newlib/winsup/cygwin/dlfcn.cc

185 lines
4.7 KiB
C++

/* dlfcn.cc
Copyright 1998, 2000, 2001, 2002, 2003, 2004, 2008, 2009, 2010 Red Hat, Inc.
This file is part of Cygwin.
This software is a copyrighted work licensed under the terms of the
Cygwin license. Please consult the file "CYGWIN_LICENSE" for
details. */
#include "winsup.h"
#include <psapi.h>
#include <stdlib.h>
#include <ctype.h>
#include "path.h"
#include "perprocess.h"
#include "dlfcn.h"
#include "cygtls.h"
#include "tls_pbuf.h"
static void __stdcall
set_dl_error (const char *str)
{
strcpy (_my_tls.locals.dl_buffer, strerror (get_errno ()));
_my_tls.locals.dl_error = 1;
}
/* Look for an executable file given the name and the environment
variable to use for searching (eg., PATH); returns the full
pathname (static buffer) if found or NULL if not. */
inline const char * __stdcall
check_path_access (const char *mywinenv, const char *name, path_conv& buf)
{
return find_exec (name, buf, mywinenv, FE_NNF | FE_NATIVE | FE_CWD | FE_DLL);
}
/* Search LD_LIBRARY_PATH for dll, if it exists.
Return Windows version of given path. */
static bool __stdcall
get_full_path_of_dll (const char* str, path_conv &real_filename)
{
int len = strlen (str);
/* empty string? */
if (len == 0)
{
set_errno (EINVAL);
return false; /* Yes. Let caller deal with it. */
}
tmp_pathbuf tp;
char *name = tp.c_get ();
strcpy (name, str); /* Put it somewhere where we can manipulate it. */
if (isabspath (name) ||
(check_path_access ("LD_LIBRARY_PATH=", name, real_filename)
?: check_path_access ("/usr/lib", name, real_filename)) == NULL)
real_filename.check (name, PC_SYM_FOLLOW | PC_NOFULL | PC_NULLEMPTY);
if (!real_filename.error)
return true;
set_errno (real_filename.error);
return false;
}
void *
dlopen (const char *name, int)
{
void *ret;
if (name == NULL)
ret = (void *) GetModuleHandle (NULL); /* handle for the current module */
else
{
/* handle for the named library */
path_conv pc;
if (!get_full_path_of_dll (name, pc))
ret = NULL;
else
{
tmp_pathbuf tp;
wchar_t *path = tp.w_get ();
pc.get_wide_win32_path (path);
/* Check if the last path component contains a dot. If so,
leave the filename alone. Otherwise add a traiing dot
to override LoadLibrary's automatic adding of a ".dll" suffix. */
wchar_t *last_bs = wcsrchr (path, L'\\');
if (last_bs && !wcschr (last_bs, L'.'))
wcscat (last_bs, L".");
/* Workaround for broken DLLs built against Cygwin versions 1.7.0-49
up to 1.7.0-57. They override the cxx_malloc pointer in their
DLL initialization code even if loaded dynamically. This is a
no-no since a later dlclose lets cxx_malloc point into nirvana.
The below kludge "fixes" that by reverting the original cxx_malloc
pointer after LoadLibrary. This implies that their overrides
won't be applied; that's OK. All overrides should be present at
final link time, as Windows doesn't allow undefined references;
it would actually be wrong for a dlopen'd DLL to opportunistically
override functions in a way that wasn't known then. We're not
going to try and reproduce the full ELF dynamic loader here! */
/* Store original cxx_malloc pointer. */
struct per_process_cxx_malloc *tmp_malloc;
tmp_malloc = __cygwin_user_data.cxx_malloc;
ret = (void *) LoadLibraryW (path);
/* Restore original cxx_malloc pointer. */
__cygwin_user_data.cxx_malloc = tmp_malloc;
if (ret == NULL)
__seterrno ();
}
}
if (!ret)
set_dl_error ("dlopen");
debug_printf ("ret %p", ret);
return ret;
}
void *
dlsym (void *handle, const char *name)
{
void *ret = NULL;
if (handle == RTLD_DEFAULT)
{ /* search all modules */
HANDLE cur_proc = GetCurrentProcess ();
HMODULE *modules;
DWORD needed, i;
if (!EnumProcessModules (cur_proc, NULL, 0, &needed))
{
dlsym_fail:
set_dl_error ("dlsym");
return NULL;
}
modules = (HMODULE*) alloca (needed);
if (!EnumProcessModules (cur_proc, modules, needed, &needed))
goto dlsym_fail;
for (i = 0; i < needed / sizeof (HMODULE); i++)
if ((ret = (void *) GetProcAddress (modules[i], name)))
break;
}
else
ret = (void *) GetProcAddress ((HMODULE)handle, name);
if (!ret)
set_dl_error ("dlsym");
debug_printf ("ret %p", ret);
return ret;
}
int
dlclose (void *handle)
{
int ret;
if (handle == GetModuleHandle (NULL))
ret = 0;
else if (FreeLibrary ((HMODULE) handle))
ret = 0;
else
ret = -1;
if (ret)
set_dl_error ("dlclose");
return ret;
}
char *
dlerror ()
{
char *res;
if (!_my_tls.locals.dl_error)
res = NULL;
else
{
_my_tls.locals.dl_error = 0;
res = _my_tls.locals.dl_buffer;
}
return res;
}