glibc/stdlib/cxa_atexit.c
Florian Weimer 58548b9d68 Use PTR_MANGLE and PTR_DEMANGLE unconditionally in C sources
In the future, this will result in a compilation failure if the
macros are unexpectedly undefined (due to header inclusion ordering
or header inclusion missing altogether).

Assembler sources are more difficult to convert.  In many cases,
they are hand-optimized for the mangling and no-mangling variants,
which is why they are not converted.

sysdeps/s390/s390-32/__longjmp.c and sysdeps/s390/s390-64/__longjmp.c
are special: These are C sources, but most of the implementation is
in assembler, so the PTR_DEMANGLE macro has to be undefined in some
cases, to match the assembler style.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2022-10-18 17:04:10 +02:00

142 lines
3.5 KiB
C

/* Copyright (C) 1999-2022 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
<https://www.gnu.org/licenses/>. */
#include <assert.h>
#include <stdlib.h>
#include <stdint.h>
#include <libc-lock.h>
#include "exit.h"
#include <pointer_guard.h>
#undef __cxa_atexit
/* See concurrency notes in stdlib/exit.h where this lock is declared. */
__libc_lock_define_initialized (, __exit_funcs_lock)
int
attribute_hidden
__internal_atexit (void (*func) (void *), void *arg, void *d,
struct exit_function_list **listp)
{
struct exit_function *new;
/* As a QoI issue we detect NULL early with an assertion instead
of a SIGSEGV at program exit when the handler is run (bug 20544). */
assert (func != NULL);
__libc_lock_lock (__exit_funcs_lock);
new = __new_exitfn (listp);
if (new == NULL)
{
__libc_lock_unlock (__exit_funcs_lock);
return -1;
}
PTR_MANGLE (func);
new->func.cxa.fn = (void (*) (void *, int)) func;
new->func.cxa.arg = arg;
new->func.cxa.dso_handle = d;
new->flavor = ef_cxa;
__libc_lock_unlock (__exit_funcs_lock);
return 0;
}
/* Register a function to be called by exit or when a shared library
is unloaded. This function is only called from code generated by
the C++ compiler. */
int
__cxa_atexit (void (*func) (void *), void *arg, void *d)
{
return __internal_atexit (func, arg, d, &__exit_funcs);
}
libc_hidden_def (__cxa_atexit)
static struct exit_function_list initial;
struct exit_function_list *__exit_funcs = &initial;
uint64_t __new_exitfn_called;
/* Must be called with __exit_funcs_lock held. */
struct exit_function *
__new_exitfn (struct exit_function_list **listp)
{
struct exit_function_list *p = NULL;
struct exit_function_list *l;
struct exit_function *r = NULL;
size_t i = 0;
if (__exit_funcs_done)
/* Exit code is finished processing all registered exit functions,
therefore we fail this registration. */
return NULL;
for (l = *listp; l != NULL; p = l, l = l->next)
{
for (i = l->idx; i > 0; --i)
if (l->fns[i - 1].flavor != ef_free)
break;
if (i > 0)
break;
/* This block is completely unused. */
l->idx = 0;
}
if (l == NULL || i == sizeof (l->fns) / sizeof (l->fns[0]))
{
/* The last entry in a block is used. Use the first entry in
the previous block if it exists. Otherwise create a new one. */
if (p == NULL)
{
assert (l != NULL);
p = (struct exit_function_list *)
calloc (1, sizeof (struct exit_function_list));
if (p != NULL)
{
p->next = *listp;
*listp = p;
}
}
if (p != NULL)
{
r = &p->fns[0];
p->idx = 1;
}
}
else
{
/* There is more room in the block. */
r = &l->fns[i];
l->idx = i + 1;
}
/* Mark entry as used, but we don't know the flavor now. */
if (r != NULL)
{
r->flavor = ef_us;
++__new_exitfn_called;
}
return r;
}