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
 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
 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
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
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  }