plugin.c

   1 /*
   2  * rpcd - 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 <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                             json_object_get_type(c->obj) == json_type_array)
 113                         {
 114                                 blobmsg_add_json_element(blob, NULL, c->obj);
 115                                 rv = UBUS_STATUS_OK;
 116                         }
 117
 118                         json_object_put(c->obj);
 119                 }
 120                 else
 121                 {
 122                         rv = UBUS_STATUS_NO_DATA;
 123                 }
 124         }
 125
 126         json_tokener_free(c->tok);
 127
 128         free(c->input);
 129         free(c->method);
 130
 131         return rv;
 132 }
 133
 134 static int
 135 rpc_plugin_call(struct ubus_context *ctx, struct ubus_object *obj,
 136                 struct ubus_request_data *req, const char *method,
 137                 struct blob_attr *msg)
 138 {
 139         int rv = UBUS_STATUS_UNKNOWN_ERROR;
 140         struct call_context *c;
 141         char *plugin;
 142
 143         c = calloc(1, sizeof(*c));
 144
 145         if (!c)
 146                 goto fail;
 147
 148         c->method = strdup(method);
 149         c->input = blobmsg_format_json(msg, true);
 150         c->tok = json_tokener_new();
 151
 152         if (!c->method || !c->input || !c->tok)
 153                 goto fail;
 154
 155         plugin = c->path + sprintf(c->path, "%s/", RPC_PLUGIN_DIRECTORY);
 156
 157         if (!rpc_plugin_lookup_plugin(ctx, obj, plugin))
 158         {
 159                 rv = UBUS_STATUS_NOT_FOUND;
 160                 goto fail;
 161         }
 162
 163         c->argv[0] = c->path;
 164         c->argv[1] = "call";
 165         c->argv[2] = c->method;
 166
 167         return rpc_exec(c->argv, rpc_plugin_call_stdin_cb,
 168                         rpc_plugin_call_stdout_cb, rpc_plugin_call_stderr_cb,
 169                         rpc_plugin_call_finish_cb, c, ctx, req);
 170
 171 fail:
 172         if (c)
 173         {
 174                 if (c->method)
 175                         free(c->method);
 176
 177                 if (c->input)
 178                         free(c->input);
 179
 180                 if (c->tok)
 181                         json_tokener_free(c->tok);
 182
 183                 free(c);
 184         }
 185
 186         return rv;
 187 }
 188
 189 static bool
 190 rpc_plugin_parse_signature(struct blob_attr *sig, struct ubus_method *method)
 191 {
 192         int rem, n_attr;
 193         enum blobmsg_type type;
 194         struct blob_attr *attr;
 195         struct blobmsg_policy *policy = NULL;
 196
 197         if (!sig || blobmsg_type(sig) != BLOBMSG_TYPE_TABLE)
 198                 return false;
 199
 200         n_attr = 0;
 201
 202         blobmsg_for_each_attr(attr, sig, rem)
 203                 n_attr++;
 204
 205         if (n_attr)
 206         {
 207                 policy = calloc(n_attr, sizeof(*policy));
 208
 209                 if (!policy)
 210                         return false;
 211
 212                 n_attr = 0;
 213
 214                 blobmsg_for_each_attr(attr, sig, rem)
 215                 {
 216                         type = blobmsg_type(attr);
 217
 218                         if (type == BLOBMSG_TYPE_INT32)
 219                         {
 220                                 switch (blobmsg_get_u32(attr))
 221                                 {
 222                                 case 8:
 223                                         type = BLOBMSG_TYPE_INT8;
 224                                         break;
 225
 226                                 case 16:
 227                                         type = BLOBMSG_TYPE_INT16;
 228                                         break;
 229
 230                                 case 64:
 231                                         type = BLOBMSG_TYPE_INT64;
 232                                         break;
 233
 234                                 default:
 235                                         type = BLOBMSG_TYPE_INT32;
 236                                         break;
 237                                 }
 238                         }
 239
 240                         policy[n_attr].name = strdup(blobmsg_name(attr));
 241                         policy[n_attr].type = type;
 242
 243                         n_attr++;
 244                 }
 245         }
 246
 247         method->name = strdup(blobmsg_name(sig));
 248         method->handler = rpc_plugin_call;
 249         method->policy = policy;
 250         method->n_policy = n_attr;
 251
 252         return true;
 253 }
 254
 255 static struct ubus_object *
 256 rpc_plugin_parse_exec(const char *name, int fd)
 257 {
 258         int len, rem, n_method;
 259         struct blob_attr *cur;
 260         struct ubus_method *methods;
 261         struct ubus_object_type *obj_type;
 262         struct ubus_object *obj;
 263         char outbuf[1024];
 264
 265         json_tokener *tok;
 266         json_object *jsobj;
 267
 268         blob_buf_init(&buf, 0);
 269
 270         tok = json_tokener_new();
 271
 272         if (!tok)
 273                 return NULL;
 274
 275         while ((len = read(fd, outbuf, sizeof(outbuf))) > 0)
 276         {
 277                 jsobj = json_tokener_parse_ex(tok, outbuf, len);
 278
 279                 if (json_tokener_get_error(tok) == json_tokener_continue)
 280                         continue;
 281
