bsd/sys/ktrace.h

   1 /*
   2  * Copyright (c) 2015 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 #ifndef SYS_KTRACE_H
  30 #define SYS_KTRACE_H
  31
  32 #include <stdint.h>
  33
  34 #include <kern/locks.h>
  35
  36 /* The states that ktrace can be in. */
  37 enum ktrace_state {
  38         /* No tool has configured ktrace. */
  39         KTRACE_STATE_OFF = 0,
  40         /* A foreground tool has configured ktrace. */
  41         KTRACE_STATE_FG,
  42         /* A background tool has configured ktrace. */
  43         KTRACE_STATE_BG
  44 };
  45
  46 extern lck_mtx_t *ktrace_lock;
  47
  48 /*
  49  * Subsystems that use ktrace to manage ownership.  These values are passed as
  50  * part of the `*_mask` arguments in `ktrace_configure` and `ktrace_reset`.
  51  */
  52 #define KTRACE_KDEBUG (1 << 0)
  53 #define KTRACE_KPERF  (1 << 1)
  54
  55 /*
  56  * Used by subsystems to inform ktrace that a configuration is occurring.
  57  * Validates whether the current process has privileges to configure
  58  * ktrace.  Pass the subsystem(s) being configured in config_mask.
  59  *
  60  * `ktrace_lock` must be held.
  61  *
  62  * Returns 0 if configuration is allowed, EPERM if process is not privileged,
  63  * and EBUSY if ktrace is owned by another process.
  64  */
  65 int ktrace_configure(uint32_t config_mask);
  66
  67 /*
  68  * Tell ktrace to reset a configuration.  Pass the susbsystem(s) that are to
  69  * be reset in the reset_mask.
  70  *
  71  * `ktrace_lock` must be held.
  72  */
  73 void ktrace_reset(uint32_t reset_mask);
  74
  75 /*
  76  * Determine if the current process can read the configuration of ktrace.
  77  * Only the owning process or a root privileged process is allowed.
  78  *
  79  * `ktrace_lock` must be held.
  80  *
  81  * Returns 0 if allowed, EPERM otherwise.
  82  */
  83 int ktrace_read_check(void);
  84
  85 /*
  86  * With certain boot-args, the kernel can start tracing without user space
  87  * intervention.  With `trace=<n_events>`, the kernel will start tracing at
  88  * boot.  With `trace_wake=<n_events>`, the kernel will start tracing on the
  89  * wake path out of hibernation (on Intel only).
  90  *
  91  * In these cases, ktrace must be aware of the state changes.  This function
  92  * should be called whenever the kernel initiates configuring ktrace.
  93  *
  94  * `ktrace_lock` must be held.
  95  */
  96 void ktrace_kernel_configure(uint32_t config_mask);
  97
  98 /*
  99  * This KPI allows kernel systems to disable ktrace.  ktrace will only be
 100  * disabled if the state matches the provided state_to_match.
 101  *
 102  * This does not reset the configuration of any subsystems -- it just makes
 103  * them stop logging events or sampling data.
 104  *
 105  * `ktrace_lock` must be held.
 106  */
 107 void ktrace_disable(enum ktrace_state state_to_match);
 108
 109 /*
 110  * Returns the pid of the process that owns ktrace.  If ktrace is unowned,
 111  * returns 0.
 112  *
 113  * `ktrace_lock` must be held.
 114  */
 115 int ktrace_get_owning_pid(void);
 116
 117 /*
 118  * Returns true if background tracing is active, false otherwise.
 119  *
 120  * `ktrace_lock` must be held.
 121  */
 122 bool ktrace_background_active(void);
 123
 124 /*
 125  * These functions exist for the transition for kperf to allow blessing other
 126  * processes.  They should not be used by other clients.
 127  */
 128 extern boolean_t ktrace_keep_ownership_on_reset;
 129 extern int ktrace_root_set_owner_allowed;
 130 int ktrace_set_owning_pid(int pid);
 131
 132 /* Initialize ktrace.  Must only be called by the bootstrap thread. */
 133 void ktrace_init(void);
 134
 135 #endif /* SYS_KTRACE_H */