#include <malloc.h>
#include <string.h>
-#include <asm/atomic.h>
#include "lttng_usertrace.h"
#define MAX_TRACES 16
-struct ltt_buf {
- void *start;
- atomic_t offset;
- atomic_t reserve_count;
- atomic_t commit_count;
- atomic_t events_lost;
-};
-
-struct lttng_trace_info {
- int active:1;
- struct {
- struct ltt_buf facilities;
- struct ltt_buf cpu;
- } channel;
-};
+/*
+ * 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
+/* TLS for the trace info
+ * http://www.dis.com/gnu/gcc/C--98-Thread-Local-Edits.html
*
* Add after paragraph 4
*
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),
}
};
-/* signal handler */
-void __lttng_sig_trace_handler(int signo)
+
+/* 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;
- sigset_t set, oldset;
- printf("LTTng signal handler : thread id : %lu, pid %lu\n", pthread_self(), getpid());
-#if 0
+ 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) {
exit(1);
}
- ret = sigprocmask(SIG_BLOCK, &set, &oldset);
+ ret = pthread_sigmask(SIG_BLOCK, &set, &oldset);
if(ret) {
printf("Error in sigprocmask\n");
exit(1);
}
-#endif //0
+
/* Get all the new traces */
-#if 0
- do {
- /* FIXME : allocate the trace structure somewhere : thread private */
- ret = ltt_update(addr, &active, &filter);
-
+ while(1) {
+ cpu_addr = fac_addr = 0;
+ active = filter = destroy = 0;
+ ret = ltt_update(&cpu_addr, &fac_addr, &active, &filter, &destroy);
if(ret) {
- printf("Error in ltt_update system call\n");
+ printf("LTTng : error in ltt_update\n");
exit(1);
}
- } while(addr);
-#endif //0
+ 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);
+ }
+ }
+ }
-#if 0
/* Enable signals */
- ret = sigprocmask(SIG_SETMASK, &oldset, NULL);
+ ret = pthread_sigmask(SIG_SETMASK, &oldset, NULL);
if(ret) {
printf("Error in sigprocmask\n");
exit(1);
}
-#endif //0
}
-static void thread_init(void)
+/* signal handler */
+void __lttng_sig_trace_handler(int signo)
{
- int err;
+ printf("LTTng signal handler : thread id : %lu, pid %lu\n", pthread_self(), getpid());
+ lttng_get_new_info();
+}
- /* TEST */
- err = ltt_switch((unsigned long)NULL);
- if(err) {
- printf("Error in ltt_switch system call\n");
- exit(1);
- }
- /* 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);
- }
+static void thread_init(void)
+{
+ int err;
+ lttng_get_new_info();
/* Make some ltt_switch syscalls */
err = ltt_switch((unsigned long)NULL);
}
-
-
-
projects / lttv.git / blobdiff