[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
};

void ktrace_lock(void);
void ktrace_unlock(void);
void ktrace_assert_lock_held(void);
void ktrace_start_single_threaded(void);
void ktrace_end_single_threaded(void);

/*
 * 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 bool 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@
0a7de745	5	*
39037602 A	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.
0a7de745	14	*
39037602 A	15	* Please obtain a copy of the License at
39037602 A	16	* http://www.opensource.apple.com/apsl/ and read it before using this file.
0a7de745	17	*
39037602 A	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.
0a7de745	25	*
39037602 A	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
5ba3f43e A	46	void ktrace_lock(void);
	47	void ktrace_unlock(void);
	48	void ktrace_assert_lock_held(void);
	49	void ktrace_start_single_threaded(void);
	50	void ktrace_end_single_threaded(void);
39037602 A	51
	52	/*
	53	* Subsystems that use ktrace to manage ownership. These values are passed as
	54	* part of the `*_mask` arguments in `ktrace_configure` and `ktrace_reset`.
	55	*/
	56	#define KTRACE_KDEBUG (1 << 0)
	57	#define KTRACE_KPERF (1 << 1)
	58
	59	/*
	60	* Used by subsystems to inform ktrace that a configuration is occurring.
	61	* Validates whether the current process has privileges to configure
	62	* ktrace. Pass the subsystem(s) being configured in config_mask.
	63	*
	64	* `ktrace_lock` must be held.
	65	*
	66	* Returns 0 if configuration is allowed, EPERM if process is not privileged,
	67	* and EBUSY if ktrace is owned by another process.
	68	*/
	69	int ktrace_configure(uint32_t config_mask);
	70
	71	/*
	72	* Tell ktrace to reset a configuration. Pass the susbsystem(s) that are to
	73	* be reset in the reset_mask.
	74	*
	75	* `ktrace_lock` must be held.
	76	*/
	77	void ktrace_reset(uint32_t reset_mask);
	78
	79	/*
	80	* Determine if the current process can read the configuration of ktrace.
	81	* Only the owning process or a root privileged process is allowed.
	82	*
	83	* `ktrace_lock` must be held.
	84	*
	85	* Returns 0 if allowed, EPERM otherwise.
	86	*/
	87	int ktrace_read_check(void);
	88
	89	/*
	90	* With certain boot-args, the kernel can start tracing without user space
	91	* intervention. With `trace=<n_events>`, the kernel will start tracing at
	92	* boot. With `trace_wake=<n_events>`, the kernel will start tracing on the
	93	* wake path out of hibernation (on Intel only).
	94	*
	95	* In these cases, ktrace must be aware of the state changes. This function
	96	* should be called whenever the kernel initiates configuring ktrace.
	97	*
	98	* `ktrace_lock` must be held.
	99	*/
	100	void ktrace_kernel_configure(uint32_t config_mask);
	101
	102	/*
	103	* This KPI allows kernel systems to disable ktrace. ktrace will only be
	104	* disabled if the state matches the provided state_to_match.
	105	*
	106	* This does not reset the configuration of any subsystems -- it just makes
	107	* them stop logging events or sampling data.
	108	*
	109	* `ktrace_lock` must be held.
	110	*/
	111	void ktrace_disable(enum ktrace_state state_to_match);
	112
	113	/*
	114	* Returns the pid of the process that owns ktrace. If ktrace is unowned,
115	* returns 0.
116	*
117	* `ktrace_lock` must be held.
118	*/
119	int ktrace_get_owning_pid(void);
120
121	/*
122	* Returns true if background tracing is active, false otherwise.
123	*
124	* `ktrace_lock` must be held.
125	*/
126	bool ktrace_background_active(void);
127
128	/*
129	* These functions exist for the transition for kperf to allow blessing other
130	* processes. They should not be used by other clients.
131	*/
5ba3f43e	132	extern bool ktrace_keep_ownership_on_reset;
39037602 A	133	extern int ktrace_root_set_owner_allowed;
	134	int ktrace_set_owning_pid(int pid);
	135
	136	/* Initialize ktrace. Must only be called by the bootstrap thread. */
	137	void ktrace_init(void);
	138
	139	#endif /* SYS_KTRACE_H */