usertrace/lttng_usertrace.c

   1
   2 /* LTTng user-space 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 <asm/atomic.h>
  22 #include "lttng_usertrace.h"
  23
  24 #define MAX_TRACES 16
  25
  26 struct ltt_buf {
  27         void *start;
  28         atomic_t        offset;
  29         atomic_t        reserve_count;
  30         atomic_t        commit_count;
  31
  32         atomic_t        events_lost;
  33 };
  34
  35 struct lttng_trace_info {
  36         int     active:1;
  37         struct {
  38                 struct ltt_buf facilities;
  39                 struct ltt_buf cpu;
  40         } channel;
  41 };
  42
  43
  44 /* TLS for the trace info */
  45 /* http://www.dis.com/gnu/gcc/C--98-Thread-Local-Edits.html
  46  *
  47  * Add after paragraph 4
  48  *
  49  *     The storage for an object of thread storage duration shall be statically
  50  *     initialized before the first statement of the thread startup function. An
  51  *     object of thread storage duration shall not require dynamic
  52  *     initialization.
  53  * GCC extention permits init of a range.
  54  */
  55
  56 static __thread struct lttng_trace_info lttng_trace_info[MAX_TRACES] =
  57 {       [ 0 ... MAX_TRACES-1 ].active = 0,
  58         [ 0 ... MAX_TRACES-1 ].channel =
  59                 { NULL,
  60                         ATOMIC_INIT(0),
  61                         ATOMIC_INIT(0),
  62                         ATOMIC_INIT(0),
  63                         ATOMIC_INIT(0),
  64                         ATOMIC_INIT(0)
  65                 }
  66 };
  67
  68 /* signal handler */
  69 void __lttng_sig_trace_handler(int signo)
  70 {
  71         int ret;
  72         sigset_t set, oldset;
  73
  74   printf("LTTng signal handler : thread id : %lu, pid %lu\n", pthread_self(), getpid());
  75 #if 0
  76         /* Disable signals */
  77         ret = sigfillset(&set);
  78         if(ret) {
  79                 printf("Error in sigfillset\n");
  80                 exit(1);
  81         }
  82
  83         ret = sigprocmask(SIG_BLOCK, &set, &oldset);
  84         if(ret) {
  85                 printf("Error in sigprocmask\n");
  86                 exit(1);
  87         }
  88 #endif //0
  89         /* Get all the new traces */
  90 #if 0
  91         do {
  92                 /* FIXME : allocate the trace structure somewhere : thread private */
  93                 ret = ltt_update(addr, &active, &filter);
  94
  95                 if(ret) {
  96                         printf("Error in ltt_update system call\n");
  97                         exit(1);
  98                 }
  99         } while(addr);
 100
 101 #endif //0
 102
 103 #if 0
 104         /* Enable signals */
 105         ret = sigprocmask(SIG_SETMASK, &oldset, NULL);
 106         if(ret) {
 107                 printf("Error in sigprocmask\n");
 108                 exit(1);
 109         }
 110 #endif //0
 111 }
 112
 113
 114 static void thread_init(void)
 115 {
 116         int err;
 117
 118         /* TEST */
 119         err = ltt_switch((unsigned long)NULL);
 120         if(err) {
 121                 printf("Error in ltt_switch system call\n");
 122                 exit(1);
 123         }
 124
 125         /* Make the first ltt_update system call */
 126         err = ltt_update(1, NULL, NULL);
 127         if(err) {
 128                 printf("Error in ltt_update system call\n");
 129                 exit(1);
 130         }
 131
 132         /* Make some ltt_switch syscalls */
 133         err = ltt_switch((unsigned long)NULL);
 134         if(err) {
 135                 printf("Error in ltt_switch system call\n");
 136                 exit(1);
 137         }
 138 }
 139
 140 void __attribute__((constructor)) __lttng_user_init(void)
 141 {
 142         static struct sigaction act;
 143         int err;
 144
 145   printf("LTTng user init\n");
 146
 147         /* Activate the signal */
 148         act.sa_handler = __lttng_sig_trace_handler;
 149         err = sigemptyset(&(act.sa_mask));
 150         if(err) perror("Error with sigemptyset");
 151         err = sigaddset(&(act.sa_mask), SIGRTMIN+3);
 152         if(err) perror("Error with sigaddset");
 153         err = sigaction(SIGRTMIN+3, &act, NULL);
 154         if(err) perror("Error with sigaction");
 155
 156         thread_init();
 157 }
 158
 159
 160 void lttng_thread_init(void)
 161 {
 162         thread_init();
 163 }
 164
 165
 166
 167
 168