core-lightning/lightningd/plugin.c
Christian Decker 230730eca4 plugin: Migrate request creation to json_stream
We can use the internal buffering of the json_stream instead of
manually building JSON-RPC calls. This makes it a lot easier to handle
these requests.

Notice that we do not flush concurrently and still buffer all the
things, but it avoids double-buffering things.

Signed-off-by: Christian Decker <decker.christian@gmail.com>
2018-12-05 23:15:59 +00:00

845 lines
24 KiB
C

#include "lightningd/plugin.h"
#include <ccan/intmap/intmap.h>
#include <ccan/io/io.h>
#include <ccan/list/list.h>
#include <ccan/opt/opt.h>
#include <ccan/pipecmd/pipecmd.h>
#include <ccan/tal/path/path.h>
#include <ccan/tal/str/str.h>
#include <ccan/utf8/utf8.h>
#include <common/memleak.h>
#include <common/timeout.h>
#include <dirent.h>
#include <errno.h>
#include <lightningd/json.h>
#include <lightningd/jsonrpc_errors.h>
#include <lightningd/lightningd.h>
#include <signal.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
/* How many seconds may the plugin take to reply to the `getmanifest
* call`? This is the maximum delay to `lightningd --help` and until
* we can start the main `io_loop` to communicate with peers. If this
* hangs we can't do much, so we put an upper bound on the time we're
* willing to wait. Plugins shouldn't do any initialization in the
* `getmanifest` call anyway, that's what `init `is for. */
#define PLUGIN_MANIFEST_TIMEOUT 10
struct plugin {
struct list_node list;
pid_t pid;
char *cmd;
struct io_conn *stdin_conn, *stdout_conn;
bool stop;
struct plugins *plugins;
const char **plugin_path;
/* Stuff we read */
char *buffer;
size_t used, len_read;
/* Our json_streams. Since multiple streams could start
* returning data at once, we always service these in order,
* freeing once empty. */
struct json_stream **js_arr;
struct log *log;
/* List of options that this plugin registered */
struct list_head plugin_opts;
const char **methods;
/* Timer to add a timeout to some plugin RPC calls. Used to
* guarantee that `getmanifest` doesn't block indefinitely. */
const struct oneshot *timeout_timer;
};
struct plugin_request {
u64 id;
struct plugin *plugin;
/* Method to be called */
const char *method;
/* JSON encoded params, either a dict or an array */
const char *json_params;
const char *response;
const jsmntok_t *resulttok, *errortok, *toks;
struct json_stream *stream;
/* The response handler to be called on success or error */
void (*cb)(const struct plugin_request *, void *);
void *arg;
};
struct plugins {
struct list_head plugins;
size_t pending_manifests;
/* Currently pending requests by their request ID */
UINTMAP(struct plugin_request *) pending_requests;
struct log *log;
struct log_book *log_book;
/* RPC interface to bind JSON-RPC methods to */
struct jsonrpc *rpc;
struct timers timers;
};
/* Represents a pending JSON-RPC request that was forwarded to a
* plugin and is currently waiting for it to return the result. */
struct plugin_rpc_request {
/* The json-serialized ID as it was passed to us by the
* client, will be used to return the result */
const char *id;
const char *method;
const char *params;
struct plugin *plugin;
struct command *cmd;
};
/* Simple storage for plugin options inbetween registering them on the
* command line and passing them off to the plugin */
struct plugin_opt {
struct list_node list;
const char *name;
const char *description;
char *value;
};
struct plugins *plugins_new(const tal_t *ctx, struct log_book *log_book,
struct jsonrpc *rpc)
{
struct plugins *p;
p = tal(ctx, struct plugins);
list_head_init(&p->plugins);
p->log_book = log_book;
p->log = new_log(p, log_book, "plugin-manager");
p->rpc = rpc;
timers_init(&p->timers, time_mono());
return p;
}
void plugin_register(struct plugins *plugins, const char* path TAKES)
{
struct plugin *p;
p = tal(plugins, struct plugin);
list_add_tail(&plugins->plugins, &p->list);
p->plugins = plugins;
p->cmd = tal_strdup(p, path);
p->js_arr = tal_arr(p, struct json_stream *, 0);
p->used = 0;
p->log = new_log(p, plugins->log_book, "plugin-%s",
path_basename(tmpctx, p->cmd));
p->methods = tal_arr(p, const char *, 0);
list_head_init(&p->plugin_opts);
}
static bool paths_match(const char *cmd, const char *name)
{
if (strchr(name, PATH_SEP)) {
const char *cmd_canon, *name_canon;
if (streq(cmd, name))
return true;
/* These return NULL path doesn't exist */
cmd_canon = path_canon(tmpctx, cmd);
name_canon = path_canon(tmpctx, name);
return cmd_canon && name_canon && streq(name_canon, cmd_canon);
} else {
/* No path separator means a basename match. */
const char *base = path_basename(tmpctx, cmd);
return streq(base, name);
}
}
bool plugin_remove(struct plugins *plugins, const char *name)
{
struct plugin *p, *next;
bool removed = false;
list_for_each_safe(&plugins->plugins, p, next, list) {
if (paths_match(p->cmd, name)) {
list_del_from(&plugins->plugins, &p->list);
tal_free(p);
removed = true;
}
}
return removed;
}
/**
* Kill a plugin process, with an error message.
