generate-dissector.py: allow creating plugin

Tweak the script used for creating a new skeleton dissector, to allow it
to create the dissector in `plugins/epan/PROTOSHORTNAME` instead of in
`epan/dissectors`. Handles modifying the appropriate CMake file in the
appropriate way, and generates the plugin's `CMakeLists.txt` if needed.

doc/CMakeLists-PROTOABBREV.txt

@@ -0,0 +1,71 @@
+# CMakeLists.txt
+#
+# Wireshark - Network traffic analyzer
+# Copyright YEARS, YOUR_NAME <YOUR_EMAIL_ADDRESS>
+#
+# SPDX-License-Identifier: LICENSE
+#
+
+include(WiresharkPlugin)
+
+# Plugin name and version info (major minor micro extra)
+set_module_info(PROTOABBREV 0 0 1 0)
+
+set(DISSECTOR_SRC
+	# Source files that directly dissect data
+	packet-PROTOABBREV.c
+)
+
+set(DISSECTOR_SUPPORT_SRC
+	# Source files that provide additional routines
+)
+
+set(PLUGIN_FILES
+	plugin.c
+	${DISSECTOR_SRC}
+	${DISSECTOR_SUPPORT_SRC}
+)
+
+set_source_files_properties(
+	${PLUGIN_FILES}
+	PROPERTIES
+	COMPILE_FLAGS "${WERROR_COMMON_FLAGS}"
+)
+
+register_plugin_files(plugin.c
+	plugin
+	${DISSECTOR_SRC}
+	${DISSECTOR_SUPPORT_SRC}
+)
+
+add_wireshark_plugin_library(PROTOABBREV epan)
+
+target_link_libraries(PROTOABBREV epan)
+
+install_plugin(PROTOABBREV epan)
+
+file(GLOB DISSECTOR_HEADERS RELATIVE "${CMAKE_CURRENT_SOURCE_DIR}" "*.h")
+CHECKAPI(
+	NAME
+	  PROTOABBREV
+	SWITCHES
+	  --group dissectors-prohibited
+	  --group dissectors-restricted
+	SOURCES
+	  ${DISSECTOR_SRC}
+	  ${DISSECTOR_SUPPORT_SRC}
+	  ${DISSECTOR_HEADERS}
+)
+
+#
+# Editor modelines  -  https://www.wireshark.org/tools/modelines.html
+#
+# Local variables:
+# c-basic-offset: 8
+# tab-width: 8
+# indent-tabs-mode: t
+# End:
+#
+# vi: set shiftwidth=8 tabstop=8 noexpandtab:
+# :indentSize=8:tabSize=8:noTabs=false:
+#

tools/generate-dissector.py

@@ -27,21 +27,29 @@ parser.add_argument("--email", help="The email address of the author", required=
 parser.add_argument("--protoname", help="The name of the protocol", required=True)
 parser.add_argument("--protoshortname", help="The protocol short name", required=True)
 parser.add_argument("--protoabbrev", help="The protocol abbreviation", required=True)
-parser.add_argument("--license", help="The license for this dissector (please use a SPDX-License-Identifier). If omitted, GPL-2.0-or-later will be used")
-parser.add_argument("--years", help="Years of validity for the license. If omitted, the current year will be used")
+parser.add_argument("--license", help="The license for this dissector (please use a SPDX-License-Identifier). If omitted, %(default)s will be used", default="GPL-2.0-or-later")
+parser.add_argument("--years", help="Years of validity for the license. If omitted, the current year will be used", default=str(datetime.now().year))
 parser.add_argument("-f", "--force", action='store_true', help="Force overwriting the dissector file if it already exists")
+parser.add_argument("-p", "--plugin", action='store_true', help="Create as a plugin. Default is to create in epan")
 
 
 def wsdir():
     return os.path.abspath(os.path.join(os.path.dirname(__file__), ".."))
 
