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
 127         return rv;
 128 }
 129
 130 static int
 131 rpc_plugin_call(struct ubus_context *ctx, struct ubus_object *obj,
 132                 struct ubus_request_data *req, const char *method,
 133                 struct blob_attr *msg)
 134 {
 135         int rv = UBUS_STATUS_UNKNOWN_ERROR;
 136         struct call_context *c;
 137         char *plugin, *mptr;
 138
 139         c = calloc_a(sizeof(*c), &mptr, strlen(method) + 1);
 140
 141         if (!c)
 142                 goto fail;
 143
 144         c->method = strcpy(mptr, method);
 145         c->input = blobmsg_format_json(msg, true);
 146         c->tok = json_tokener_new();
 147
 148         if (!c->input || !c->tok)
 149                 goto fail;
 150
 151         plugin = c->path + sprintf(c->path, "%s/", RPC_PLUGIN_DIRECTORY);
 152
 153         if (!rpc_plugin_lookup_plugin(ctx, obj, plugin))
 154         {
 155                 rv = UBUS_STATUS_NOT_FOUND;
 156                 goto fail;
 157         }
 158
 159         c->argv[0] = c->path;
 160         c->argv[1] = "call";
 161         c->argv[2] = c->method;
 162
 163         rv = rpc_exec(c->argv, rpc_plugin_call_stdin_cb,
 164                       rpc_plugin_call_stdout_cb, rpc_plugin_call_stderr_cb,
 165                       rpc_plugin_call_finish_cb, c, ctx, req);
 166
 167         if (rv == UBUS_STATUS_OK)
 168                 return rv;
 169
 170 fail:
 171         if (c)
 172         {
 173                 if (c->input)
 174                         free(c->input);
 175
 176                 if (c->tok)
 177                         json_tokener_free(c->tok);
 178
 179                 free(c);
 180         }
 181
 182         return rv;
 183 }
 184
 185 static bool
 186 rpc_plugin_parse_signature(struct blob_attr *sig, struct ubus_method *method)
 187 {
 188         int rem, n_attr;
 189         enum blobmsg_type type;
 190         struct blob_attr *attr;
 191         struct blobmsg_policy *policy = NULL;
 192
 193         if (!sig || blobmsg_type(sig) != BLOBMSG_TYPE_TABLE)
 194                 return false;
 195
 196         n_attr = 0;
 197
 198         blobmsg_for_each_attr(attr, sig, rem)
 199                 n_attr++;
 200
 201         if (n_attr)
 202         {
 203                 policy = calloc(n_attr, sizeof(*policy));
 204
 205                 if (!policy)
 206                         return false;
 207
 208                 n_attr = 0;
 209
 210                 blobmsg_for_each_attr(attr, sig, rem)
 211                 {
 212                         type = blobmsg_type(attr);
 213
 214                         if (type == BLOBMSG_TYPE_INT32)
 215                         {
 216                                 switch (blobmsg_get_u32(attr))
 217                                 {
 218                                 case 8:
 219                                         type = BLOBMSG_TYPE_INT8;
 220                                         break;
 221
 222                                 case 16:
 223                                         type = BLOBMSG_TYPE_INT16;
 224                                         break;
 225
 226                                 case 64:
 227                                         type = BLOBMSG_TYPE_INT64;
 228                                         break;
 229
 230                                 default:
 231                                         type = BLOBMSG_TYPE_INT32;
 232                                         break;
 233                                 }
 234                         }
 235
 236                         policy[n_attr].name = strdup(blobmsg_name(attr));
 237                         policy[n_attr].type = type;
 238
 239                         n_attr++;
 240                 }
 241         }
 242
 243         method->name = strdup(blobmsg_name(sig));
 244         method->handler = rpc_plugin_call;
 245         method->policy = policy;
 246         method->n_policy = n_attr;
 247
 248         return true;
 249 }
 250
 251 static struct ubus_object *
 252 rpc_plugin_parse_exec(const char *name, int fd)
 253 {
 254         int len, rem, n_method;
 255         struct blob_attr *cur;
 256         struct ubus_method *methods;
 257         struct ubus_object_type *obj_type;
 258         struct ubus_object *obj;
 259         char outbuf[1024];
 260
 261         json_tokener *tok;
 262         json_object *jsobj;
 263
 264         blob_buf_init(&buf, 0);
 265
 266         tok = json_tokener_new();
 267
 268         if (!tok)
 269                 return NULL;
 270
 271         while ((len = read(fd, outbuf, sizeof(outbuf))) > 0)
 272         {
 273                 jsobj = json_tokener_parse_ex(tok, outbuf, len);
 274
 275                 if (json_tokener_get_error(tok) == json_tokener_continue)
 276                         continue;
 277
 278                 if (json_tokener_get_error(tok) != json_tokener_success)
 279                         break;
 280
 281                 if (jsobj)
 282                 {
 283                         if (json_object_get_type(jsobj) == json_type_object)
 284                                 blobmsg_add_object(&buf, jsobj);
 285
 286                         json_object_put(jsobj);
 287                         break;
 288                 }
 289         }
 290
 291         json_tokener_free(tok);
