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 #include <os/base.h> 34 #include <kern/locks.h> 35 36 __enum_decl(ktrace_state_t, unsigned int, { 37 /* No tool has configured ktrace. */ 38 KTRACE_STATE_OFF = 0, 39 /* A foreground tool has configured ktrace. */ 40 KTRACE_STATE_FG, 41 /* A background tool has configured ktrace. */ 42 KTRACE_STATE_BG, 43 }); 44 45 void ktrace_lock(void); 46 void ktrace_unlock(void); 47 void ktrace_assert_lock_held(void); 48 void ktrace_start_single_threaded(void); 49 void ktrace_end_single_threaded(void); 50 51 /* 52 * Subsystems that use ktrace to manage ownership. These values are passed as 53 * part of the `*_mask` arguments in `ktrace_configure` and `ktrace_reset`. 54 */ 55 #define KTRACE_KDEBUG (1 << 0) 56 #define KTRACE_KPERF (1 << 1) 57 58 /* 59 * Used by subsystems to inform ktrace that a configuration is occurring. 60 * Validates whether the current process has privileges to configure 61 * ktrace. Pass the subsystem(s) being configured in config_mask. 62 * 63 * `ktrace_lock` must be held. 64 * 65 * Returns 0 if configuration is allowed, EPERM if process is not privileged, 66 * and EBUSY if ktrace is owned by another process. 67 */ 68 int ktrace_configure(uint32_t config_mask); 69 70 /* 71 * Tell ktrace to reset a configuration. Pass the susbsystem(s) that are to 72 * be reset in the reset_mask. 73 * 74 * `ktrace_lock` must be held. 75 */ 76 void ktrace_reset(uint32_t reset_mask); 77 78 /* 79 * Determine if the current process can read the configuration of ktrace. 80 * Only the owning process or a root privileged process is allowed. 81 * 82 * `ktrace_lock` must be held. 83 * 84 * Returns 0 if allowed, EPERM otherwise. 85 */ 86 int ktrace_read_check(void); 87 88 /* 89 * With certain boot-args, the kernel can start tracing without user space 90 * intervention. With `trace=<n_events>`, the kernel will start tracing at 91 * boot. With `trace_wake=<n_events>`, the kernel will start tracing on the 92 * wake path out of hibernation (on Intel only). 93 * 94 * In these cases, ktrace must be aware of the state changes. This function 95 * should be called whenever the kernel initiates configuring ktrace. 96 * 97 * `ktrace_lock` must be held. 98 */ 99 void ktrace_kernel_configure(uint32_t config_mask); 100 101 /* 102 * This KPI allows kernel systems to disable ktrace. ktrace will only be 103 * disabled if the state matches the provided state_to_match. 104 * 105 * This does not reset the configuration of any subsystems -- it just makes 106 * them stop logging events or sampling data. 107 * 108 * `ktrace_lock` must be held. 109 */ 110 void ktrace_disable(ktrace_state_t state_to_match); 111 112 /* 113 * Returns the pid of the process that owns ktrace. If ktrace is unowned, 114 * returns 0. 115 * 116 * `ktrace_lock` must be held. 117 */ 118 int ktrace_get_owning_pid(void); 119 120 /* 121 * Returns true if background tracing is active, false otherwise. 122 * 123 * `ktrace_lock` must be held. 124 */ 125 bool ktrace_background_active(void); 126 127 /* 128 * These functions exist for the transition for kperf to allow blessing other 129 * processes. They should not be used by other clients. 130 */ 131 extern bool ktrace_keep_ownership_on_reset; 132 extern int ktrace_root_set_owner_allowed; 133 int ktrace_set_owning_pid(int pid); 134 135 #endif /* SYS_KTRACE_H */ 136