Fix crash when using legacy send API with NN_MSG.

We introduced the compat_msg.c from the old msg.c in the nanomsg
repo.  While here, we found that the handling for send() was badly
wrong, by a level of indirection.  We simplified the code to so that
nn_send() and nn_recv() are simple wrappers around the nn_sendmsg()
and nn_recvmsg() APIs (as in old nanomsg).  This may not be quite as
fast, but it's more likely to be correct and reduces complexity.

3 files changed, 158 insertions, 54 deletions

diff --git a/src/nng_compat.c b/src/nng_compat.c
index 523358f3..9515dc31 100644
--- a/src/nng_compat.c
+++ b/src/nng_compat.c
@@ -1,5 +1,6 @@
 //
 // Copyright 2017 Garrett D'Amore <garrett@damore.org>
+// Copyright 2017 Capitar IT Group BV <info@capitar.com>
 //
 // This software is supplied under the terms of the MIT License, a
 // copy of which should be located in the distribution where this
@@ -255,24 +256,19 @@ nn_flags(int flags)
 int
 nn_send(int s, const void *buf, size_t len, int flags)
 {
-	int rv;
+	int              rv;
+	struct nn_iovec  iov;
+	struct nn_msghdr hdr;
 
-	if ((flags = nn_flags(flags)) == -1) {
-		return (-1);
-	}
-	if (len == NN_MSG) {
-		nng_msg *msg;
-		memcpy(&msg, ((char *) buf) - sizeof(msg), sizeof(msg));
-		len = nng_msg_len(msg);
-		rv  = nng_sendmsg((nng_socket) s, msg, flags);
-	} else {
-		rv = nng_send((nng_socket) s, (void *) buf, len, flags);
-	}
-	if (rv != 0) {
-		nn_seterror(rv);
-		return (-1);
-	}
-	return ((int) len);
+	iov.iov_base = (void *) buf;
+	iov.iov_len  = len;
+
+	hdr.msg_iov        = &iov;
+	hdr.msg_iovlen     = 1;
+	hdr.msg_control    = NULL;
+	hdr.msg_controllen = 0;
+
+	return (nn_sendmsg(s, &hdr, flags));
 }
 
 int
@@ -280,42 +276,18 @@ nn_recv(int s, void *buf, size_t len, int flags)
 {
 	int rv;
 
-	if ((flags = nn_flags(flags)) == -1) {
-		return (-1);
-	}
+	struct nn_iovec  iov;
+	struct nn_msghdr hdr;
 
-	if (len == NN_MSG) {
-		nng_msg *msg;
+	iov.iov_base = buf;
+	iov.iov_len  = len;
 
-		if ((rv = nng_recvmsg((nng_socket) s, &msg, flags)) != 0) {
-			nn_seterror(rv);
-			return (-1);
-		}
-
-		// prepend our header to the body...
-		// Note that this *can* alter the message,
-		// although for performance reasons it ought not.
-		// (There should be sufficient headroom.)
-		if ((rv = nng_msg_prepend(msg, &msg, sizeof(msg))) != 0) {
-			nng_msg_free(msg);
-			nn_seterror(rv);
-			return (-1);
-		}
+	hdr.msg_iov        = &iov;
+	hdr.msg_iovlen     = 1;
+	hdr.msg_control    = NULL;
+	hdr.msg_controllen = 0;
 
-		// now "trim" it off... the value is still there, but the
-		// contents are unreferenced.  We rely on legacy nanomsg's
-		// ignorance of nng msgs to preserve this.
-		nng_msg_trim(msg, sizeof(msg));
-
-		*(void **) buf = nng_msg_body(msg);
-		return ((int) nng_msg_len(msg));
-	}
-
-	if ((rv = nng_recv((nng_socket) s, buf, &len, flags)) != 0) {
-		nn_seterror(rv);
-		return (-1);
-	}
-	return ((int) len);
+	return (nn_recvmsg(s, &hdr, flags));
 }
 
 int
@@ -463,8 +435,9 @@ nn_sendmsg(int s, const struct nn_msghdr *mh, int flags)
 	}
 
 	if ((mh->msg_iovlen == 1) && (mh->msg_iov[0].iov_len == NN_MSG)) {
-		msg = *(nng_msg **) (((char *) mh->msg_iov[0].iov_base) -
-		    sizeof(msg));
+		char *bufp = *(char **) (mh->msg_iov[0].iov_base);
+
+		msg  = *(nng_msg **) (bufp - sizeof(msg));
 		keep = 1; // keep the message on error
 	} else {
 		char *ptr;
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 5dcc1379..47c086d2 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -2,8 +2,9 @@
 #   Copyright (c) 2012 Martin Sustrik  All rights reserved.
 #   Copyright (c) 2013 GoPivotal, Inc.  All rights reserved.
 #   Copyright (c) 2015-2016 Jack R. Dunaway. All rights reserved.
-#   Copyright 2017 Garrett D'Amore <garrett@damore.org>
 #   Copyright 2016 Franklin "Snaipe" Mathieu <franklinmathieu@gmail.com>
+#   Copyright 2017 Garrett D'Amore <garrett@damore.org>
+#   Copyright 2017 Capitar IT Group BV <info@capitar.com>
 #
 #   Permission is hereby granted, free of charge, to any person obtaining a copy
 #   of this software and associated documentation files (the "Software"),
@@ -60,7 +61,7 @@ if (NNG_TESTS)
             target_link_libraries (${NAME} "${CMAKE_THREAD_LIBS_INIT}")
         endif()
 
