| 1 | /* |
| 2 | * Copyright (C) 2010 Pierre-Marc Fournier |
| 3 | * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 4 | * |
| 5 | * This library is free software; you can redistribute it and/or |
| 6 | * modify it under the terms of the GNU Lesser General Public |
| 7 | * License as published by the Free Software Foundation; version 2.1 of |
| 8 | * the License. |
| 9 | * |
| 10 | * This library is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | * Lesser General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU Lesser General Public |
| 16 | * License along with this library; if not, write to the Free Software |
| 17 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 18 | */ |
| 19 | |
| 20 | #ifndef _UST_CLOCK_H |
| 21 | #define _UST_CLOCK_H |
| 22 | |
| 23 | #include <time.h> |
| 24 | #include <sys/time.h> |
| 25 | #include <stdint.h> |
| 26 | #include <stddef.h> |
| 27 | #include <stdio.h> |
| 28 | #include "lttng-ust-uuid.h" |
| 29 | |
| 30 | /* TRACE CLOCK */ |
| 31 | |
| 32 | /* |
| 33 | * Currently using the kernel MONOTONIC clock, waiting for kernel-side |
| 34 | * LTTng to implement mmap'd trace clock. |
| 35 | */ |
| 36 | |
| 37 | /* Choosing correct trace clock */ |
| 38 | |
| 39 | static __inline__ |
| 40 | uint64_t trace_clock_read64(void) |
| 41 | { |
| 42 | struct timespec ts; |
| 43 | |
| 44 | clock_gettime(CLOCK_MONOTONIC, &ts); |
| 45 | return ((uint64_t) ts.tv_sec * 1000000000ULL) + ts.tv_nsec; |
| 46 | } |
| 47 | |
| 48 | static __inline__ |
| 49 | uint64_t trace_clock_freq(void) |
| 50 | { |
| 51 | return 1000000000ULL; |
| 52 | } |
| 53 | |
| 54 | static __inline__ |
| 55 | int trace_clock_uuid(char *uuid) |
| 56 | { |
| 57 | int ret = 0; |
| 58 | size_t len; |
| 59 | FILE *fp; |
| 60 | |
| 61 | /* |
| 62 | * boot_id needs to be read once before being used concurrently |
| 63 | * to deal with a Linux kernel race. A fix is proposed for |
| 64 | * upstream, but the work-around is needed for older kernels. |
| 65 | */ |
| 66 | fp = fopen("/proc/sys/kernel/random/boot_id", "r"); |
| 67 | if (!fp) { |
| 68 | return -ENOENT; |
| 69 | } |
| 70 | len = fread(uuid, 1, LTTNG_UST_UUID_STR_LEN - 1, fp); |
| 71 | if (len < LTTNG_UST_UUID_STR_LEN - 1) { |
| 72 | ret = -EINVAL; |
| 73 | goto end; |
| 74 | } |
| 75 | uuid[LTTNG_UST_UUID_STR_LEN - 1] = '\0'; |
| 76 | end: |
| 77 | fclose(fp); |
| 78 | return ret; |
| 79 | } |
| 80 | |
| 81 | #endif /* _UST_CLOCK_H */ |