*/
static void PRINTF_FMT(2,3) plugin_kill(struct plugin *plugin, char *fmt, ...)
{
char *msg;
va_list ap;
va_start(ap, fmt);
msg = tal_vfmt(plugin, fmt, ap);
va_end(ap);
log_broken(plugin->log, "Killing plugin: %s", msg);
plugin->stop = true;
io_wake(plugin);
kill(plugin->pid, SIGKILL);
list_del(&plugin->list);
tal_free(plugin);
}
/**
* Create the header of a JSON-RPC request and return open stream.
*
* This is a partial request, missing the params element, which the
* caller needs to add. We can't open it yet since we don't know
* whether it is supposed to be an object (name-value pairs) or an
* array.
*/
static struct plugin_request *
plugin_request_new_(struct plugin *plugin, const char *method,
void (*cb)(const struct plugin_request *, void *),
void *arg)
{
static u64 next_request_id = 0;
struct plugin_request *req = tal(plugin, struct plugin_request);
u64 request_id = next_request_id++;
req->id = request_id;
req->method = tal_strdup(req, method);
req->cb = cb;
req->arg = arg;
req->plugin = plugin;
/* We will not concurrently drain, if we do we must set the
* writer to non-NULL */
req->stream = new_json_stream(req, NULL);
/* Add to map so we can find it later when routing the response */
uintmap_add(&plugin->plugins->pending_requests, req->id, req);
json_object_start(req->stream, NULL);
json_add_string(req->stream, "jsonrpc", "2.0");
json_add_string(req->stream, "method", method);
json_add_u64(req->stream, "id", request_id);
return req;
}
#define plugin_request_new(plugin, method, cb, arg) \
plugin_request_new_( \
(plugin), (method), \
typesafe_cb_preargs(void, void *, (cb), (arg), \
const struct plugin_request *), \
(arg))
/**
* Given a request, send it to the plugin.
*/
static void plugin_request_queue(struct plugin_request *req)
{
/* Finish the `params` object and submit the request */
json_object_end(req->stream); /* root element */
json_stream_append(req->stream, "\n\n");
*tal_arr_expand(&req->plugin->js_arr) = req->stream;
io_wake(req->plugin);
}
/**
* Try to parse a complete message from the plugin's buffer.
