ping: Fix the spacing between the time stamp and cp/dp

When an echo reply packet is received, the data is compared with the
sent data.  When a wrong byte is detected the command displays a report
with the differences.

The first row (the first 8-bytes of data after the ICMP header) should
include the time stamp (if data is at least 8-bytes), this value is not
taken into consideration for the comparison.  The remaining rows
represent the data (padded pattern) received/sent, with each byte being
compared for differences.

Print the space before (not after), to add an extra space after cp:/dp:
for better readability when the first time stamp octet is not
zero-padded, and to remove trailing spaces in the output.

Before:
    cp:99  0  0  c  1  5  c  0␣
    	ab cd ab cd ab cd ab cd ab cd ab cd ab cd ab cd␣
    	...

After:
    cp: 99  0  0  c  1  5  c  0
    	 ab cd ab cd ab cd ab cd ab cd ab cd ab cd ab cd
    	 ...

Reviewed by:	markj
MFC after:	1 week
Pull Request:	https://github.com/freebsd/freebsd-src/pull/863
Differential Revision:	https://reviews.freebsd.org/D39492

2 files changed, 37 insertions, 2 deletions

diff --git a/sbin/ping/ping.c b/sbin/ping/ping.c
index bbb103a7361f..fcc27d34ee54 100644
--- a/sbin/ping/ping.c
+++ b/sbin/ping/ping.c
@@ -1261,14 +1261,14 @@ pr_pack(char *buf, ssize_t cc, struct sockaddr_in *from, struct timespec *tv)
 					for (i = 0; i < datalen; ++i, ++cp) {
 						if ((i % 16) == 8)
 							(void)printf("\n\t");
-						(void)printf("%2x ", *cp);
+						(void)printf(" %2x", *cp);
 					}
 					(void)printf("\ndp:");
 					cp = &outpack[ICMP_MINLEN];
 					for (i = 0; i < datalen; ++i, ++cp) {
 						if ((i % 16) == 8)
 							(void)printf("\n\t");
-						(void)printf("%2x ", *cp);
+						(void)printf(" %2x", *cp);
 					}
 					break;
 				}
diff --git a/sbin/ping/tests/test_ping.py b/sbin/ping/tests/test_ping.py
index c51823103133..545e680fbc9f 100644
--- a/sbin/ping/tests/test_ping.py
+++ b/sbin/ping/tests/test_ping.py
@@ -275,6 +275,8 @@ def redact(output):
         ("hlim=[0-9]*", "hlim="),
         ("ttl=[0-9]*", "ttl="),
         ("time=[0-9.-]*", "time="),
+        ("cp: .*", "cp: xx xx xx xx xx xx xx xx"),
+        ("dp: .*", "dp: xx xx xx xx xx xx xx xx"),
         ("\(-[0-9\.]+[0-9]+ ms\)", "(- ms)"),
         ("[0-9\.]+/[0-9.]+", "/"),
     ]
@@ -1401,6 +1403,39 @@ ping: time of day goes back (- ms), clamping time to 0
             },
             id="_0_0_special_warp",
         ),
+        pytest.param(
+            {
+                "src": "192.0.2.1",
+                "dst": "192.0.2.2",
+                "icmp_type": 0,
+                "icmp_code": 0,
+                "special": "wrong",
+            },
+            {
+                "returncode": 0,
+                "stdout": """\
+PATTERN: 0x01
+PING 192.0.2.2 (192.0.2.2): 56 data bytes
+64 bytes from: icmp_seq=0 ttl= time= ms
+wrong data byte #55 should be 0x1 but was 0x0
+cp: xx xx xx xx xx xx xx xx
+	  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1
+	  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1
+	  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  0
+dp: xx xx xx xx xx xx xx xx
+	  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1
+	  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1
+	  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1
+
+--- 192.0.2.2 ping statistics ---
+1 packets transmitted, 1 packets received, 0.0% packet loss
+round-trip min/avg/max/stddev = /// ms
+""",
+                "stderr": "",
+                "redacted": True,
+            },
+            id="_0_0_special_wrong",
+        ),
     ]
 
     @pytest.mark.parametrize("pinger_kargs, expected", pinger_testdata)