/** Inserts a backtrace marker into the provided context
*
* Allows for maximum laziness and will initialise a circular buffer if one has not already been created.
*
* Code augmentation should look something like:
@verbatim
// Create a static cbuffer pointer, the first call to backtrace_attach will initialise it
static fr_cbuff *my_obj_bt;
my_obj_t *alloc_my_obj(TALLOC_CTX *ctx) {
my_obj_t *this;
this = talloc(ctx, my_obj_t);
// Attach backtrace marker to object
backtrace_attach(&my_obj_bt, this);
return this;
}
@endverbatim
*
* Then, later when a double free occurs:
@verbatim
(gdb) call backtrace_print(&my_obj_bt, <pointer to double freed memory>)
@endverbatim
*
* which should print a limited backtrace to stderr. Note, this backtrace will not include any argument
* values, but should at least show the code path taken.
*
* @param cbuff this should be a pointer to a static *fr_cbuff.
* @param obj we want to generate a backtrace for.
*/
fr_bt_marker_t *fr_backtrace_attach(fr_cbuff_t **cbuff, TALLOC_CTX *obj)
{
fr_bt_marker_t *marker;
if (*cbuff == NULL) {
PTHREAD_MUTEX_LOCK(&fr_debug_init);
/* Check again now we hold the mutex - eww*/
if (*cbuff == NULL) {
TALLOC_CTX *ctx;
ctx = fr_autofree_ctx();
*cbuff = fr_cbuff_alloc(ctx, MAX_BT_CBUFF, true);
}
PTHREAD_MUTEX_UNLOCK(&fr_debug_init);
}
marker = talloc(obj, fr_bt_marker_t);
if (!marker) {
return NULL;
}
marker->obj = (void *) obj;
marker->cbuff = *cbuff;
talloc_set_destructor(marker, _fr_do_bt);
return marker;
}
/** Inserts a backtrace marker into the provided context
*
* Allows for maximum laziness and will initialise a circular buffer if one has not already been created.
*
* Code augmentation should look something like:
@verbatim
// Create a static cbuffer pointer, the first call to backtrace_attach will initialise it
static fr_cbuff_t *my_obj_bt;
my_obj_t *alloc_my_obj(TALLOC_CTX *ctx) {
my_obj_t *this;
this = talloc(ctx, my_obj_t);
// Attach backtrace marker to object
backtrace_attach(&my_obj_bt, this);
return this;
}
@endverbatim
*
* Then, later when a double free occurs:
@verbatim
(gdb) call backtrace_print(&my_obj_bt, <pointer to double freed memory>)
@endverbatim
*
* which should print a limited backtrace to stderr. Note, this backtrace will not include any argument
* values, but should at least show the code path taken.
*
* @param cbuff this should be a pointer to a static *fr_cbuff.
* @param obj we want to generate a backtrace for.
*/
fr_bt_marker_t *fr_backtrace_attach(fr_cbuff_t **cbuff, TALLOC_CTX *obj)
{
fr_bt_marker_t *marker;
if (*cbuff == NULL) {
PTHREAD_MUTEX_LOCK(&fr_debug_init);
/* Check again now we hold the mutex - eww*/
if (*cbuff == NULL) *cbuff = fr_cbuff_alloc(NULL, MAX_BT_CBUFF, true);
PTHREAD_MUTEX_UNLOCK(&fr_debug_init);
}
marker = talloc(obj, fr_bt_marker_t);
if (!marker) {
return NULL;
}
marker->obj = (void *) obj;
marker->cbuff = *cbuff;
fprintf(stderr, "Backtrace attached to %s %p\n", talloc_get_name(obj), obj);
/*
* Generate the backtrace for memory allocation
*/
fr_backtrace_do(marker);
talloc_set_destructor(marker, fr_backtrace_do);
return marker;
}
