plugin: Some cleanups that didn't make it into part 2 of the plugin saga

CHANGELOG.md

@@ -11,7 +11,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - JSON API: `getinfo` now returns `num_peers` `num_pending_channels`,
   `num_active_channels` and `num_inactive_channels` fields.
 - JSON API: use `\n\n` to terminate responses, for simplified parsing (pylightning now relies on this)
-- Plugins: Added plugins to `lightningd` and implemented the option passthrough.
+- Plugins: Added plugins to `lightningd`, including option passthrough and JSON-RPC passthrough.
 
 ### Changed
 

common/utils.c

@@ -49,3 +49,15 @@ void clean_tmpctx(void)
 	while ((p = tal_first(tmpctx)) != NULL)
 		tal_free(p);
 }
+
+void tal_arr_remove_(void *p, size_t elemsize, size_t n)
+{
+    // p is a pointer-to-pointer for tal_resize.
+    char *objp = *(char **)p;
+    size_t len = tal_bytelen(objp);
+    assert(len % elemsize == 0);
+    assert((n + 1) * elemsize <= len);
+    memmove(objp + elemsize * n, objp + elemsize * (n+1),
+                      len - (elemsize * (n+1)));
+    tal_resize((char **)p, len - elemsize);
+}

common/utils.h

@@ -29,6 +29,15 @@ u8 *tal_hexdata(const tal_t *ctx, const void *str, size_t len);
 	(tal_resize((p), tal_count(*(p))+1), (*p) + tal_count(*(p))-1)
 #endif
 
+/**
+ * Remove an element from an array
+ *
+ * This will shift the elements past the removed element, changing
+ * their position in memory, so only use this for arrays of pointers.
+ */
+#define tal_arr_remove(p, n) tal_arr_remove_((p), sizeof(**p), (n))
+void tal_arr_remove_(void *p, size_t elemsize, size_t n);
+
 /* Use the POSIX C locale. */
 void setup_locale(void);
 

contrib/plugins/fail/failtimeout.py

@@ -0,0 +1,58 @@
+#!/usr/bin/env python3
+"""An example plugin that fails to answer to `getmanifest`
+
+Used to test the `getmanifest` timeout.
+"""
+import json
+import sys
+import time
+
+
+def json_getmanifest(request):
+    # Timeout is 10 seconds, so wait 11
+    time.sleep(11)
+    return {
+        "options": [
+        ],
+        "rpcmethods": [
+        ]
+    }
+
+
+methods = {
+    'getmanifest': json_getmanifest,
+}
+
+
+partial = ""
+for l in sys.stdin:
+    try:
+        partial += l
+        request = json.loads(partial)
+    except Exception:
+        continue
+
+    result = None
+    method = methods[request['method']]
+    params = request['params']
+    try:
+        if isinstance(params, dict):
+            result = method(request, **params)
+        else:
+            result = method(request, *params)
+        result = {
+            "jsonrpc": "2.0",
+            "result": result,
+            "id": request['id']
+        }
+    except Exception as e:
+        result = {
+            "jsonrpc": "2.0",
+            "error": "Error while processing {}".format(request['method']),
+            "id": request['id']
+        }
+
+    json.dump(result, fp=sys.stdout)
+    sys.stdout.write('\n')
+    sys.stdout.flush()
+    partial = ""

lightningd/jsonrpc.c

@@ -347,11 +347,8 @@ static const struct json_command *find_cmd(const struct jsonrpc *rpc,
 {
 	struct json_command **commands = rpc->commands;
 
-	/* commands[i] can be NULL if the plugin that registered it
-	 * was killed, commands[i]->name can be NULL in test code. */
 	for (size_t i = 0; i < tal_count(commands); i++)
-		if (commands[i] && commands[i]->name &&
-		    json_tok_streq(buffer, tok, commands[i]->name))
+		if (json_tok_streq(buffer, tok, commands[i]->name))
 			return commands[i];
 	return NULL;
 }
@@ -731,8 +728,7 @@ bool jsonrpc_command_add(struct jsonrpc *rpc, struct json_command *command)
 
 	/* Check that we don't clobber a method */
 	for (size_t i = 0; i < count; i++)
-		if (rpc->commands[i] != NULL &&
-		    streq(rpc->commands[i]->name, command->name))
+		if (streq(rpc->commands[i]->name, command->name))
 			return false;
 
 	*tal_arr_expand(&rpc->commands) = command;
@@ -741,12 +737,12 @@ bool jsonrpc_command_add(struct jsonrpc *rpc, struct json_command *command)
 
 void jsonrpc_command_remove(struct jsonrpc *rpc, const char *method)
 {
-	// FIXME: Currently leaves NULL entries in the table, if we
-	// restart plugins we should shift them out.
 	for (size_t i=0; i<tal_count(rpc->commands); i++) {
 		struct json_command *cmd = rpc->commands[i];
-		if (cmd && streq(cmd->name, method)) {
-			rpc->commands[i] = tal_free(cmd);
+		if (streq(cmd->name, method)) {
+			tal_arr_remove(&rpc->commands, i);
+			tal_free(cmd);
+			break;
 		}
 	}
 }