ubusd.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/socket.h>
  15 #include <sys/stat.h>
  16 #include <sys/uio.h>
  17 #ifdef FreeBSD
  18 #include <sys/param.h>
  19 #endif
  20 #include <syslog.h>
  21 #include <signal.h>
  22 #include <stdio.h>
  23 #include <unistd.h>
  24 #include <fcntl.h>
  25
  26 #include <libubox/blob.h>
  27 #include <libubox/uloop.h>
  28 #include <libubox/usock.h>
  29 #include <libubox/list.h>
  30
  31 #include "ubusd.h"
  32
  33 static struct ubus_msg_buf *ubus_msg_ref(struct ubus_msg_buf *ub)
  34 {
  35         struct ubus_msg_buf *new_ub;
  36         if (ub->refcount == ~0) {
  37                 new_ub = ubus_msg_new(ub->data, ub->len, false);
  38                 if (!new_ub)
  39                         return NULL;
  40                 memcpy(&new_ub->hdr, &ub->hdr, sizeof(struct ubus_msghdr));
  41                 new_ub->fd = ub->fd;
  42                 return new_ub;
  43         }
  44
  45         ub->refcount++;
  46         return ub;
  47 }
  48
  49 struct ubus_msg_buf *ubus_msg_new(void *data, int len, bool shared)
  50 {
  51         struct ubus_msg_buf *ub;
  52         int buflen = sizeof(*ub);
  53
  54         if (!shared)
  55                 buflen += len;
  56
  57         ub = calloc(1, buflen);
  58         if (!ub)
  59                 return NULL;
  60
  61         ub->fd = -1;
  62
  63         if (shared) {
  64                 ub->refcount = ~0;
  65                 ub->data = data;
  66         } else {
  67                 ub->refcount = 1;
  68                 ub->data = (void *) (ub + 1);
  69                 if (data)
  70                         memcpy(ub + 1, data, len);
  71         }
  72
  73         ub->len = len;
  74         return ub;
  75 }
  76
  77 void ubus_msg_free(struct ubus_msg_buf *ub)
  78 {
  79         switch (ub->refcount) {
  80         case 1:
  81         case ~0:
  82                 if (ub->fd >= 0)
  83                         close(ub->fd);
  84
  85                 free(ub);
  86                 break;
  87         default:
  88                 ub->refcount--;
  89                 break;
  90         }
  91 }
  92
  93 static int ubus_msg_writev(int fd, struct ubus_msg_buf *ub, int offset)
  94 {
  95         static struct iovec iov[2];
  96         static struct {
  97                 struct cmsghdr h;
  98                 int fd;
  99         } fd_buf = {
 100                 .h = {
 101                         .cmsg_len = sizeof(fd_buf),
 102                         .cmsg_level = SOL_SOCKET,
 103                         .cmsg_type = SCM_RIGHTS,
 104                 },
 105         };
 106         struct msghdr msghdr = {
 107                 .msg_iov = iov,
 108                 .msg_iovlen = ARRAY_SIZE(iov),
 109                 .msg_control = &fd_buf,
 110                 .msg_controllen = sizeof(fd_buf),
 111         };
 112         struct ubus_msghdr hdr;
 113         int ret;
 114
 115         fd_buf.fd = ub->fd;
 116         if (ub->fd < 0 || offset) {
 117                 msghdr.msg_control = NULL;
 118                 msghdr.msg_controllen = 0;
 119         }
 120
 121         if (offset < sizeof(ub->hdr)) {
 122                 hdr.version = ub->hdr.version;
 123                 hdr.type = ub->hdr.type;
 124                 hdr.seq = cpu_to_be16(ub->hdr.seq);
 125                 hdr.peer = cpu_to_be32(ub->hdr.peer);
 126
 127                 iov[0].iov_base = ((char *) &hdr) + offset;
 128                 iov[0].iov_len = sizeof(hdr) - offset;
 129                 iov[1].iov_base = (char *) ub->data;
 130                 iov[1].iov_len = ub->len;
 131         } else {
 132                 offset -= sizeof(ub->hdr);
 133                 iov[0].iov_base = ((char *) ub->data) + offset;
 134                 iov[0].iov_len = ub->len - offset;
 135                 msghdr.msg_iovlen = 1;
 136         }
 137
 138         do {
 139                 ret = sendmsg(fd, &msghdr, 0);
 140         } while (ret < 0 && errno == EINTR);
 141
 142         return ret;
 143 }
 144
 145 static void ubus_msg_enqueue(struct ubus_client *cl, struct ubus_msg_buf *ub)
 146 {
 147         if (cl->tx_queue[cl->txq_tail])
 148                 return;
 149
 150         cl->tx_queue[cl->txq_tail] = ubus_msg_ref(ub);
 151         cl->txq_tail = (cl->txq_tail + 1) % ARRAY_SIZE(cl->tx_queue);
 152 }
 153
 154 /* takes the msgbuf reference */
 155 void ubus_msg_send(struct ubus_client *cl, struct ubus_msg_buf *ub)
 156 {
 157         int written;
 158
 159         if (ub->hdr.type != UBUS_MSG_MONITOR)
 160                 ubusd_monitor_message(cl, ub, true);
