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/* Error handling for runtime dynamic linker.
Copyright (C) 1995-2013 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, see
<http://www.gnu.org/licenses/>. */
#include <libintl.h>
#include <setjmp.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <ldsodefs.h>
/* 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;
}
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