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 static const struct blob_attr_info ubus_policy[UBUS_ATTR_MAX] = {
  32         [UBUS_ATTR_STATUS] = { .type = BLOB_ATTR_INT32 },
  33         [UBUS_ATTR_OBJID] = { .type = BLOB_ATTR_INT32 },
  34         [UBUS_ATTR_OBJPATH] = { .type = BLOB_ATTR_STRING },
  35         [UBUS_ATTR_METHOD] = { .type = BLOB_ATTR_STRING },
  36         [UBUS_ATTR_ACTIVE] = { .type = BLOB_ATTR_INT8 },
  37         [UBUS_ATTR_NO_REPLY] = { .type = BLOB_ATTR_INT8 },
  38         [UBUS_ATTR_SUBSCRIBERS] = { .type = BLOB_ATTR_NESTED },
  39 };
  40
  41 static struct blob_attr *attrbuf[UBUS_ATTR_MAX];
  42
  43 __hidden struct blob_attr **ubus_parse_msg(struct blob_attr *msg)
  44 {
  45         blob_parse(msg, attrbuf, ubus_policy, UBUS_ATTR_MAX);
  46         return attrbuf;
  47 }
  48
  49 static void wait_data(int fd, bool write)
  50 {
  51         struct pollfd pfd = { .fd = fd };
  52
  53         pfd.events = write ? POLLOUT : POLLIN;
  54         poll(&pfd, 1, 0);
  55 }
  56
  57 static int writev_retry(int fd, struct iovec *iov, int iov_len, int sock_fd)
  58 {
  59         static struct {
  60                 struct cmsghdr h;
  61                 int fd;
  62         } fd_buf = {
  63                 .h = {
  64                         .cmsg_len = sizeof(fd_buf),
  65                         .cmsg_level = SOL_SOCKET,
  66                         .cmsg_type = SCM_RIGHTS,
  67                 }
  68         };
  69         struct msghdr msghdr = {
  70                 .msg_iov = iov,
  71                 .msg_iovlen = iov_len,
  72                 .msg_control = &fd_buf,
  73                 .msg_controllen = sizeof(fd_buf),
  74         };
  75         int len = 0;
  76
  77         do {
  78                 int cur_len;
  79
  80                 if (sock_fd < 0) {
  81                         msghdr.msg_control = NULL;
  82                         msghdr.msg_controllen = 0;
  83                 } else {
  84                         fd_buf.fd = sock_fd;
  85                 }
  86
  87                 cur_len = sendmsg(fd, &msghdr, 0);
  88                 if (cur_len < 0) {
  89                         switch(errno) {
  90                         case EAGAIN:
  91                                 wait_data(fd, true);
  92                                 break;
  93                         case EINTR:
  94                                 break;
  95                         default:
  96                                 return -1;
  97                         }
  98                         continue;
  99                 }
 100
 101                 if (len > 0)
 102                         sock_fd = -1;
 103
 104                 len += cur_len;
 105                 while (cur_len >= iov->iov_len) {
 106                         cur_len -= iov->iov_len;
 107                         iov_len--;
 108                         iov++;
 109                         if (!iov_len)
 110                                 return len;
 111                 }
 112                 iov->iov_len -= cur_len;
 113         } while (1);
 114
 115         /* Should never reach here */
 116         return -1;
 117 }
 118
 119 int __hidden ubus_send_msg(struct ubus_context *ctx, uint32_t seq,
 120                            struct blob_attr *msg, int cmd, uint32_t peer, int fd)
 121 {
 122         struct ubus_msghdr hdr;
 123         struct iovec iov[2] = {
 124                 STATIC_IOV(hdr)
 125         };
 126         int ret;
 127
 128         hdr.version = 0;
 129         hdr.type = cmd;
 130         hdr.seq = seq;
 131         hdr.peer = peer;
 132
 133         if (!msg) {
 134                 blob_buf_init(&b, 0);
 135                 msg = b.head;
