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/* Atfork handling. Hurd pthread version.
Copyright (C) 2002-2020 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 <errno.h>
#include <stdlib.h>
#include <libc-lock.h>
#include <fork.h>
struct atfork
{
void (*prepare) (void);
void (*parent) (void);
void (*child) (void);
void *dso_handle;
struct atfork *prev;
struct atfork *next;
};
/* TODO: better locking */
__libc_lock_define_initialized (static, atfork_lock);
static struct atfork *fork_handlers, *fork_last_handler;
static void
atfork_pthread_prepare (void)
{
struct atfork *handlers, *last_handler;
__libc_lock_lock (atfork_lock);
handlers = fork_handlers;
last_handler = fork_last_handler;
__libc_lock_unlock (atfork_lock);
if (last_handler == NULL)
return;
while (1)
{
if (last_handler->prepare != NULL)
last_handler->prepare ();
if (last_handler == handlers)
break;
last_handler = last_handler->prev;
}
}
text_set_element (_hurd_atfork_prepare_hook, atfork_pthread_prepare);
static void
atfork_pthread_parent (void)
{
struct atfork *handlers;
__libc_lock_lock (atfork_lock);
handlers = fork_handlers;
__libc_lock_unlock (atfork_lock);
while (handlers != NULL)
{
if (handlers->parent != NULL)
handlers->parent ();
handlers = handlers->next;
}
}
text_set_element (_hurd_atfork_parent_hook, atfork_pthread_parent);
static void
atfork_pthread_child (void)
{
struct atfork *handlers;
__libc_lock_lock (atfork_lock);
handlers = fork_handlers;
__libc_lock_unlock (atfork_lock);
while (handlers != NULL)
{
if (handlers->child != NULL)
handlers->child ();
handlers = handlers->next;
}
}
text_set_element (_hurd_atfork_child_hook, atfork_pthread_child);
int
__register_atfork (void (*prepare) (void),
void (*parent) (void),
void (*child) (void),
void *dso_handle)
{
struct atfork *new = malloc (sizeof (*new));
if (new == NULL)
return errno;
new->prepare = prepare;
new->parent = parent;
new->child = child;
new->dso_handle = dso_handle;
new->next = NULL;
__libc_lock_lock (atfork_lock);
new->prev = fork_last_handler;
if (fork_last_handler != NULL)
fork_last_handler->next = new;
if (fork_handlers == NULL)
fork_handlers = new;
fork_last_handler = new;
__libc_lock_unlock (atfork_lock);
return 0;
}
libc_hidden_def (__register_atfork)
void
__unregister_atfork (void *dso_handle)
{
struct atfork **handlers, *prev = NULL, *next;
__libc_lock_lock (atfork_lock);
handlers = &fork_handlers;
while (*handlers != NULL)
{
if ((*handlers)->dso_handle == dso_handle)
{
/* Drop this handler from the list. */
if (*handlers == fork_last_handler)
{
/* Was last, new last is prev, if any. */
fork_last_handler = prev;
}
next = (*handlers)->next;
if (next != NULL)
next->prev = prev;
*handlers = next;
}
else
{
/* Just proceed to next handler. */
prev = *handlers;
handlers = &prev->next;
}
}
__libc_lock_unlock (atfork_lock);
}
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