 292
 293         n_method = 0;
 294
 295         blob_for_each_attr(cur, buf.head, rem)
 296                 n_method++;
 297
 298         if (!n_method)
 299                 return NULL;
 300
 301         methods = calloc(n_method, sizeof(*methods));
 302
 303         if (!methods)
 304                 return NULL;
 305
 306         n_method = 0;
 307
 308         blob_for_each_attr(cur, buf.head, rem)
 309         {
 310                 if (!rpc_plugin_parse_signature(cur, &methods[n_method]))
 311                         continue;
 312
 313                 n_method++;
 314         }
 315
 316         obj = calloc(1, sizeof(*obj));
 317
 318         if (!obj)
 319                 return NULL;
 320
 321         obj_type = calloc(1, sizeof(*obj_type));
 322
 323         if (!obj_type) {
 324                 free(obj);
 325                 return NULL;
 326         }
 327
 328         if (asprintf((char **)&obj_type->name, "luci-rpc-plugin-%s", name) < 0) {
 329                 free(obj);
 330                 free(obj_type);
 331                 return NULL;
 332         }
 333
 334         obj_type->methods = methods;
 335         obj_type->n_methods = n_method;
 336
 337         obj->name = strdup(name);
 338         obj->type = obj_type;
 339         obj->methods = methods;
 340         obj->n_methods = n_method;
 341
 342         return obj;
 343 }
 344
 345 static int
 346 rpc_plugin_register_exec(struct ubus_context *ctx, const char *path)
 347 {
 348         pid_t pid;
 349         int rv = UBUS_STATUS_NO_DATA, fd, fds[2];
 350         const char *name;
 351         struct ubus_object *plugin;
 352
 353         name = strrchr(path, '/');
 354
 355         if (!name)
 356                 return UBUS_STATUS_INVALID_ARGUMENT;
 357
 358         if (pipe(fds))
 359                 return UBUS_STATUS_UNKNOWN_ERROR;
 360
 361         switch ((pid = fork()))
 362         {
 363         case -1:
 364                 return UBUS_STATUS_UNKNOWN_ERROR;
 365
 366         case 0:
 367                 fd = open("/dev/null", O_RDWR);
 368
 369                 if (fd > -1)
 370                 {
 371                         dup2(fd, 0);
 372                         dup2(fd, 2);
 373
 374                         if (fd > 2)
 375                                 close(fd);
 376                 }
 377
 378                 dup2(fds[1], 1);
 379
 380                 close(fds[0]);
 381                 close(fds[1]);
 382
 383                 if (execl(path, path, "list", NULL))
 384                         return UBUS_STATUS_UNKNOWN_ERROR;
 385
 386         default:
 387                 plugin = rpc_plugin_parse_exec(name + 1, fds[0]);
 388
 389                 if (!plugin)
 390                         goto out;
 391
 392                 rv = ubus_add_object(ctx, plugin);
 393
 394 out:
 395                 close(fds[0]);
 396                 close(fds[1]);
 397                 waitpid(pid, NULL, 0);
 398
 399                 return rv;
 400         }
 401 }
 402
 403
 404 static LIST_HEAD(plugins);
 405
 406 static const struct rpc_daemon_ops ops = {
 407         .session_access     = rpc_session_access,
 408         .session_create_cb  = rpc_session_create_cb,
 409         .session_destroy_cb = rpc_session_destroy_cb,
 410         .exec               = rpc_exec,
 411         .exec_timeout       = &rpc_exec_timeout,
 412 };
 413
 414 static int
 415 rpc_plugin_register_library(struct ubus_context *ctx, const char *path)
 416 {
 417         struct rpc_plugin *p;
 418         void *dlh;
 419
 420         dlh = dlopen(path, RTLD_LAZY | RTLD_LOCAL);
 421
 422         if (!dlh)
 423                 return UBUS_STATUS_UNKNOWN_ERROR;
 424
 425         p = dlsym(dlh, "rpc_plugin");
 426
 427         if (!p)
 428                 return UBUS_STATUS_NOT_FOUND;
 429
 430         list_add(&p->list, &plugins);
 431
 432         return p->init(&ops, ctx);
 433 }
 434
 435 int rpc_plugin_api_init(struct ubus_context *ctx)
 436 {
 437         DIR *d;
 438         int rv = 0;
 439         struct stat s;
 440         struct dirent *e;
 441         char path[PATH_MAX];
 442
 443         if ((d = opendir(RPC_PLUGIN_DIRECTORY)) != NULL)
 444         {
 445                 while ((e = readdir(d)) != NULL)
 446                 {
 447                         snprintf(path, sizeof(path) - 1,
 448                                  RPC_PLUGIN_DIRECTORY "/%s", e->d_name);
 449
 450                         if (stat(path, &s) || !S_ISREG(s.st_mode) || !(s.st_mode & S_IXUSR))
 451                                 continue;
 452
 453                         rv |= rpc_plugin_register_exec(ctx, path);
 454                 }
 455
 456                 closedir(d);
 457         }
 458
 459         if ((d = opendir(RPC_LIBRARY_DIRECTORY)) != NULL)
 460         {
 461                 while ((e = readdir(d)) != NULL)
 462                 {
 463                         snprintf(path, sizeof(path) - 1,
 464                                  RPC_LIBRARY_DIRECTORY "/%s", e->d_name);
 465
 466                         if (stat(path, &s) || !S_ISREG(s.st_mode))
 467                                 continue;
 468
 469                         rv |= rpc_plugin_register_library(ctx, path);
 470                 }
 471
 472                 closedir(d);
 473         }
 474
 475         return rv;
 476 }