 282                 if (json_tokener_get_error(tok) != json_tokener_success)
 283                         break;
 284
 285                 if (jsobj)
 286                 {
 287                         if (json_object_get_type(jsobj) == json_type_object)
 288                                 blobmsg_add_object(&buf, jsobj);
 289
 290                         json_object_put(jsobj);
 291                         break;
 292                 }
 293         }
 294
 295         json_tokener_free(tok);
 296
 297         n_method = 0;
 298
 299         blob_for_each_attr(cur, buf.head, rem)
 300                 n_method++;
 301
 302         if (!n_method)
 303                 return NULL;
 304
 305         methods = calloc(n_method, sizeof(*methods));
 306
 307         if (!methods)
 308                 return NULL;
 309
 310         n_method = 0;
 311
 312         blob_for_each_attr(cur, buf.head, rem)
 313         {
 314                 if (!rpc_plugin_parse_signature(cur, &methods[n_method]))
 315                         continue;
 316
 317                 n_method++;
 318         }
 319
 320         obj = calloc(1, sizeof(*obj));
 321
 322         if (!obj)
 323                 return NULL;
 324
 325         obj_type = calloc(1, sizeof(*obj_type));
 326
 327         if (!obj_type)
 328                 return NULL;
 329
 330         asprintf((char **)&obj_type->name, "luci-rpc-plugin-%s", name);
 331         obj_type->methods = methods;
 332         obj_type->n_methods = n_method;
 333
 334         obj->name = strdup(name);
 335         obj->type = obj_type;
 336         obj->methods = methods;
 337         obj->n_methods = n_method;
 338
 339         return obj;
 340 }
 341
 342 static int
 343 rpc_plugin_register_exec(struct ubus_context *ctx, const char *path)
 344 {
 345         pid_t pid;
 346         int rv = UBUS_STATUS_NO_DATA, fd, fds[2];
 347         const char *name;
 348         struct ubus_object *plugin;
 349
 350         name = strrchr(path, '/');
 351
 352         if (!name)
 353                 return UBUS_STATUS_INVALID_ARGUMENT;
 354
 355         if (pipe(fds))
 356                 return UBUS_STATUS_UNKNOWN_ERROR;
 357
 358         switch ((pid = fork()))
 359         {
 360         case -1:
 361                 return UBUS_STATUS_UNKNOWN_ERROR;
 362
 363         case 0:
 364                 fd = open("/dev/null", O_RDWR);
 365
 366                 if (fd > -1)
 367                 {
 368                         dup2(fd, 0);
 369                         dup2(fd, 2);
 370
 371                         if (fd > 2)
 372                                 close(fd);
 373                 }
 374
 375                 dup2(fds[1], 1);
 376
 377                 close(fds[0]);
 378                 close(fds[1]);
 379
 380                 if (execl(path, path, "list", NULL))
 381                         return UBUS_STATUS_UNKNOWN_ERROR;
 382
 383         default:
 384                 plugin = rpc_plugin_parse_exec(name + 1, fds[0]);
 385
 386                 if (!plugin)
 387                         goto out;
 388
 389                 rv = ubus_add_object(ctx, plugin);
 390
 391 out:
 392                 close(fds[0]);
 393                 close(fds[1]);
 394                 waitpid(pid, NULL, 0);
 395
 396                 return rv;
 397         }
 398 }
 399
 400
 401 static LIST_HEAD(plugins);
 402
 403 static const struct rpc_daemon_ops ops = {
 404         .session_access     = rpc_session_access,
 405         .session_create_cb  = rpc_session_create_cb,
 406         .session_destroy_cb = rpc_session_destroy_cb,
 407         .exec               = rpc_exec,
 408 };
 409
 410 static int
 411 rpc_plugin_register_library(struct ubus_context *ctx, const char *path)
 412 {
 413         struct rpc_plugin *p;
 414         void *dlh;
 415
 416         dlh = dlopen(path, RTLD_LAZY | RTLD_GLOBAL);
 417
 418         if (!dlh)
 419                 return UBUS_STATUS_UNKNOWN_ERROR;
 420
 421         p = dlsym(dlh, "rpc_plugin");
 422
 423         if (!p)
 424                 return UBUS_STATUS_NOT_FOUND;
 425
 426         list_add(&p->list, &plugins);
 427
 428         return p->init(&ops, ctx);
 429 }
 430
 431 int rpc_plugin_api_init(struct ubus_context *ctx)
 432 {
 433         DIR *d;
 434         int rv = 0;
 435         struct stat s;
 436         struct dirent *e;
 437         char path[PATH_MAX];
 438
 439         if ((d = opendir(RPC_PLUGIN_DIRECTORY)) != NULL)
 440         {
 441                 while ((e = readdir(d)) != NULL)
 442                 {
 443                         snprintf(path, sizeof(path) - 1,
 444                                  RPC_PLUGIN_DIRECTORY "/%s", e->d_name);
 445
 446                         if (stat(path, &s) || !S_ISREG(s.st_mode) || !(s.st_mode & S_IXUSR))
 447                                 continue;
 448
 449                         rv |= rpc_plugin_register_exec(ctx, path);
 450                 }
 451
 452                 closedir(d);
 453         }
 454
 455         if ((d = opendir(RPC_LIBRARY_DIRECTORY)) != NULL)
 456         {
 457                 while ((e = readdir(d)) != NULL)
 458                 {
 459                         snprintf(path, sizeof(path) - 1,
 460                                  RPC_LIBRARY_DIRECTORY "/%s", e->d_name);
 461
 462                         if (stat(path, &s) || !S_ISREG(s.st_mode))
 463                                 continue;
 464
 465                         rv |= rpc_plugin_register_library(ctx, path);
 466                 }
 467
 468                 closedir(d);
 469         }
 470
 471         return rv;
 472 }