plugin.c

   1 /*
   2  * rpcd - UBUS RPC server
   3  *
   4  *   Copyright (C) 2013-2014 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 <rpcd/plugin.h>
  20
  21 static struct blob_buf buf;
  22
  23 struct rpc_plugin_lookup_context {
  24         uint32_t id;
  25         char *name;
  26         bool found;
  27 };
  28
  29 static void
  30 rpc_plugin_lookup_plugin_cb(struct ubus_context *ctx,
  31                             struct ubus_object_data *obj, void *priv)
  32 {
  33         struct rpc_plugin_lookup_context *c = priv;
  34
  35         if (c->id == obj->id)
  36         {
  37                 c->found = true;
  38                 sprintf(c->name, "%s", obj->path);
  39         }
  40 }
  41
  42 static bool
  43 rpc_plugin_lookup_plugin(struct ubus_context *ctx, struct ubus_object *obj,
  44                          char *strptr)
  45 {
  46         struct rpc_plugin_lookup_context c = { .id = obj->id, .name = strptr };
  47
  48         if (ubus_lookup(ctx, NULL, rpc_plugin_lookup_plugin_cb, &c))
  49                 return false;
  50
  51         return c.found;
  52 }
  53
  54 struct call_context {
  55         char path[PATH_MAX];
  56         const char *argv[4];
  57         char *method;
  58         char *input;
  59         json_tokener *tok;
  60         json_object *obj;
  61         bool input_done;
  62         bool output_done;
  63 };
  64
  65 static int
  66 rpc_plugin_call_stdin_cb(struct ustream *s, void *priv)
  67 {
  68         struct call_context *c = priv;
  69
  70         if (!c->input_done)
  71         {
  72                 ustream_write(s, c->input, strlen(c->input), false);
  73                 c->input_done = true;
  74         }
  75
  76         return 0;
  77 }
  78
  79 static int
  80 rpc_plugin_call_stdout_cb(struct blob_buf *blob, char *buf, int len, void *priv)
  81 {
  82         struct call_context *c = priv;
  83
  84         if (!c->output_done)
  85         {
  86                 c->obj = json_tokener_parse_ex(c->tok, buf, len);
  87
  88                 if (json_tokener_get_error(c->tok) != json_tokener_continue)
  89                         c->output_done = true;
  90         }
  91
  92         return len;
  93 }
  94
  95 static int
  96 rpc_plugin_call_stderr_cb(struct blob_buf *blob, char *buf, int len, void *priv)
  97 {
  98         return len;
  99 }
 100
 101 static int
 102 rpc_plugin_call_finish_cb(struct blob_buf *blob, int stat, void *priv)
 103 {
 104         struct call_context *c = priv;
 105         int rv = UBUS_STATUS_INVALID_ARGUMENT;
 106
 107         if (json_tokener_get_error(c->tok) == json_tokener_success)
 108         {
 109                 if (c->obj)
 110                 {
 111                         if (json_object_get_type(c->obj) == json_type_object &&
 112                             blobmsg_add_object(blob, c->obj))
 113                                 rv = UBUS_STATUS_OK;
 114
 115                         json_object_put(c->obj);
 116                 }
 117                 else
 118                 {
 119                         rv = UBUS_STATUS_NO_DATA;
 120                 }
 121         }
 122
 123         json_tokener_free(c->tok);
 124
 125         free(c->input);
 126         free(c->method);
 127
 128         return rv;
 129 }
 130
 131 static int
 132 rpc_plugin_call(struct ubus_context *ctx, struct ubus_object *obj,
 133                 struct ubus_request_data *req, const char *method,
 134                 struct blob_attr *msg)
 135 {
 136         int rv = UBUS_STATUS_UNKNOWN_ERROR;
 137         struct call_context *c;
 138         char *plugin;
 139
 140         c = calloc(1, sizeof(*c));
 141
 142         if (!c)
 143                 goto fail;
 144
 145         c->method = strdup(method);
 146         c->input = blobmsg_format_json(msg, true);
 147         c->tok = json_tokener_new();
 148
 149         if (!c->method || !c->input || !c->tok)
 150                 goto fail;
 151
 152         plugin = c->path + sprintf(c->path, "%s/", RPC_PLUGIN_DIRECTORY);
 153
 154         if (!rpc_plugin_lookup_plugin(ctx, obj, plugin))
 155         {
 156                 rv = UBUS_STATUS_NOT_FOUND;
 157                 goto fail;
 158         }
 159
 160         c->argv[0] = c->path;
 161         c->argv[1] = "call";
 162         c->argv[2] = c->method;
 163
 164         return rpc_exec(c->argv, rpc_plugin_call_stdin_cb,
 165                         rpc_plugin_call_stdout_cb, rpc_plugin_call_stderr_cb,
 166                         rpc_plugin_call_finish_cb, c, ctx, req);
 167
