libubus-io.c

   1 /*
   2  * Copyright (C) 2011-2014 Felix Fietkau <nbd@openwrt.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU Lesser General Public License version 2.1
   6  * as published by the Free Software Foundation
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #include <sys/types.h>
  15 #include <sys/uio.h>
  16 #include <sys/socket.h>
  17
  18 #include <unistd.h>
  19 #include <fcntl.h>
  20 #include <poll.h>
  21
  22 #include <libubox/usock.h>
  23 #include <libubox/blob.h>
  24 #include <libubox/blobmsg.h>
  25
  26 #include "libubus.h"
  27 #include "libubus-internal.h"
  28
  29 #define STATIC_IOV(_var) { .iov_base = (char *) &(_var), .iov_len = sizeof(_var) }
  30
  31 #define UBUS_MSGBUF_REDUCTION_INTERVAL  16
  32
  33 static const struct blob_attr_info ubus_policy[UBUS_ATTR_MAX] = {
  34         [UBUS_ATTR_STATUS] = { .type = BLOB_ATTR_INT32 },
  35         [UBUS_ATTR_OBJID] = { .type = BLOB_ATTR_INT32 },
  36         [UBUS_ATTR_OBJPATH] = { .type = BLOB_ATTR_STRING },
  37         [UBUS_ATTR_METHOD] = { .type = BLOB_ATTR_STRING },
  38         [UBUS_ATTR_ACTIVE] = { .type = BLOB_ATTR_INT8 },
  39         [UBUS_ATTR_NO_REPLY] = { .type = BLOB_ATTR_INT8 },
  40         [UBUS_ATTR_SUBSCRIBERS] = { .type = BLOB_ATTR_NESTED },
  41 };
  42
  43 static struct blob_attr *attrbuf[UBUS_ATTR_MAX];
  44
  45 __hidden struct blob_attr **ubus_parse_msg(struct blob_attr *msg)
  46 {
  47         blob_parse(msg, attrbuf, ubus_policy, UBUS_ATTR_MAX);
  48         return attrbuf;
  49 }
  50
  51 static void wait_data(int fd, bool write)
  52 {
  53         struct pollfd pfd = { .fd = fd };
  54
  55         pfd.events = write ? POLLOUT : POLLIN;
  56         poll(&pfd, 1, 0);
  57 }
  58
  59 static int writev_retry(int fd, struct iovec *iov, int iov_len, int sock_fd)
  60 {
  61         static struct {
  62                 struct cmsghdr h;
  63                 int fd;
  64         } fd_buf = {
  65                 .h = {
  66                         .cmsg_len = sizeof(fd_buf),
  67                         .cmsg_level = SOL_SOCKET,
  68                         .cmsg_type = SCM_RIGHTS,
  69                 }
  70         };
  71         struct msghdr msghdr = {
  72                 .msg_iov = iov,
  73                 .msg_iovlen = iov_len,
  74                 .msg_control = &fd_buf,
  75                 .msg_controllen = sizeof(fd_buf),
  76         };
  77         int len = 0;
  78
  79         do {
  80                 int cur_len;
  81
  82                 if (sock_fd < 0) {
  83                         msghdr.msg_control = NULL;
  84                         msghdr.msg_controllen = 0;
  85                 } else {
  86                         fd_buf.fd = sock_fd;
  87                 }
  88
  89                 cur_len = sendmsg(fd, &msghdr, 0);
  90                 if (cur_len < 0) {
  91                         switch(errno) {
  92                         case EAGAIN:
  93                                 wait_data(fd, true);
  94                                 break;
  95                         case EINTR:
  96                                 break;
  97                         default:
  98                                 return -1;
  99                         }
 100                         continue;
 101                 }
 102
 103                 if (len > 0)
 104                         sock_fd = -1;
 105
 106                 len += cur_len;
 107                 while (cur_len >= iov->iov_len) {
 108                         cur_len -= iov->iov_len;
 109                         iov_len--;
 110                         iov++;
 111                         if (!iov_len)
 112                                 return len;
 113                 }
 114                 iov->iov_base += cur_len;
 115                 iov->iov_len -= cur_len;
 116                 msghdr.msg_iov = iov;
 117                 msghdr.msg_iovlen = iov_len;
 118         } while (1);
 119
 120         /* Should never reach here */
 121         return -1;
 122 }
 123
 124 int __hidden ubus_send_msg(struct ubus_context *ctx, uint32_t seq,
 125                            struct blob_attr *msg, int cmd, uint32_t peer, int fd)
 126 {
 127         struct ubus_msghdr hdr;
 128         struct iovec iov[2] = {
 129                 STATIC_IOV(hdr)
 130         };
