Protect kernel hooks exechook, exithook and forkhook with rwlock.
Lock as writer on establish/disestablish and as reader on list traverse. For exechook ride "exec_lock" as it is already take as reader when traversing the list. Add local locks for exithook and forkhook. Move exec_init before signal_init as signal_init calls exechook_establish() that needs "exec_lock". PR kern/39913 "exec, fork, exit hooks need locking"
This commit is contained in:
hannken
parent
ca4932dc6d
commit
29964953ba
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@ -1,4 +1,4 @@
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/* $NetBSD: init_main.c,v 1.546 2023/09/23 18:21:11 ad Exp $ */
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/* $NetBSD: init_main.c,v 1.547 2024/01/17 10:18:41 hannken Exp $ */
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/*-
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* Copyright (c) 2008, 2009, 2019, 2023 The NetBSD Foundation, Inc.
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@ -97,7 +97,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: init_main.c,v 1.546 2023/09/23 18:21:11 ad Exp $");
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__KERNEL_RCSID(0, "$NetBSD: init_main.c,v 1.547 2024/01/17 10:18:41 hannken Exp $");
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#include "opt_cnmagic.h"
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#include "opt_ddb.h"
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@ -407,6 +407,9 @@ main(void)
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/* Must be called after lwpinit (lwpinit_specificdata) */
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psref_init();
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/* Initialize exec structures */
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exec_init(1); /* signal_init calls exechook_establish() */
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/* Initialize signal-related data structures. */
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signal_init();
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@ -579,9 +582,6 @@ main(void)
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vmem_rehash_start(); /* must be before exec_init */
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/* Initialize exec structures */
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exec_init(1); /* seminit calls exithook_establish() */
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#if NVERIEXEC > 0
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/*
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* Initialise the Veriexec subsystem.
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@ -1,4 +1,4 @@
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/* $NetBSD: kern_hook.c,v 1.14 2022/10/26 23:21:06 riastradh Exp $ */
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/* $NetBSD: kern_hook.c,v 1.15 2024/01/17 10:18:41 hannken Exp $ */
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/*-
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* Copyright (c) 1997, 1998, 1999, 2002, 2007, 2008 The NetBSD Foundation, Inc.
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@ -31,7 +31,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: kern_hook.c,v 1.14 2022/10/26 23:21:06 riastradh Exp $");
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__KERNEL_RCSID(0, "$NetBSD: kern_hook.c,v 1.15 2024/01/17 10:18:41 hannken Exp $");
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#include <sys/param.h>
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@ -42,6 +42,7 @@ __KERNEL_RCSID(0, "$NetBSD: kern_hook.c,v 1.14 2022/10/26 23:21:06 riastradh Exp
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#include <sys/hook.h>
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#include <sys/kmem.h>
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#include <sys/malloc.h>
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#include <sys/once.h>
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#include <sys/rwlock.h>
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#include <sys/systm.h>
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@ -74,25 +75,48 @@ struct khook_list {
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int powerhook_debug = 0;
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static ONCE_DECL(hook_control);
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static krwlock_t exithook_lock;
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static krwlock_t forkhook_lock;
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static int
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hook_init(void)
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{
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rw_init(&exithook_lock);
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rw_init(&forkhook_lock);
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return 0;
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}
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static void *
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hook_establish(hook_list_t *list, void (*fn)(void *), void *arg)
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hook_establish(hook_list_t *list, krwlock_t *lock,
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void (*fn)(void *), void *arg)
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{
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struct hook_desc *hd;
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hd = malloc(sizeof(*hd), M_DEVBUF, M_NOWAIT);
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if (hd == NULL)
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return (NULL);
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RUN_ONCE(&hook_control, hook_init);
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hd->hk_fn = fn;
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hd->hk_arg = arg;
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LIST_INSERT_HEAD(list, hd, hk_list);
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hd = malloc(sizeof(*hd), M_DEVBUF, M_NOWAIT);
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if (hd != NULL) {
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if (lock)
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rw_enter(lock, RW_WRITER);
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hd->hk_fn = fn;
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hd->hk_arg = arg;
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LIST_INSERT_HEAD(list, hd, hk_list);
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if (lock)
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rw_exit(lock);
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}
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return (hd);
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}
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static void
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hook_disestablish(hook_list_t *list, void *vhook)
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hook_disestablish(hook_list_t *list, krwlock_t *lock, void *vhook)
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{
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if (lock)
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rw_enter(lock, RW_WRITER);
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#ifdef DIAGNOSTIC
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struct hook_desc *hd;
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@ -106,6 +130,8 @@ hook_disestablish(hook_list_t *list, void *vhook)
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#endif
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LIST_REMOVE((struct hook_desc *)vhook, hk_list);
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free(vhook, M_DEVBUF);
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if (lock)
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rw_exit(lock);
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}
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static void
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@ -120,14 +146,20 @@ hook_destroy(hook_list_t *list)
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}
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static void
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hook_proc_run(hook_list_t *list, struct proc *p)
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hook_proc_run(hook_list_t *list, krwlock_t *lock, struct proc *p)
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{
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struct hook_desc *hd;
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RUN_ONCE(&hook_control, hook_init);
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if (lock)
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rw_enter(lock, RW_READER);
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LIST_FOREACH(hd, list, hk_list) {
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__FPTRCAST(void (*)(struct proc *, void *), *hd->hk_fn)(p,
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hd->hk_arg);
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}
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if (lock)
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rw_exit(lock);
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}
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/*
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@ -146,13 +178,13 @@ static hook_list_t shutdownhook_list = LIST_HEAD_INITIALIZER(shutdownhook_list);
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void *
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shutdownhook_establish(void (*fn)(void *), void *arg)
