const char *path,
						 char **pargz,
						 size_t *pargz_len));
static	FILE   *find_file	      LT_PARAMS((const char *search_path,
						 const char *base_name,
						 char **pdir));
static	lt_dlhandle *find_handle      LT_PARAMS((const char *search_path,
						 const char *base_name,
						 lt_dlhandle *handle));
static	int	find_module	      LT_PARAMS((lt_dlhandle *handle,
						 const char *dir,
						 const char *libdir,
						 const char *dlname,
						 const char *old_name,
						 int installed));
static	int	free_vars	      LT_PARAMS((char *dlname, char *oldname,
						 char *libdir, char *deplibs));
static	int	load_deplibs	      LT_PARAMS((lt_dlhandle handle,
						 char *deplibs));
static	int	trim		      LT_PARAMS((char **dest,
						 const char *str));
static	int	try_dlopen	      LT_PARAMS((lt_dlhandle *handle,
						 const char *filename));
static	int	tryall_dlopen	      LT_PARAMS((lt_dlhandle *handle,
						 const char *filename));
static	int	unload_deplibs	      LT_PARAMS((lt_dlhandle handle));
static	int	lt_argz_insert	      LT_PARAMS((char **pargz,
						 size_t *pargz_len,
						 char *before,
						 const char *entry));
static	int	lt_argz_insertinorder LT_PARAMS((char **pargz,
						 size_t *pargz_len,
						 const char *entry));
static	int	lt_argz_insertdir     LT_PARAMS((char **pargz,
						 size_t *pargz_len,
						 const char *dirnam,
						 struct dirent *dp));
static	int	lt_dlpath_insertdir   LT_PARAMS((char **ppath,
						 char *before,
						 const char *dir));
static	int	list_files_by_dir     LT_PARAMS((const char *dirnam,
						 char **pargz,
						 size_t *pargz_len));
static	int	file_not_found	      LT_PARAMS((void));

static	char	       *user_search_path= 0;
static	lt_dlloader    *loaders		= 0;
static	lt_dlhandle	handles 	= 0;
static	int		initialized 	= 0;

/* Initialize libltdl. */
int
lt_dlinit ()
{
  int	      errors   = 0;

  LT_DLMUTEX_LOCK ();

  /* Initialize only at first call. */
  if (++initialized == 1)
    {
      handles = 0;
      user_search_path = 0; /* empty search path */

#if HAVE_LIBDL
      errors += lt_dlloader_add (lt_dlloader_next (0), &sys_dl, "dlopen");
#endif
#if HAVE_SHL_LOAD
      errors += lt_dlloader_add (lt_dlloader_next (0), &sys_shl, "dlopen");
#endif
#ifdef __WINDOWS__
      errors += lt_dlloader_add (lt_dlloader_next (0), &sys_wll, "dlopen");
#endif
#ifdef __BEOS__
      errors += lt_dlloader_add (lt_dlloader_next (0), &sys_bedl, "dlopen");
#endif
#if HAVE_DLD
      errors += lt_dlloader_add (lt_dlloader_next (0), &sys_dld, "dld");
#endif
#if HAVE_DYLD
       errors += lt_dlloader_add (lt_dlloader_next (0), &sys_dyld, "dyld");
       errors += sys_dyld_init();
#endif
      errors += lt_dlloader_add (lt_dlloader_next (0), &presym, "dlpreload");

      if (presym_init (presym.dlloader_data))
	{
	  LT_DLMUTEX_SETERROR (LT_DLSTRERROR (INIT_LOADER));
	  ++errors;
	}
      else if (errors != 0)
	{
	  LT_DLMUTEX_SETERROR (LT_DLSTRERROR (DLOPEN_NOT_SUPPORTED));
	  ++errors;
	}
    }

  LT_DLMUTEX_UNLOCK ();

  return errors;
}

int
lt_dlpreload (preloaded)
     const lt_dlsymlist *preloaded;
{
  int errors = 0;

  if (preloaded)
    {
      errors = presym_add_symlist (preloaded);
    }
  else
    {
      presym_free_symlists();

      LT_DLMUTEX_LOCK ();
      if (default_preloaded_symbols)
	{
	  errors = lt_dlpreload (default_preloaded_symbols);
	}
      LT_DLMUTEX_UNLOCK ();
    }

  return errors;
}

int
lt_dlpreload_default (preloaded)
     const lt_dlsymlist *preloaded;
{
  LT_DLMUTEX_LOCK ();
  default_preloaded_symbols = preloaded;
  LT_DLMUTEX_UNLOCK ();
  return 0;
}

int
lt_dlexit ()
{
  /* shut down libltdl */
  lt_dlloader *loader;
  int	       errors   = 0;

  LT_DLMUTEX_LOCK ();
  loader = loaders;

  if (!initialized)
    {
      LT_DLMUTEX_SETERROR (LT_DLSTRERROR (SHUTDOWN));
      ++errors;
      goto done;
    }

  /* shut down only at last call. */
  if (--initialized == 0)
    {
      int	level;

      while (handles && LT_DLIS_RESIDENT (handles))
	{
	  handles = handles->next;
	}

      /* close all modules */
      for (level = 1; handles; ++level)
	{
	  lt_dlhandle cur = handles;
	  int saw_nonresident = 0;

	  while (cur)
	    {
	      lt_dlhandle tmp = cur;
	      cur = cur->next;
	      if (!LT_DLIS_RESIDENT (tmp))
		saw_nonresident = 1;
	      if (!LT_DLIS_RESIDENT (tmp) && tmp->info.ref_count <= level)
		{
		  if (lt_dlclose (tmp))
		    {
		      ++errors;
		    }
		}
	    }
	  /* done if only resident modules are left */
	  if (!saw_nonresident)
	    break;
	}

      /* close all loaders */
      while (loader)
	{
	  lt_dlloader *next = loader->next;
	  lt_user_data data = loader->dlloader_data;
	  if (loader->dlloader_exit && loader->dlloader_exit (data))
	    {
	      ++errors;
	    }

	  LT_DLMEM_REASSIGN (loader, next);