plugin.c

   1 /*
   2  * luci-rpcd - LuCI UBUS RPC server
   3  *
   4  *   Copyright (C) 2013 Jo-Philipp Wich <jow@openwrt.org>
   5  *
   6  * Permission to use, copy, modify, and/or distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 #include "plugin.h"
  20 #include "exec.h"
  21
  22 static struct blob_buf buf;
  23
  24 struct rpc_plugin_lookup_context {
  25         uint32_t id;
  26         char *name;
  27         bool found;
  28 };
  29
  30 static void
  31 rpc_plugin_lookup_plugin_cb(struct ubus_context *ctx,
  32                             struct ubus_object_data *obj, void *priv)
  33 {
  34         struct rpc_plugin_lookup_context *c = priv;
  35
  36         if (c->id == obj->id)
  37         {
  38                 c->found = true;
  39                 sprintf(c->name, "%s", obj->path);
  40         }
  41 }
  42
  43 static bool
  44 rpc_plugin_lookup_plugin(struct ubus_context *ctx, struct ubus_object *obj,
  45                          char *strptr)
  46 {
  47         struct rpc_plugin_lookup_context c = { .id = obj->id, .name = strptr };
  48
  49         if (ubus_lookup(ctx, NULL, rpc_plugin_lookup_plugin_cb, &c))
  50                 return false;
  51
  52         return c.found;
  53 }
  54
  55 struct call_context {
  56         char path[PATH_MAX];
  57         const char *argv[4];
  58         char *method;
  59         char *input;
  60         json_tokener *tok;
  61         json_object *obj;
  62         bool input_done;
  63         bool output_done;
  64 };
  65
  66 static int
  67 rpc_plugin_call_stdin_cb(struct ustream *s, void *priv)
  68 {
  69         struct call_context *c = priv;
  70
  71         if (!c->input_done)
  72         {
  73                 ustream_write(s, c->input, strlen(c->input), false);
  74                 c->input_done = true;
  75         }
  76
  77         return 0;
  78 }
  79
  80 static int
  81 rpc_plugin_call_stdout_cb(struct blob_buf *blob, char *buf, int len, void *priv)
  82 {
  83         struct call_context *c = priv;
  84
  85         if (!c->output_done)
  86         {
  87                 c->obj = json_tokener_parse_ex(c->tok, buf, len);
  88
  89                 if (json_tokener_get_error(c->tok) != json_tokener_continue)
  90                         c->output_done = true;
  91         }
  92
  93         return len;
  94 }
  95
  96 static int
  97 rpc_plugin_call_finish_cb(struct blob_buf *blob, int stat, void *priv)
  98 {
  99         struct call_context *c = priv;
 100         int rv = UBUS_STATUS_INVALID_ARGUMENT;
 101
 102         if (json_tokener_get_error(c->tok) == json_tokener_success)
 103         {
 104                 if (c->obj)
 105                 {
 106                         if (json_object_get_type(c->obj) == json_type_object ||
 107                             json_object_get_type(c->obj) == json_type_array)
 108                         {
 109                                 blobmsg_add_json_element(blob, NULL, c->obj);
 110                                 rv = UBUS_STATUS_OK;
 111                         }
 112
 113                         json_object_put(c->obj);
 114                 }
 115                 else
 116                 {
 117                         rv = UBUS_STATUS_NO_DATA;
 118                 }
 119         }
 120
 121         json_tokener_free(c->tok);
 122
 123         free(c->input);
 124         free(c->method);
 125
 126         return rv;
 127 }
 128
 129 static int
 130 rpc_plugin_call(struct ubus_context *ctx, struct ubus_object *obj,
 131                 struct ubus_request_data *req, const char *method,
 132                 struct blob_attr *msg)
 133 {
 134         int rv = UBUS_STATUS_UNKNOWN_ERROR;
 135         struct call_context *c;
 136         char *plugin;
 137
 138         c = calloc(1, sizeof(*c));
 139
 140         if (!c)
 141                 goto fail;
 142
 143         c->method = strdup(method);
 144         c->input = blobmsg_format_json(msg, true);
 145         c->tok = json_tokener_new();
 146
 147         if (!c->method || !c->input || !c->tok)
