| 1 | /* |
| 2 | * SPDX-License-Identifier: LGPL-2.1-only |
| 3 | * |
| 4 | * Copyright (C) 2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 5 | */ |
| 6 | |
| 7 | #define _LGPL_SOURCE |
| 8 | #include <error.h> |
| 9 | #include <dlfcn.h> |
| 10 | #include <stdlib.h> |
| 11 | #include <stdint.h> |
| 12 | #include <usterr-signal-safe.h> |
| 13 | #include <lttng/ust-clock.h> |
| 14 | #include <urcu/system.h> |
| 15 | #include <urcu/arch.h> |
| 16 | |
| 17 | #include "clock.h" |
| 18 | #include "getenv.h" |
| 19 | |
| 20 | struct lttng_trace_clock *lttng_trace_clock; |
| 21 | |
| 22 | static |
| 23 | struct lttng_trace_clock user_tc; |
| 24 | |
| 25 | static |
| 26 | void *clock_handle; |
| 27 | |
| 28 | int lttng_ust_trace_clock_set_read64_cb(uint64_t (*read64)(void)) |
| 29 | { |
| 30 | if (CMM_LOAD_SHARED(lttng_trace_clock)) |
| 31 | return -EBUSY; |
| 32 | user_tc.read64 = read64; |
| 33 | return 0; |
| 34 | } |
| 35 | |
| 36 | int lttng_ust_trace_clock_set_freq_cb(uint64_t (*freq)(void)) |
| 37 | { |
| 38 | if (CMM_LOAD_SHARED(lttng_trace_clock)) |
| 39 | return -EBUSY; |
| 40 | user_tc.freq = freq; |
| 41 | return 0; |
| 42 | } |
| 43 | |
| 44 | int lttng_ust_trace_clock_set_uuid_cb(int (*uuid)(char *uuid)) |
| 45 | { |
| 46 | if (CMM_LOAD_SHARED(lttng_trace_clock)) |
| 47 | return -EBUSY; |
| 48 | user_tc.uuid = uuid; |
| 49 | return 0; |
| 50 | } |
| 51 | |
| 52 | int lttng_ust_trace_clock_set_name_cb(const char *(*name)(void)) |
| 53 | { |
| 54 | if (CMM_LOAD_SHARED(lttng_trace_clock)) |
| 55 | return -EBUSY; |
| 56 | user_tc.name = name; |
| 57 | return 0; |
| 58 | } |
| 59 | |
| 60 | int lttng_ust_trace_clock_set_description_cb(const char *(*description)(void)) |
| 61 | { |
| 62 | if (CMM_LOAD_SHARED(lttng_trace_clock)) |
| 63 | return -EBUSY; |
| 64 | user_tc.description = description; |
| 65 | return 0; |
| 66 | } |
| 67 | |
| 68 | int lttng_ust_enable_trace_clock_override(void) |
| 69 | { |
| 70 | if (CMM_LOAD_SHARED(lttng_trace_clock)) |
| 71 | return -EBUSY; |
| 72 | if (!user_tc.read64) |
| 73 | return -EINVAL; |
| 74 | if (!user_tc.freq) |
| 75 | return -EINVAL; |
| 76 | if (!user_tc.name) |
| 77 | return -EINVAL; |
| 78 | if (!user_tc.description) |
| 79 | return -EINVAL; |
| 80 | /* Use default uuid cb when NULL */ |
| 81 | cmm_smp_mb(); /* Store callbacks before trace clock */ |
| 82 | CMM_STORE_SHARED(lttng_trace_clock, &user_tc); |
| 83 | return 0; |
| 84 | } |
| 85 | |
| 86 | void lttng_ust_clock_init(void) |
| 87 | { |
| 88 | const char *libname; |
| 89 | void (*libinit)(void); |
| 90 | |
| 91 | if (clock_handle) |
| 92 | return; |
| 93 | libname = lttng_getenv("LTTNG_UST_CLOCK_PLUGIN"); |
| 94 | if (!libname) |
| 95 | return; |
| 96 | clock_handle = dlopen(libname, RTLD_NOW); |
| 97 | if (!clock_handle) { |
| 98 | PERROR("Cannot load LTTng UST clock override library %s", |
| 99 | libname); |
| 100 | return; |
| 101 | } |
| 102 | dlerror(); |
| 103 | libinit = (void (*)(void)) dlsym(clock_handle, |
| 104 | "lttng_ust_clock_plugin_init"); |
| 105 | if (!libinit) { |
| 106 | PERROR("Cannot find LTTng UST clock override library %s initialization function lttng_ust_clock_plugin_init()", |
| 107 | libname); |
| 108 | return; |
| 109 | } |
| 110 | libinit(); |
| 111 | } |