+++ /dev/null
-
-/* LTTng user-space tracing code
- *
- * Copyright 2006 Mathieu Desnoyers
- *
- */
-
-
-#include <sys/types.h>
-#include <sys/wait.h>
-#include <unistd.h>
-#include <stdlib.h>
-#include <stdio.h>
-#include <signal.h>
-#include <syscall.h>
-#include <features.h>
-#include <pthread.h>
-#include <malloc.h>
-#include <string.h>
-
-#include "lttng_usertrace.h"
-
-#define MAX_TRACES 16
-
-
-/*
- * Notes :
- *
- * ltt_update :
- *
- * it should send the information on the traces that has their status MODIFIED.
- * It's a necessary assumption to have a correct lttng_free_trace_info, which
- * would not be reentrant otherwise.
- */
-
-
-/* TLS for the trace info
- * http://www.dis.com/gnu/gcc/C--98-Thread-Local-Edits.html
- *
- * Add after paragraph 4
- *
- * The storage for an object of thread storage duration shall be statically
- * initialized before the first statement of the thread startup function. An
- * object of thread storage duration shall not require dynamic
- * initialization.
- * GCC extention permits init of a range.
- */
-
-static __thread struct lttng_trace_info lttng_trace_info[MAX_TRACES] =
-{ [ 0 ... MAX_TRACES-1 ].active = 0,
- [ 0 ... MAX_TRACES-1 ].filter = 0,
- [ 0 ... MAX_TRACES-1 ].destroy = 0,
- [ 0 ... MAX_TRACES-1 ].nesting = ATOMIC_INIT(0),
- [ 0 ... MAX_TRACES-1 ].channel =
- { NULL,
- 0,
- ATOMIC_INIT(0),
- ATOMIC_INIT(0),
- ATOMIC_INIT(0),
- ATOMIC_INIT(0),
- ATOMIC_INIT(0)
- }
-};
-
-
-/* Must be called we sure nobody else is using the info.
- * It implies that the trace should have been previously stopped
- * and that every writer has finished.
- *
- * Writers should always check if the trace must be destroyed when they
- * finish writing and the nesting level is 0.
- */
-void lttng_free_trace_info(struct lttng_trace_info *info)
-{
- int ret;
-
- if(info->active) {
- printf(
- "LTTng ERROR : lttng_free_trace_info should be called on inactive trace\n");
- exit(1);
- }
- if(!info->destroy) {
- printf(
- "LTTng ERROR : lttng_free_trace_info should be called on destroyed trace\n");
- exit(1);
- }
- if(atomic_read(&info->nesting) > 0) {
- printf(
- "LTTng ERROR : lttng_free_trace_info should not be nested on tracing\n");
- exit(1);
- }
-
- /* Remove the maps */
- ret = munmap(info->channel.cpu.start, info->channel.cpu.length);
- if(ret) {
- perror("LTTNG : error in munmap");
- }
- ret = munmap(info->channel.facilities.start, info->channel.facilities.length);
- if(ret) {
- perror("LTTNG : error in munmap");
- }
-
- /* Zero the structure */
- memset(info, 0, sizeof(struct lttng_trace_info));
-}
-
-
-static struct lttng_trace_info* find_info(unsigned long cpu_addr,
- unsigned long fac_addr, unsigned int *first_empty)
-{
- struct lttng_trace_info *found = NULL;
- unsigned int i;
-
- *first_empty = MAX_TRACES;
-
- /* Try to find the trace */
- for(i=0;i<MAX_TRACES;i++) {
- if(i<*first_empty && !lttng_trace_info[i].channel.cpu.start)
- *first_empty = i;
- if(cpu_addr ==
- (unsigned long)lttng_trace_info[i].channel.cpu.start &&
- fac_addr ==
- (unsigned long)lttng_trace_info[i].channel.facilities.start) {
- /* Found */
- found = <tng_trace_info[i];
- break;
- }
- }
- return found;
-}
-
-
-static void lttng_get_new_info(void)
-{
- unsigned long cpu_addr, fac_addr;
- unsigned int i, first_empty;
- int active, filter, destroy;
- int ret;
- struct lttng_trace_info *info;
- sigset_t set, oldset;
-
- /* Disable signals */
- ret = sigfillset(&set);
- if(ret) {
- printf("Error in sigfillset\n");
- exit(1);
- }
-
- ret = pthread_sigmask(SIG_BLOCK, &set, &oldset);
- if(ret) {
- printf("Error in sigprocmask\n");
- exit(1);
- }
-
- /* Get all the new traces */
- while(1) {
- cpu_addr = fac_addr = 0;
- active = filter = destroy = 0;
- ret = ltt_update(&cpu_addr, &fac_addr, &active, &filter, &destroy);
- if(ret) {
- printf("LTTng : error in ltt_update\n");
- exit(1);
- }
-
- if(!cpu_addr || !fac_addr) break;
-
- info = find_info(cpu_addr, fac_addr, &first_empty);
- if(info) {
- info->filter = filter;
- info->active = active;
- info->destroy = destroy;
- if(destroy && !atomic_read(&info->nesting))
- lttng_free_trace_info(info);
- } else {
- /* Not found. Must take an empty slot */
- if(first_empty == MAX_TRACES) {
- printf(
- "LTTng WARNING : too many traces requested for pid %d by the kernel.\n"
- " Compilation defined maximum is %u\n",
- getpid(), MAX_TRACES);
-
- } else {
- info = <tng_trace_info[first_empty];
- info->channel.cpu.start = (void*)cpu_addr;
- info->channel.cpu.length = PAGE_SIZE;
- info->channel.facilities.start = (void*)fac_addr;
- info->channel.facilities.length = PAGE_SIZE;
- info->filter = filter;
- info->active = active;
- info->destroy = destroy;
- if(destroy && !atomic_read(&info->nesting))
- lttng_free_trace_info(info);
- }
- }
- }
-
- /* Enable signals */
- ret = pthread_sigmask(SIG_SETMASK, &oldset, NULL);
- if(ret) {
- printf("Error in sigprocmask\n");
- exit(1);
- }
-}
-
-
-/* signal handler */
-void __lttng_sig_trace_handler(int signo)
-{
- printf("LTTng signal handler : thread id : %lu, pid %lu\n", pthread_self(), getpid());
- lttng_get_new_info();
-}
-
-
-static void thread_init(void)
-{
- int err;
- lttng_get_new_info();
-
- /* Make some ltt_switch syscalls */
- err = ltt_switch((unsigned long)NULL);
- if(err) {
- printf("Error in ltt_switch system call\n");
- exit(1);
- }
-}
-
-void __attribute__((constructor)) __lttng_user_init(void)
-{
- static struct sigaction act;
- int err;
-
- printf("LTTng user init\n");
-
- /* Activate the signal */
- act.sa_handler = __lttng_sig_trace_handler;
- err = sigemptyset(&(act.sa_mask));
- if(err) perror("Error with sigemptyset");
- err = sigaddset(&(act.sa_mask), SIGRTMIN+3);
- if(err) perror("Error with sigaddset");
- err = sigaction(SIGRTMIN+3, &act, NULL);
- if(err) perror("Error with sigaction");
-
- thread_init();
-}
-
-
-void lttng_thread_init(void)
-{
- thread_init();
-}
-
-
projects / lttv.git / blobdiff