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Diffstat (limited to 'libltdl/loaders/loadlibrary.c')
| -rw-r--r-- | libltdl/loaders/loadlibrary.c | 369 |
1 files changed, 369 insertions, 0 deletions
diff --git a/libltdl/loaders/loadlibrary.c b/libltdl/loaders/loadlibrary.c new file mode 100644 index 0000000..179c009 --- /dev/null +++ b/libltdl/loaders/loadlibrary.c @@ -0,0 +1,369 @@ +/* loader-loadlibrary.c -- dynamic linking for Win32 + + Copyright (C) 1998, 1999, 2000, 2004, 2005, 2006, + 2007, 2008, 2010 Free Software Foundation, Inc. + Written by Thomas Tanner, 1998 + + NOTE: The canonical source of this file is maintained with the + GNU Libtool package. Report bugs to bug-libtool@gnu.org. + +GNU Libltdl is free software; you can redistribute it and/or +modify it under the terms of the GNU Lesser General Public +License as published by the Free Software Foundation; either +version 2 of the License, or (at your option) any later version. + +As a special exception to the GNU Lesser General Public License, +if you distribute this file as part of a program or library that +is built using GNU Libtool, you may include this file under the +same distribution terms that you use for the rest of that program. + +GNU Libltdl 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 Lesser General Public License for more details. + +You should have received a copy of the GNU Lesser General Public +License along with GNU Libltdl; see the file COPYING.LIB. If not, a +copy can be downloaded from http://www.gnu.org/licenses/lgpl.html, +or obtained by writing to the Free Software Foundation, Inc., +51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. +*/ + +#include "lt__private.h" +#include "lt_dlloader.h" + +#if defined(__CYGWIN__) +# include <sys/cygwin.h> +#endif + +/* Use the preprocessor to rename non-static symbols to avoid namespace + collisions when the loader code is statically linked into libltdl. + Use the "<module_name>_LTX_" prefix so that the symbol addresses can + be fetched from the preloaded symbol list by lt_dlsym(): */ +#define get_vtable loadlibrary_LTX_get_vtable + +LT_BEGIN_C_DECLS +LT_SCOPE lt_dlvtable *get_vtable (lt_user_data loader_data); +LT_END_C_DECLS + + +/* Boilerplate code to set up the vtable for hooking this loader into + libltdl's loader list: */ +static int vl_exit (lt_user_data loader_data); +static lt_module vm_open (lt_user_data loader_data, const char *filename, + lt_dladvise advise); +static int vm_close (lt_user_data loader_data, lt_module module); +static void * vm_sym (lt_user_data loader_data, lt_module module, + const char *symbolname); + +static lt_dlinterface_id iface_id = 0; +static lt_dlvtable *vtable = 0; + +/* Return the vtable for this loader, only the name and sym_prefix + attributes (plus the virtual function implementations, obviously) + change between loaders. */ +lt_dlvtable * +get_vtable (lt_user_data loader_data) +{ + if (!vtable) + { + vtable = (lt_dlvtable *) lt__zalloc (sizeof *vtable); + iface_id = lt_dlinterface_register ("ltdl loadlibrary", NULL); + } + + if (vtable && !vtable->name) + { + vtable->name = "lt_loadlibrary"; + vtable->module_open = vm_open; + vtable->module_close = vm_close; + vtable->find_sym = vm_sym; + vtable->dlloader_exit = vl_exit; + vtable->dlloader_data = loader_data; + vtable->priority = LT_DLLOADER_APPEND; + } + + if (vtable && (vtable->dlloader_data != loader_data)) + { + LT__SETERROR (INIT_LOADER); + return 0; + } + + return vtable; +} + + + +/* --- IMPLEMENTATION --- */ + + +#include <windows.h> + +#define LOCALFREE(mem) LT_STMT_START { \ + if (mem) { LocalFree ((void *)mem); mem = NULL; } } LT_STMT_END +#define LOADLIB__SETERROR(errmsg) LT__SETERRORSTR (loadlibraryerror (errmsg)) +#define LOADLIB_SETERROR(errcode) LOADLIB__SETERROR (LT__STRERROR (errcode)) + +static const char *loadlibraryerror (const char *default_errmsg); +static DWORD WINAPI wrap_getthreaderrormode (void); +static DWORD WINAPI fallback_getthreaderrormode (void); +static BOOL WINAPI wrap_setthreaderrormode (DWORD mode, DWORD *oldmode); +static BOOL WINAPI fallback_setthreaderrormode (DWORD mode, DWORD *oldmode); + +typedef DWORD (WINAPI getthreaderrormode_type) (void); +typedef BOOL (WINAPI setthreaderrormode_type) (DWORD, DWORD *); + +static getthreaderrormode_type *getthreaderrormode = wrap_getthreaderrormode; +static setthreaderrormode_type *setthreaderrormode = wrap_setthreaderrormode; +static char *error_message = 0; + + +/* A function called through the vtable when this loader is no + longer needed by the application. */ +static int +vl_exit (lt_user_data LT__UNUSED loader_data) +{ + vtable = NULL; + LOCALFREE (error_message); + return 0; +} + +/* A function called through the vtable to open a module with this + loader. Returns an opaque representation of the newly opened + module for processing with this loader's other vtable functions. */ +static lt_module +vm_open (lt_user_data LT__UNUSED loader_data, const char *filename, + lt_dladvise LT__UNUSED advise) +{ + lt_module module = 0; + char *ext; + char wpath[MAX_PATH]; + size_t len; + + if (!filename) + { + /* Get the name of main module */ + *wpath = 0; + GetModuleFileName (NULL, wpath, sizeof (wpath)); + filename = wpath; + } + else + { + len = LT_STRLEN (filename); + + if (len >= MAX_PATH) + { + LT__SETERROR (CANNOT_OPEN); + return 0; + } + +#if HAVE_DECL_CYGWIN_CONV_PATH + if (cygwin_conv_path (CCP_POSIX_TO_WIN_A, filename, wpath, MAX_PATH)) + { + LT__SETERROR (CANNOT_OPEN); + return 0; + } + len = 0; +#elif defined(__CYGWIN__) + cygwin_conv_to_full_win32_path (filename, wpath); + len = 0; +#else + strcpy(wpath, filename); +#endif + + ext = strrchr (wpath, '.'); + if (!ext) + { + /* Append a `.' to stop Windows from adding an + implicit `.dll' extension. */ + if (!len) + len = strlen (wpath); + + if (len + 1 >= MAX_PATH) + { + LT__SETERROR (CANNOT_OPEN); + return 0; + } + + wpath[len] = '.'; + wpath[len+1] = '\0'; + } + } + + { + /* Silence dialog from LoadLibrary on some failures. */ + DWORD errormode = getthreaderrormode (); + DWORD last_error; + + setthreaderrormode (errormode | SEM_FAILCRITICALERRORS, NULL); + + module = LoadLibrary (wpath); + + /* Restore the error mode. */ + last_error = GetLastError (); + setthreaderrormode (errormode, NULL); + SetLastError (last_error); + } + + /* 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_dlhandle cur = 0; + + while ((cur = lt_dlhandle_iterate (iface_id, cur))) + { + if (!cur->module) + { + cur = 0; + break; + } + + if (cur->module == module) + { + break; + } + } + + if (!module) + LOADLIB_SETERROR (CANNOT_OPEN); + else if (cur) + { + LT__SETERROR (CANNOT_OPEN); + module = 0; + } + } + + return module; +} + + +/* A function called through the vtable when a particular module + should be unloaded. */ +static int +vm_close (lt_user_data LT__UNUSED loader_data, lt_module module) +{ + int errors = 0; + + if (FreeLibrary ((HMODULE) module) == 0) + { + LOADLIB_SETERROR (CANNOT_CLOSE); + ++errors; + } + + return errors; +} + + +/* A function called through the vtable to get the address of + a symbol loaded from a particular module. */ +static void * +vm_sym (lt_user_data LT__UNUSED loader_data, lt_module module, const char *name) +{ + void *address = (void *) GetProcAddress ((HMODULE) module, name); + + if (!address) + { + LOADLIB_SETERROR (SYMBOL_NOT_FOUND); + } + + return address; +} + + + +/* --- HELPER FUNCTIONS --- */ + + +/* Return the windows error message, or the passed in error message on + failure. */ +static const char * +loadlibraryerror (const char *default_errmsg) +{ + size_t len; + LOCALFREE (error_message); + + FormatMessageA (FORMAT_MESSAGE_ALLOCATE_BUFFER | + FORMAT_MESSAGE_FROM_SYSTEM | + FORMAT_MESSAGE_IGNORE_INSERTS, + NULL, + GetLastError (), + 0, + (char *) &error_message, + 0, NULL); + + /* Remove trailing CRNL */ + len = LT_STRLEN (error_message); + if (len && error_message[len - 1] == '\n') + error_message[--len] = LT_EOS_CHAR; + if (len && error_message[len - 1] == '\r') + error_message[--len] = LT_EOS_CHAR; + + return len ? error_message : default_errmsg; +} + +/* A function called through the getthreaderrormode variable which checks + if the system supports GetThreadErrorMode (or GetErrorMode) and arranges + for it or a fallback implementation to be called directly in the future. + The selected version is then called. */ +static DWORD WINAPI +wrap_getthreaderrormode (void) +{ + HMODULE kernel32 = GetModuleHandleA ("kernel32.dll"); + getthreaderrormode + = (getthreaderrormode_type *) GetProcAddress (kernel32, + "GetThreadErrorMode"); + if (!getthreaderrormode) + getthreaderrormode + = (getthreaderrormode_type *) GetProcAddress (kernel32, + "GetErrorMode"); + if (!getthreaderrormode) + getthreaderrormode = fallback_getthreaderrormode; + return getthreaderrormode (); +} + +/* A function called through the getthreaderrormode variable for cases + where the system does not support GetThreadErrorMode or GetErrorMode */ +static DWORD WINAPI +fallback_getthreaderrormode (void) +{ + /* Prior to Windows Vista, the only way to get the current error + mode was to set a new one. In our case, we are setting a new + error mode right after "getting" it while ignoring the error + mode in effect when setting the new error mode, so that's + fairly ok. */ + return (DWORD) SetErrorMode (SEM_FAILCRITICALERRORS); +} + +/* A function called through the setthreaderrormode variable which checks + if the system supports SetThreadErrorMode and arranges for it or a + fallback implementation to be called directly in the future. + The selected version is then called. */ +static BOOL WINAPI +wrap_setthreaderrormode (DWORD mode, DWORD *oldmode) +{ + HMODULE kernel32 = GetModuleHandleA ("kernel32.dll"); + setthreaderrormode + = (setthreaderrormode_type *) GetProcAddress (kernel32, + "SetThreadErrorMode"); + if (!setthreaderrormode) + setthreaderrormode = fallback_setthreaderrormode; + return setthreaderrormode (mode, oldmode); +} + +/* A function called through the setthreaderrormode variable for cases + where the system does not support SetThreadErrorMode. */ +static BOOL WINAPI +fallback_setthreaderrormode (DWORD mode, DWORD *oldmode) +{ + /* Prior to Windows 7, there was no way to set the thread local error + mode, so set the process global error mode instead. */ + DWORD old = (DWORD) SetErrorMode (mode); + if (oldmode) + *oldmode = old; + return TRUE; +} |