*
* 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)
{
jsmntok_t *toks;
bool valid;
u64 id;
const jsmntok_t *idtok, *resulttok, *errortok;
struct plugin_request *request;
/* FIXME: This could be done more efficiently by storing the
* toks and doing an incremental parse, like lightning-cli
* does. */
toks = json_parse_input(plugin->buffer, plugin->used, &valid);
if (!toks) {
if (!valid) {
plugin_kill(plugin, "Failed to parse JSON response");
return false;
}
/* We need more. */
return false;
}
/* Empty buffer? (eg. just whitespace). */
if (tal_count(toks) == 1) {
plugin->used = 0;
return false;
}
resulttok = json_get_member(plugin->buffer, toks, "result");
errortok = json_get_member(plugin->buffer, toks, "error");
idtok = json_get_member(plugin->buffer, toks, "id");
if (!idtok) {
plugin_kill(plugin, "JSON-RPC response does not contain an \"id\"-field");
return false;
} else if (!resulttok && !errortok) {
plugin_kill(plugin, "JSON-RPC response does not contain a \"result\" or \"error\" field");
return false;
}
/* We only send u64 ids, so if this fails it's a critical error */
if (!json_to_u64(plugin->buffer, idtok, &id)) {
plugin_kill(plugin, "JSON-RPC response \"id\"-field is not a u64");
return false;
}
request = uintmap_get(&plugin->plugins->pending_requests, id);
if (!request) {
plugin_kill(plugin, "Received a JSON-RPC response for non-existent request");
return false;
}
/* We expect the request->cb to copy if needed */
request->response = plugin->buffer;
request->errortok = errortok;
request->resulttok = resulttok;
request->toks = toks;
request->cb(request, request->arg);
tal_free(request);
uintmap_del(&plugin->plugins->pending_requests, id);
/* 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,
struct plugin *plugin)
{
bool success;
plugin->used += plugin->len_read;
if (plugin->used == tal_count(plugin->buffer))
tal_resize(&plugin->buffer, plugin->used * 2);
/* Read and process all messages from the connection */
do {
success = plugin_read_json_one(plugin);
} while (success);
if (plugin->stop)
return io_close(plugin->stdout_conn);
/* Now read more from the connection */
return io_read_partial(plugin->stdout_conn,
plugin->buffer + plugin->used,
tal_count(plugin->buffer) - plugin->used,
&plugin->len_read, plugin_read_json, plugin);
}
/* Mutual recursion */
static struct io_plan *plugin_write_json(struct io_conn *conn,
struct plugin *plugin);
static struct io_plan *plugin_stream_complete(struct io_conn *conn, struct json_stream *js, struct plugin *plugin)
{
size_t pending = tal_count(plugin->js_arr);
/* Remove js and shift all remainig over */
tal_free(plugin->js_arr[0]);
memmove(plugin->js_arr, plugin->js_arr + 1, (pending - 1) * sizeof(plugin->js_arr[0]));
tal_resize(&plugin->js_arr, pending-1);
return plugin_write_json(conn, plugin);
}
static struct io_plan *plugin_write_json(struct io_conn *conn,
struct plugin *plugin)
{
if (tal_count(plugin->js_arr)) {
return json_stream_output(plugin->js_arr[0], plugin->stdin_conn, plugin_stream_complete, plugin);
}
return io_out_wait(conn, plugin, plugin_write_json, plugin);
}
static struct io_plan *plugin_stdin_conn_init(struct io_conn *conn,
struct plugin *plugin)
{
/* We write to their stdin */
/* We don't have anything queued yet, wait for notification */
plugin->stdin_conn = conn;
return io_wait(plugin->stdin_conn, plugin, plugin_write_json, plugin);
}
static struct io_plan *plugin_stdout_conn_init(struct io_conn *conn,
struct plugin *plugin)
{
/* We read from their stdout */
plugin->stdout_conn = conn;
return io_read_partial(plugin->stdout_conn, plugin->buffer,
tal_bytelen(plugin->buffer), &plugin->len_read,
plugin_read_json, plugin);
}
/* Callback called when parsing options. It just stores the value in
* the plugin_opt */
static char *plugin_opt_set(const char *arg, struct plugin_opt *popt)
{
tal_free(popt->value);
popt->value = tal_strdup(popt, arg);
return NULL;
}
/* Add a single plugin option to the plugin as well as registering it with the
* command line options. */
static bool plugin_opt_add(struct plugin *plugin, const char *buffer,