 136         }
 137
 138         iov[1].iov_base = (char *) msg;
 139         iov[1].iov_len = blob_raw_len(msg);
 140
 141         ret = writev_retry(ctx->sock.fd, iov, ARRAY_SIZE(iov), fd);
 142         if (ret < 0)
 143                 ctx->sock.eof = true;
 144
 145         if (fd >= 0)
 146                 close(fd);
 147
 148         return ret;
 149 }
 150
 151 static int recv_retry(int fd, struct iovec *iov, bool wait, int *recv_fd)
 152 {
 153         int bytes, total = 0;
 154         static struct {
 155                 struct cmsghdr h;
 156                 int fd;
 157         } fd_buf = {
 158                 .h = {
 159                         .cmsg_type = SCM_RIGHTS,
 160                         .cmsg_level = SOL_SOCKET,
 161                         .cmsg_len = sizeof(fd_buf),
 162                 },
 163         };
 164         struct msghdr msghdr = {
 165                 .msg_iov = iov,
 166                 .msg_iovlen = 1,
 167         };
 168
 169         while (iov->iov_len > 0) {
 170                 if (wait)
 171                         wait_data(fd, false);
 172
 173                 if (recv_fd) {
 174                         msghdr.msg_control = &fd_buf;
 175                         msghdr.msg_controllen = sizeof(fd_buf);
 176                 } else {
 177                         msghdr.msg_control = NULL;
 178                         msghdr.msg_controllen = 0;
 179                 }
 180
 181                 fd_buf.fd = -1;
 182                 bytes = recvmsg(fd, &msghdr, 0);
 183                 if (!bytes)
 184                         return -1;
 185
 186                 if (bytes < 0) {
 187                         bytes = 0;
 188                         if (uloop_cancelled)
 189                                 return 0;
 190                         if (errno == EINTR)
 191                                 continue;
 192
 193                         if (errno != EAGAIN)
 194                                 return -1;
 195                 }
 196                 if (!wait && !bytes)
 197                         return 0;
 198
 199                 if (recv_fd)
 200                         *recv_fd = fd_buf.fd;
 201
 202                 recv_fd = NULL;
 203
 204                 wait = true;
 205                 iov->iov_len -= bytes;
 206                 iov->iov_base += bytes;
 207                 total += bytes;
 208         }
 209
 210         return total;
 211 }
 212
 213 static bool ubus_validate_hdr(struct ubus_msghdr *hdr)
 214 {
 215         struct blob_attr *data = (struct blob_attr *) (hdr + 1);
 216
 217         if (hdr->version != 0)
 218                 return false;
 219
 220         if (blob_raw_len(data) < sizeof(*data))
 221                 return false;
 222
 223         if (blob_pad_len(data) > UBUS_MAX_MSGLEN)
 224                 return false;
 225
 226         return true;
 227 }
 228
 229 static bool get_next_msg(struct ubus_context *ctx, int *recv_fd)
 230 {
 231         struct {
 232                 struct ubus_msghdr hdr;
 233                 struct blob_attr data;
 234         } hdrbuf;
 235         struct iovec iov = STATIC_IOV(hdrbuf);
 236         int r;
 237
 238         /* receive header + start attribute */
 239         r = recv_retry(ctx->sock.fd, &iov, false, recv_fd);
 240         if (r <= 0) {
 241                 if (r < 0)
 242                         ctx->sock.eof = true;
 243
 244                 return false;
 245         }
 246
 247         if (!ubus_validate_hdr(&hdrbuf.hdr))
 248                 return false;
 249
 250         memcpy(&ctx->msgbuf.hdr, &hdrbuf.hdr, sizeof(hdrbuf.hdr));
 251         memcpy(ctx->msgbuf.data, &hdrbuf.data, sizeof(hdrbuf.data));
 252
