cyclic command: improve UX (#1522)

pwndbg/commands/cyclic.py

@@ -66,10 +66,19 @@ def cyclic_cmd(alphabet, length, lookup, count=100) -> None:
             lookup = bytes(lookup, "utf-8")
 
         if len(lookup) != length:
-            print(message.error(f"Lookup pattern must be {length} bytes"))
+            print(
+                message.error(
+                    f"Lookup pattern must be {length} bytes (use `-n <length>` to lookup pattern of different length)"
+                )
+            )
             return
 
-        print(message.notice(f"Lookup value: {str(lookup)}"))
+        hexstr = "0x" + lookup.hex()
+        print(
+            message.notice(
+                f"Finding cyclic pattern of {length} bytes: {str(lookup)} (hex: {hexstr})"
+            )
+        )
 
         if any(c not in alphabet for c in lookup):
             print(message.error("Pattern contains characters not present in the alphabet"))
@@ -80,7 +89,7 @@ def cyclic_cmd(alphabet, length, lookup, count=100) -> None:
         if offset == -1:
             print(message.error("Given lookup pattern does not exist in the sequence"))
         else:
-            print(message.success(offset))
+            print(message.success(f"Found at offset {offset}"))
     else:
         sequence = cyclic(int(count), alphabet, length)
         print(sequence.decode())

tests/gdb-tests/tests/test_command_cyclic.py

@@ -21,7 +21,10 @@ def test_command_cyclic_value(start_binary):
     val = int.from_bytes(pattern[test_offset : test_offset + ptr_size], pwndbg.gdblib.arch.endian)
     out = gdb.execute(f"cyclic -l {hex(val)}", to_string=True)
 
-    assert int(out.split("\n")[1]) == test_offset
+    assert out == (
+        "Finding cyclic pattern of 8 bytes: b'aaafaaaa' (hex: 0x6161616661616161)\n"
+        "Found at offset 37\n"
+    )
 
 
 def test_command_cyclic_register(start_binary):
@@ -38,7 +41,10 @@ def test_command_cyclic_register(start_binary):
     )
     out = gdb.execute("cyclic -l $rdi", to_string=True)
 
-    assert int(out.split("\n")[1]) == test_offset
+    assert out == (
+        "Finding cyclic pattern of 8 bytes: b'aaagaaaa' (hex: 0x6161616761616161)\n"
+        "Found at offset 45\n"
+    )
 
 
 def test_command_cyclic_address(start_binary):
@@ -54,4 +60,22 @@ def test_command_cyclic_address(start_binary):
     pwndbg.gdblib.memory.write(addr, pattern)
     out = gdb.execute(f"cyclic -l '{{unsigned long}}{hex(addr + test_offset)}'", to_string=True)
 
-    assert int(out.split("\n")[1]) == test_offset
+    assert out == (
+        "Finding cyclic pattern of 8 bytes: b'gaaaaaaa' (hex: 0x6761616161616161)\n"
+        "Found at offset 48\n"
+    )
+
+
+def test_command_cyclic_wrong_alphabet():
+    out = gdb.execute("cyclic -l 1234", to_string=True)
+    assert out == (
+        "Finding cyclic pattern of 4 bytes: b'\\xd2\\x04\\x00\\x00' (hex: 0xd2040000)\n"
+        "Pattern contains characters not present in the alphabet\n"
+    )
+
+
+def test_command_cyclic_wrong_length():
+    out = gdb.execute("cyclic -l qwerty", to_string=True)
+    assert out == (
+        "Lookup pattern must be 4 bytes (use `-n <length>` to lookup pattern of different length)\n"
+    )