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_stderr_cb(struct blob_buf *blob, char *buf, int len, void *priv)
  98 {
  99         return len;
 100 }
 101
 102 static int
 103 rpc_plugin_call_finish_cb(struct blob_buf *blob, int stat, void *priv)
 104 {
 105         struct call_context *c = priv;
 106         int rv = UBUS_STATUS_INVALID_ARGUMENT;
 107
 108         if (json_tokener_get_error(c->tok) == json_tokener_success)
 109         {
 110                 if (c->obj)
 111                 {
 112                         if (json_object_get_type(c->obj) == json_type_object ||
 113                             json_object_get_type(c->obj) == json_type_array)
 114                         {
 115                                 blobmsg_add_json_element(blob, NULL, c->obj);
 116                                 rv = UBUS_STATUS_OK;
 117                         }
 118
 119                         json_object_put(c->obj);
 120                 }
 121                 else
 122                 {
 123                         rv = UBUS_STATUS_NO_DATA;
 124                 }
 125         }
 126
 127         json_tokener_free(c->tok);
 128
 129         free(c->input);
 130         free(c->method);
 131
 132         return rv;
 133 }
 134
 135 static int
 136 rpc_plugin_call(struct ubus_context *ctx, struct ubus_object *obj,
 137                 struct ubus_request_data *req, const char *method,
 138                 struct blob_attr *msg)
 139 {
 140         int rv = UBUS_STATUS_UNKNOWN_ERROR;
 141         struct call_context *c;
 142         char *plugin;
 143
 144         c = calloc(1, sizeof(*c));
 145
 146         if (!c)
 147                 goto fail;
 148
 149         c->method = strdup(method);
 150         c->input = blobmsg_format_json(msg, true);
 151         c->tok = json_tokener_new();
 152
 153         if (!c->method || !c->input || !c->tok)
 154                 goto fail;
 155
 156         plugin = c->path + sprintf(c->path, "%s/", RPC_PLUGIN_DIRECTORY);
 157
 158         if (!rpc_plugin_lookup_plugin(ctx, obj, plugin))
 159         {
 160                 rv = UBUS_STATUS_NOT_FOUND;
 161                 goto fail;
 162         }
 163
 164         c->argv[0] = c->path;
 165         c->argv[1] = "call";
 166         c->argv[2] = c->method;
 167
 168         return rpc_exec(c->argv, rpc_plugin_call_stdin_cb,
 169                         rpc_plugin_call_stdout_cb, rpc_plugin_call_stderr_cb,
 170                         rpc_plugin_call_finish_cb, c, ctx, req);
 171
 172 fail:
 173         if (c)
 174         {
 175                 if (c->method)
 176                         free(c->method);
 177
 178                 if (c->input)
 179                         free(c->input);
 180
 181                 if (c->tok)
 182                         json_tokener_free(c->tok);
 183
 184                 free(c);
 185         }
 186
 187         return rv;
 188 }
 189
 190 static bool
 191 rpc_plugin_parse_signature(struct blob_attr *sig, struct ubus_method *method)
 192 {
 193         int rem, n_attr;
 194         enum blobmsg_type type;
 195         struct blob_attr *attr;
 196         struct blobmsg_policy *policy = NULL;
 197
 198         if (!sig || blob_id(sig) != BLOBMSG_TYPE_TABLE)
 199                 return false;
 200
 201         n_attr = 0;
 202
 203         blobmsg_for_each_attr(attr, sig, rem)
 204                 n_attr++;
 205
 206         if (n_attr)
 207         {
 208                 policy = calloc(n_attr, sizeof(*policy));
 209
 210                 if (!policy)
 211                         return false;
 212
 213                 n_attr = 0;
 214
 215                 blobmsg_for_each_attr(attr, sig, rem)
 216                 {
 217                         type = blob_id(attr);
 218
 219                         if (type == BLOBMSG_TYPE_INT32)
 220                         {
 221                                 switch (blobmsg_get_u32(attr))
 222                                 {
 223                                 case 8:
 224                                         type = BLOBMSG_TYPE_INT8;
 225                                         break;
 226
 227                                 case 16:
 228                                         type = BLOBMSG_TYPE_INT16;
 229                                         break;
 230
 231                                 case 64:
 232                                         type = BLOBMSG_TYPE_INT64;
 233                                         break;
 234
 235                                 default:
 236                                         type = BLOBMSG_TYPE_INT32;
 237                                         break;
 238                                 }
 239                         }
 240
 241                         policy[n_attr].name = strdup(blobmsg_name(attr));
 242                         policy[n_attr].type = type;
 243
 244                         n_attr++;
 245                 }
 246         }
 247
 248         method->name = strdup(blobmsg_name(sig));
 249         method->handler = rpc_plugin_call;