const jsmntok_t *opt)
{
const jsmntok_t *nametok, *typetok, *defaulttok, *desctok;
struct plugin_opt *popt;
nametok = json_get_member(buffer, opt, "name");
typetok = json_get_member(buffer, opt, "type");
desctok = json_get_member(buffer, opt, "description");
defaulttok = json_get_member(buffer, opt, "default");
if (!typetok || !nametok || !desctok) {
plugin_kill(plugin,
"An option is missing either \"name\", \"description\" or \"type\"");
return false;
}
/* FIXME(cdecker) Support numeric and boolean options as well */
if (!json_tok_streq(buffer, typetok, "string")) {
plugin_kill(plugin,
"Only \"string\" options currently supported");
return false;
}
popt = tal(plugin, struct plugin_opt);
popt->name = tal_fmt(plugin, "--%.*s", nametok->end - nametok->start,
buffer + nametok->start);
popt->value = NULL;
if (defaulttok) {
popt->value = tal_strndup(popt, buffer + defaulttok->start,
defaulttok->end - defaulttok->start);
popt->description = tal_fmt(
popt, "%.*s (default: %s)", desctok->end - desctok->start,
buffer + desctok->start, popt->value);
} else {
popt->description = tal_strndup(popt, buffer + desctok->start,
desctok->end - desctok->start);
}
list_add_tail(&plugin->plugin_opts, &popt->list);
opt_register_arg(popt->name, plugin_opt_set, NULL, popt,
popt->description);
return true;
}
/* Iterate through the options in the manifest response, and add them
* to the plugin and the command line options */
static bool plugin_opts_add(const struct plugin_request *req)
{
const char *buffer = req->plugin->buffer;
const jsmntok_t *options =
json_get_member(req->plugin->buffer, req->resulttok, "options");
if (!options) {
plugin_kill(req->plugin,
"\"result.options\" was not found in the manifest");
return false;
}
if (options->type != JSMN_ARRAY) {
plugin_kill(req->plugin, "\"result.options\" is not an array");
return false;
}
for (size_t i = 0; i < options->size; i++)
if (!plugin_opt_add(req->plugin, buffer, json_get_arr(options, i)))
return false;
return true;
}
static void plugin_rpcmethod_destroy(struct json_command *cmd,
struct jsonrpc *rpc)
{
jsonrpc_command_remove(rpc, cmd->name);
}
static void plugin_rpcmethod_cb(const struct plugin_request *req,
struct plugin_rpc_request *rpc_req)
{
struct json_stream *response;
const jsmntok_t *res;
assert(req->resulttok || req->errortok);
if (req->errortok) {
res = req->errortok;
command_fail(rpc_req->cmd, PLUGIN_ERROR, "%.*s",
res->end - res->start, req->response + res->start);
tal_free(rpc_req);
return;
}
res = req->resulttok;
response = json_stream_success(rpc_req->cmd);
json_add_member(response, NULL, "%.*s", json_tok_len(res),
json_tok_contents(req->response, res));
command_success(rpc_req->cmd, response);
tal_free(rpc_req);
}
static void plugin_rpcmethod_dispatch(struct command *cmd, const char *buffer,
const jsmntok_t *params)
{
const jsmntok_t *toks = params, *methtok, *idtok;
struct plugin_rpc_request *request;
struct plugins *plugins = cmd->ld->plugins;
struct plugin *plugin;
struct plugin_request *req;
if (cmd->mode == CMD_USAGE) {
cmd->usage = "[params]";
return;
}
/* We're given the params, but we need to walk back to the
* root object, so just walk backwards until the current
* element has no parents, that's going to be the root
* element. */
while (toks->parent != -1)
toks--;
methtok = json_get_member(buffer, toks, "method");
idtok = json_get_member(buffer, toks, "id");
/* We've parsed them before, these should not fail! */
assert(idtok != NULL && methtok != NULL);
request = tal(NULL, struct plugin_rpc_request);
request->method = tal_strndup(request, buffer + methtok->start,
methtok->end - methtok->start);
request->id = tal_strndup(request, buffer + idtok->start,
idtok->end - idtok->start);
request->params = tal_strndup(request, buffer + params->start,
params->end - params->start);
request->plugin = NULL;
request->cmd = cmd;
/* Find the plugin that registered this RPC call */
list_for_each(&plugins->plugins, plugin, list) {
for (size_t i=0; i<tal_count(plugin->methods); i++) {
