+++ /dev/null
-/*
- * SPDX-License-Identifier: LGPL-2.1-only
- *
- * Copyright (C) 2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- */
-
-#define _LGPL_SOURCE
-#include <error.h>
-#include <dlfcn.h>
-#include <stdlib.h>
-#include <stdint.h>
-#include <stdio.h>
-#include <usterr-signal-safe.h>
-#include <lttng/ust-clock.h>
-#include <urcu/system.h>
-#include <urcu/arch.h>
-
-#include "clock.h"
-#include "getenv.h"
-
-struct lttng_ust_trace_clock *lttng_ust_trace_clock;
-
-static
-struct lttng_ust_trace_clock user_tc;
-
-static
-void *clock_handle;
-
-static
-uint64_t trace_clock_freq_monotonic(void)
-{
- return 1000000000ULL;
-}
-
-static
-int trace_clock_uuid_monotonic(char *uuid)
-{
- int ret = 0;
- size_t len;
- FILE *fp;
-
- /*
- * boot_id needs to be read once before being used concurrently
- * to deal with a Linux kernel race. A fix is proposed for
- * upstream, but the work-around is needed for older kernels.
- */
- fp = fopen("/proc/sys/kernel/random/boot_id", "r");
- if (!fp) {
- return -ENOENT;
- }
- len = fread(uuid, 1, LTTNG_UST_UUID_STR_LEN - 1, fp);
- if (len < LTTNG_UST_UUID_STR_LEN - 1) {
- ret = -EINVAL;
- goto end;
- }
- uuid[LTTNG_UST_UUID_STR_LEN - 1] = '\0';
-end:
- fclose(fp);
- return ret;
-}
-
-static
-const char *trace_clock_name_monotonic(void)
-{
- return "monotonic";
-}
-
-static
-const char *trace_clock_description_monotonic(void)
-{
- return "Monotonic Clock";
-}
-
-int lttng_ust_trace_clock_set_read64_cb(lttng_ust_clock_read64_function read64_cb)
-{
- if (CMM_LOAD_SHARED(lttng_ust_trace_clock))
- return -EBUSY;
- user_tc.read64 = read64_cb;
- return 0;
-}
-
-int lttng_ust_trace_clock_get_read64_cb(lttng_ust_clock_read64_function *read64_cb)
-{
- struct lttng_ust_trace_clock *ltc = CMM_LOAD_SHARED(lttng_ust_trace_clock);
-
- if (caa_likely(!ltc)) {
- *read64_cb = &trace_clock_read64_monotonic;
- } else {
- cmm_read_barrier_depends(); /* load ltc before content */
- *read64_cb = ltc->read64;
- }
- return 0;
-}
-
-int lttng_ust_trace_clock_set_freq_cb(lttng_ust_clock_freq_function freq_cb)
-{
- if (CMM_LOAD_SHARED(lttng_ust_trace_clock))
- return -EBUSY;
- user_tc.freq = freq_cb;
- return 0;
-}
-
-int lttng_ust_trace_clock_get_freq_cb(lttng_ust_clock_freq_function *freq_cb)
-{
- struct lttng_ust_trace_clock *ltc = CMM_LOAD_SHARED(lttng_ust_trace_clock);
-
- if (caa_likely(!ltc)) {
- *freq_cb = &trace_clock_freq_monotonic;
- } else {
- cmm_read_barrier_depends(); /* load ltc before content */
- *freq_cb = ltc->freq;
- }
- return 0;
-}
-
-int lttng_ust_trace_clock_set_uuid_cb(lttng_ust_clock_uuid_function uuid_cb)
-{
- if (CMM_LOAD_SHARED(lttng_ust_trace_clock))
- return -EBUSY;
- user_tc.uuid = uuid_cb;
- return 0;
-}
-
-int lttng_ust_trace_clock_get_uuid_cb(lttng_ust_clock_uuid_function *uuid_cb)
-{
- struct lttng_ust_trace_clock *ltc = CMM_LOAD_SHARED(lttng_ust_trace_clock);
-
- if (caa_likely(!ltc)) {
- *uuid_cb = &trace_clock_uuid_monotonic;
- } else {
- cmm_read_barrier_depends(); /* load ltc before content */
- *uuid_cb = ltc->uuid;
- }
- return 0;
-}
-
-int lttng_ust_trace_clock_set_name_cb(lttng_ust_clock_name_function name_cb)
-{
- if (CMM_LOAD_SHARED(lttng_ust_trace_clock))
- return -EBUSY;
- user_tc.name = name_cb;
- return 0;
-}
-
-int lttng_ust_trace_clock_get_name_cb(lttng_ust_clock_name_function *name_cb)
-{
- struct lttng_ust_trace_clock *ltc = CMM_LOAD_SHARED(lttng_ust_trace_clock);
-
- if (caa_likely(!ltc)) {
- *name_cb = &trace_clock_name_monotonic;
- } else {
- cmm_read_barrier_depends(); /* load ltc before content */
- *name_cb = ltc->name;
- }
- return 0;
-}
-
-int lttng_ust_trace_clock_set_description_cb(lttng_ust_clock_description_function description_cb)
-{
- if (CMM_LOAD_SHARED(lttng_ust_trace_clock))
- return -EBUSY;
- user_tc.description = description_cb;
- return 0;
-}
-
-int lttng_ust_trace_clock_get_description_cb(lttng_ust_clock_description_function *description_cb)
-{
- struct lttng_ust_trace_clock *ltc = CMM_LOAD_SHARED(lttng_ust_trace_clock);
-
- if (caa_likely(!ltc)) {
- *description_cb = &trace_clock_description_monotonic;
- } else {
- cmm_read_barrier_depends(); /* load ltc before content */
- *description_cb = ltc->description;
- }
- return 0;
-}
-
-int lttng_ust_enable_trace_clock_override(void)
-{
- if (CMM_LOAD_SHARED(lttng_ust_trace_clock))
- return -EBUSY;
- if (!user_tc.read64)
- return -EINVAL;
- if (!user_tc.freq)
- return -EINVAL;
- if (!user_tc.name)
- return -EINVAL;
- if (!user_tc.description)
- return -EINVAL;
- /* Use default uuid cb when NULL */
- cmm_smp_mb(); /* Store callbacks before trace clock */
- CMM_STORE_SHARED(lttng_ust_trace_clock, &user_tc);
- return 0;
-}
-
-void lttng_ust_clock_init(void)
-{
- const char *libname;
- void (*libinit)(void);
-
- if (clock_handle)
- return;
- libname = lttng_ust_getenv("LTTNG_UST_CLOCK_PLUGIN");
- if (!libname)
- return;
- clock_handle = dlopen(libname, RTLD_NOW);
- if (!clock_handle) {
- PERROR("Cannot load LTTng UST clock override library %s",
- libname);
- return;
- }
- dlerror();
- libinit = (void (*)(void)) dlsym(clock_handle,
- "lttng_ust_clock_plugin_init");
- if (!libinit) {
- PERROR("Cannot find LTTng UST clock override library %s initialization function lttng_ust_clock_plugin_init()",
- libname);
- return;
- }
- libinit();
-}
projects / lttng-ust.git / blobdiff