OS-4602 lxbrand support recvmsg(MSG_PEEK|MSG_TRUNC) behavior
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>
Reviewed by: Joshua M. Clulow <jmc@joyent.com>

*** 668,681 ****
--- 668,686 ----
          boolean_t partial_read;
          boolean_t reset_atmark = B_FALSE;
          int more = 0;
          int error;
          ssize_t oobmark;
+         ssize_t copied = 0;
          sodirect_t *sodp = so->so_direct;
+         xuio_t *xuio = NULL;
  
          partial_read = B_FALSE;
          *mctlp = NULL;
+         if ((uiop->uio_extflg & UIO_XUIO) != 0) {
+                 xuio = (xuio_t *)uiop;
+         }
  again:
          mutex_enter(&so->so_lock);
  again1:
  #ifdef DEBUG
          if (so_debug_length) {
*** 782,793 ****
                  /*
                   * Now process DATA blocks, if any. Note that for sodirect
                   * enabled socket, uio_resid can be 0.
                   */
                  if (uiop->uio_resid >= 0) {
-                         ssize_t copied = 0;
- 
                          if (sodp != NULL && (DB_FLAGS(mp) & DBLK_UIOA)) {
                                  mutex_enter(&so->so_lock);
                                  ASSERT(uiop == (uio_t *)&sodp->sod_uioa);
                                  copied = sod_uioa_mblk(so, mp);
                                  if (copied > 0)
--- 787,796 ----
*** 841,850 ****
--- 844,865 ----
                                  rvalp->r_val2 = so_check_flow_control(so);
                          }
                  }
                  if (mp != NULL) { /* more data blocks in msg */
                          more |= MOREDATA;
+ 
+                         /*
+                          * If requested, tally up remaining data along with the
+                          * amount already copied.
+                          */
+                         if (xuio != NULL &&
+                             xuio->xu_type == UIOTYPE_PEEKSIZE) {
+                                 xuio->xu_ext.xu_ps.xu_ps_set = B_TRUE;
+                                 xuio->xu_ext.xu_ps.xu_ps_size =
+                                     copied + msgdsize(mp);
+                         }
+ 
                          if ((flags & (MSG_PEEK|MSG_TRUNC))) {
                                  if (flags & MSG_PEEK) {
                                          freemsg(mp);
                                  } else {
                                          unsigned int msize = msgdsize(mp);