if (streq(request->method, plugin->methods[i])) {
request->plugin = plugin;
goto found;
}
}
}
found:
/* This should never happen, it'd mean that a plugin didn't
* cleanup after dying */
assert(request->plugin);
tal_steal(request->plugin, request);
req = plugin_request_new(request->plugin, request->method, plugin_rpcmethod_cb, request);
json_stream_append_fmt(req->stream, ", \"params\": %s", request->params);
plugin_request_queue(req);
command_still_pending(cmd);
}
static bool plugin_rpcmethod_add(struct plugin *plugin, const char *buffer,
const jsmntok_t *meth)
{
const jsmntok_t *nametok, *desctok, *longdesctok;
struct json_command *cmd;
nametok = json_get_member(buffer, meth, "name");
desctok = json_get_member(buffer, meth, "description");
longdesctok = json_get_member(buffer, meth, "long_description");
if (!nametok || nametok->type != JSMN_STRING) {
plugin_kill(plugin,
"rpcmethod does not have a string \"name\": %.*s",
meth->end - meth->start, buffer + meth->start);
return false;
}
if (!desctok || desctok->type != JSMN_STRING) {
plugin_kill(plugin,
"rpcmethod does not have a string "
"\"description\": %.*s",
meth->end - meth->start, buffer + meth->start);
return false;
}
if (longdesctok && longdesctok->type != JSMN_STRING) {
plugin_kill(plugin,
"\"long_description\" is not a string: %.*s",
meth->end - meth->start, buffer + meth->start);
return false;
}
cmd = notleak(tal(plugin, struct json_command));
cmd->name = tal_strndup(cmd, buffer + nametok->start,
nametok->end - nametok->start);
cmd->description = tal_strndup(cmd, buffer + desctok->start,
desctok->end - desctok->start);
if (longdesctok)
cmd->verbose =
tal_strndup(cmd, buffer + longdesctok->start,
longdesctok->end - longdesctok->start);
else
cmd->verbose = cmd->description;
cmd->deprecated = false;
cmd->dispatch = plugin_rpcmethod_dispatch;
tal_add_destructor2(cmd, plugin_rpcmethod_destroy, plugin->plugins->rpc);
if (!jsonrpc_command_add(plugin->plugins->rpc, cmd)) {
log_broken(plugin->log,
"Could not register method \"%s\", a method with "
"that name is already registered",
cmd->name);
return false;
}
*tal_arr_expand(&plugin->methods) = cmd->name;
return true;
}
static bool plugin_rpcmethods_add(const struct plugin_request *req)
{
const char *buffer = req->plugin->buffer;
const jsmntok_t *methods =
json_get_member(req->plugin->buffer, req->resulttok, "rpcmethods");
if (!methods)
return false;
if (methods->type != JSMN_ARRAY) {
plugin_kill(req->plugin,
"\"result.rpcmethods\" is not an array");
return false;
}
for (size_t i = 0; i < methods->size; i++)
if (!plugin_rpcmethod_add(req->plugin, buffer,
json_get_arr(methods, i)))
return false;
return true;
}
static void plugin_manifest_timeout(struct plugin *plugin)
{
log_broken(plugin->log, "The plugin failed to respond to \"getmanifest\" in time, terminating.");
fatal("Can't recover from plugin failure, terminating.");
}
/**
* Callback for the plugin_manifest request.
*/
static void plugin_manifest_cb(const struct plugin_request *req, struct plugin *plugin)
{
/* Check if all plugins have replied to getmanifest, and break
* if they are */
plugin->plugins->pending_manifests--;
if (plugin->plugins->pending_manifests == 0)
io_break(plugin->plugins);
if (req->resulttok->type != JSMN_OBJECT) {
plugin_kill(plugin,
"\"getmanifest\" response is not an object");
return;
}
if (!plugin_opts_add(req) || !plugin_rpcmethods_add(req))
plugin_kill(plugin, "Failed to register options or methods");
/* Reset timer, it'd kill us otherwise. */
tal_free(plugin->timeout_timer);
}
/* If this is a valid plugin return full path name, otherwise NULL */
static const char *plugin_fullpath(const tal_t *ctx, const char *dir,
const char *basename)
{
struct stat st;
const char *fullname;
struct utf8_state utf8 = UTF8_STATE_INIT;
for (size_t i = 0; basename[i]; i++) {
if (!utf8_decode(&utf8, basename[i]))
continue;
/* Not valid UTF8? Let's not go there... */
if (errno != 0)
return NULL;
if (utf8.used_len != 1)
continue;
if (!cispunct(utf8.c))
continue;
if (utf8.c != '-' && utf8.c != '_' && utf8.c != '.')
