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_len -= cur_len;
 115         } while (1);
 116
 117         /* Should never reach here */
 118         return -1;
 119 }
 120
 121 int __hidden ubus_send_msg(struct ubus_context *ctx, uint32_t seq,
 122                            struct blob_attr *msg, int cmd, uint32_t peer, int fd)
 123 {
 124         struct ubus_msghdr hdr;
 125         struct iovec iov[2] = {
 126                 STATIC_IOV(hdr)
 127         };
 128         int ret;
 129
 130         hdr.version = 0;
 131         hdr.type = cmd;
 132         hdr.seq = seq;
 133         hdr.peer = peer;
 134
 135         if (!msg) {
 136                 blob_buf_init(&b, 0);
 137                 msg = b.head;
 138         }
 139
 140         iov[1].iov_base = (char *) msg;
 141         iov[1].iov_len = blob_raw_len(msg);
 142
 143         ret = writev_retry(ctx->sock.fd, iov, ARRAY_SIZE(iov), fd);
 144         if (ret < 0)
 145                 ctx->sock.eof = true;
 146
 147         if (fd >= 0)
 148                 close(fd);
 149
 150         return ret;
 151 }
 152
 153 static int recv_retry(int fd, struct iovec *iov, bool wait, int *recv_fd)
 154 {
 155         int bytes, total = 0;
 156         static struct {
 157                 struct cmsghdr h;
 158                 int fd;
 159         } fd_buf = {
 160                 .h = {
 161                         .cmsg_type = SCM_RIGHTS,
 162                         .cmsg_level = SOL_SOCKET,
 163                         .cmsg_len = sizeof(fd_buf),
 164                 },
 165         };
 166         struct msghdr msghdr = {
 167                 .msg_iov = iov,
 168                 .msg_iovlen = 1,
 169         };
 170
 171         while (iov->iov_len > 0) {
 172                 if (wait)
 173                         wait_data(fd, false);
 174
 175                 if (recv_fd) {
 176                         msghdr.msg_control = &fd_buf;
 177                         msghdr.msg_controllen = sizeof(fd_buf);
 178                 } else {
 179                         msghdr.msg_control = NULL;
 180                         msghdr.msg_controllen = 0;
 181                 }
 182
 183                 fd_buf.fd = -1;
 184                 bytes = recvmsg(fd, &msghdr, 0);
 185                 if (!bytes)
 186                         return -1;
 187
 188                 if (bytes < 0) {
 189                         bytes = 0;
 190                         if (uloop_cancelled)
 191                                 return 0;
 192                         if (errno == EINTR)
 193                                 continue;
 194
 195                         if (errno != EAGAIN)
 196                                 return -1;
 197                 }
 198                 if (!wait && !bytes)
 199                         return 0;
 200
 201                 if (recv_fd)
 202                         *recv_fd = fd_buf.fd;
 203
 204                 recv_fd = NULL;
 205
 206                 wait = true;
 207                 iov->iov_len -= bytes;
 208                 iov->iov_base += bytes;
 209                 total += bytes;
 210         }
 211
 212         return total;
 213 }
 214
 215 static bool ubus_validate_hdr(struct ubus_msghdr *hdr)
 216 {
 217         struct blob_attr *data = (struct blob_attr *) (hdr + 1);
 218
 219         if (hdr->version != 0)
 220                 return false;
 221
 222         if (blob_raw_len(data) < sizeof(*data))
 223                 return false;
 224
 225         if (blob_pad_len(data) > UBUS_MAX_MSGLEN)
 226                 return false;
 227
 228         return true;
 229 }
 230
 231 static bool get_next_msg(struct ubus_context *ctx, int *recv_fd)
 232 {
 233         struct {
 234                 struct ubus_msghdr hdr;
 235                 struct blob_attr data;
 236         } hdrbuf;
 237         struct iovec iov = STATIC_IOV(hdrbuf);
 238         int len;
 239         int r;
 240
 241         /* receive header + start attribute */
 242         r = recv_retry(ctx->sock.fd, &iov, false, recv_fd);
 243         if (r <= 0) {
 244                 if (r < 0)
 245                         ctx->sock.eof = true;
 246
 247                 return false;
 248         }
 249
 250         if (!ubus_validate_hdr(&hdrbuf.hdr))
 251                 return false;
 252
 253         len = blob_raw_len(&hdrbuf.data);
 254         if (len > ctx->msgbuf_data_len) {
 255                 ctx->msgbuf_reduction_counter = UBUS_MSGBUF_REDUCTION_INTERVAL;
 256         } else if (ctx->msgbuf_data_len > UBUS_MSG_CHUNK_SIZE) {
