Fix dumping of recvmmsg syscall in case of short read

* net.c (dumpiov_in_mmsghdr): Call dumpiov_upto instead of dumpiov,
pass data size limit to dumpiov_upto.
* NEWS: Mention this fix.
* tests/mmsg.c (main): Update.

Author: ldv-alt

NEWS

@@ -14,7 +14,7 @@ Noteworthy changes in release ?.?? (????-??-??)
   * Fixed decoding of syscalls unknown to the kernel on s390/s390x.
     (addresses Debian bug #485979 and Fedora bug #1298294).
   * Fixed decoding and dumping of readv syscall in case of short read.
-  * Fixed dumping of recvmsg syscall in case of short read.
+  * Fixed dumping of recvmsg and recvmmsg syscalls in case of short read.
 
 Noteworthy changes in release 4.11 (2015-12-21)
 ===============================================

net.c

@@ -763,8 +763,8 @@ dumpiov_in_mmsghdr(struct tcb *tcp, long addr)
 		if (extractmmsghdr(tcp, addr, i, &mmsg)) {
 			tprintf(" = %lu buffers in vector %u\n",
 				(unsigned long)mmsg.msg_hdr.msg_iovlen, i);
-			dumpiov(tcp, mmsg.msg_hdr.msg_iovlen,
-				(long)mmsg.msg_hdr.msg_iov);
+			dumpiov_upto(tcp, mmsg.msg_hdr.msg_iovlen,
+				(long)mmsg.msg_hdr.msg_iov, mmsg.msg_len);
 		}
 	}
 }

tests/mmsg.c

@@ -87,102 +87,150 @@ main(void)
 {
 	tprintf("%s", "");
 
-	const int R = 0, W = 1;
-	int sv[2];
-	if (socketpair(AF_UNIX, SOCK_DGRAM, 0, sv))
+	int fds[2];
+	if (socketpair(AF_UNIX, SOCK_DGRAM, 0, fds))
 		perror_msg_and_skip("socketpair");
-	assert(R == sv[0]);
-	assert(W == sv[1]);
+	assert(0 == fds[0]);
+	assert(1 == fds[1]);
 
-	static const char one[] = "one";
-	static const char two[] = "two";
-	static const char three[] = "three";
-	static const char ascii_one[] = "6f 6e 65";
-	static const char ascii_two[] = "74 77 6f";
-	static const char ascii_three[] = "74 68 72 65 65";
+	static const char w0_c[] = "012";
+	const char *w0_d = hexdump_strdup(w0_c);
+	void *w0 = tail_memdup(w0_c, LENGTH_OF(w0_c));
 
-	void *copy_one = tail_memdup(one, LENGTH_OF(one));
-	void *copy_two = tail_memdup(two, LENGTH_OF(two));
-	void *copy_three = tail_memdup(three, LENGTH_OF(three));
+	static const char w1_c[] = "34567";
+	const char *w1_d = hexdump_strdup(w1_c);
+	void *w1 = tail_memdup(w1_c, LENGTH_OF(w1_c));
 
-	struct iovec iov[] = {
+	static const char w2_c[] = "89abcde";
+	const char *w2_d = hexdump_strdup(w2_c);
+	void *w2 = tail_memdup(w2_c, LENGTH_OF(w2_c));
+
+	const struct iovec w0_iov_[] = {
 		{
-			.iov_base = copy_one,
-			.iov_len = LENGTH_OF(one)
-		}, {
-			.iov_base = copy_two,
-			.iov_len = LENGTH_OF(two)
+			.iov_base = w0,
+			.iov_len = LENGTH_OF(w0_c)
 		}, {
-			.iov_base = copy_three,
-			.iov_len = LENGTH_OF(three)
+			.iov_base = w1,
+			.iov_len = LENGTH_OF(w1_c)
 		}
 	};
-	struct iovec *copy_iov = tail_memdup(iov, sizeof(iov));
+	struct iovec *w0_iov = tail_memdup(w0_iov_, sizeof(w0_iov_));
 