 250         method->policy = policy;
 251         method->n_policy = n_attr;
 252
 253         return true;
 254 }
 255
 256 static struct ubus_object *
 257 rpc_plugin_parse_plugin(const char *name, int fd)
 258 {
 259         int len, rem, n_method;
 260         struct blob_attr *cur;
 261         struct ubus_method *methods;
 262         struct ubus_object_type *obj_type;
 263         struct ubus_object *obj;
 264         char outbuf[1024];
 265
 266         json_tokener *tok;
 267         json_object *jsobj;
 268
 269         blob_buf_init(&buf, 0);
 270
 271         tok = json_tokener_new();
 272
 273         if (!tok)
 274                 return NULL;
 275
 276         while ((len = read(fd, outbuf, sizeof(outbuf))) > 0)
 277         {
 278                 jsobj = json_tokener_parse_ex(tok, outbuf, len);
 279
 280                 if (json_tokener_get_error(tok) == json_tokener_continue)
 281                         continue;
 282
 283                 if (json_tokener_get_error(tok) != json_tokener_success)
 284                         break;
 285
 286                 if (jsobj)
 287                 {
 288                         if (json_object_get_type(jsobj) == json_type_object)
 289                                 blobmsg_add_object(&buf, jsobj);
 290
 291                         json_object_put(jsobj);
 292                         break;
 293                 }
 294         }
 295
 296         json_tokener_free(tok);
 297
 298         n_method = 0;
 299
 300         blob_for_each_attr(cur, buf.head, rem)
 301                 n_method++;
 302
 303         if (!n_method)
 304                 return NULL;
 305
 306         methods = calloc(n_method, sizeof(*methods));
 307
 308         if (!methods)
 309                 return NULL;
 310
 311         n_method = 0;
 312
 313         blob_for_each_attr(cur, buf.head, rem)
 314         {
 315                 if (!rpc_plugin_parse_signature(cur, &methods[n_method]))
 316                         continue;
 317
 318                 n_method++;
 319         }
 320
 321         obj = calloc(1, sizeof(*obj));
 322
 323         if (!obj)
 324                 return NULL;
 325
 326         obj_type = calloc(1, sizeof(*obj_type));
 327
 328         if (!obj_type)
 329                 return NULL;
 330
 331         asprintf((char **)&obj_type->name, "luci-rpc-plugin-%s", name);
 332         obj_type->methods = methods;
 333         obj_type->n_methods = n_method;
 334
 335         obj->name = strdup(name);
 336         obj->type = obj_type;
 337         obj->methods = methods;
 338         obj->n_methods = n_method;
 339
 340         return obj;
 341 }
 342
 343 static int
 344 rpc_plugin_register(struct ubus_context *ctx, const char *path)
 345 {
 346         pid_t pid;
 347         int rv = UBUS_STATUS_NO_DATA, fd, fds[2];
 348         const char *name;
 349         struct ubus_object *plugin;
 350
 351         name = strrchr(path, '/');
 352
 353         if (!name)
 354                 return UBUS_STATUS_INVALID_ARGUMENT;
 355
 356         if (pipe(fds))
 357                 return UBUS_STATUS_UNKNOWN_ERROR;
 358
 359         switch ((pid = fork()))
 360         {
 361         case -1:
 362                 return UBUS_STATUS_UNKNOWN_ERROR;
 363
 364         case 0:
 365                 fd = open("/dev/null", O_RDWR);
 366
 367                 if (fd > -1)
 368                 {
 369                         dup2(fd, 0);
 370                         dup2(fd, 2);
 371
 372                         if (fd > 2)
 373                                 close(fd);
 374                 }
 375
 376                 dup2(fds[1], 1);
 377
 378                 close(fds[0]);
 379                 close(fds[1]);
 380
 381                 if (execl(path, path, "list", NULL))
 382                         return UBUS_STATUS_UNKNOWN_ERROR;
 383
 384         default:
 385                 plugin = rpc_plugin_parse_plugin(name + 1, fds[0]);
 386
 387                 if (!plugin)
 388                         goto out;
 389
 390                 rv = ubus_add_object(ctx, plugin);
 391
 392 out:
 393                 close(fds[0]);
 394                 close(fds[1]);
 395                 waitpid(pid, NULL, 0);
 396
 397                 return rv;
 398         }
 399 }
 400
 401 int rpc_plugin_api_init(struct ubus_context *ctx)
 402 {
 403         DIR *d;
 404         int rv = 0;
 405         struct stat s;
 406         struct dirent *e;
 407         char path[PATH_MAX];
 408
 409         d = opendir(RPC_PLUGIN_DIRECTORY);
 410
 411         if (!d)
 412                 return UBUS_STATUS_NOT_FOUND;
 413
 414         while ((e = readdir(d)) != NULL)
 415         {
 416                 snprintf(path, sizeof(path) - 1, RPC_PLUGIN_DIRECTORY "/%s", e->d_name);
 417
 418                 if (stat(path, &s) || !S_ISREG(s.st_mode) || !(s.st_mode & S_IXUSR))
 419                         continue;
 420
 421                 rv |= rpc_plugin_register(ctx, path);
 422         }
 423
 424         closedir(d);
 425
 426         return rv;
 427 }