usertrace-fast/ltt-usertrace-fast.c

   1
   2 /* LTTng user-space "fast" tracing code
   3  *
   4  * Copyright 2006 Mathieu Desnoyers
   5  *
   6  */
   7
   8
   9 #include <sys/types.h>
  10 #include <sys/wait.h>
  11 #include <unistd.h>
  12 #include <stdlib.h>
  13 #include <stdio.h>
  14 #include <signal.h>
  15 #include <syscall.h>
  16 #include <features.h>
  17 #include <pthread.h>
  18 #include <malloc.h>
  19 #include <string.h>
  20
  21 #include "ltt-usertrace-fast.h"
  22
  23 /* TLS for the trace buffer
  24  * http://www.dis.com/gnu/gcc/C--98-Thread-Local-Edits.html
  25  *
  26  * Add after paragraph 4
  27  *
  28  *     The storage for an object of thread storage duration shall be statically
  29  *     initialized before the first statement of the thread startup function. An
  30  *     object of thread storage duration shall not require dynamic
  31  *     initialization.
  32  */
  33
  34 __thread struct lttng_trace_info lttng_trace_info =
  35 {
  36         .init = 0,
  37         .filter = 0,
  38         .nesting = ATOMIC_INIT(0),
  39         .channel.facilities =
  40                 {       ATOMIC_INIT(0),
  41                         ATOMIC_INIT(0),
  42                         ATOMIC_INIT(0),
  43                         ATOMIC_INIT(0)
  44                 },
  45         .channel.cpu =
  46                 { ATOMIC_INIT(0),
  47                         ATOMIC_INIT(0),
  48                         ATOMIC_INIT(0),
  49                         ATOMIC_INIT(0)
  50                 },
  51 };
  52
  53
  54 static void ltt_cleanup_thread(void *arg)
  55 {
  56         /* Flush the data in the lttng_trace_info */
  57
  58 }
  59
  60
  61 void ltt_thread_init(void)
  62 {
  63         _pthread_cleanup_push(&lttng_trace_info.cleanup,
  64                         ltt_cleanup_thread, NULL);
  65 }
  66
  67
  68 void __attribute__((constructor)) __ltt_usertrace_fast_init(void)
  69 {
  70         int err;
  71
  72   printf("LTTng usertrace-fast init\n");
  73
  74         ltt_thread_init();
  75
  76 }
  77