ltdl.c

MSYS在windows下模拟了一个类unix的终端

     lt_user_data loader_data;
     const char *filename;
{
  static shl_t self = (shl_t) 0;
  lt_module module = shl_load (filename, LT_BIND_FLAGS, 0L);

  /* Since searching for a symbol against a NULL module handle will also
     look in everything else that was already loaded and exported with
     the -E compiler flag, we always cache a handle saved before any
     modules are loaded.  */
  if (!self)
    {
      lt_ptr address;
      shl_findsym (&self, "main", TYPE_UNDEFINED, &address);
    }

  if (!filename)
    {
      module = self;
    }
  else
    {
      module = shl_load (filename, LT_BIND_FLAGS, 0L);

      if (!module)
	{
	  LT_DLMUTEX_SETERROR (LT_DLSTRERROR (CANNOT_OPEN));
	}
    }

  return module;
}

static int
sys_shl_close (loader_data, module)
     lt_user_data loader_data;
     lt_module module;
{
  int errors = 0;

  if (module && (shl_unload ((shl_t) (module)) != 0))
    {
      LT_DLMUTEX_SETERROR (LT_DLSTRERROR (CANNOT_CLOSE));
      ++errors;
    }

  return errors;
}

static lt_ptr
sys_shl_sym (loader_data, module, symbol)
     lt_user_data loader_data;
     lt_module module;
     const char *symbol;
{
  lt_ptr address = 0;

  /* sys_shl_open should never return a NULL module handle */
  if (module == (lt_module) 0)
  {
    LT_DLMUTEX_SETERROR (LT_DLSTRERROR (INVALID_HANDLE));
  }
  else if (!shl_findsym((shl_t*) &module, symbol, TYPE_UNDEFINED, &address))
    {
      if (!address)
	{
	  LT_DLMUTEX_SETERROR (LT_DLSTRERROR (SYMBOL_NOT_FOUND));
	}
    }

  return address;
}

static struct lt_user_dlloader sys_shl = {
  0, sys_shl_open, sys_shl_close, sys_shl_sym, 0, 0
};

#endif /* HAVE_SHL_LOAD */




/* --- LOADLIBRARY() INTERFACE LOADER --- */

#ifdef __WINDOWS__

/* dynamic linking for Win32 */

#include <windows.h>

/* Forward declaration; required to implement handle search below. */
static lt_dlhandle handles;

static lt_module
sys_wll_open (loader_data, filename)
     lt_user_data loader_data;
     const char *filename;
{
  lt_dlhandle	cur;
  lt_module	module	   = 0;
  const char   *errormsg   = 0;
  char	       *searchname = 0;
  char	       *ext;
  char		self_name_buf[MAX_PATH];

  if (!filename)
    {
      /* Get the name of main module */
      *self_name_buf = 0;
      GetModuleFileName (NULL, self_name_buf, sizeof (self_name_buf));
      filename = ext = self_name_buf;
    }
  else
    {
      ext = strrchr (filename, '.');
    }

  if (ext)
    {
      /* FILENAME already has an extension. */
      searchname = lt_estrdup (filename);
    }
  else
    {
      /* Append a `.' to stop Windows from adding an
	 implicit `.dll' extension. */
      searchname = LT_EMALLOC (char, 2+ LT_STRLEN (filename));
      if (searchname)
	sprintf (searchname, "%s.", filename);
    }
  if (!searchname)
    return 0;

#if __CYGWIN__
  {
    char wpath[MAX_PATH];
    cygwin_conv_to_full_win32_path(searchname, wpath);
    module = LoadLibrary(wpath);
  }
#else
  module = LoadLibrary (searchname);
#endif
  LT_DLFREE (searchname);

  /* libltdl expects this function to fail if it is unable
     to physically load the library.  Sadly, LoadLibrary
     will search the loaded libraries for a match and return
     one of them if the path search load fails.

