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 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); 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 */ 132 extern bool ktrace_keep_ownership_on_reset; 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 */ 140