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plugin: handle corner case where rpc_command is to stop the plugin.

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Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell
2019-12-06 14:38:27 +10:30
committed by Christian Decker
parent d8fc5332c3
commit f6ed7f2e89
4 changed files with 73 additions and 13 deletions
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69
lightningd/plugin.c
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@@ -233,6 +233,7 @@ static void plugin_response_handle(struct plugin *plugin,
const jsmntok_t *toks,
const jsmntok_t *idtok)
{
struct plugin_destroyed *pd;
struct jsonrpc_request *request;
u64 id;
/* We only send u64 ids, so if this fails it's a critical error (note
@@ -253,9 +254,13 @@ static void plugin_response_handle(struct plugin *plugin,
}
/* We expect the request->cb to copy if needed */
pd = plugin_detect_destruction(plugin);
request->response_cb(plugin->buffer, toks, idtok, request->response_cb_arg);
tal_free(request);
/* Note that in the case of 'plugin stop' this can free request (since
* plugin is parent), so detect that case */
if (!was_plugin_destroyed(pd))
tal_free(request);
}
/**
@@ -264,10 +269,15 @@ static void plugin_response_handle(struct plugin *plugin,
* Internally calls the handler if it was able to fully parse a JSON message,
* and returns true in that case.
*/
static bool plugin_read_json_one(struct plugin *plugin)
static bool plugin_read_json_one(struct plugin *plugin, bool *destroyed)
{
bool valid;
const jsmntok_t *toks, *jrtok, *idtok;
struct plugin_destroyed *pd;
*destroyed = false;
/* Note that in the case of 'plugin stop' this can free request (since
* plugin is parent), so detect that case */
/* FIXME: This could be done more efficiently by storing the
* toks and doing an incremental parse, like lightning-cli
@@ -300,6 +310,7 @@ static bool plugin_read_json_one(struct plugin *plugin)
return false;
}
pd = plugin_detect_destruction(plugin);
if (!idtok) {
/* A Notification is a Request object without an "id"
* member. A Request object that is a Notification
@@ -345,15 +356,21 @@ static bool plugin_read_json_one(struct plugin *plugin)
plugin_response_handle(plugin, toks, idtok);
}
/* Move this object out of the buffer */
memmove(plugin->buffer, plugin->buffer + toks[0].end,
tal_count(plugin->buffer) - toks[0].end);
plugin->used -= toks[0].end;
tal_free(toks);
/* Corner case: rpc_command hook can destroy plugin for 'plugin
* stop'! */
if (was_plugin_destroyed(pd)) {
*destroyed = true;
} else {
/* Move this object out of the buffer */
memmove(plugin->buffer, plugin->buffer + toks[0].end,
tal_count(plugin->buffer) - toks[0].end);
plugin->used -= toks[0].end;
tal_free(toks);
}
return true;
}
static struct io_plan *plugin_read_json(struct io_conn *conn UNUSED,
static struct io_plan *plugin_read_json(struct io_conn *conn,
struct plugin *plugin)
{
bool success;
@@ -367,7 +384,12 @@ static struct io_plan *plugin_read_json(struct io_conn *conn UNUSED,
/* Read and process all messages from the connection */
do {
success = plugin_read_json_one(plugin);
bool destroyed;
success = plugin_read_json_one(plugin, &destroyed);
/* If it's destroyed, conn is already freed! */
if (destroyed)
return io_close(NULL);
/* Processing the message from the plugin might have
* resulted in it stopping, so let's check. */
@@ -1203,3 +1225,32 @@ struct log *plugin_get_log(struct plugin *plugin)
{
return plugin->log;
}
struct plugin_destroyed {
const struct plugin *plugin;
};
static void mark_plugin_destroyed(const struct plugin *unused,
struct plugin_destroyed *pd)
{
pd->plugin = NULL;
}
struct plugin_destroyed *plugin_detect_destruction(const struct plugin *plugin)
{
struct plugin_destroyed *pd = tal(NULL, struct plugin_destroyed);
pd->plugin = plugin;
tal_add_destructor2(plugin, mark_plugin_destroyed, pd);
return pd;
}
bool was_plugin_destroyed(struct plugin_destroyed *pd)
{
if (pd->plugin) {
tal_del_destructor2(pd->plugin, mark_plugin_destroyed, pd);
tal_free(pd);
return false;
}
tal_free(pd);
return true;
}