/* Error handling for runtime dynamic linker. Copyright (C) 1995-2002,2004,2005 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library 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 2.1 of the License, or (at your option) any later version. The GNU C Library 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 the GNU C Library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */ #include #include #include #include #include #include #include /* This structure communicates state between _dl_catch_error and _dl_signal_error. */ struct catch { const char *objname; /* Object/File name. */ const char *errstring; /* Error detail filled in here. */ bool malloced; /* Nonzero if the string is malloced by the libc malloc. */ jmp_buf env; /* longjmp here on error. */ }; /* Multiple threads at once can use the `_dl_catch_error' function. The calls can come from `_dl_map_object_deps', `_dlerror_run', or from any of the libc functionality which loads dynamic objects (NSS, iconv). Therefore we have to be prepared to save the state in thread-local memory. The _dl_error_catch_tsd function pointer is reset by the thread library so that it returns the address of a thread-local variable. */ /* This message we return as a last resort. We define the string in a variable since we have to avoid freeing it and so have to enable a pointer comparison. See below and in dlfcn/dlerror.c. */ static const char _dl_out_of_memory[] = "out of memory"; /* This points to a function which is called when an continuable error is received. Unlike the handling of `catch' this function may return. The arguments will be the `errstring' and `objname'. Since this functionality is not used in normal programs (only in ld.so) we do not care about multi-threaded programs here. We keep this as a global variable. */ static receiver_fct receiver; #ifdef _LIBC_REENTRANT # define CATCH_HOOK (*(struct catch **) (*GL(dl_error_catch_tsd)) ()) #else static struct catch *catch_hook; # define CATCH_HOOK catch_hook #endif void internal_function _dl_signal_error (int errcode, const char *objname, const char *occation, const char *errstring) { struct catch *lcatch; if (! errstring) errstring = N_("DYNAMIC LINKER BUG!!!"); lcatch = CATCH_HOOK; if (objname == NULL) objname = ""; if (lcatch != NULL) { /* We are inside _dl_catch_error. Return to it. We have to duplicate the error string since it might be allocated on the stack. The object name is always a string constant. */ size_t len_objname = strlen (objname) + 1; size_t len_errstring = strlen (errstring) + 1; lcatch->errstring = (char *) malloc (len_objname + len_errstring); if (lcatch->errstring != NULL) { /* Make a copy of the object file name and the error string. */ lcatch->objname = memcpy (__mempcpy ((char *) lcatch->errstring, errstring, len_errstring), objname, len_objname); /* If the main executable is relocated it means the libc's malloc is used. */ #ifdef SHARED lcatch->malloced = (GL(dl_ns)[LM_ID_BASE]._ns_loaded != NULL && (GL(dl_ns)[LM_ID_BASE]._ns_loaded->l_relocated != 0)); #else lcatch->malloced = true; #endif } else { /* This is better than nothing. */ lcatch->objname = ""; lcatch->errstring = _dl_out_of_memory; lcatch->malloced = false; } /* We do not restore the signal mask because none was saved. */ __longjmp (lcatch->env[0].__jmpbuf, errcode ?: -1); } else { /* Lossage while resolving the program's own symbols is always fatal. */ char buffer[1024]; _dl_fatal_printf ("%s: %s: %s%s%s%s%s\n", rtld_progname ?: "", occation ?: N_("error while loading shared libraries"), objname, *objname ? ": " : "", errstring, errcode ? ": " : "", (errcode ? __strerror_r (errcode, buffer, sizeof buffer) : "")); } } void internal_function _dl_signal_cerror (int errcode, const char *objname, const char *occation, const char *errstring) { if (__builtin_expect (GLRO(dl_debug_mask) & ~(DL_DEBUG_STATISTICS|DL_DEBUG_PRELINK), 0)) _dl_debug_printf ("%s: error: %s: %s (%s)\n", objname, occation, errstring, receiver ? "continued" : "fatal"); if (receiver) { /* We are inside _dl_receive_error. Call the user supplied handler and resume the work. The receiver will still be installed. */ (*receiver) (errcode, objname, errstring); } else _dl_signal_error (errcode, objname, occation, errstring); } int internal_function _dl_catch_error (const char **objname, const char **errstring, bool *mallocedp, void (*operate) (void *), void *args) { int errcode; struct catch *volatile old; struct catch c; /* We need not handle `receiver' since setting a `catch' is handled before it. */ /* Some systems (e.g., SPARC) handle constructors to local variables inefficient. So we initialize `c' by hand. */ c.errstring = NULL; struct catch **const catchp = &CATCH_HOOK; old = *catchp; /* Do not save the signal mask. */ errcode = __sigsetjmp (c.env, 0); if (__builtin_expect (errcode, 0) == 0) { *catchp = &c; (*operate) (args); *catchp = old; *objname = NULL; *errstring = NULL; *mallocedp = false; return 0; } /* We get here only if we longjmp'd out of OPERATE. */ *catchp = old; *objname = c.objname; *errstring = c.errstring; *mallocedp = c.malloced; return errcode == -1 ? 0 : errcode; } void internal_function _dl_receive_error (receiver_fct fct, void (*operate) (void *), void *args) { struct catch **const catchp = &CATCH_HOOK; struct catch *old_catch; receiver_fct old_receiver; old_catch = *catchp; old_receiver = receiver; /* Set the new values. */ *catchp = NULL; receiver = fct; (*operate) (args); *catchp = old_catch; receiver = old_receiver; }