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{
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return hook_establish(&shutdownhook_list, fn, arg);
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return hook_establish(&shutdownhook_list, NULL, fn, arg);
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}
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void
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shutdownhook_disestablish(void *vhook)
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{
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hook_disestablish(&shutdownhook_list, vhook);
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hook_disestablish(&shutdownhook_list, NULL, vhook);
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}
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/*
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@ -193,14 +225,14 @@ static hook_list_t mountroothook_list=LIST_HEAD_INITIALIZER(mountroothook_list);
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void *
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mountroothook_establish(void (*fn)(device_t), device_t dev)
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{
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return hook_establish(&mountroothook_list, __FPTRCAST(void (*), fn),
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dev);
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return hook_establish(&mountroothook_list, NULL,
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__FPTRCAST(void (*), fn), dev);
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}
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void
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mountroothook_disestablish(void *vhook)
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{
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hook_disestablish(&mountroothook_list, vhook);
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hook_disestablish(&mountroothook_list, NULL, vhook);
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}
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void
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@ -227,14 +259,14 @@ static hook_list_t exechook_list = LIST_HEAD_INITIALIZER(exechook_list);
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void *
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exechook_establish(void (*fn)(struct proc *, void *), void *arg)
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{
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return hook_establish(&exechook_list, __FPTRCAST(void (*)(void *), fn),
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arg);
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return hook_establish(&exechook_list, &exec_lock,
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__FPTRCAST(void (*)(void *), fn), arg);
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}
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void
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exechook_disestablish(void *vhook)
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{
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hook_disestablish(&exechook_list, vhook);
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hook_disestablish(&exechook_list, &exec_lock, vhook);
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}
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/*
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@ -243,7 +275,9 @@ exechook_disestablish(void *vhook)
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void
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doexechooks(struct proc *p)
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{
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hook_proc_run(&exechook_list, p);
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KASSERT(rw_lock_held(&exec_lock));
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hook_proc_run(&exechook_list, NULL, p);
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}
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static hook_list_t exithook_list = LIST_HEAD_INITIALIZER(exithook_list);
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@ -251,22 +285,16 @@ static hook_list_t exithook_list = LIST_HEAD_INITIALIZER(exithook_list);
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void *
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exithook_establish(void (*fn)(struct proc *, void *), void *arg)
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{
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void *rv;
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rw_enter(&exec_lock, RW_WRITER);
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rv = hook_establish(&exithook_list, __FPTRCAST(void (*)(void *), fn),
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arg);
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rw_exit(&exec_lock);
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return rv;
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return hook_establish(&exithook_list, &exithook_lock,
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__FPTRCAST(void (*)(void *), fn), arg);
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}
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void
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exithook_disestablish(void *vhook)
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{
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rw_enter(&exec_lock, RW_WRITER);
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hook_disestablish(&exithook_list, vhook);
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rw_exit(&exec_lock);
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hook_disestablish(&exithook_list, &exithook_lock, vhook);
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}
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/*
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void
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doexithooks(struct proc *p)
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{
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hook_proc_run(&exithook_list, p);
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hook_proc_run(&exithook_list, &exithook_lock, p);
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}
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static hook_list_t forkhook_list = LIST_HEAD_INITIALIZER(forkhook_list);
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void *
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forkhook_establish(void (*fn)(struct proc *, struct proc *))
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{
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return hook_establish(&forkhook_list, __FPTRCAST(void (*)(void *), fn),
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NULL);
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return hook_establish(&forkhook_list, &forkhook_lock,
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__FPTRCAST(void (*)(void *), fn), NULL);
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}
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void
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forkhook_disestablish(void *vhook)
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{
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hook_disestablish(&forkhook_list, vhook);
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hook_disestablish(&forkhook_list, &forkhook_lock, vhook);
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}
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/*
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{
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struct hook_desc *hd;
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RUN_ONCE(&hook_control, hook_init);
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rw_enter(&forkhook_lock, RW_READER);
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LIST_FOREACH(hd, &forkhook_list, hk_list) {
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__FPTRCAST(void (*)(struct proc *, struct proc *), *hd->hk_fn)
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(p2, p1);
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}
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rw_exit(&forkhook_lock);
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}
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static hook_list_t critpollhook_list = LIST_HEAD_INITIALIZER(critpollhook_list);
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@ -312,13 +344,13 @@ static hook_list_t critpollhook_list = LIST_HEAD_INITIALIZER(critpollhook_list);
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void *
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critpollhook_establish(void (*fn)(void *), void *arg)
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{
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return hook_establish(&critpollhook_list, fn, arg);
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return hook_establish(&critpollhook_list, NULL, fn, arg);
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}
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void
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critpollhook_disestablish(void *vhook)
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{
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hook_disestablish(&critpollhook_list, vhook);
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hook_disestablish(&critpollhook_list, NULL, vhook);
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}
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/*
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