crashme: a framework to test kernel faults.
so far, only a basic panic() and null deref nodes are added. with options DEBUG, one can now use: # sysctl -w kern.crashme_enable=1 # sysctl -w kern.crashme.panic=1 # sysctl -w kern.crashme.null_deref=1 to trigger a crash. crashme_enable must be set to 1 before any of the nodes will be writeable. supports dynamic additional/removal of crashme nodes. (obsoletes kern.panic_now, which will be removed later.)
This commit is contained in:
mrg
parent
276d4f85dc
commit
f40d255452
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@ -1,4 +1,4 @@
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# $NetBSD: files.kern,v 1.29 2018/12/24 16:58:54 thorpej Exp $
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# $NetBSD: files.kern,v 1.30 2019/01/09 04:01:20 mrg Exp $
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#
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#
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# kernel sources
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# kernel sources
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@ -77,6 +77,7 @@ file kern/kern_rwlock.c kern
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file kern/kern_rwlock_obj.c kern
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file kern/kern_rwlock_obj.c kern
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file kern/kern_scdebug.c kern
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file kern/kern_scdebug.c kern
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file kern/kern_sdt.c kdtrace_hooks
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file kern/kern_sdt.c kdtrace_hooks
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file kern/kern_crashme.c debug
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file kern/kern_sig.c kern
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file kern/kern_sig.c kern
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file kern/kern_sleepq.c kern
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file kern/kern_sleepq.c kern
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file kern/kern_softint.c kern
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file kern/kern_softint.c kern
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@ -0,0 +1,236 @@
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/* $NetBSD: kern_crashme.c,v 1.1 2019/01/09 04:01:20 mrg Exp $ */
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/*
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* Copyright (c) 2018, 2019 Matthew R. Green
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* kern_crashme.c: special debugging routines only enabled in DEBUG
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* enabled kernels, designed for debugging kernel crashes.
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*
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* supports crashme sysctl nodes, to test various ways the system can
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* panic or crash. you can add and remove nodes.
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*/
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#include <sys/param.h>
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#include <sys/sysctl.h>
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#include <sys/systm.h>
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#include <sys/kthread.h>
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#include <sys/kmem.h>
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#include <sys/mutex.h>
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#include <sys/crashme.h>
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#define DPRINTF(fmt, ...) \
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printf("%s:%d: " fmt "\n", __func__, __LINE__, ## __VA_ARGS__)
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static int crashme_sysctl_forwarder(SYSCTLFN_PROTO);
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static int crashme_panic(int);
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static int crashme_null_deref(int);
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#define CMNODE(name, lname, func) \
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{ \
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.cn_name = name, \
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.cn_longname = lname, \
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.cn_fn = func, \
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}
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static crashme_node nodes[] = {
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CMNODE("panic", "plain old panic", crashme_panic),
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CMNODE("null_deref", "null dereference", crashme_null_deref),
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};
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static crashme_node *first_node;
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static kmutex_t crashme_lock;
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static const struct sysctlnode *crashme_root = NULL;
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static bool crashme_enable = 0;
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/*
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* add a crashme node dynamically. return -1 on failure, 0 on success.
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*/
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int
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crashme_add(crashme_node *ncn)
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{
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int rv = -1;
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crashme_node *cn;
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crashme_node *last = NULL;
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if (crashme_root == NULL)
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return -1;
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mutex_enter(&crashme_lock);
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for (cn = first_node; cn; last = cn, cn = cn->cn_next) {
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if (strcmp(cn->cn_name, ncn->cn_name) == 0)
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break;
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}
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if (!cn) {
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ncn->cn_next = NULL;
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rv = sysctl_createv(NULL, 0,
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&crashme_root, &ncn->cn_sysctl,
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CTLFLAG_PERMANENT | CTLFLAG_READWRITE,
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CTLTYPE_INT, ncn->cn_name,
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SYSCTL_DESCR(ncn->cn_longname),
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crashme_sysctl_forwarder, 0,
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NULL, 0,
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CTL_CREATE, CTL_EOL);
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/* don't insert upon failure */
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if (rv == 0) {
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if (last)
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last->cn_next = ncn;
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if (first_node == NULL)
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first_node = ncn;
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}
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}
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mutex_exit(&crashme_lock);
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return rv;
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}
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/*
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* remove a crashme node. return -1 on failure, 0 on success.
