newlib/winsup/cygwin/dlfcn.cc

444 lines
11 KiB
C++

/* dlfcn.cc
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 <dlfcn.h>
#include <ctype.h>
#include <wctype.h>
#include "path.h"
#include "fhandler.h"
#include "dtable.h"
#include "cygheap.h"
#include "perprocess.h"
#include "cygtls.h"
#include "tls_pbuf.h"
#include "ntdll.h"
#include "shared_info.h"
#include "dll_init.h"
#include "pathfinder.h"
/* Dumb allocator using memory from tmp_pathbuf.w_get ().
Does not reuse free'd memory areas. Instead, memory
is released when the tmp_pathbuf goes out of scope.
ATTENTION: Requesting memory from an instance of tmp_pathbuf breaks
when another instance on a newer stack frame has provided memory. */
class tmp_pathbuf_allocator
: public allocator_interface
{
tmp_pathbuf & tp_;
union
{
PWCHAR wideptr;
void * voidptr;
char * byteptr;
} freemem_;
size_t freesize_;
/* allocator_interface */
virtual void * alloc (size_t need)
{
if (need == 0)
need = 1; /* GNU-ish */
size_t chunksize = NT_MAX_PATH * sizeof (WCHAR);
if (need > chunksize)
api_fatal ("temporary buffer too small for %d bytes", need);
if (need > freesize_)
{
/* skip remaining, use next chunk */
freemem_.wideptr = tp_.w_get ();
freesize_ = chunksize;
}
void * ret = freemem_.voidptr;
/* adjust remaining, aligned at 8 byte boundary */
need = need + 7 - (need - 1) % 8;
freemem_.byteptr += need;
if (need > freesize_)
freesize_ = 0;
else
freesize_ -= need;
return ret;
}
/* allocator_interface */
virtual void free (void *)
{
/* no-op: released by tmp_pathbuf at end of scope */
}
tmp_pathbuf_allocator ();
tmp_pathbuf_allocator (tmp_pathbuf_allocator const &);
tmp_pathbuf_allocator & operator = (tmp_pathbuf_allocator const &);
public:
/* use tmp_pathbuf of current stack frame */
tmp_pathbuf_allocator (tmp_pathbuf & tp)
: allocator_interface ()
, tp_ (tp)
, freemem_ ()
, freesize_ (0)
{}
};
static void
set_dl_error (const char *str)
{
strcpy (_my_tls.locals.dl_buffer, strerror (get_errno ()));
_my_tls.locals.dl_error = 1;
}
/* Identify basename and baselen within name,
return true if there is a dir in name. */
static bool
spot_basename (const char * &basename, int &baselen, const char * name)
{
basename = strrchr (name, '/');
basename = basename ? basename + 1 : name;
baselen = name + strlen (name) - basename;
return basename > name;
}
/* Setup basenames using basename and baselen,
return true if basenames do have some suffix. */
static void
collect_basenames (pathfinder::basenamelist & basenames,
const char * basename, int baselen)
{
/* like strrchr (basename, '.'), but limited to baselen */
const char *suffix = basename + baselen;
while (--suffix >= basename)
if (*suffix == '.')
break;
int suffixlen;
if (suffix >= basename)
suffixlen = basename + baselen - suffix;
else
{
suffixlen = 0;
suffix = NULL;
}
char const * ext = "";
/* Without some suffix, reserve space for a trailing dot to override
GetModuleHandleExA's automatic adding of the ".dll" suffix. */
int extlen = suffix ? 0 : 1;
/* If we have the ".so" suffix, ... */
if (suffixlen == 3 && !strncmp (suffix, ".so", 3))
{
/* ... keep the basename with original suffix, before ... */
basenames.appendv (basename, baselen, NULL);
/* ... replacing the ".so" with the ".dll" suffix. */
baselen -= 3;
ext = ".dll";
extlen = 4;
}
/* If the basename starts with "lib", ... */
if (!strncmp (basename, "lib", 3))
{
/* ... replace "lib" with "cyg", before ... */
basenames.appendv ("cyg", 3, basename+3, baselen-3, ext, extlen, NULL);
}
/* ... using original basename with new suffix. */
basenames.appendv (basename, baselen, ext, extlen, NULL);
}
/* Identify dir of current executable into exedirbuf using wpathbuf buffer.