     We check whether LoadLibrary is returning a handle to
     an already loaded module, and simulate failure if we
     find one. */
  LT_DLMUTEX_LOCK ();
  cur = handles;
  while (cur)
    {
      if (!cur->module)
	{
	  cur = 0;
	  break;
	}

      if (cur->module == module)
	{
	  break;
	}

      cur = cur->next;
  }
  LT_DLMUTEX_UNLOCK ();

  if (cur || !module)
    {
      LT_DLMUTEX_SETERROR (LT_DLSTRERROR (CANNOT_OPEN));
      module = 0;
    }

  return module;
}

static int
sys_wll_close (loader_data, module)
     lt_user_data loader_data;
     lt_module module;
{
  int	      errors   = 0;

  if (FreeLibrary(module) == 0)
    {
      LT_DLMUTEX_SETERROR (LT_DLSTRERROR (CANNOT_CLOSE));
      ++errors;
    }

  return errors;
}

static lt_ptr
sys_wll_sym (loader_data, module, symbol)
     lt_user_data loader_data;
     lt_module module;
     const char *symbol;
{
  lt_ptr      address  = GetProcAddress (module, symbol);

  if (!address)
    {
      LT_DLMUTEX_SETERROR (LT_DLSTRERROR (SYMBOL_NOT_FOUND));
    }

  return address;
}

static struct lt_user_dlloader sys_wll = {
  0, sys_wll_open, sys_wll_close, sys_wll_sym, 0, 0
};

#endif /* __WINDOWS__ */




/* --- LOAD_ADD_ON() INTERFACE LOADER --- */


#ifdef __BEOS__

/* dynamic linking for BeOS */

#include <kernel/image.h>

static lt_module
sys_bedl_open (loader_data, filename)
     lt_user_data loader_data;
     const char *filename;
{
  image_id image = 0;

  if (filename)
    {
      image = load_add_on (filename);
    }
  else
    {
      image_info info;
      int32 cookie = 0;
      if (get_next_image_info (0, &cookie, &info) == B_OK)
	image = load_add_on (info.name);
    }

  if (image <= 0)
    {
      LT_DLMUTEX_SETERROR (LT_DLSTRERROR (CANNOT_OPEN));
      image = 0;
    }

  return (lt_module) image;
}

static int
sys_bedl_close (loader_data, module)
     lt_user_data loader_data;
     lt_module module;
{
  int errors = 0;

  if (unload_add_on ((image_id) module) != B_OK)
    {
      LT_DLMUTEX_SETERROR (LT_DLSTRERROR (CANNOT_CLOSE));
      ++errors;
    }

  return errors;
}

static lt_ptr
sys_bedl_sym (loader_data, module, symbol)
     lt_user_data loader_data;
     lt_module module;
     const char *symbol;
{
  lt_ptr address = 0;
  image_id image = (image_id) module;

  if (get_image_symbol (image, symbol, B_SYMBOL_TYPE_ANY, address) != B_OK)
    {
      LT_DLMUTEX_SETERROR (LT_DLSTRERROR (SYMBOL_NOT_FOUND));
      address = 0;
    }

  return address;
}

static struct lt_user_dlloader sys_bedl = {
  0, sys_bedl_open, sys_bedl_close, sys_bedl_sym, 0, 0
};

#endif /* __BEOS__ */




/* --- DLD_LINK() INTERFACE LOADER --- */


#if HAVE_DLD

/* dynamic linking with dld */

#if HAVE_DLD_H
#include <dld.h>
#endif

static lt_module
sys_dld_open (loader_data, filename)
     lt_user_data loader_data;
     const char *filename;
{
  lt_module module = strdup (filename);

  if (dld_link (filename) != 0)
    {
      LT_DLMUTEX_SETERROR (LT_DLSTRERROR (CANNOT_OPEN));
      LT_DLFREE (module);
      module = 0;
    }

  return module;
}

static int
sys_dld_close (loader_data, module)
     lt_user_data loader_data;
     lt_module module;
{
  int errors = 0;

  if (dld_unlink_by_file ((char*)(module), 1) != 0)
    {
      LT_DLMUTEX_SETERROR (LT_DLSTRERROR (CANNOT_CLOSE));
      ++errors;
    }
  else
    {
      LT_DLFREE (module);
    }

  return errors;
}

static lt_ptr
sys_dld_sym (loader_data, module, symbol)
     lt_user_data loader_data;
     lt_module module;
     const char *symbol;
{
  lt_ptr address = dld_get_func (symbol);

  if (!address)
    {
      LT_DLMUTEX_SETERROR (LT_DLSTRERROR (SYMBOL_NOT_FOUND));
    }

  return address;
}

static struct lt_user_dlloader sys_dld = {
  0, sys_dld_open, sys_dld_close, sys_dld_sym, 0, 0
};

#endif /* HAVE_DLD */




/* --- 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,