/**
* Registers a new thread to the runtime system. This includes
* initialization of the hardware performance counters
*/
void rec_sched_register_thread(pid_t parent, pid_t child, int flags)
{
struct tasklist_entry* entry = sys_malloc_zero(sizeof(*entry));
struct task* t = &entry->t;
assert(child > 0 && child < MAX_TID);
t->status = 0;
t->rec_tid = t->tid = child;
t->child_mem_fd = sys_open_child_mem(child);
push_placeholder_event(t);
if (parent) {
struct task* parent_t = get_task(parent);
struct sighandlers* parent_handlers = parent_t->sighandlers;
t->syscallbuf_lib_start = parent_t->syscallbuf_lib_start;
t->syscallbuf_lib_end = parent_t->syscallbuf_lib_end;
t->task_group =
(SHARE_TASK_GROUP & flags) ?
task_group_add_and_ref(parent_t->task_group, t) :
task_group_new_and_add(t);
t->sighandlers = (SHARE_SIGHANDLERS & flags) ?
sighandlers_ref(parent_handlers) :
sighandlers_copy(parent_handlers);
} else {
/* After the first task is forked, we always need to
* know the parent in order to initialize some task
* state. */
static int is_first_task = 1;
assert(is_first_task);
is_first_task = 0;
t->task_group = task_group_new_and_add(t);
/* The very first task we fork inherits our
* sighandlers (which should all be default at this
* point, but ...). From there on, new tasks will
* transitively inherit from this first task. */
t->sighandlers = sighandlers_new();
sighandlers_init_from_current_process(t->sighandlers);
}
/* These will be initialized when the syscall buffer is. */
t->desched_fd = t->desched_fd_child = -1;
sys_ptrace_setup(child);
init_hpc(t);
start_hpc(t, rr_flags()->max_rbc);
CIRCLEQ_INSERT_TAIL(&head, entry, entries);
num_active_threads++;
tid_to_entry[child] = entry;
}
static size_t checked_pread(struct context *ctx, void *buf, size_t size,off_t offset) {
size_t read = pread(ctx->child_mem_fd, buf, size, offset);
// for some reason reading from the child process requires to re-open the fd
// who knows why??
if (read == 0 && errno == 0) {
sys_close(ctx->child_mem_fd);
ctx->child_mem_fd = sys_open_child_mem(ctx->child_tid);
}
return pread(ctx->child_mem_fd, buf, size, offset);
}