 148                 goto fail;
 149
 150         plugin = c->path + sprintf(c->path, "%s/", RPC_PLUGIN_DIRECTORY);
 151
 152         if (!rpc_plugin_lookup_plugin(ctx, obj, plugin))
 153         {
 154                 rv = UBUS_STATUS_NOT_FOUND;
 155                 goto fail;
 156         }
 157
 158         c->argv[0] = c->path;
 159         c->argv[1] = "call";
 160         c->argv[2] = c->method;
 161
 162         return rpc_exec(c->argv, rpc_plugin_call_stdin_cb,
 163                         rpc_plugin_call_stdout_cb, NULL, rpc_plugin_call_finish_cb,
 164                         c, ctx, req);
 165
 166 fail:
 167         if (c)
 168         {
 169                 if (c->method)
 170                         free(c->method);
 171
 172                 if (c->input)
 173                         free(c->input);
 174
 175                 if (c->tok)
 176                         json_tokener_free(c->tok);
 177
 178                 free(c);
 179         }
 180
 181         return rv;
 182 }
 183
 184 static bool
 185 rpc_plugin_parse_signature(struct blob_attr *sig, struct ubus_method *method)
 186 {
 187         int rem, n_attr;
 188         enum blobmsg_type type;
 189         struct blob_attr *attr;
 190         struct blobmsg_policy *policy = NULL;
 191
 192         if (!sig || blob_id(sig) != BLOBMSG_TYPE_TABLE)
 193                 return false;
 194
 195         n_attr = 0;
 196
 197         blobmsg_for_each_attr(attr, sig, rem)
 198                 n_attr++;
 199
 200         if (n_attr)
 201         {
 202                 policy = calloc(n_attr, sizeof(*policy));
 203
 204                 if (!policy)
 205                         return false;
 206
 207                 n_attr = 0;
 208
 209                 blobmsg_for_each_attr(attr, sig, rem)
 210                 {
 211                         type = blob_id(attr);
 212
 213                         if (type == BLOBMSG_TYPE_INT32)
 214                         {
 215                                 switch (blobmsg_get_u32(attr))
 216                                 {
 217                                 case 8:
 218                                         type = BLOBMSG_TYPE_INT8;
 219                                         break;
 220
 221                                 case 16:
 222                                         type = BLOBMSG_TYPE_INT16;
 223                                         break;
 224
 225                                 case 64:
 226                                         type = BLOBMSG_TYPE_INT64;
 227                                         break;
 228
 229                                 default:
 230                                         type = BLOBMSG_TYPE_INT32;
 231                                         break;
 232                                 }
 233                         }
 234
 235                         policy[n_attr].name = strdup(blobmsg_name(attr));
 236                         policy[n_attr].type = type;
 237
 238                         n_attr++;
 239                 }
 240         }
 241
 242         method->name = strdup(blobmsg_name(sig));
 243         method->handler = rpc_plugin_call;
 244         method->policy = policy;
 245         method->n_policy = n_attr;
 246
 247         return true;
 248 }
 249
 250 static struct ubus_object *
 251 rpc_plugin_parse_plugin(const char *name, int fd)
 252 {
 253         int len, rem, n_method;
 254         struct blob_attr *cur;
 255         struct ubus_method *methods;
 256         struct ubus_object_type *obj_type;
 257         struct ubus_object *obj;
 258         char outbuf[1024];
 259
 260         json_tokener *tok;
 261         json_object *jsobj;
 262
 263         blob_buf_init(&buf, 0);
 264
 265         tok = json_tokener_new();
 266
 267         if (!tok)
 268                 return NULL;
 269
 270         while ((len = read(fd, outbuf, sizeof(outbuf))) > 0)
 271         {
 272                 jsobj = json_tokener_parse_ex(tok, outbuf, len);
 273
 274                 if (json_tokener_get_error(tok) == json_tokener_continue)
 275                         continue;
 276