 168 fail:
 169         if (c)
 170         {
 171                 if (c->method)
 172                         free(c->method);
 173
 174                 if (c->input)
 175                         free(c->input);
 176
 177                 if (c->tok)
 178                         json_tokener_free(c->tok);
 179
 180                 free(c);
 181         }
 182
 183         return rv;
 184 }
 185
 186 static bool
 187 rpc_plugin_parse_signature(struct blob_attr *sig, struct ubus_method *method)
 188 {
 189         int rem, n_attr;
 190         enum blobmsg_type type;
 191         struct blob_attr *attr;
 192         struct blobmsg_policy *policy = NULL;
 193
 194         if (!sig || blobmsg_type(sig) != BLOBMSG_TYPE_TABLE)
 195                 return false;
 196
 197         n_attr = 0;
 198
 199         blobmsg_for_each_attr(attr, sig, rem)
 200                 n_attr++;
 201
 202         if (n_attr)
 203         {
 204                 policy = calloc(n_attr, sizeof(*policy));
 205
 206                 if (!policy)
 207                         return false;
 208
 209                 n_attr = 0;
 210
 211                 blobmsg_for_each_attr(attr, sig, rem)
 212                 {
 213                         type = blobmsg_type(attr);
 214
 215                         if (type == BLOBMSG_TYPE_INT32)
 216                         {
 217                                 switch (blobmsg_get_u32(attr))
 218                                 {
 219                                 case 8:
 220                                         type = BLOBMSG_TYPE_INT8;
 221                                         break;
 222
 223                                 case 16:
 224                                         type = BLOBMSG_TYPE_INT16;
 225                                         break;
 226
 227                                 case 64:
 228                                         type = BLOBMSG_TYPE_INT64;
 229                                         break;
 230
 231                                 default:
 232                                         type = BLOBMSG_TYPE_INT32;
 233                                         break;
 234                                 }
 235                         }
 236
 237                         policy[n_attr].name = strdup(blobmsg_name(attr));
 238                         policy[n_attr].type = type;
 239
 240                         n_attr++;
 241                 }
 242         }
 243
 244         method->name = strdup(blobmsg_name(sig));
 245         method->handler = rpc_plugin_call;
 246         method->policy = policy;
 247         method->n_policy = n_attr;
 248
 249         return true;
 250 }
 251
 252 static struct ubus_object *
 253 rpc_plugin_parse_exec(const char *name, int fd)
 254 {
 255         int len, rem, n_method;
 256         struct blob_attr *cur;
 257         struct ubus_method *methods;
 258         struct ubus_object_type *obj_type;
 259         struct ubus_object *obj;
 260         char outbuf[1024];
 261
 262         json_tokener *tok;
 263         json_object *jsobj;
 264
 265         blob_buf_init(&buf, 0);
 266
 267         tok = json_tokener_new();
 268
 269         if (!tok)
 270                 return NULL;
 271
 272         while ((len = read(fd, outbuf, sizeof(outbuf))) > 0)
 273         {
 274                 jsobj = json_tokener_parse_ex(tok, outbuf, len);
 275
 276                 if (json_tokener_get_error(tok) == json_tokener_continue)
 277                         continue;
 278
 279                 if (json_tokener_get_error(tok) != json_tokener_success)
 280                         break;
 281
 282                 if (jsobj)
 283                 {
 284                         if (json_object_get_type(jsobj) == json_type_object)
 285                                 blobmsg_add_object(&buf, jsobj);
 286
 287                         json_object_put(jsobj);
 288                         break;
 289                 }
 290         }
 291
 292         json_tokener_free(tok);
 293
 294         n_method = 0;
 295
 296         blob_for_each_attr(cur, buf.head, rem)
 297                 n_method++;
 298
 299         if (!n_method)
 300                 return NULL;
 301
 302         methods = calloc(n_method, sizeof(*methods));
 303
 304         if (!methods)
 305                 return NULL;
 306
 307         n_method = 0;
 308
 309         blob_for_each_attr(cur, buf.head, rem)
 310         {
 311                 if (!rpc_plugin_parse_signature(cur, &methods[n_method]))
 312                         continue;
 313
 314                 n_method++;