-	struct mmsghdr mmh[] = {
+	const struct iovec w1_iov_[] = {
+		{
+			.iov_base = w2,
+			.iov_len = LENGTH_OF(w2_c)
+		}
+	};
+	struct iovec *w1_iov = tail_memdup(w1_iov_, sizeof(w1_iov_));
+
+	const struct mmsghdr w_mmh_[] = {
 		{
 			.msg_hdr = {
-				.msg_iov = copy_iov + 0,
-				.msg_iovlen = 2,
+				.msg_iov = w0_iov,
+				.msg_iovlen = ARRAY_SIZE(w0_iov_),
 			}
 		}, {
 			.msg_hdr = {
-				.msg_iov = copy_iov + 2,
-				.msg_iovlen = 1,
+				.msg_iov = w1_iov,
+				.msg_iovlen = ARRAY_SIZE(w1_iov_),
 			}
 		}
 	};
-	void *copy_mmh = tail_memdup(mmh, sizeof(mmh));
-# define n_mmh ((unsigned int) (sizeof(mmh)/sizeof(mmh[0])))
+	void *w_mmh = tail_memdup(w_mmh_, sizeof(w_mmh_));
+	const unsigned int n_w_mmh = ARRAY_SIZE(w_mmh_);
 
-	int r = send_mmsg(W, copy_mmh, n_mmh, MSG_DONTROUTE | MSG_NOSIGNAL);
+	int r = send_mmsg(1, w_mmh, n_w_mmh, MSG_DONTROUTE | MSG_NOSIGNAL);
 	if (r < 0 && errno == ENOSYS)
 		perror_msg_and_skip("sendmmsg");
-	assert(r == (int) n_mmh);
-	assert(close(W) == 0);
-	tprintf("sendmmsg(%d, {{{msg_name(0)=NULL, msg_iov(%u)=[{\"%s\", %u}"
+	assert(r == (int) n_w_mmh);
+	assert(close(1) == 0);
+	tprintf("sendmmsg(1, {{{msg_name(0)=NULL, msg_iov(%u)=[{\"%s\", %u}"
 		", {\"%s\", %u}], msg_controllen=0, msg_flags=0}, %u}"
 		", {{msg_name(0)=NULL, msg_iov(%u)=[{\"%s\", %u}]"
 		", msg_controllen=0, msg_flags=0}, %u}}, %u"
 		", MSG_DONTROUTE|MSG_NOSIGNAL) = %d\n"
 		" = %u buffers in vector 0\n"
 		" * %u bytes in buffer 0\n"
-		" | 00000  %-48s  %-16s |\n"
+		" | 00000 %-49s  %-16s |\n"
 		" * %u bytes in buffer 1\n"
-		" | 00000  %-48s  %-16s |\n"
+		" | 00000 %-49s  %-16s |\n"
 		" = %u buffers in vector 1\n"
 		" * %u bytes in buffer 0\n"
-		" | 00000  %-48s  %-16s |\n",
-		W, 2, one, LENGTH_OF(one), two, LENGTH_OF(two),
-		LENGTH_OF(one) + LENGTH_OF(two),
-		1, three, LENGTH_OF(three), LENGTH_OF(three),
-		n_mmh, r,
-		2, LENGTH_OF(one), ascii_one, one,
-		LENGTH_OF(two), ascii_two, two,
-		1, LENGTH_OF(three), ascii_three, three);
-
-	assert(recv_mmsg(R, copy_mmh, n_mmh, MSG_DONTWAIT, NULL) == (int) n_mmh);
-	assert(close(R) == 0);
-	tprintf("recvmmsg(%d, {{{msg_name(0)=NULL, msg_iov(%u)=[{\"%s\", %u}"
-		", {\"%s\", %u}], msg_controllen=0, msg_flags=0}, %u}"
-		", {{msg_name(0)=NULL, msg_iov(%u)=[{\"%s\", %u}]"
+		" | 00000 %-49s  %-16s |\n",
+		ARRAY_SIZE(w0_iov_), w0_c, LENGTH_OF(w0_c),
+		w1_c, LENGTH_OF(w1_c),
+		LENGTH_OF(w0_c) + LENGTH_OF(w1_c),
+		ARRAY_SIZE(w1_iov_), w2_c, LENGTH_OF(w2_c), LENGTH_OF(w2_c),
+		n_w_mmh, r,