-        add_test (NAME ${NAME} COMMAND ${NAME} -v ${TEST_PORT})
+        add_test (NAME ${NAME} COMMAND ${NAME} ${TEST_PORT})
         set_tests_properties (${NAME} PROPERTIES TIMEOUT ${TIMEOUT})
         math (EXPR TEST_PORT "${TEST_PORT}+10")
     endmacro (add_nng_compat_test)
@@ -92,5 +93,6 @@ add_nng_compat_test(compat_block 5)
 add_nng_compat_test(compat_bug777 5)
 add_nng_compat_test(compat_bus 5)
 add_nng_compat_test(compat_cmsg 5)
+add_nng_compat_test(compat_msg 5)
 add_nng_compat_test(compat_device 5)
 add_nng_compat_test(compat_reqrep 5)
diff --git a/tests/compat_msg.c b/tests/compat_msg.c
new file mode 100644
index 00000000..683739d3
--- /dev/null
+++ b/tests/compat_msg.c
@@ -0,0 +1,129 @@
+/*
+    Copyright (c) 2013 Martin Sustrik  All rights reserved.
+    Copyright 2016 Franklin "Snaipe" Mathieu <franklinmathieu@gmail.com>
+    Copyright 2017 Garrett D'Amore <garrett@damore.org>
+    Copyright 2017 Capitar IT Group BV <info@capitar.com>
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"),
+    to deal in the Software without restriction, including without limitation
+    the rights to use, copy, modify, merge, publish, distribute, sublicense,
+    and/or sell copies of the Software, and to permit persons to whom
+    the Software is furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included
+    in all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+    IN THE SOFTWARE.
+*/
+
+#include "nng_compat.h"
+#include "compat_testutil.h"
+
+#include <string.h>
+
+#define SOCKET_ADDRESS "inproc://a"
+
+char longdata[1 << 20];
+
+int main (int argc, const char *argv[])
+{
+    int rc;
+    int sb;
+    int sc;
+    unsigned char *buf1, *buf2;
+    int i;
+    struct nn_iovec iov;
+    struct nn_msghdr hdr;
+    char socket_address_tcp[128];
+
+    test_addr_from(socket_address_tcp, "tcp", "127.0.0.1",
+            get_test_port(argc, argv));
+
+    sb = test_socket (AF_SP, NN_PAIR);
+    test_bind (sb, SOCKET_ADDRESS);
+    sc = test_socket (AF_SP, NN_PAIR);
+    test_connect (sc, SOCKET_ADDRESS);
+
+    buf1 = nn_allocmsg (256, 0);
+    alloc_assert (buf1);
+    for (i = 0; i != 256; ++i)
+        buf1 [i] = (unsigned char) i;
+    rc = nn_send (sc, &buf1, NN_MSG, 0);
+    errno_assert (rc >= 0);
+    nn_assert (rc == 256);
+
+    buf2 = NULL;
+    rc = nn_recv (sb, &buf2, NN_MSG, 0);
+    errno_assert (rc >= 0);
+    nn_assert (rc == 256);
+    nn_assert (buf2);
+    for (i = 0; i != 256; ++i)
+        nn_assert (buf2 [i] == (unsigned char) i);
+    rc = nn_freemsg (buf2);
+    errno_assert (rc == 0);
+
+    buf1 = nn_allocmsg (256, 0);
+    alloc_assert (buf1);
+    for (i = 0; i != 256; ++i)
+        buf1 [i] = (unsigned char) i;
+    iov.iov_base = &buf1;
+    iov.iov_len = NN_MSG;
+    memset (&hdr, 0, sizeof (hdr));
+    hdr.msg_iov = &iov;
+    hdr.msg_iovlen = 1;
+    rc = nn_sendmsg (sc, &hdr, 0);
+    errno_assert (rc >= 0);
+    nn_assert (rc == 256);
+
+    buf2 = NULL;
+    iov.iov_base = &buf2;
+    iov.iov_len = NN_MSG;
+    memset (&hdr, 0, sizeof (hdr));
+    hdr.msg_iov = &iov;
+    hdr.msg_iovlen = 1;
+    rc = nn_recvmsg (sb, &hdr, 0);
+    errno_assert (rc >= 0);
+    nn_assert (rc == 256);
+    nn_assert (buf2);
+    for (i = 0; i != 256; ++i)
+        nn_assert (buf2 [i] == (unsigned char) i);
+    rc = nn_freemsg (buf2);
+    errno_assert (rc == 0);
+
+    test_close (sc);
+    test_close (sb);
+
+    /*  Test receiving of large message  */
+
+    sb = test_socket (AF_SP, NN_PAIR);
+    test_bind (sb, socket_address_tcp);
+    sc = test_socket (AF_SP, NN_PAIR);
+    test_connect (sc, socket_address_tcp);
+
+    for (i = 0; i < (int) sizeof (longdata); ++i)
+        longdata[i] = '0' + (i % 10);
+    longdata [sizeof (longdata) - 1] = 0;
+    test_send (sb, longdata);
+
+    rc = nn_recv (sc, &buf2, NN_MSG, 0);
+    errno_assert (rc >= 0);
+    nn_assert (rc == sizeof (longdata) - 1);
+    nn_assert (buf2);
+    for (i = 0; i < (int) sizeof (longdata) - 1; ++i)
+        nn_assert (buf2 [i] == longdata [i]);
+    rc = nn_freemsg (buf2);
+    errno_assert (rc == 0);
+
+    test_close (sc);
+    test_close (sb);
+
+    return 0;
+}
+