 161
 162         if (!cl->tx_queue[cl->txq_cur]) {
 163                 written = ubus_msg_writev(cl->sock.fd, ub, 0);
 164
 165                 if (written < 0)
 166                         written = 0;
 167
 168                 if (written >= ub->len + sizeof(ub->hdr))
 169                         return;
 170
 171                 cl->txq_ofs = written;
 172
 173                 /* get an event once we can write to the socket again */
 174                 uloop_fd_add(&cl->sock, ULOOP_READ | ULOOP_WRITE | ULOOP_EDGE_TRIGGER);
 175         }
 176         ubus_msg_enqueue(cl, ub);
 177 }
 178
 179 static struct ubus_msg_buf *ubus_msg_head(struct ubus_client *cl)
 180 {
 181         return cl->tx_queue[cl->txq_cur];
 182 }
 183
 184 static void ubus_msg_dequeue(struct ubus_client *cl)
 185 {
 186         struct ubus_msg_buf *ub = ubus_msg_head(cl);
 187
 188         if (!ub)
 189                 return;
 190
 191         ubus_msg_free(ub);
 192         cl->txq_ofs = 0;
 193         cl->tx_queue[cl->txq_cur] = NULL;
 194         cl->txq_cur = (cl->txq_cur + 1) % ARRAY_SIZE(cl->tx_queue);
 195 }
 196
 197 static void handle_client_disconnect(struct ubus_client *cl)
 198 {
 199         while (ubus_msg_head(cl))
 200                 ubus_msg_dequeue(cl);
 201
 202         ubusd_monitor_disconnect(cl);
 203         ubusd_proto_free_client(cl);
 204         if (cl->pending_msg_fd >= 0)
 205                 close(cl->pending_msg_fd);
 206         uloop_fd_delete(&cl->sock);
 207         close(cl->sock.fd);
 208         free(cl);
 209 }
 210
 211 static void client_cb(struct uloop_fd *sock, unsigned int events)
 212 {
 213         struct ubus_client *cl = container_of(sock, struct ubus_client, sock);
 214         struct ubus_msg_buf *ub;
 215         static struct iovec iov;
 216         static struct {
 217                 struct cmsghdr h;
 218                 int fd;
 219         } fd_buf = {
 220                 .h = {
 221                         .cmsg_type = SCM_RIGHTS,
 222                         .cmsg_level = SOL_SOCKET,
 223                         .cmsg_len = sizeof(fd_buf),
 224                 }
 225         };
 226         struct msghdr msghdr = {
 227                 .msg_iov = &iov,
 228                 .msg_iovlen = 1,
 229         };
 230
 231         /* first try to tx more pending data */
 232         while ((ub = ubus_msg_head(cl))) {
 233                 int written;
 234
 235                 written = ubus_msg_writev(sock->fd, ub, cl->txq_ofs);
 236                 if (written < 0) {
 237                         switch(errno) {
 238                         case EINTR:
 239                         case EAGAIN:
 240                                 break;
 241                         default:
 242                                 goto disconnect;
 243                         }
 244                         break;
 245                 }
 246
 247                 cl->txq_ofs += written;
 248                 if (cl->txq_ofs < ub->len + sizeof(ub->hdr))
 249                         break;
 250
 251                 ubus_msg_dequeue(cl);
 252         }
 253
 254         /* prevent further ULOOP_WRITE events if we don't have data
 255          * to send anymore */
 256         if (!ubus_msg_head(cl) && (events & ULOOP_WRITE))
 257                 uloop_fd_add(sock, ULOOP_READ | ULOOP_EDGE_TRIGGER);
 258
 259 retry:
 260         if (!sock->eof && cl->pending_msg_offset < sizeof(cl->hdrbuf)) {
 261                 int offset = cl->pending_msg_offset;
 262                 int bytes;
 263
 264                 fd_buf.fd = -1;
 265
 266                 iov.iov_base = ((char *) &cl->hdrbuf) + offset;
 267                 iov.iov_len = sizeof(cl->hdrbuf) - offset;
 268
 269                 if (cl->pending_msg_fd < 0) {
 270                         msghdr.msg_control = &fd_buf;
 271                         msghdr.msg_controllen = sizeof(fd_buf);
 272                 } else {
 273                         msghdr.msg_control = NULL;
 274                         msghdr.msg_controllen = 0;
 275                 }
 276
 277                 bytes = recvmsg(sock->fd, &msghdr, 0);
 278                 if (bytes < 0)
 279                         goto out;
 280
 281                 if (fd_buf.fd >= 0)
 282                         cl->pending_msg_fd = fd_buf.fd;
 283
 284                 cl->pending_msg_offset += bytes;
 285                 if (cl->pending_msg_offset < sizeof(cl->hdrbuf))
 286                         goto out;
 287
 288                 if (blob_pad_len(&cl->hdrbuf.data) > UBUS_MAX_MSGLEN)
 289                         goto disconnect;