+		ARRAY_SIZE(w0_iov_), LENGTH_OF(w0_c), w0_d, w0_c,
+		LENGTH_OF(w1_c), w1_d, w1_c,
+		ARRAY_SIZE(w1_iov_), LENGTH_OF(w2_c), w2_d, w2_c);
+
+	const unsigned int w_len =
+		LENGTH_OF(w0_c) + LENGTH_OF(w1_c) + LENGTH_OF(w2_c);
+	const unsigned int r_len = (w_len + 1) / 2;
+	void *r0 = tail_alloc(r_len);
+	void *r1 = tail_alloc(r_len);
+	void *r2 = tail_alloc(r_len);
+	const struct iovec r0_iov_[] = {
+		{
+			.iov_base = r0,
+			.iov_len = r_len
+		}
+	};
+	struct iovec *r0_iov = tail_memdup(r0_iov_, sizeof(r0_iov_));
+	const struct iovec r1_iov_[] = {
+		{
+			.iov_base = r1,
+			.iov_len = r_len
+		},
+		{
+			.iov_base = r2,
+			.iov_len = r_len
+		}
+	};
+	struct iovec *r1_iov = tail_memdup(r1_iov_, sizeof(r1_iov_));
+
+	const struct mmsghdr r_mmh_[] = {
+		{
+			.msg_hdr = {
+				.msg_iov = r0_iov,
+				.msg_iovlen = ARRAY_SIZE(r0_iov_),
+			}
+		}, {
+			.msg_hdr = {
+				.msg_iov = r1_iov,
+				.msg_iovlen = ARRAY_SIZE(r1_iov_),
+			}
+		}
+	};
+	void *r_mmh = tail_memdup(r_mmh_, sizeof(r_mmh_));
+	const unsigned int n_r_mmh = ARRAY_SIZE(r_mmh_);
+
+	static const char r0_c[] = "01234567";
+	const char *r0_d = hexdump_strdup(r0_c);
+	static const char r1_c[] = "89abcde";
+	const char *r1_d = hexdump_strdup(r1_c);
+
+	assert(recv_mmsg(0, r_mmh, n_r_mmh, MSG_DONTWAIT, NULL) == (int) n_r_mmh);
+	assert(close(0) == 0);
+	tprintf("recvmmsg(0, {{{msg_name(0)=NULL, msg_iov(%u)=[{\"%s\", %u}]"
+		", msg_controllen=0, msg_flags=0}, %u}"
+		", {{msg_name(0)=NULL, msg_iov(%u)=[{\"%s\", %u}, {\"\", %u}]"
 		", msg_controllen=0, msg_flags=0}, %u}}, %u"
 		", MSG_DONTWAIT, NULL) = %d (left NULL)\n"
 		" = %u buffers in vector 0\n"
 		" * %u bytes in buffer 0\n"
-		" | 00000  %-48s  %-16s |\n"
-		" * %u bytes in buffer 1\n"
-		" | 00000  %-48s  %-16s |\n"
+		" | 00000 %-49s  %-16s |\n"
 		" = %u buffers in vector 1\n"
 		" * %u bytes in buffer 0\n"
-		" | 00000  %-48s  %-16s |\n",
-		R, 2, one, LENGTH_OF(one), two, LENGTH_OF(two),
-		LENGTH_OF(one) + LENGTH_OF(two),
-		1, three, LENGTH_OF(three), LENGTH_OF(three),
-		n_mmh, r,
-		2, LENGTH_OF(one), ascii_one, one,
-		LENGTH_OF(two), ascii_two, two,
-		1, LENGTH_OF(three), ascii_three, three);
+		" | 00000 %-49s  %-16s |\n",
+		ARRAY_SIZE(r0_iov_), r0_c, r_len, LENGTH_OF(r0_c),
+		ARRAY_SIZE(r1_iov_), r1_c, r_len, r_len, LENGTH_OF(r1_c),
+		n_r_mmh, r,
+		ARRAY_SIZE(r0_iov_), LENGTH_OF(r0_c), r0_d, r0_c,
+		ARRAY_SIZE(r1_iov_), LENGTH_OF(r1_c), r1_d, r1_c);
 
 	tprintf("+++ exited with 0 +++\n");
 	return 0;