1 /*
2 * Copyright (c) 2011 Apple 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 <mach/mach_types.h>
30
31 #include <kern/host.h>
32 #include <kern/thread.h>
33 #include <kern/task.h>
34 #include <kern/extmod_statistics.h>
35 #include <libkern/OSAtomic.h>
36
37 #include <uuid/uuid.h>
38
39 /*
40 * This code module adds statistics to track when
41 * a userspace task is modified by another userspace
42 * task. This can facilitate triage of crashes
43 * and abberant behavior, which are not expected
44 * to occur when the program is running in its
45 * qualified environment.
46 *
47 * We assume the target task has a lifecycle lock
48 * that will prevent it from exiting
49 * (task_reference/task_reference_internal), which
50 * should be called either explicitly, or implicitly
51 * via MIG glue code (convert_port_to_task).
52 *
53 * Host-wide statistics don't asssume any locks are
54 * held, and use atomic operations.
55 *
56 * If we can detect that the kernel proper is
57 * performing these operations, don't count
58 * it as an external modification. Some of the
59 * external modification routines are called
60 * by the kernel during thread setup, in which
61 * case we rename the userspace entrypoint called
62 * by the MIG demuxer to have a "_from_user" suffix.
63 */
64
65 /* externs for BSD kernel */
66 extern void fslog_extmod_msgtracer(void *, void *);
67
68 /* local routines */
69 static void
70 extmod_statistics_log(task_t current_task, task_t target);
71
72 void
extmod_statistics_incr_task_for_pid(task_t target)73 extmod_statistics_incr_task_for_pid(task_t target)
74 {
75 task_t ctask = current_task();
76
77 if ((ctask == kernel_task) || (target == TASK_NULL)) {
78 return;
79 }
80
81 if (target != ctask) {
82 ctask->extmod_statistics.task_for_pid_caller_count++;
83 target->extmod_statistics.task_for_pid_count++;
84 OSIncrementAtomic64(&host_extmod_statistics.task_for_pid_count);
85 }
86 }
87
88 void
extmod_statistics_incr_thread_set_state(thread_t target)89 extmod_statistics_incr_thread_set_state(thread_t target)
90 {
91 task_t ctask = current_task();
92 task_t ttask;
93
94 if ((ctask == kernel_task) || (target == THREAD_NULL)) {
95 return;
96 }
97
98 ttask = get_threadtask(target);
99
100 if (ttask == TASK_NULL) {
101 return;
102 }
103
104 if (ttask != ctask) {
105 ctask->extmod_statistics.thread_set_state_caller_count++;
106 ttask->extmod_statistics.thread_set_state_count++;
107 OSIncrementAtomic64(&host_extmod_statistics.thread_set_state_count);
108 }
109 }
110
111 void
extmod_statistics_incr_thread_create(task_t target)112 extmod_statistics_incr_thread_create(task_t target)
113 {
114 task_t ctask = current_task();
115
116 if ((ctask == kernel_task) || (target == TASK_NULL)) {
117 return;
118 }
119
120 if (target != ctask) {
121 ctask->extmod_statistics.thread_creation_caller_count++;
122 target->extmod_statistics.thread_creation_count++;
123 OSIncrementAtomic64(&host_extmod_statistics.thread_creation_count);
124
125 extmod_statistics_log(ctask, target);
126 }
127 }
128
129 static void
extmod_statistics_log(task_t current_task,task_t target)130 extmod_statistics_log(task_t current_task, task_t target)
131 {
132 void *c_proc;
133 void *t_proc;
134
135 c_proc = get_bsdtask_info(current_task);
136 t_proc = get_bsdtask_info(target);
137 if (c_proc && t_proc) {
138 fslog_extmod_msgtracer(c_proc, t_proc);
139 }
140 }
141