[apple/xnu.git] / bsd / kern / kern_backtrace.c

/*
 * Copyright (c) 2016, 2019 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */

#include <kern/backtrace.h>
#include <kern/kalloc.h>
#include <sys/errno.h>
#include <sys/sysctl.h>
#include <sys/systm.h>

#if DEVELOPMENT || DEBUG

#define MAX_BACKTRACE  (128)

#define BACKTRACE_USER (0)

static int backtrace_sysctl SYSCTL_HANDLER_ARGS;

SYSCTL_NODE(_kern, OID_AUTO, backtrace, CTLFLAG_RW | CTLFLAG_LOCKED, 0,
    "backtrace");

SYSCTL_PROC(_kern_backtrace, OID_AUTO, user,
    CTLFLAG_RW | CTLFLAG_LOCKED, (void *)BACKTRACE_USER,
    sizeof(uint64_t), backtrace_sysctl, "O",
    "take user backtrace of current thread");

static int
backtrace_sysctl SYSCTL_HANDLER_ARGS
{
#pragma unused(oidp, arg2)
	uintptr_t type = (uintptr_t)arg1;
	uintptr_t *bt = NULL;
	uint32_t bt_len = 0, bt_filled = 0;
	size_t bt_size = 0;
	int error = 0;

	if (type != BACKTRACE_USER) {
		return EINVAL;
	}

	if (req->oldptr == USER_ADDR_NULL || req->oldlen == 0) {
		return EFAULT;
	}

	bt_len = req->oldlen > MAX_BACKTRACE ? MAX_BACKTRACE : req->oldlen;
	bt_size = sizeof(bt[0]) * bt_len;
	bt = kalloc(bt_size);
	if (!bt) {
		return ENOBUFS;
	}
	memset(bt, 0, bt_size);
	bt_filled = backtrace_user(bt, bt_len, &error, NULL, NULL);
	if (error != 0) {
		goto out;
	}
	bt_filled = min(bt_filled, bt_len);

	error = copyout(bt, req->oldptr, sizeof(bt[0]) * bt_filled);
	if (error) {
		goto out;
	}
	req->oldidx = bt_filled;

out:
	kfree(bt, bt_size);
	return error;
}

#endif /* DEVELOPMENT || DEBUG */
Commit	Line	Data
39037602	1	/*
0a7de745	2	* Copyright (c) 2016, 2019 Apple Computer, Inc. All rights reserved.
39037602 A	3	*
	4	* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
	5	*
	6	* This file contains Original Code and/or Modifications of Original Code
	7	* as defined in and that are subject to the Apple Public Source License
	8	* Version 2.0 (the 'License'). You may not use this file except in
	9	* compliance with the License. The rights granted to you under the License
	10	* may not be used to create, or enable the creation or redistribution of,
	11	* unlawful or unlicensed copies of an Apple operating system, or to
	12	* circumvent, violate, or enable the circumvention or violation of, any
	13	* terms of an Apple operating system software license agreement.
	14	*
	15	* Please obtain a copy of the License at
	16	* http://www.opensource.apple.com/apsl/ and read it before using this file.
	17	*
	18	* The Original Code and all software distributed under the License are
	19	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	20	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	21	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	22	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	23	* Please see the License for the specific language governing rights and
	24	* limitations under the License.
	25	*
	26	* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
	27	*/
	28
	29	#include <kern/backtrace.h>
	30	#include <kern/kalloc.h>
	31	#include <sys/errno.h>
	32	#include <sys/sysctl.h>
	33	#include <sys/systm.h>
	34
0a7de745 A	35	#if DEVELOPMENT \|\| DEBUG
0a7de745 A	36
39037602 A	37	#define MAX_BACKTRACE (128)
	38
	39	#define BACKTRACE_USER (0)
	40
	41	static int backtrace_sysctl SYSCTL_HANDLER_ARGS;
	42
	43	SYSCTL_NODE(_kern, OID_AUTO, backtrace, CTLFLAG_RW \| CTLFLAG_LOCKED, 0,
0a7de745	44	"backtrace");
39037602 A	45
39037602 A	46	SYSCTL_PROC(_kern_backtrace, OID_AUTO, user,
0a7de745 A	47	CTLFLAG_RW \| CTLFLAG_LOCKED, (void *)BACKTRACE_USER,
	48	sizeof(uint64_t), backtrace_sysctl, "O",
	49	"take user backtrace of current thread");
39037602 A	50
	51	static int
	52	backtrace_sysctl SYSCTL_HANDLER_ARGS
	53	{
	54	#pragma unused(oidp, arg2)
39037602	55	uintptr_t type = (uintptr_t)arg1;
0a7de745 A	56	uintptr_t *bt = NULL;
	57	uint32_t bt_len = 0, bt_filled = 0;
	58	size_t bt_size = 0;
	59	int error = 0;
39037602 A	60
	61	if (type != BACKTRACE_USER) {
	62	return EINVAL;
	63	}
	64
	65	if (req->oldptr == USER_ADDR_NULL \|\| req->oldlen == 0) {
	66	return EFAULT;
	67	}
	68
	69	bt_len = req->oldlen > MAX_BACKTRACE ? MAX_BACKTRACE : req->oldlen;
0a7de745 A	70	bt_size = sizeof(bt[0]) * bt_len;
0a7de745 A	71	bt = kalloc(bt_size);
39037602 A	72	if (!bt) {
	73	return ENOBUFS;
	74	}
0a7de745	75	memset(bt, 0, bt_size);
ea3f0419 A	76	bt_filled = backtrace_user(bt, bt_len, &error, NULL, NULL);
ea3f0419 A	77	if (error != 0) {
39037602 A	78	goto out;
39037602 A	79	}
0a7de745	80	bt_filled = min(bt_filled, bt_len);
39037602	81
0a7de745 A	82	error = copyout(bt, req->oldptr, sizeof(bt[0]) * bt_filled);
0a7de745 A	83	if (error) {
39037602 A	84	goto out;
	85	}
	86	req->oldidx = bt_filled;
	87
	88	out:
0a7de745 A	89	kfree(bt, bt_size);
0a7de745 A	90	return error;
39037602	91	}
0a7de745 A	92
0a7de745 A	93	#endif /* DEVELOPMENT \|\| DEBUG */