 131         int ret;
 132
 133         hdr.version = 0;
 134         hdr.type = cmd;
 135         hdr.seq = seq;
 136         hdr.peer = peer;
 137
 138         if (!msg) {
 139                 blob_buf_init(&b, 0);
 140                 msg = b.head;
 141         }
 142
 143         iov[1].iov_base = (char *) msg;
 144         iov[1].iov_len = blob_raw_len(msg);
 145
 146         ret = writev_retry(ctx->sock.fd, iov, ARRAY_SIZE(iov), fd);
 147         if (ret < 0)
 148                 ctx->sock.eof = true;
 149
 150         if (fd >= 0)
 151                 close(fd);
 152
 153         return ret;
 154 }
 155
 156 static int recv_retry(int fd, struct iovec *iov, bool wait, int *recv_fd)
 157 {
 158         int bytes, total = 0;
 159         static struct {
 160                 struct cmsghdr h;
 161                 int fd;
 162         } fd_buf = {
 163                 .h = {
 164                         .cmsg_type = SCM_RIGHTS,
 165                         .cmsg_level = SOL_SOCKET,
 166                         .cmsg_len = sizeof(fd_buf),
 167                 },
 168         };
 169         struct msghdr msghdr = {
 170                 .msg_iov = iov,
 171                 .msg_iovlen = 1,
 172         };
 173
 174         while (iov->iov_len > 0) {
 175                 if (wait)
 176                         wait_data(fd, false);
 177
 178                 if (recv_fd) {
 179                         msghdr.msg_control = &fd_buf;
 180                         msghdr.msg_controllen = sizeof(fd_buf);
 181                 } else {
 182                         msghdr.msg_control = NULL;
 183                         msghdr.msg_controllen = 0;
 184                 }
 185
 186                 fd_buf.fd = -1;
 187                 bytes = recvmsg(fd, &msghdr, 0);
 188                 if (!bytes)
 189                         return -1;
 190
 191                 if (bytes < 0) {
 192                         bytes = 0;
 193                         if (uloop_cancelled)
 194                                 return 0;
 195                         if (errno == EINTR)
 196                                 continue;
 197
 198                         if (errno != EAGAIN)
 199                                 return -1;
 200                 }
 201                 if (!wait && !bytes)
 202                         return 0;
 203
 204                 if (recv_fd)
 205                         *recv_fd = fd_buf.fd;
 206
 207                 recv_fd = NULL;
 208
 209                 wait = true;
 210                 iov->iov_len -= bytes;
 211                 iov->iov_base += bytes;
 212                 total += bytes;
 213         }
 214
 215         return total;
 216 }
 217
 218 static bool ubus_validate_hdr(struct ubus_msghdr *hdr)
 219 {
 220         struct blob_attr *data = (struct blob_attr *) (hdr + 1);
 221
 222         if (hdr->version != 0)
 223                 return false;
 224
 225         if (blob_raw_len(data) < sizeof(*data))
 226                 return false;
 227
 228         if (blob_pad_len(data) > UBUS_MAX_MSGLEN)
 229                 return false;
 230
 231         return true;
 232 }
 233
 234 static bool alloc_msg_buf(struct ubus_context *ctx, int len)
 235 {
 236         void *ptr;
 237         int buf_len = ctx->msgbuf_data_len;
 238         int rem;
 239
 240         if (!ctx->msgbuf.data)
 241                 buf_len = 0;
 242
 243         rem = (len % UBUS_MSG_CHUNK_SIZE);
 244         if (rem > 0)
 245                 len += UBUS_MSG_CHUNK_SIZE - rem;
 246
 247         if (len < buf_len &&
 248             ++ctx->msgbuf_reduction_counter > UBUS_MSGBUF_REDUCTION_INTERVAL) {
 249                 ctx->msgbuf_reduction_counter = 0;
 250                 buf_len = 0;
 251         }
 252
 253         if (len <= buf_len)
 254                 return true;
 255
 256         ptr = realloc(ctx->msgbuf.data, len);
 257         if (!ptr)
 258                 return false;
 259
 260         ctx->msgbuf.data = ptr;
 261         return true;
 262 }
 263
 264 static bool get_next_msg(struct ubus_context *ctx, int *recv_fd)
 265 {
 266         struct {
 267                 struct ubus_msghdr hdr;
 268                 struct blob_attr data;
 269         } hdrbuf;
 270         struct iovec iov = STATIC_IOV(hdrbuf);
 271         int len;
 272         int r;
 273
