Fix recvmmsg decode: do not show more data than actually returned

This change complements recent fix for recvmsg decoding.

* net.c (printmmsghdr): Add msg_len parameter to pass down to do_msghdr.
When this parameter is zero, pass mmsghdr.msg_len to do_msghdr instead.
(decode_mmsg): Add msg_len parameter, pass it down to printmmsghdr.
(sys_sendmmsg): Call decode_mmsg with msg_len == (unsigned long) -1L.
(sys_recvmmsg): Call decode_mmsg with msg_len == 0.

diff --git a/net.c b/net.c
index 050b746bf377922e58ff2d2450dbc9f242ad8d65..2911c73da9303876d449ac3bfdc5b0588ddfe79b 100644 (file)
--- a/net.c
+++ b/net.c
@@ -1441,7 +1441,7 @@ printmsghdr(struct tcb *tcp, long addr, unsigned long data_size)
 }
 
 static void
-printmmsghdr(struct tcb *tcp, long addr, unsigned int idx)
+printmmsghdr(struct tcb *tcp, long addr, unsigned int idx, unsigned long msg_len)
 {
        struct mmsghdr {
                struct msghdr msg_hdr;
@@ -1454,12 +1454,12 @@ printmmsghdr(struct tcb *tcp, long addr, unsigned int idx)
                return;
        }
        tprints("{");
-       do_msghdr(tcp, &mmsg.msg_hdr, (unsigned long) -1L);
+       do_msghdr(tcp, &mmsg.msg_hdr, msg_len ? msg_len : mmsg.msg_len);
        tprintf(", %u}", mmsg.msg_len);
 }
 
 static void
-decode_mmsg(struct tcb *tcp)
+decode_mmsg(struct tcb *tcp, unsigned long msg_len)
 {
        /* mmsgvec */
        if (syserror(tcp)) {
@@ -1472,7 +1472,7 @@ decode_mmsg(struct tcb *tcp)
                for (i = 0; i < len; ++i) {
                        if (i)
                                tprints(", ");
-                       printmmsghdr(tcp, tcp->u_arg[1], i);
+                       printmmsghdr(tcp, tcp->u_arg[1], i, msg_len);
                }
                tprints("}");
        }
@@ -1659,7 +1659,7 @@ sys_sendmmsg(struct tcb *tcp)
                }
        } else {
                if (verbose(tcp))
-                       decode_mmsg(tcp);
+                       decode_mmsg(tcp, (unsigned long) -1L);
        }
        return 0;
 }
@@ -1769,7 +1769,7 @@ sys_recvmmsg(struct tcb *tcp)
                return 0;
        } else {
                if (verbose(tcp)) {
-                       decode_mmsg(tcp);
+                       decode_mmsg(tcp, 0);
                        /* timeout on entrance */
                        tprintf(", %s", tcp->auxstr ? tcp->auxstr : "{...}");
                        free((void *) tcp->auxstr);