+static void
+do_background_socket(struct proc *p, thread_t thread, int priority)
+{
+ struct filedesc *fdp;
+ struct fileproc *fp;
+ int i;
+
+ if (priority == PRIO_DARWIN_BG) {
+ /*
+ * For PRIO_DARWIN_PROCESS (thread is NULL), simply mark
+ * the sockets with the background flag. There's nothing
+ * to do here for the PRIO_DARWIN_THREAD case.
+ */
+ if (thread == NULL) {
+ proc_fdlock(p);
+ fdp = p->p_fd;
+
+ for (i = 0; i < fdp->fd_nfiles; i++) {
+ struct socket *sockp;
+
+ fp = fdp->fd_ofiles[i];
+ if (fp == NULL || (fdp->fd_ofileflags[i] & UF_RESERVED) != 0 ||
+ fp->f_fglob->fg_type != DTYPE_SOCKET) {
+ continue;
+ }
+ sockp = (struct socket *)fp->f_fglob->fg_data;
+ socket_set_traffic_mgt_flags(sockp, TRAFFIC_MGT_SO_BACKGROUND);
+ sockp->so_background_thread = NULL;
+ }
+ proc_fdunlock(p);
+ }
+
+ } else {
+
+ /* disable networking IO throttle.
+ * NOTE - It is a known limitation of the current design that we
+ * could potentially clear TRAFFIC_MGT_SO_BACKGROUND bit for
+ * sockets created by other threads within this process.
+ */
+ proc_fdlock(p);
+ fdp = p->p_fd;
+ for ( i = 0; i < fdp->fd_nfiles; i++ ) {
+ struct socket *sockp;
+
+ fp = fdp->fd_ofiles[ i ];
+ if ( fp == NULL || (fdp->fd_ofileflags[ i ] & UF_RESERVED) != 0 ||
+ fp->f_fglob->fg_type != DTYPE_SOCKET ) {
+ continue;
+ }
+ sockp = (struct socket *)fp->f_fglob->fg_data;
+ /* skip if only clearing this thread's sockets */
+ if ((thread) && (sockp->so_background_thread != thread)) {
+ continue;
+ }
+ socket_clear_traffic_mgt_flags(sockp, TRAFFIC_MGT_SO_BACKGROUND);
+ sockp->so_background_thread = NULL;
+ }
+ proc_fdunlock(p);
+ }
+}
+
+
+/*
+ * do_background_thread
+ * Returns: 0 Success
+ * XXX - todo - does this need a MACF hook?
+ *
+ * NOTE: To maintain binary compatibility with PRIO_DARWIN_THREAD with respect
+ * to network traffic management, UT_BACKGROUND_TRAFFIC_MGT is set/cleared
+ * along with UT_BACKGROUND flag, as the latter alone no longer implies
+ * any form of traffic regulation (it simply means that the thread is
+ * background.) With PRIO_DARWIN_PROCESS, any form of network traffic
+ * management must be explicitly requested via whatever means appropriate,
+ * and only TRAFFIC_MGT_SO_BACKGROUND is set via do_background_socket().
+ */
+static int
+do_background_thread(struct proc *curp __unused, thread_t thread, int priority)
+{
+ struct uthread *ut;
+ int error = 0;
+
+ ut = get_bsdthread_info(thread);
+
+ /* Backgrounding is unsupported for threads in vfork */
+ if ( (ut->uu_flag & UT_VFORK) != 0) {
+ return(EPERM);
+ }
+
+ error = proc_set_and_apply_bgthreadpolicy(curp->task, thread_tid(thread), priority);
+ return(error);
+
+}
+
+#if CONFIG_EMBEDDED
+int mach_do_background_thread(thread_t thread, int prio);
+