/* 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 #include #include #include #include "path.h" #include "fhandler.h" #include "dtable.h" #include "cygheap.h" #include "perprocess.h" #include "dlfcn.h" #include "cygtls.h" #include "tls_pbuf.h" #include "ntdll.h" static void 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 * check_path_access (const char *mywinenv, const char *name, path_conv& buf) { return find_exec (name, buf, mywinenv, FE_NNF | FE_DLL); } /* Search LD_LIBRARY_PATH for dll, if it exists. Search /usr/bin and /usr/lib by default. Return valid full path in path_conv real_filename. */ static inline bool gfpod_helper (const char *name, path_conv &real_filename) { if (strchr (name, '/')) real_filename.check (name, PC_SYM_FOLLOW | PC_NULLEMPTY); else if (!check_path_access ("LD_LIBRARY_PATH", name, real_filename)) check_path_access ("/usr/bin:/usr/lib", name, real_filename); if (!real_filename.exists ()) real_filename.error = ENOENT; return !real_filename.error; } static bool 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. */ char *basename = strrchr (name, '/'); basename = basename ? basename + 1 : name; char *suffix = strrchr (name, '.'); if (suffix && suffix < basename) suffix = NULL; /* Is suffix ".so"? */ if (suffix && !strcmp (suffix, ".so")) { /* Does the file exist? */ if (gfpod_helper (name, real_filename)) return true; /* No, replace ".so" with ".dll". */ strcpy (suffix, ".dll"); } /* Does the filename start with "lib"? */ if (!strncmp (basename, "lib", 3)) { /* Yes, replace "lib" with "cyg". */ strncpy (basename, "cyg", 3); /* Does the file exist? */ if (gfpod_helper (name, real_filename)) return true; /* No, revert back to "lib". */ strncpy (basename, "lib", 3); } if (gfpod_helper (name, real_filename)) return true; /* 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 (str, PC_SYM_FOLLOW | PC_NOFULL | PC_NULLEMPTY); if (!real_filename.error) return true; set_errno (real_filename.error); return false; } extern "C" void * dlopen (const char *name, int flags) { void *ret = NULL; if (name == NULL) { ret = (void *) GetModuleHandle (NULL); /* handle for the current module */ if (!ret) __seterrno (); } else { /* handle for the named library */ path_conv pc; if (get_full_path_of_dll (name, pc)) { 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 trailing dot to override LoadLibrary's automatic adding of a ".dll" suffix. */ wchar_t *last_bs = wcsrchr (path, L'\\') ?: path; if (last_bs && !wcschr (last_bs, L'.')) wcscat (last_bs, L"."); #ifndef __x86_64__ /* 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 if (flags & RTLD_NOLOAD) GetModuleHandleExW (0, path, (HMODULE *) &ret); else ret = (void *) LoadLibraryW (path); if (ret && (flags & RTLD_NODELETE)) GetModuleHandleExW (GET_MODULE_HANDLE_EX_FLAG_PIN, path, (HMODULE *) &ret); #ifndef __x86_64__ /* Restore original cxx_malloc pointer. */ __cygwin_user_data.cxx_malloc = tmp_malloc; #endif if (!ret) __seterrno (); } } 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; if (handle == GetModuleHandle (NULL)) ret = 0; else if (FreeLibrary ((HMODULE) handle)) ret = 0; else 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; }