 
+def output_dir(args):
+    if args.plugin:
+        os.makedirs(os.path.join(wsdir(), "plugins/epan/" + args.protoabbrev), exist_ok=True)
+        return os.path.join(wsdir(), "plugins/epan/" + args.protoabbrev)
+    return os.path.join(wsdir(), "epan/dissectors")
+
+
 def output_file(args):
-    return os.path.join(wsdir(), "epan/dissectors/packet-" + args.protoabbrev + ".c")
+    return os.path.join(output_dir(args), "packet-" + args.protoabbrev + ".c")
 
 
-def read_skeleton():
-    skeletonfile = os.path.join(wsdir(), "doc/packet-PROTOABBREV.c")
+def read_skeleton(filename):
+    skeletonfile = os.path.join(wsdir(), "doc/" + filename)
     print("Reading skeleton file: " + skeletonfile)
     return open(skeletonfile).read()
 
@@ -68,17 +76,9 @@ def replace_fields(buffer, args):
         .replace("PI_GROUP", "PI_PROTOCOL")\
         .replace("PI_SEVERITY", "PI_ERROR")\
         .replace("TEST_EXPERT_condition", "0")\
-        .replace("const char *subtree", "\"\"")
-
-    if args.license:
-        output = output.replace("LICENSE", args.license)
-    else:
-        output = output.replace("LICENSE", "GPL-2.0-or-later")
-
-    if args.years:
-        output = output.replace("YEARS", args.years)
-    else:
-        output = output.replace("YEARS", str(datetime.now().year))
+        .replace("const char *subtree", "\"\"")\
+        .replace("LICENSE", args.license)\
+        .replace("YEARS", args.years)
 
     return output
 
@@ -92,10 +92,16 @@ def write_dissector(buffer, args):
 
 
 def patch_makefile(args):
+    if args.plugin:
+        cmakefile = os.path.join(wsdir(), "CMakeLists.txt")
+        patchline = "\t\tplugins/epan/" + args.protoabbrev
+        groupstart = "set(PLUGIN_SRC_DIRS"
+    else:
         cmakefile = os.path.join(wsdir(), "epan/dissectors/CMakeLists.txt")
+        patchline = "\t${CMAKE_CURRENT_SOURCE_DIR}/packet-" + args.protoabbrev + ".c"
+        groupstart = "set(DISSECTOR_SRC"
     print("Patching makefile: " + cmakefile)
     output = ""
-    patchline = "${CMAKE_CURRENT_SOURCE_DIR}/packet-" + args.protoabbrev + ".c"
     in_group = False
     patched = False
     for line in open(cmakefile):
@@ -103,15 +109,24 @@ def patch_makefile(args):
         if in_group and line_strip == ")":
             in_group = False
         if in_group and not patched and line_strip > patchline:
-            output += "\t" + patchline + "\n"
+            output += patchline + "\n"
             patched = True
-        if line_strip == "set(DISSECTOR_SRC":
+        if line_strip == groupstart:
             in_group = True
         if line_strip != patchline:
             output += line
     open(cmakefile, "w").write(output)
 
 
+def write_plugin_makefile(args):
+    if not args.plugin:
+        return True
+    buffer = replace_fields(read_skeleton("CMakeLists-PROTOABBREV.txt"), args)
+    ofile = os.path.join(output_dir(args), "CMakeLists.txt")
+    print("Writing output file: " + ofile)
+    return open(ofile, "w").write(buffer)
+
+
 def print_header():
     print("")
     print("**************************************************")
@@ -136,7 +151,8 @@ def print_trailer(args):
 if __name__ == '__main__':
     print_header()
     args = parser.parse_args()
-    buffer = replace_fields(read_skeleton(), args)
+    buffer = replace_fields(read_skeleton("packet-PROTOABBREV.c"), args)
     write_dissector(buffer, args)
     patch_makefile(args)
+    write_plugin_makefile(args)
     print_trailer(args)