1/*
2 * Copyright (c) 2016 Apple Computer, Inc. All rights reserved.
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
35#define MAX_BACKTRACE (128)
36
37#define BACKTRACE_USER (0)
38
39static int backtrace_sysctl SYSCTL_HANDLER_ARGS;
40
41SYSCTL_NODE(_kern, OID_AUTO, backtrace, CTLFLAG_RW | CTLFLAG_LOCKED, 0,
42 "backtrace");
43
44SYSCTL_PROC(_kern_backtrace, OID_AUTO, user,
45 CTLFLAG_RW | CTLFLAG_LOCKED, (void *)BACKTRACE_USER,
46 sizeof(uint64_t), backtrace_sysctl, "O", "take user backtrace of current thread");
47
48static int
49backtrace_sysctl SYSCTL_HANDLER_ARGS
50{
51#pragma unused(oidp, arg2)
52 uintptr_t *bt;
53 uint32_t bt_len, bt_filled;
54 uintptr_t type = (uintptr_t)arg1;
55 bool user_64;
56 int err = 0;
57
58 if (type != BACKTRACE_USER) {
59 return EINVAL;
60 }
61
62 if (req->oldptr == USER_ADDR_NULL || req->oldlen == 0) {
63 return EFAULT;
64 }
65
66 bt_len = req->oldlen > MAX_BACKTRACE ? MAX_BACKTRACE : req->oldlen;
67 bt = kalloc(sizeof(uintptr_t) * bt_len);
68 if (!bt) {
69 return ENOBUFS;
70 }
71 bzero(bt, sizeof(uintptr_t) * bt_len);
72 err = backtrace_user(bt, bt_len, &bt_filled, &user_64);
73 if (err) {
74 goto out;
75 }
76
77 err = copyout(bt, req->oldptr, bt_filled * sizeof(uint64_t));
78 if (err) {
79 goto out;
80 }
81 req->oldidx = bt_filled;
82
83out:
84 kfree(bt, sizeof(uintptr_t) * bt_len);
85 return err;
86}
87