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
  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 static int
  55 rpc_plugin_call(struct ubus_context *ctx, struct ubus_object *obj,
  56                 struct ubus_request_data *req, const char *method,
  57                 struct blob_attr *msg)
  58 {
  59         pid_t pid;
  60         struct stat s;
  61         int rv, fd, in_fds[2], out_fds[2];
  62         char *input, *plugin, *meth, output[4096] = { 0 }, path[PATH_MAX] = { 0 };
  63
  64         meth = strdup(method);
  65         input = blobmsg_format_json(msg, true);
  66         plugin = path + sprintf(path, "%s/", RPC_PLUGIN_DIRECTORY);
  67
  68         if (!rpc_plugin_lookup_plugin(ctx, obj, plugin))
  69                 return UBUS_STATUS_NOT_FOUND;
  70
  71         if (stat(path, &s) || !(s.st_mode & S_IXUSR))
  72                 return UBUS_STATUS_NOT_FOUND;
  73
  74         if (pipe(in_fds) || pipe(out_fds))
  75                 return UBUS_STATUS_UNKNOWN_ERROR;
  76
  77         switch ((pid = fork()))
  78         {
  79         case -1:
  80                 return UBUS_STATUS_UNKNOWN_ERROR;
  81
  82         case 0:
  83                 uloop_done();
  84
  85                 fd = open("/dev/null", O_RDWR);
  86
  87                 if (fd > -1)
  88                 {
  89                         dup2(fd, 2);
  90
  91                         if (fd > 2)
  92                                 close(fd);
  93                 }
  94
  95                 dup2(in_fds[0], 0);
  96                 dup2(out_fds[1], 1);
  97
  98                 close(in_fds[0]);
  99                 close(in_fds[1]);
 100                 close(out_fds[0]);
 101                 close(out_fds[1]);
 102
 103                 if (execl(path, plugin, "call", meth, NULL))
 104                         return UBUS_STATUS_UNKNOWN_ERROR;
 105
 106         default:
 107                 rv = UBUS_STATUS_NO_DATA;
 108
 109                 if (input)
 110                 {
 111                         write(in_fds[1], input, strlen(input));
 112                         free(input);
 113                 }
 114
 115                 close(in_fds[0]);
 116                 close(in_fds[1]);
 117
 118                 if (read(out_fds[0], output, sizeof(output) - 1) > 0)
 119                 {
 120                         blob_buf_init(&buf, 0);
 121
 122                         if (!blobmsg_add_json_from_string(&buf, output))
 123                                 rv = UBUS_STATUS_INVALID_ARGUMENT;
 124
 125                         rv = UBUS_STATUS_OK;
 126                 }
 127
 128                 close(out_fds[0]);
 129                 close(out_fds[1]);
 130
 131                 waitpid(pid, NULL, 0);
 132
 133                 if (!rv)
 134                         ubus_send_reply(ctx, req, buf.head);
 135
 136                 free(meth);
 137
 138                 return rv;
 139         }
 140 }
 141
 142 static bool
 143 rpc_plugin_parse_signature(struct blob_attr *sig, struct ubus_method *method)
 144 {
 145         int rem, n_attr;
 146         enum blobmsg_type type;
 147         struct blob_attr *attr;
 148         struct blobmsg_policy *policy = NULL;
 149
 150         if (!sig || blob_id(sig) != BLOBMSG_TYPE_TABLE)
 151                 return false;
 152
 153         n_attr = 0;
 154
 155         blobmsg_for_each_attr(attr, sig, rem)
 156                 n_attr++;
 157
 158         if (n_attr)
 159         {
 160                 policy = calloc(n_attr, sizeof(*policy));
 161
 162                 if (!policy)
 163                         return false;
 164
 165                 n_attr = 0;
 166
 167                 blobmsg_for_each_attr(attr, sig, rem)
 168                 {
 169                         type = blob_id(attr);
 170
 171                         if (type == BLOBMSG_TYPE_INT32)
 172                         {
 173                                 switch (blobmsg_get_u32(attr))
 174                                 {
 175                                 case 8:
 176                                         type = BLOBMSG_TYPE_INT8;
 177                                         break;
 178
 179                                 case 16:
 180                                         type = BLOBMSG_TYPE_INT16;
 181                                         break;
 182
 183                                 case 64:
 184                                         type = BLOBMSG_TYPE_INT64;
 185                                         break;
 186
 187                                 default:
 188                                         type = BLOBMSG_TYPE_INT32;
 189                                         break;