Return length of exedirbuf on success, or zero on error. */
static int
get_exedir (char * exedirbuf, wchar_t * wpathbuf)
{
/* Unless we have a special cygwin loader, there is no such thing like
DT_RUNPATH on Windows we can use to search for dlls, except for the
directory of the main executable. */
*exedirbuf = '\0';
wchar_t * wlastsep = wcpcpy (wpathbuf, global_progname);
/* like wcsrchr(L'\\'), but we know the wcslen already */
while (--wlastsep > wpathbuf)
if (*wlastsep == L'\\')
break;
if (wlastsep <= wpathbuf)
return 0;
*wlastsep = L'\0';
if (mount_table->conv_to_posix_path (wpathbuf, exedirbuf, 0))
return 0;
return strlen (exedirbuf);
}
extern "C" void *
dlopen (const char *name, int flags)
{
void *ret = NULL;
do
{
if (name == NULL || *name == '\0')
{
ret = (void *) GetModuleHandle (NULL); /* handle for the current module */
if (!ret)
__seterrno ();
break;
}
DWORD gmheflags = (flags & RTLD_NODELETE)
? GET_MODULE_HANDLE_EX_FLAG_PIN
: 0;
tmp_pathbuf tp; /* single one per stack frame */
tmp_pathbuf_allocator allocator (tp);
pathfinder::basenamelist basenames (allocator);
const char *basename;
int baselen;
bool have_dir = spot_basename (basename, baselen, name);
collect_basenames (basenames, basename, baselen);
/* handle for the named library */
path_conv real_filename;
wchar_t *wpath = tp.w_get ();
char *cpath = tp.c_get ();
pathfinder finder (allocator, basenames); /* eats basenames */
if (have_dir)
{
int dirlen = basename - 1 - name;
/* if the specified dir is x/lib, and the current executable
dir is x/bin, do the /lib -> /bin mapping, which is the
same actually as adding the executable dir */
if (dirlen >= 4 && !strncmp (name + dirlen - 4, "/lib", 4))
{
int exedirlen = get_exedir (cpath, wpath);
if (exedirlen == dirlen &&
!strncmp (cpath, name, dirlen - 4) &&
!strcmp (cpath + dirlen - 4, "/bin"))
finder.add_searchdir (cpath, exedirlen);
}
/* search the specified dir */
finder.add_searchdir (name, dirlen);
}
else
{
/* NOTE: The Windows loader (for linked dlls) does
not use the LD_LIBRARY_PATH environment variable. */
finder.add_envsearchpath ("LD_LIBRARY_PATH");
/* Finally we better have some fallback. */
finder.add_searchdir ("/usr/bin", 8);
finder.add_searchdir ("/usr/lib", 8);
}
/* now search the file system */
if (!finder.find (pathfinder::
exists_and_not_dir (real_filename,
PC_SYM_FOLLOW | PC_POSIX)))
{
/* If nothing worked, create a relative path from the original
incoming filename and let LoadLibrary search for it using the
system default DLL search path. */
real_filename.check (name, PC_SYM_FOLLOW | PC_NOFULL | PC_NULLEMPTY);
if (real_filename.error)
break;
}
real_filename.get_wide_win32_path (wpath);
/* Check if the last path component contains a dot. If so,
leave the filename alone. Otherwise add a trailing dot
to override LoadLibrary's automatic adding of a ".dll" suffix. */
wchar_t *last_bs = wcsrchr (wpath, L'\\') ?: wpath;
if (last_bs && !wcschr (last_bs, L'.'))
wcscat (last_bs, L".");
if (flags & RTLD_NOLOAD)
{
GetModuleHandleExW (gmheflags, wpath, (HMODULE *) &ret);
if (ret)
break;
}
#ifdef __i386__
/* 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;
#endif
ret = (void *) LoadLibraryW (wpath);
/* reference counting */
if (ret)
{
dll *d = dlls.find (ret);
if (d)
++d->count;
}
#ifdef __i386__
/* Restore original cxx_malloc pointer. */
__cygwin_user_data.cxx_malloc = tmp_malloc;
#endif
if (ret && gmheflags)
GetModuleHandleExW (gmheflags, wpath, (HMODULE *) &ret);
if (!ret)
__seterrno ();
}
while (0);
if (!ret)
set_dl_error ("dlopen");
debug_printf ("ret %p", ret);
return ret;
}
extern "C" void *
dlsym (void *handle, const char *name)
{
void *ret = NULL;
if (handle == RTLD_DEFAULT)
{ /* search all modules */
PDEBUG_BUFFER buf;
NTSTATUS status;
buf = RtlCreateQueryDebugBuffer (0, FALSE);
if (!buf)
{
set_errno (ENOMEM);
set_dl_error ("dlsym");
return NULL;
}
status = RtlQueryProcessDebugInformation (GetCurrentProcessId (),
PDI_MODULES, buf);
if (!NT_SUCCESS (status))
__seterrno_from_nt_status (status);
else
{
PDEBUG_MODULE_ARRAY mods = (PDEBUG_MODULE_ARRAY)
buf->ModuleInformation;
for (ULONG i = 0; i < mods->Count; ++i)
if ((ret = (void *)
GetProcAddress ((HMODULE) mods->Modules[i].Base, name)))
break;
if (!ret)
set_errno (ENOENT);
}
RtlDestroyQueryDebugBuffer (buf);
}
else
{
ret = (void *) GetProcAddress ((HMODULE) handle, name);
if (!ret)
__seterrno ();
}
if (!ret)
set_dl_error ("dlsym");
debug_printf ("ret %p", ret);
return ret;
}
extern "C" int
dlclose (void *handle)
{
int ret = 0;
if (handle != GetModuleHandle (NULL))
{
/* reference counting */
dll *d = dlls.find (handle);
if (!d || d->count <= 0)
{
errno = ENOENT;
ret = -1;
}
else
{
--d->count;
if (!FreeLibrary ((HMODULE) handle))
{
__seterrno ();
ret = -1;
}
}
}
if (ret)
set_dl_error ("dlclose");
return ret;
}
extern "C" 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;
}
extern "C" int
dladdr (const void *addr, Dl_info *info)
{
HMODULE hModule;
BOOL ret = GetModuleHandleEx (GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS,
(LPCSTR) addr,
&hModule);
if (!ret)
return 0;
/* Module handle happens to be equal to it's base load address. */
info->dli_fbase = hModule;
/* Get the module filename. This pathname may be in short-, long- or //?/
format, depending on how it was specified when loaded, but we assume this
is always an absolute pathname. */
WCHAR fname[MAX_PATH];
DWORD length = GetModuleFileNameW (hModule, fname, MAX_PATH);
if ((length == 0) || (length == MAX_PATH))
return 0;
/* Convert to a cygwin pathname */
ssize_t conv = cygwin_conv_path (CCP_WIN_W_TO_POSIX | CCP_ABSOLUTE, fname,
info->dli_fname, MAX_PATH);
if (conv)
return 0;
/* Always indicate no symbol matching addr could be found. */
info->dli_sname = NULL;
info->dli_saddr = NULL;
return 1;
}