+
+struct interfork_clone_info {
+ int (*fn)(void *);
+ void *arg;
+ ust_fork_info_t *fork_info;
+};
+
+static int clone_fn(void *arg)
+{
+ struct interfork_clone_info *info = (struct interfork_clone_info *)arg;
+
+ /* clone is now done and we are in child */
+ ust_after_fork_child(&info->fork_info);
+
+ return info->fn(info->arg);
+}
+
+int clone(int (*fn)(void *), void *child_stack, int flags, void *arg, ...)
+{
+ static int (*plibc_func)(int (*fn)(void *), void *child_stack, int flags, void *arg, pid_t *ptid, struct user_desc *tls, pid_t *ctid) = NULL;
+
+ /* varargs */
+ pid_t *ptid;
+ struct user_desc *tls;
+ pid_t *ctid;
+
+ int retval;
+
+ va_list ap;
+
+ va_start(ap, arg);
+ ptid = va_arg(ap, pid_t *);
+ tls = va_arg(ap, struct user_desc *);
+ ctid = va_arg(ap, pid_t *);
+ va_end(ap);
+
+ if(plibc_func == NULL) {
+ plibc_func = dlsym(RTLD_NEXT, "clone");
+ if(plibc_func == NULL) {
+ fprintf(stderr, "libinterfork: unable to find clone\n");
+ return -1;
+ }
+ }
+
+ if(flags & CLONE_VM) {
+ /* creating a thread, no need to intervene, just pass on the arguments */
+ retval = plibc_func(fn, child_stack, flags, arg, ptid, tls, ctid);
+ }
+ else {
+ /* creating a real process, we need to intervene */
+ struct interfork_clone_info info = { fn: fn, arg: arg };
+
+ ust_before_fork(&info.fork_info);
+
+ retval = plibc_func(clone_fn, child_stack, flags, &info, ptid, tls, ctid);
+
+ /* The child doesn't get here */
+ ust_after_fork_parent(&info.fork_info);
+ }
+
+ return retval;
+}