 274         /* receive header + start attribute */
 275         r = recv_retry(ctx->sock.fd, &iov, false, recv_fd);
 276         if (r <= 0) {
 277                 if (r < 0)
 278                         ctx->sock.eof = true;
 279
 280                 return false;
 281         }
 282
 283         if (!ubus_validate_hdr(&hdrbuf.hdr))
 284                 return false;
 285
 286         len = blob_raw_len(&hdrbuf.data);
 287         if (!alloc_msg_buf(ctx, len))
 288                 return false;
 289
 290         memcpy(&ctx->msgbuf.hdr, &hdrbuf.hdr, sizeof(hdrbuf.hdr));
 291         memcpy(ctx->msgbuf.data, &hdrbuf.data, sizeof(hdrbuf.data));
 292
 293         iov.iov_base = (char *)ctx->msgbuf.data + sizeof(hdrbuf.data);
 294         iov.iov_len = blob_len(ctx->msgbuf.data);
 295         if (iov.iov_len > 0 && !recv_retry(ctx->sock.fd, &iov, true, NULL))
 296                 return false;
 297
 298         return true;
 299 }
 300
 301 void __hidden ubus_handle_data(struct uloop_fd *u, unsigned int events)
 302 {
 303         struct ubus_context *ctx = container_of(u, struct ubus_context, sock);
 304         int recv_fd = -1;
 305
 306         while (get_next_msg(ctx, &recv_fd)) {
 307                 ubus_process_msg(ctx, &ctx->msgbuf, recv_fd);
 308                 if (uloop_cancelled)
 309                         break;
 310         }
 311
 312         if (u->eof)
 313                 ctx->connection_lost(ctx);
 314 }
 315
 316 void __hidden ubus_poll_data(struct ubus_context *ctx, int timeout)
 317 {
 318         struct pollfd pfd = {
 319                 .fd = ctx->sock.fd,
 320                 .events = POLLIN | POLLERR,
 321         };
 322
 323         poll(&pfd, 1, timeout);
 324         ubus_handle_data(&ctx->sock, ULOOP_READ);
 325 }
 326
 327 static void
 328 ubus_refresh_state(struct ubus_context *ctx)
 329 {
 330         struct ubus_object *obj, *tmp;
 331         struct ubus_object **objs;
 332         int n, i = 0;
 333
 334         /* clear all type IDs, they need to be registered again */
 335         avl_for_each_element(&ctx->objects, obj, avl)
 336                 if (obj->type)
 337                         obj->type->id = 0;
 338
 339         /* push out all objects again */
 340         objs = alloca(ctx->objects.count * sizeof(*objs));
 341         avl_remove_all_elements(&ctx->objects, obj, avl, tmp) {
 342                 objs[i++] = obj;
 343                 obj->id = 0;
 344         }
 345
 346         for (n = i, i = 0; i < n; i++)
 347                 ubus_add_object(ctx, objs[i]);
 348 }
 349
 350 int ubus_reconnect(struct ubus_context *ctx, const char *path)
 351 {
 352         struct {
 353                 struct ubus_msghdr hdr;
 354                 struct blob_attr data;
 355         } hdr;
 356         struct blob_attr *buf;
 357         int ret = UBUS_STATUS_UNKNOWN_ERROR;
 358
 359         if (!path)
 360                 path = UBUS_UNIX_SOCKET;
 361
 362         if (ctx->sock.fd >= 0) {
 363                 if (ctx->sock.registered)
 364                         uloop_fd_delete(&ctx->sock);
 365
 366                 close(ctx->sock.fd);
 367         }
 368
 369         ctx->sock.fd = usock(USOCK_UNIX, path, NULL);
 370         if (ctx->sock.fd < 0)
 371                 return UBUS_STATUS_CONNECTION_FAILED;
 372
 373         if (read(ctx->sock.fd, &hdr, sizeof(hdr)) != sizeof(hdr))
 374                 goto out_close;
 375
 376         if (!ubus_validate_hdr(&hdr.hdr))
 377                 goto out_close;
 378
 379         if (hdr.hdr.type != UBUS_MSG_HELLO)
 380                 goto out_close;
 381
 382         buf = calloc(1, blob_raw_len(&hdr.data));
 383         if (!buf)
 384                 goto out_close;
 385
 386         memcpy(buf, &hdr.data, sizeof(hdr.data));
 387         if (read(ctx->sock.fd, blob_data(buf), blob_len(buf)) != blob_len(buf))
 388                 goto out_free;
 389
 390         ctx->local_id = hdr.hdr.peer;
 391         if (!ctx->local_id)
 392                 goto out_free;
 393
 394         ret = UBUS_STATUS_OK;
 395         fcntl(ctx->sock.fd, F_SETFL, fcntl(ctx->sock.fd, F_GETFL) | O_NONBLOCK | O_CLOEXEC);
 396
 397         ubus_refresh_state(ctx);
 398
 399 out_free:
 400         free(buf);
 401 out_close:
 402         if (ret)
 403                 close(ctx->sock.fd);
 404
 405         return ret;
 406 }