| 1 | /* |
| 2 | * lttng-clock-override-example.c |
| 3 | * |
| 4 | * Copyright (c) 2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 5 | * |
| 6 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
| 7 | * of this software and associated documentation files (the "Software"), to deal |
| 8 | * in the Software without restriction, including without limitation the rights |
| 9 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| 10 | * copies of the Software, and to permit persons to whom the Software is |
| 11 | * furnished to do so, subject to the following conditions: |
| 12 | * |
| 13 | * The above copyright notice and this permission notice shall be included in |
| 14 | * all copies or substantial portions of the Software. |
| 15 | * |
| 16 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| 17 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 18 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| 19 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| 20 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| 21 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
| 22 | * SOFTWARE. |
| 23 | */ |
| 24 | |
| 25 | #include <stdlib.h> |
| 26 | #include <time.h> |
| 27 | #include <string.h> |
| 28 | #include <stdio.h> |
| 29 | #include <lttng/ust-clock.h> |
| 30 | |
| 31 | static |
| 32 | uint64_t plugin_read64(void) |
| 33 | { |
| 34 | struct timespec ts; |
| 35 | |
| 36 | clock_gettime(CLOCK_MONOTONIC, &ts); |
| 37 | /* |
| 38 | * This is a rather dumb example, but it illustrates the plugin |
| 39 | * mechanism: we take the monotonic clock, and transform it into |
| 40 | * a very coarse clock, which increment only at 1KHz frequency. |
| 41 | */ |
| 42 | return ((uint64_t) ts.tv_sec * 1000ULL) + (ts.tv_nsec / 1000000ULL); |
| 43 | } |
| 44 | |
| 45 | static |
| 46 | uint64_t plugin_freq(void) |
| 47 | { |
| 48 | return 1000; /* 1KHz clock (very coarse!) */ |
| 49 | } |
| 50 | |
| 51 | static |
| 52 | int plugin_uuid(char *uuid) |
| 53 | { |
| 54 | const char myuuid[] = "123456789012345678901234567890123456"; |
| 55 | |
| 56 | /* |
| 57 | * Should read some unique identifier for this clock shared |
| 58 | * across all components of the system using this clock for |
| 59 | * tracing. |
| 60 | */ |
| 61 | memcpy(uuid, myuuid, LTTNG_UST_UUID_STR_LEN); |
| 62 | return 0; |
| 63 | } |
| 64 | |
| 65 | static |
| 66 | const char *plugin_name(void) |
| 67 | { |
| 68 | return "my_example_clock"; |
| 69 | } |
| 70 | |
| 71 | static |
| 72 | const char *plugin_description(void) |
| 73 | { |
| 74 | return "Coarse monotonic clock at 1KHz"; |
| 75 | } |
| 76 | |
| 77 | void lttng_ust_clock_plugin_init(void) |
| 78 | { |
| 79 | int ret; |
| 80 | |
| 81 | ret = lttng_ust_trace_clock_set_read64_cb(plugin_read64); |
| 82 | if (ret) { |
| 83 | fprintf(stderr, "Error setting clock override read64 callback: %s\n", |
| 84 | strerror(-ret)); |
| 85 | goto error; |
| 86 | } |
| 87 | ret = lttng_ust_trace_clock_set_freq_cb(plugin_freq); |
| 88 | if (ret) { |
| 89 | fprintf(stderr, "Error setting clock override freq callback: %s\n", |
| 90 | strerror(-ret)); |
| 91 | goto error; |
| 92 | } |
| 93 | ret = lttng_ust_trace_clock_set_uuid_cb(plugin_uuid); |
| 94 | if (ret) { |
| 95 | fprintf(stderr, "Error setting clock override uuid callback: %s\n", |
| 96 | strerror(-ret)); |
| 97 | goto error; |
| 98 | } |
| 99 | |
| 100 | ret = lttng_ust_trace_clock_set_name_cb(plugin_name); |
| 101 | if (ret) { |
| 102 | fprintf(stderr, "Error setting clock override name callback: %s\n", |
| 103 | strerror(-ret)); |
| 104 | goto error; |
| 105 | } |
| 106 | |
| 107 | ret = lttng_ust_trace_clock_set_description_cb(plugin_description); |
| 108 | if (ret) { |
| 109 | fprintf(stderr, "Error setting clock override description callback: %s\n", |
| 110 | strerror(-ret)); |
| 111 | goto error; |
| 112 | } |
| 113 | |
| 114 | ret = lttng_ust_enable_trace_clock_override(); |
| 115 | if (ret) { |
| 116 | fprintf(stderr, "Error enabling clock override: %s\n", |
| 117 | strerror(-ret)); |
| 118 | goto error; |
| 119 | } |
| 120 | |
| 121 | return; |
| 122 | |
| 123 | error: |
| 124 | exit(EXIT_FAILURE); |
| 125 | } |