[apple/xnu.git] / bsd / sys / ktrace.h

/*
 * Copyright (c) 2015 Apple 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@
 */

#ifndef SYS_KTRACE_H
#define SYS_KTRACE_H

#include <stdint.h>

#include <kern/locks.h>

/* The states that ktrace can be in. */
enum ktrace_state {
	/* No tool has configured ktrace. */
	KTRACE_STATE_OFF = 0,
	/* A foreground tool has configured ktrace. */
	KTRACE_STATE_FG,
	/* A background tool has configured ktrace. */
	KTRACE_STATE_BG
};

extern lck_mtx_t *ktrace_lock;

/*
 * Subsystems that use ktrace to manage ownership.  These values are passed as
 * part of the `*_mask` arguments in `ktrace_configure` and `ktrace_reset`.
 */
#define KTRACE_KDEBUG (1 << 0)
#define KTRACE_KPERF  (1 << 1)

/*
 * Used by subsystems to inform ktrace that a configuration is occurring.
 * Validates whether the current process has privileges to configure
 * ktrace.  Pass the subsystem(s) being configured in config_mask.
 *
 * `ktrace_lock` must be held.
 *
 * Returns 0 if configuration is allowed, EPERM if process is not privileged,
 * and EBUSY if ktrace is owned by another process.
 */
int ktrace_configure(uint32_t config_mask);

/*
 * Tell ktrace to reset a configuration.  Pass the susbsystem(s) that are to
 * be reset in the reset_mask.
 *
 * `ktrace_lock` must be held.
 */
void ktrace_reset(uint32_t reset_mask);

/*
 * Determine if the current process can read the configuration of ktrace.
 * Only the owning process or a root privileged process is allowed.
 *
 * `ktrace_lock` must be held.
 *
 * Returns 0 if allowed, EPERM otherwise.
 */
int ktrace_read_check(void);

/*
 * With certain boot-args, the kernel can start tracing without user space
 * intervention.  With `trace=<n_events>`, the kernel will start tracing at
 * boot.  With `trace_wake=<n_events>`, the kernel will start tracing on the
 * wake path out of hibernation (on Intel only).
 *
 * In these cases, ktrace must be aware of the state changes.  This function
 * should be called whenever the kernel initiates configuring ktrace.
 *
 * `ktrace_lock` must be held.
 */
void ktrace_kernel_configure(uint32_t config_mask);

/*
 * This KPI allows kernel systems to disable ktrace.  ktrace will only be
 * disabled if the state matches the provided state_to_match.
 *
 * This does not reset the configuration of any subsystems -- it just makes
 * them stop logging events or sampling data.
 *
 * `ktrace_lock` must be held.
 */
void ktrace_disable(enum ktrace_state state_to_match);

/*
 * Returns the pid of the process that owns ktrace.  If ktrace is unowned,
 * returns 0.
 *
 * `ktrace_lock` must be held.
 */
int ktrace_get_owning_pid(void);

/*
 * Returns true if background tracing is active, false otherwise.
 *
 * `ktrace_lock` must be held.
 */
bool ktrace_background_active(void);

/*
 * These functions exist for the transition for kperf to allow blessing other
 * processes.  They should not be used by other clients.
 */
extern boolean_t ktrace_keep_ownership_on_reset;
extern int ktrace_root_set_owner_allowed;
int ktrace_set_owning_pid(int pid);

/* Initialize ktrace.  Must only be called by the bootstrap thread. */
void ktrace_init(void);

#endif /* SYS_KTRACE_H */
Commit	Line	Data
39037602 A	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 */