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*/
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int
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crashme_remove(crashme_node *rcn)
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{
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crashme_node *cn, *prev = NULL;
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mutex_enter(&crashme_lock);
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for (cn = first_node; cn; prev = cn, cn = cn->cn_next) {
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int rv;
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if (cn != rcn)
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continue;
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if (cn == first_node)
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first_node = cn->cn_next;
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if (prev)
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prev->cn_next = cn->cn_next;
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if ((rv = sysctl_destroyv(NULL, CTL_DEBUG, crashme_root,
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cn->cn_name, CTL_EOL)) == 0)
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printf("%s: unable to remove %s from sysctl\n",
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__func__, cn->cn_name);
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break;
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}
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mutex_exit(&crashme_lock);
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if (cn == NULL)
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return -1;
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return 0;
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}
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/*
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* list or execute a crashme node
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*/
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static int
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crashme_sysctl_forwarder(SYSCTLFN_ARGS)
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{
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struct sysctlnode node;
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crashme_node *cn;
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int error, arg = 0;
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for (cn = first_node; cn; cn = cn->cn_next) {
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if (cn->cn_sysctl == rnode)
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break;
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}
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if (!cn) {
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return EINVAL;
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}
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node = *rnode;
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node.sysctl_data = &arg;
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error = sysctl_lookup(SYSCTLFN_CALL(&node));
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if (error || newp == NULL)
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return (error);
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if (!crashme_enable)
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return EACCES;
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DPRINTF("invoking \"%s\" (%s)", cn->cn_name, cn->cn_longname);
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if ((*cn->cn_fn)(arg) != 0)
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panic("crashme on %s failed!\n", cn->cn_name);
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return 0;
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}
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/*
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* register the various nodes with sysctl.
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*/
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SYSCTL_SETUP(selfdebug_crashme, "sysctl crashme setup")
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{
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int rv;
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size_t n;
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mutex_init(&crashme_lock, MUTEX_DEFAULT, IPL_NONE);
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rv = sysctl_createv(NULL, 0, NULL, &crashme_root,
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CTLFLAG_PERMANENT,
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CTLTYPE_NODE, "crashme",
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SYSCTL_DESCR("Crashme options"),
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NULL, 0, NULL, 0,
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CTL_DEBUG, CTL_CREATE, CTL_EOL);
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if (rv != 0 || crashme_root == NULL)
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return;
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rv = sysctl_createv(NULL, 0, NULL, NULL,
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CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
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CTLTYPE_BOOL, "crashme_enable",
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SYSCTL_DESCR("Enable crashme"),
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NULL, 0, &crashme_enable, 0,
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CTL_DEBUG, CTL_CREATE, CTL_EOL);
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for (n = 0; n < __arraycount(nodes); n++) {
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crashme_node *cn = &nodes[n];
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rv = crashme_add(cn);
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/* don't insert */
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if (rv != 0)
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continue;
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}
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}
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/*
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* actual panic functions below
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*/
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static int
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crashme_panic(int flags)
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{
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panic("crashme plain old panic");
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return -1;
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}
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static int
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crashme_null_deref(int flags)
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{
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*(char *)0 = 0;
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return -1;
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}
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@ -0,0 +1,57 @@
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/* $NetBSD: crashme.h,v 1.1 2019/01/09 04:01:20 mrg Exp $ */
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/*
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* Copyright (c) 2018, 2019 Matthew R. Green
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/* header for kernel crashme node handling. */
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#ifndef _SYS_CRASHME_H_
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#define _SYS_CRASHME_H_
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/*
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* don't mark this __dead. crashme nodes failures should return to
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* the caller so it can be handled.
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*
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* return zero if successful, and should return to user (may be part
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* of the setup needed.) return non-zero otherwise (will call plain
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* panic().)
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*/
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typedef int (*crashme_fn)(int);
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typedef struct crashme_node {
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const char *cn_name;
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const char *cn_longname;
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crashme_fn cn_fn;
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const struct sysctlnode *cn_sysctl;
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struct crashme_node *cn_next;
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} crashme_node;
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int crashme_add(crashme_node *ncn);
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int crashme_remove(crashme_node *ncn);
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#endif /* _SYS_CRASHME_H_ */
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Loading…
Reference in New Issue