 315         }
 316
 317         obj = calloc(1, sizeof(*obj));
 318
 319         if (!obj)
 320                 return NULL;
 321
 322         obj_type = calloc(1, sizeof(*obj_type));
 323
 324         if (!obj_type)
 325                 return NULL;
 326
 327         if (asprintf((char **)&obj_type->name, "luci-rpc-plugin-%s", name) < 0)
 328                 return NULL;
 329
 330         obj_type->methods = methods;
 331         obj_type->n_methods = n_method;
 332
 333         obj->name = strdup(name);
 334         obj->type = obj_type;
 335         obj->methods = methods;
 336         obj->n_methods = n_method;
 337
 338         return obj;
 339 }
 340
 341 static int
 342 rpc_plugin_register_exec(struct ubus_context *ctx, const char *path)
 343 {
 344         pid_t pid;
 345         int rv = UBUS_STATUS_NO_DATA, fd, fds[2];
 346         const char *name;
 347         struct ubus_object *plugin;
 348
 349         name = strrchr(path, '/');
 350
 351         if (!name)
 352                 return UBUS_STATUS_INVALID_ARGUMENT;
 353
 354         if (pipe(fds))
 355                 return UBUS_STATUS_UNKNOWN_ERROR;
 356
 357         switch ((pid = fork()))
 358         {
 359         case -1:
 360                 return UBUS_STATUS_UNKNOWN_ERROR;
 361
 362         case 0:
 363                 fd = open("/dev/null", O_RDWR);
 364
 365                 if (fd > -1)
 366                 {
 367                         dup2(fd, 0);
 368                         dup2(fd, 2);
 369
 370                         if (fd > 2)
 371                                 close(fd);
 372                 }
 373
 374                 dup2(fds[1], 1);
 375
 376                 close(fds[0]);
 377                 close(fds[1]);
 378
 379                 if (execl(path, path, "list", NULL))
 380                         return UBUS_STATUS_UNKNOWN_ERROR;
 381
 382         default:
 383                 plugin = rpc_plugin_parse_exec(name + 1, fds[0]);
 384
 385                 if (!plugin)
 386                         goto out;
 387
 388                 rv = ubus_add_object(ctx, plugin);
 389
 390 out:
 391                 close(fds[0]);
 392                 close(fds[1]);
 393                 waitpid(pid, NULL, 0);
 394
 395                 return rv;
 396         }
 397 }
 398
 399
 400 static LIST_HEAD(plugins);
 401
 402 static const struct rpc_daemon_ops ops = {
 403         .session_access     = rpc_session_access,
 404         .session_create_cb  = rpc_session_create_cb,
 405         .session_destroy_cb = rpc_session_destroy_cb,
 406         .exec               = rpc_exec,
 407 };
 408
 409 static int
 410 rpc_plugin_register_library(struct ubus_context *ctx, const char *path)
 411 {
 412         struct rpc_plugin *p;
 413         void *dlh;
 414
 415         dlh = dlopen(path, RTLD_LAZY | RTLD_GLOBAL);
 416
 417         if (!dlh)
 418                 return UBUS_STATUS_UNKNOWN_ERROR;
 419
 420         p = dlsym(dlh, "rpc_plugin");
 421
 422         if (!p)
 423                 return UBUS_STATUS_NOT_FOUND;
 424
 425         list_add(&p->list, &plugins);
 426
 427         return p->init(&ops, ctx);
 428 }
 429
 430 int rpc_plugin_api_init(struct ubus_context *ctx)
 431 {
 432         DIR *d;
 433         int rv = 0;
 434         struct stat s;
 435         struct dirent *e;
 436         char path[PATH_MAX];
 437
 438         if ((d = opendir(RPC_PLUGIN_DIRECTORY)) != NULL)
 439         {
 440                 while ((e = readdir(d)) != NULL)
 441                 {
 442                         snprintf(path, sizeof(path) - 1,
 443                                  RPC_PLUGIN_DIRECTORY "/%s", e->d_name);
 444
 445                         if (stat(path, &s) || !S_ISREG(s.st_mode) || !(s.st_mode & S_IXUSR))
 446                                 continue;
 447
 448                         rv |= rpc_plugin_register_exec(ctx, path);
 449                 }
 450
 451                 closedir(d);
 452         }
 453
 454         if ((d = opendir(RPC_LIBRARY_DIRECTORY)) != NULL)
 455         {
 456                 while ((e = readdir(d)) != NULL)
 457                 {
 458                         snprintf(path, sizeof(path) - 1,
 459                                  RPC_LIBRARY_DIRECTORY "/%s", e->d_name);
 460
 461                         if (stat(path, &s) || !S_ISREG(s.st_mode))
 462                                 continue;
 463
 464                         rv |= rpc_plugin_register_library(ctx, path);
 465                 }
 466
 467                 closedir(d);
 468         }
 469
 470         return rv;
 471 }