 290
 291                 cl->pending_msg = ubus_msg_new(NULL, blob_raw_len(&cl->hdrbuf.data), false);
 292                 if (!cl->pending_msg)
 293                         goto disconnect;
 294
 295                 cl->hdrbuf.hdr.seq = be16_to_cpu(cl->hdrbuf.hdr.seq);
 296                 cl->hdrbuf.hdr.peer = be32_to_cpu(cl->hdrbuf.hdr.peer);
 297
 298                 memcpy(&cl->pending_msg->hdr, &cl->hdrbuf.hdr, sizeof(cl->hdrbuf.hdr));
 299                 memcpy(cl->pending_msg->data, &cl->hdrbuf.data, sizeof(cl->hdrbuf.data));
 300         }
 301
 302         ub = cl->pending_msg;
 303         if (ub) {
 304                 int offset = cl->pending_msg_offset - sizeof(ub->hdr);
 305                 int len = blob_raw_len(ub->data) - offset;
 306                 int bytes = 0;
 307
 308                 if (len > 0) {
 309                         bytes = read(sock->fd, (char *) ub->data + offset, len);
 310                         if (bytes <= 0)
 311                                 goto out;
 312                 }
 313
 314                 if (bytes < len) {
 315                         cl->pending_msg_offset += bytes;
 316                         goto out;
 317                 }
 318
 319                 /* accept message */
 320                 ub->fd = cl->pending_msg_fd;
 321                 cl->pending_msg_fd = -1;
 322                 cl->pending_msg_offset = 0;
 323                 cl->pending_msg = NULL;
 324                 ubusd_monitor_message(cl, ub, false);
 325                 ubusd_proto_receive_message(cl, ub);
 326                 goto retry;
 327         }
 328
 329 out:
 330         if (!sock->eof || ubus_msg_head(cl))
 331                 return;
 332
 333 disconnect:
 334         handle_client_disconnect(cl);
 335 }
 336
 337 static bool get_next_connection(int fd)
 338 {
 339         struct ubus_client *cl;
 340         int client_fd;
 341
 342         client_fd = accept(fd, NULL, 0);
 343         if (client_fd < 0) {
 344                 switch (errno) {
 345                 case ECONNABORTED:
 346                 case EINTR:
 347                         return true;
 348                 default:
 349                         return false;
 350                 }
 351         }
 352
 353         cl = ubusd_proto_new_client(client_fd, client_cb);
 354         if (cl)
 355                 uloop_fd_add(&cl->sock, ULOOP_READ | ULOOP_EDGE_TRIGGER);
 356         else
 357                 close(client_fd);
 358
 359         return true;
 360 }
 361
 362 static void server_cb(struct uloop_fd *fd, unsigned int events)
 363 {
 364         bool next;
 365
 366         do {
 367                 next = get_next_connection(fd->fd);
 368         } while (next);
 369 }
 370
 371 static struct uloop_fd server_fd = {
 372         .cb = server_cb,
 373 };
 374
 375 static int usage(const char *progname)
 376 {
 377         fprintf(stderr, "Usage: %s [<options>]\n"
 378                 "Options: \n"
 379                 "  -A <path>:           Set the path to ACL files\n"
 380                 "  -s <socket>:         Set the unix domain socket to listen on\n"
 381                 "\n", progname);
 382         return 1;
 383 }
 384
 385 static void sighup_handler(int sig)
 386 {
 387         ubusd_acl_load();
 388 }
 389
 390 int main(int argc, char **argv)
 391 {
 392         const char *ubus_socket = UBUS_UNIX_SOCKET;
 393         int ret = 0;
 394         int ch;
 395
 396         signal(SIGPIPE, SIG_IGN);
 397         signal(SIGHUP, sighup_handler);
 398
 399         openlog("ubusd", LOG_PID, LOG_DAEMON);
 400         uloop_init();
 401
 402         while ((ch = getopt(argc, argv, "A:s:")) != -1) {
 403                 switch (ch) {
 404                 case 's':
 405                         ubus_socket = optarg;
 406                         break;
 407                 case 'A':
 408                         ubusd_acl_dir = optarg;
 409                         break;
 410                 default:
 411                         return usage(argv[0]);
 412                 }
 413         }
 414
 415         unlink(ubus_socket);
 416         umask(0111);
 417         server_fd.fd = usock(USOCK_UNIX | USOCK_SERVER | USOCK_NONBLOCK, ubus_socket, NULL);
 418         if (server_fd.fd < 0) {
 419                 perror("usock");
 420                 ret = -1;
 421                 goto out;
 422         }
 423         uloop_fd_add(&server_fd, ULOOP_READ | ULOOP_EDGE_TRIGGER);
 424         ubusd_acl_load();
 425
 426         uloop_run();
 427         unlink(ubus_socket);
 428
 429 out:
 430         uloop_done();
 431         return ret;
 432 }