 257                 if (ctx->msgbuf_reduction_counter > 0) {
 258                         len = -1;
 259                         --ctx->msgbuf_reduction_counter;
 260                 } else
 261                         len = UBUS_MSG_CHUNK_SIZE;
 262         } else
 263                 len = -1;
 264
 265         if (len > -1) {
 266                 ctx->msgbuf.data = realloc(ctx->msgbuf.data, len * sizeof(char));
 267                 if (ctx->msgbuf.data)
 268                         ctx->msgbuf_data_len = len;
 269         }
 270         if (!ctx->msgbuf.data)
 271                 return false;
 272
 273         memcpy(&ctx->msgbuf.hdr, &hdrbuf.hdr, sizeof(hdrbuf.hdr));
 274         memcpy(ctx->msgbuf.data, &hdrbuf.data, sizeof(hdrbuf.data));
 275
 276         iov.iov_base = (char *)ctx->msgbuf.data + sizeof(hdrbuf.data);
 277         iov.iov_len = blob_len(ctx->msgbuf.data);
 278         if (iov.iov_len > 0 && !recv_retry(ctx->sock.fd, &iov, true, NULL))
 279                 return false;
 280
 281         return true;
 282 }
 283
 284 void __hidden ubus_handle_data(struct uloop_fd *u, unsigned int events)
 285 {
 286         struct ubus_context *ctx = container_of(u, struct ubus_context, sock);
 287         struct ubus_msghdr *hdr = &ctx->msgbuf.hdr;
 288         int recv_fd = -1;
 289
 290         while (get_next_msg(ctx, &recv_fd)) {
 291                 ubus_process_msg(ctx, hdr, recv_fd);
 292                 if (uloop_cancelled)
 293                         break;
 294         }
 295
 296         if (u->eof)
 297                 ctx->connection_lost(ctx);
 298 }
 299
 300 void __hidden ubus_poll_data(struct ubus_context *ctx, int timeout)
 301 {
 302         struct pollfd pfd = {
 303                 .fd = ctx->sock.fd,
 304                 .events = POLLIN | POLLERR,
 305         };
 306
 307         poll(&pfd, 1, timeout);
 308         ubus_handle_data(&ctx->sock, ULOOP_READ);
 309 }
 310
 311 static void
 312 ubus_refresh_state(struct ubus_context *ctx)
 313 {
 314         struct ubus_object *obj, *tmp;
 315         struct ubus_object **objs;
 316         int n, i = 0;
 317
 318         /* clear all type IDs, they need to be registered again */
 319         avl_for_each_element(&ctx->objects, obj, avl)
 320                 if (obj->type)
 321                         obj->type->id = 0;
 322
 323         /* push out all objects again */
 324         objs = alloca(ctx->objects.count * sizeof(*objs));
 325         avl_remove_all_elements(&ctx->objects, obj, avl, tmp) {
 326                 objs[i++] = obj;
 327                 obj->id = 0;
 328         }
 329
 330         for (n = i, i = 0; i < n; i++)
 331                 ubus_add_object(ctx, objs[i]);
 332 }
 333
 334 int ubus_reconnect(struct ubus_context *ctx, const char *path)
 335 {
 336         struct {
 337                 struct ubus_msghdr hdr;
 338                 struct blob_attr data;
 339         } hdr;
 340         struct blob_attr *buf;
 341         int ret = UBUS_STATUS_UNKNOWN_ERROR;
 342
 343         if (!path)
 344                 path = UBUS_UNIX_SOCKET;
 345
 346         if (ctx->sock.fd >= 0) {
 347                 if (ctx->sock.registered)
 348                         uloop_fd_delete(&ctx->sock);
 349
 350                 close(ctx->sock.fd);
 351         }
 352
 353         ctx->sock.fd = usock(USOCK_UNIX, path, NULL);
 354         if (ctx->sock.fd < 0)
 355                 return UBUS_STATUS_CONNECTION_FAILED;
 356
 357         if (read(ctx->sock.fd, &hdr, sizeof(hdr)) != sizeof(hdr))
 358                 goto out_close;
 359
 360         if (!ubus_validate_hdr(&hdr.hdr))
 361                 goto out_close;
 362
 363         if (hdr.hdr.type != UBUS_MSG_HELLO)
 364                 goto out_close;
 365
 366         buf = calloc(1, blob_raw_len(&hdr.data));
 367         if (!buf)
 368                 goto out_close;
 369
 370         memcpy(buf, &hdr.data, sizeof(hdr.data));
 371         if (read(ctx->sock.fd, blob_data(buf), blob_len(buf)) != blob_len(buf))
 372                 goto out_free;
 373
 374         ctx->local_id = hdr.hdr.peer;
 375         if (!ctx->local_id)
 376                 goto out_free;
 377
 378         ret = UBUS_STATUS_OK;
 379         fcntl(ctx->sock.fd, F_SETFL, fcntl(ctx->sock.fd, F_GETFL) | O_NONBLOCK);
 380
 381         ubus_refresh_state(ctx);
 382
 383 out_free:
 384         free(buf);
 385 out_close:
 386         if (ret)
 387                 close(ctx->sock.fd);
 388
 389         return ret;
 390 }