 253         iov.iov_base = (char *)ctx->msgbuf.data + sizeof(hdrbuf.data);
 254         iov.iov_len = blob_len(ctx->msgbuf.data);
 255         if (iov.iov_len > 0 && !recv_retry(ctx->sock.fd, &iov, true, NULL))
 256                 return false;
 257
 258         return true;
 259 }
 260
 261 void __hidden ubus_handle_data(struct uloop_fd *u, unsigned int events)
 262 {
 263         struct ubus_context *ctx = container_of(u, struct ubus_context, sock);
 264         struct ubus_msghdr *hdr = &ctx->msgbuf.hdr;
 265         int recv_fd = -1;
 266
 267         while (get_next_msg(ctx, &recv_fd)) {
 268                 ubus_process_msg(ctx, hdr, recv_fd);
 269                 if (uloop_cancelled)
 270                         break;
 271         }
 272
 273         if (u->eof)
 274                 ctx->connection_lost(ctx);
 275 }
 276
 277 void __hidden ubus_poll_data(struct ubus_context *ctx, int timeout)
 278 {
 279         struct pollfd pfd = {
 280                 .fd = ctx->sock.fd,
 281                 .events = POLLIN | POLLERR,
 282         };
 283
 284         poll(&pfd, 1, timeout);
 285         ubus_handle_data(&ctx->sock, ULOOP_READ);
 286 }
 287
 288 static void
 289 ubus_refresh_state(struct ubus_context *ctx)
 290 {
 291         struct ubus_object *obj, *tmp;
 292         struct ubus_object **objs;
 293         int n, i = 0;
 294
 295         /* clear all type IDs, they need to be registered again */
 296         avl_for_each_element(&ctx->objects, obj, avl)
 297                 if (obj->type)
 298                         obj->type->id = 0;
 299
 300         /* push out all objects again */
 301         objs = alloca(ctx->objects.count * sizeof(*objs));
 302         avl_remove_all_elements(&ctx->objects, obj, avl, tmp) {
 303                 objs[i++] = obj;
 304                 obj->id = 0;
 305         }
 306
 307         for (n = i, i = 0; i < n; i++)
 308                 ubus_add_object(ctx, objs[i]);
 309 }
 310
 311 int ubus_reconnect(struct ubus_context *ctx, const char *path)
 312 {
 313         struct {
 314                 struct ubus_msghdr hdr;
 315                 struct blob_attr data;
 316         } hdr;
 317         struct blob_attr *buf;
 318         int ret = UBUS_STATUS_UNKNOWN_ERROR;
 319
 320         if (!path)
 321                 path = UBUS_UNIX_SOCKET;
 322
 323         if (ctx->sock.fd >= 0) {
 324                 if (ctx->sock.registered)
 325                         uloop_fd_delete(&ctx->sock);
 326
 327                 close(ctx->sock.fd);
 328         }
 329
 330         ctx->sock.fd = usock(USOCK_UNIX, path, NULL);
 331         if (ctx->sock.fd < 0)
 332                 return UBUS_STATUS_CONNECTION_FAILED;
 333
 334         if (read(ctx->sock.fd, &hdr, sizeof(hdr)) != sizeof(hdr))
 335                 goto out_close;
 336
 337         if (!ubus_validate_hdr(&hdr.hdr))
 338                 goto out_close;
 339
 340         if (hdr.hdr.type != UBUS_MSG_HELLO)
 341                 goto out_close;
 342
 343         buf = calloc(1, blob_raw_len(&hdr.data));
 344         if (!buf)
 345                 goto out_close;
 346
 347         memcpy(buf, &hdr.data, sizeof(hdr.data));
 348         if (read(ctx->sock.fd, blob_data(buf), blob_len(buf)) != blob_len(buf))
 349                 goto out_free;
 350
 351         ctx->local_id = hdr.hdr.peer;
 352         if (!ctx->local_id)
 353                 goto out_free;
 354
 355         ret = UBUS_STATUS_OK;
 356         fcntl(ctx->sock.fd, F_SETFL, fcntl(ctx->sock.fd, F_GETFL) | O_NONBLOCK);
 357
 358         ubus_refresh_state(ctx);
 359
 360 out_free:
 361         free(buf);
 362 out_close:
 363         if (ret)
 364                 close(ctx->sock.fd);
 365
 366         return ret;
 367 }