 277                 if (json_tokener_get_error(tok) != json_tokener_success)
 278                         break;
 279
 280                 if (jsobj)
 281                 {
 282                         if (json_object_get_type(jsobj) == json_type_object)
 283                                 blobmsg_add_object(&buf, jsobj);
 284
 285                         json_object_put(jsobj);
 286                         break;
 287                 }
 288         }
 289
 290         json_tokener_free(tok);
 291
 292         n_method = 0;
 293
 294         blob_for_each_attr(cur, buf.head, rem)
 295                 n_method++;
 296
 297         if (!n_method)
 298                 return NULL;
 299
 300         methods = calloc(n_method, sizeof(*methods));
 301
 302         if (!methods)
 303                 return NULL;
 304
 305         n_method = 0;
 306
 307         blob_for_each_attr(cur, buf.head, rem)
 308         {
 309                 if (!rpc_plugin_parse_signature(cur, &methods[n_method]))
 310                         continue;
 311
 312                 n_method++;
 313         }
 314
 315         obj = calloc(1, sizeof(*obj));
 316
 317         if (!obj)
 318                 return NULL;
 319
 320         obj_type = calloc(1, sizeof(*obj_type));
 321
 322         if (!obj_type)
 323                 return NULL;
 324
 325         asprintf((char **)&obj_type->name, "luci-rpc-plugin-%s", name);
 326         obj_type->methods = methods;
 327         obj_type->n_methods = n_method;
 328
 329         obj->name = strdup(name);
 330         obj->type = obj_type;
 331         obj->methods = methods;
 332         obj->n_methods = n_method;
 333
 334         return obj;
 335 }
 336
 337 static int
 338 rpc_plugin_register(struct ubus_context *ctx, const char *path)
 339 {
 340         pid_t pid;
 341         int rv = UBUS_STATUS_NO_DATA, fd, fds[2];
 342         const char *name;
 343         struct ubus_object *plugin;
 344
 345         name = strrchr(path, '/');
 346
 347         if (!name)
 348                 return UBUS_STATUS_INVALID_ARGUMENT;
 349
 350         if (pipe(fds))
 351                 return UBUS_STATUS_UNKNOWN_ERROR;
 352
 353         switch ((pid = fork()))
 354         {
 355         case -1:
 356                 return UBUS_STATUS_UNKNOWN_ERROR;
 357
 358         case 0:
 359                 fd = open("/dev/null", O_RDWR);
 360
 361                 if (fd > -1)
 362                 {
 363                         dup2(fd, 0);
 364                         dup2(fd, 2);
 365
 366                         if (fd > 2)
 367                                 close(fd);
 368                 }
 369
 370                 dup2(fds[1], 1);
 371
 372                 close(fds[0]);
 373                 close(fds[1]);
 374
 375                 if (execl(path, path, "list", NULL))
 376                         return UBUS_STATUS_UNKNOWN_ERROR;
 377
 378         default:
 379                 plugin = rpc_plugin_parse_plugin(name + 1, fds[0]);
 380
 381                 if (!plugin)
 382                         goto out;
 383
 384                 rv = ubus_add_object(ctx, plugin);
 385
 386 out:
 387                 close(fds[0]);
 388                 close(fds[1]);
 389                 waitpid(pid, NULL, 0);
 390
 391                 return rv;
 392         }
 393 }
 394
 395 int rpc_plugin_api_init(struct ubus_context *ctx)
 396 {
 397         DIR *d;
 398         int rv = 0;
 399         struct stat s;
 400         struct dirent *e;
 401         char path[PATH_MAX];
 402
 403         d = opendir(RPC_PLUGIN_DIRECTORY);
 404
 405         if (!d)
 406                 return UBUS_STATUS_NOT_FOUND;
 407
 408         while ((e = readdir(d)) != NULL)
 409         {
 410                 snprintf(path, sizeof(path) - 1, RPC_PLUGIN_DIRECTORY "/%s", e->d_name);
 411
 412                 if (stat(path, &s) || !S_ISREG(s.st_mode) || !(s.st_mode & S_IXUSR))
 413                         continue;
 414
 415                 rv |= rpc_plugin_register(ctx, path);
 416         }
 417
 418         closedir(d);
 419
 420         return rv;
 421 }