X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=usertrace%2Flttng_usertrace.c;h=5e32b0cd4e640df69e2fe66b62de04fd1d4da1bf;hb=2d6c6b76f73668703e823a0638e7a67262668aee;hp=b4de26767a11bcedfb88c23f5b8860c07e5c253c;hpb=b8b006881f98b1193db5c45ef8f2d054f6b02f39;p=lttv.git

diff --git a/usertrace/lttng_usertrace.c b/usertrace/lttng_usertrace.c
index b4de2676..5e32b0cd 100644
--- a/usertrace/lttng_usertrace.c
+++ b/usertrace/lttng_usertrace.c
@@ -9,19 +9,220 @@
 #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 = &lttng_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 = &lttng_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 Sig handler : pid : %lu\n", getpid());
+  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)
 {
@@ -39,10 +240,13 @@ void __attribute__((constructor)) __lttng_user_init(void)
 	err = sigaction(SIGRTMIN+3, &act, NULL);
 	if(err) perror("Error with sigaction");
 
-	/* Make the first ltt_update system call */
-	err = ltt_update(1, NULL, NULL);
-	if(err) {
-		printf("Error in ltt_update system call\n");
-		exit(1);
-	}
+	thread_init();
+}
+
+
+void lttng_thread_init(void)
+{
+	thread_init();
 }
+
+