return NULL;
}
fullname = path_join(ctx, dir, basename);
if (stat(fullname, &st) != 0)
return tal_free(fullname);
if (!(st.st_mode & (S_IXUSR|S_IXGRP|S_IXOTH)) || st.st_mode & S_IFDIR)
return tal_free(fullname);
/* Ignore directories, they have exec mode, but aren't executable. */
if (st.st_mode & S_IFDIR)
return tal_free(fullname);
return fullname;
}
char *add_plugin_dir(struct plugins *plugins, const char *dir, bool nonexist_ok)
{
struct dirent *di;
DIR *d = opendir(dir);
if (!d) {
if (nonexist_ok && errno == ENOENT)
return NULL;
return tal_fmt("Failed to open plugin-dir %s: %s",
dir, strerror(errno));
}
while ((di = readdir(d)) != NULL) {
const char *fullpath;
if (streq(di->d_name, ".") || streq(di->d_name, ".."))
continue;
fullpath = plugin_fullpath(NULL, dir, di->d_name);
if (fullpath)
plugin_register(plugins, take(fullpath));
}
return NULL;
}
void clear_plugins(struct plugins *plugins)
{
struct plugin *p;
log_info(plugins->log, "clear-plugins removing all plugins");
while ((p = list_pop(&plugins->plugins, struct plugin, list)) != NULL)
tal_free(p);
}
void plugins_init(struct plugins *plugins)
{
struct plugin *p;
char **cmd;
int stdin, stdout;
struct timer *expired;
struct plugin_request *req;
plugins->pending_manifests = 0;
uintmap_init(&plugins->pending_requests);
/* Spawn the plugin processes before entering the io_loop */
list_for_each(&plugins->plugins, p, list) {
cmd = tal_arr(p, char *, 2);
cmd[0] = p->cmd;
cmd[1] = NULL;
p->pid = pipecmdarr(&stdout, &stdin, NULL, cmd);
if (p->pid == -1)
fatal("error starting plugin '%s': %s", p->cmd,
strerror(errno));
p->buffer = tal_arr(p, char, 64);
p->stop = false;
/* Create two connections, one read-only on top of p->stdin, and one
* write-only on p->stdout */
io_new_conn(p, stdout, plugin_stdout_conn_init, p);
io_new_conn(p, stdin, plugin_stdin_conn_init, p);
req = plugin_request_new(p, "getmanifest", plugin_manifest_cb, p);
json_array_start(req->stream, "params");
json_array_end(req->stream);
plugin_request_queue(req);
plugins->pending_manifests++;
p->timeout_timer = new_reltimer(
&plugins->timers, p, time_from_sec(PLUGIN_MANIFEST_TIMEOUT),
plugin_manifest_timeout, p);
tal_free(cmd);
}
while (plugins->pending_manifests > 0) {
void *v = io_loop(&plugins->timers, &expired);
if (v == plugins)
break;
if (expired)
timer_expired(plugins, expired);
}
}
static void plugin_config_cb(const struct plugin_request *req,
struct plugin *plugin)
{
/* Nothing to be done here, this is just a report */
}
/* FIXME(cdecker) This just builds a string for the request because
* the json_stream is tightly bound to the command interface. It
* should probably be generalized and fixed up. */
static void plugin_config(struct plugin *plugin)
{
struct plugin_opt *opt;
const char *name;
struct plugin_request *req;
/* No writer since we don't flush concurrently. */
req = plugin_request_new(plugin, "init", plugin_config_cb, plugin);
json_object_start(req->stream, "params"); /* start of .params */
/* Add .params.options */
json_object_start(req->stream, "options");
list_for_each(&plugin->plugin_opts, opt, list) {
/* Trim the `--` that we added before */
name = opt->name + 2;
json_add_string(req->stream, name, opt->value);
}
json_object_end(req->stream); /* end of .params.options */
json_object_end(req->stream); /* end of .params */
plugin_request_queue(req);
}
void plugins_config(struct plugins *plugins)
{
struct plugin *p;
list_for_each(&plugins->plugins, p, list) {
plugin_config(p);
}
}
void json_add_opt_plugins(struct json_stream *response,
const struct plugins *plugins)
{
struct plugin *p;
list_for_each(&plugins->plugins, p, list) {
json_add_string(response, "plugin", p->cmd);
}
}