 190                                 }
 191                         }
 192
 193                         policy[n_attr].name = strdup(blobmsg_name(attr));
 194                         policy[n_attr].type = type;
 195
 196                         n_attr++;
 197                 }
 198         }
 199
 200         method->name = strdup(blobmsg_name(sig));
 201         method->handler = rpc_plugin_call;
 202         method->policy = policy;
 203         method->n_policy = n_attr;
 204
 205         return true;
 206 }
 207
 208 static struct ubus_object *
 209 rpc_plugin_parse_plugin(const char *name, const char *listbuf)
 210 {
 211         int rem, n_method;
 212         struct blob_attr *cur;
 213         struct ubus_method *methods;
 214         struct ubus_object_type *obj_type;
 215         struct ubus_object *obj;
 216
 217         blob_buf_init(&buf, 0);
 218
 219         if (!blobmsg_add_json_from_string(&buf, listbuf))
 220                 return NULL;
 221
 222         n_method = 0;
 223
 224         blob_for_each_attr(cur, buf.head, rem)
 225                 n_method++;
 226
 227         if (!n_method)
 228                 return NULL;
 229
 230         methods = calloc(n_method, sizeof(*methods));
 231
 232         if (!methods)
 233                 return NULL;
 234
 235         n_method = 0;
 236
 237         blob_for_each_attr(cur, buf.head, rem)
 238         {
 239                 if (!rpc_plugin_parse_signature(cur, &methods[n_method]))
 240                         continue;
 241
 242                 n_method++;
 243         }
 244
 245         obj = calloc(1, sizeof(*obj));
 246
 247         if (!obj)
 248                 return NULL;
 249
 250         obj_type = calloc(1, sizeof(*obj_type));
 251
 252         if (!obj_type)
 253                 return NULL;
 254
 255         asprintf((char **)&obj_type->name, "luci-rpc-plugin-%s", name);
 256         obj_type->methods = methods;
 257         obj_type->n_methods = n_method;
 258
 259         obj->name = strdup(name);
 260         obj->type = obj_type;
 261         obj->methods = methods;
 262         obj->n_methods = n_method;
 263
 264         return obj;
 265 }
 266
 267 static int
 268 rpc_plugin_register(struct ubus_context *ctx, const char *path)
 269 {
 270         pid_t pid;
 271         int rv, fd, fds[2];
 272         const char *name;
 273         char listbuf[4096] = { 0 };
 274         struct ubus_object *plugin;
 275
 276         name = strrchr(path, '/');
 277
 278         if (!name)
 279                 return UBUS_STATUS_INVALID_ARGUMENT;
 280
 281         if (pipe(fds))
 282                 return UBUS_STATUS_UNKNOWN_ERROR;
 283
 284         switch ((pid = fork()))
 285         {
 286         case -1:
 287                 return UBUS_STATUS_UNKNOWN_ERROR;
 288
 289         case 0:
 290                 fd = open("/dev/null", O_RDWR);
 291
 292                 if (fd > -1)
 293                 {
 294                         dup2(fd, 0);
 295                         dup2(fd, 2);
 296
 297                         if (fd > 2)
 298                                 close(fd);
 299                 }
 300
 301                 dup2(fds[1], 1);
 302
 303                 close(fds[0]);
 304                 close(fds[1]);
 305
 306                 if (execl(path, path, "list", NULL))
 307                         return UBUS_STATUS_UNKNOWN_ERROR;
 308
 309         default:
 310                 rv = 0;
 311
 312                 if (read(fds[0], listbuf, sizeof(listbuf) - 1) <= 0)
 313                         goto out;
 314
 315                 plugin = rpc_plugin_parse_plugin(name + 1, listbuf);
 316
 317                 if (!plugin)
 318                         goto out;
 319
 320                 rv = ubus_add_object(ctx, plugin);
 321
 322 out:
 323                 close(fds[0]);
 324                 close(fds[1]);
 325                 waitpid(pid, NULL, 0);
 326
 327                 return rv;
 328         }
 329 }
 330
 331 int rpc_plugin_api_init(struct ubus_context *ctx)
 332 {
 333         DIR *d;
 334         int rv = 0;
 335         struct stat s;
 336         struct dirent *e;
 337         char path[PATH_MAX];
 338
 339         d = opendir(RPC_PLUGIN_DIRECTORY);
 340
 341         if (!d)
 342                 return UBUS_STATUS_NOT_FOUND;
 343
 344         while ((e = readdir(d)) != NULL)
 345         {
 346                 snprintf(path, sizeof(path) - 1, RPC_PLUGIN_DIRECTORY "/%s", e->d_name);
 347
 348                 if (stat(path, &s) || !S_ISREG(s.st_mode) || !(s.st_mode & S_IXUSR))
 349                         continue;
 350
 351                 rv |= rpc_plugin_register(ctx, path);
 352         }
 353
 354         closedir(d);
 355
 356         return rv;
 357 }