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 #define USES_EXTERNAL_BUFFER ~0U
  34
  35 static struct ubus_msg_buf *ubus_msg_ref(struct ubus_msg_buf *ub)
  36 {
  37         struct ubus_msg_buf *new_ub;
  38         if (ub->refcount == USES_EXTERNAL_BUFFER) {
  39                 new_ub = ubus_msg_new(ub->data, ub->len, false);
  40                 if (!new_ub)
  41                         return NULL;
  42                 memcpy(&new_ub->hdr, &ub->hdr, sizeof(struct ubus_msghdr));
  43                 new_ub->fd = ub->fd;
  44                 return new_ub;
  45         }
  46
  47         ub->refcount++;
  48         return ub;
  49 }
  50
  51 struct ubus_msg_buf *ubus_msg_new(void *data, int len, bool shared)
  52 {
  53         struct ubus_msg_buf *ub;
  54         int buflen = sizeof(*ub);
  55
  56         if (!shared)
  57                 buflen += len;
  58
  59         ub = calloc(1, buflen);
  60         if (!ub)
  61                 return NULL;
  62
  63         ub->fd = -1;
  64
  65         if (shared) {
  66                 ub->refcount = USES_EXTERNAL_BUFFER;
  67                 ub->data = data;
  68         } else {
  69                 ub->refcount = 1;
  70                 ub->data = (void *) (ub + 1);
  71                 if (data)
  72                         memcpy(ub + 1, data, len);
  73         }
  74
  75         ub->len = len;
  76         return ub;
  77 }
  78
  79 void ubus_msg_free(struct ubus_msg_buf *ub)
  80 {
  81         switch (ub->refcount) {
  82         case 1:
  83         case USES_EXTERNAL_BUFFER:
  84                 if (ub->fd >= 0)
  85                         close(ub->fd);
  86
  87                 free(ub);
  88                 break;
  89         default:
  90                 ub->refcount--;
  91                 break;
  92         }
  93 }
  94
  95 static int ubus_msg_writev(int fd, struct ubus_msg_buf *ub, int offset)
  96 {
  97         static struct iovec iov[2];
  98         static struct {
  99                 struct cmsghdr h;
 100                 int fd;
 101         } fd_buf = {
 102                 .h = {
 103                         .cmsg_len = sizeof(fd_buf),
 104                         .cmsg_level = SOL_SOCKET,
 105                         .cmsg_type = SCM_RIGHTS,
 106                 },
 107         };
 108         struct msghdr msghdr = {
 109                 .msg_iov = iov,
 110                 .msg_iovlen = ARRAY_SIZE(iov),
 111                 .msg_control = &fd_buf,
 112                 .msg_controllen = sizeof(fd_buf),
 113         };
 114         struct ubus_msghdr hdr;
 115         int ret;
 116
 117         fd_buf.fd = ub->fd;
 118         if (ub->fd < 0 || offset) {
 119                 msghdr.msg_control = NULL;
 120                 msghdr.msg_controllen = 0;
 121         }
 122
 123         if (offset < sizeof(ub->hdr)) {
 124                 hdr.version = ub->hdr.version;
 125                 hdr.type = ub->hdr.type;
 126                 hdr.seq = cpu_to_be16(ub->hdr.seq);
 127                 hdr.peer = cpu_to_be32(ub->hdr.peer);
 128
 129                 iov[0].iov_base = ((char *) &hdr) + offset;
 130                 iov[0].iov_len = sizeof(hdr) - offset;
 131                 iov[1].iov_base = (char *) ub->data;
 132                 iov[1].iov_len = ub->len;
 133         } else {
 134                 offset -= sizeof(ub->hdr);
 135                 iov[0].iov_base = ((char *) ub->data) + offset;
 136                 iov[0].iov_len = ub->len - offset;
 137                 msghdr.msg_iovlen = 1;
 138         }
 139
 140         do {
 141                 ret = sendmsg(fd, &msghdr, 0);
 142         } while (ret < 0 && errno == EINTR);
 143
 144         return ret;
 145 }
 146
 147 static void ubus_msg_enqueue(struct ubus_client *cl, struct ubus_msg_buf *ub)
 148 {
 149         if (cl->tx_queue[cl->txq_tail])
 150                 return;
 151
 152         cl->tx_queue[cl->txq_tail] = ubus_msg_ref(ub);
 153         cl->txq_tail = (cl->txq_tail + 1) % ARRAY_SIZE(cl->tx_queue);
 154 }
 155
 156 /* takes the msgbuf reference */
 157 void ubus_msg_send(struct ubus_client *cl, struct ubus_msg_buf *ub)
 158 {
 159         int written;
 160
 161         if (ub->hdr.type != UBUS_MSG_MONITOR)
 162                 ubusd_monitor_message(cl, ub, true);
 163
 164         if (!cl->tx_queue[cl->txq_cur]) {
 165                 written = ubus_msg_writev(cl->sock.fd, ub, 0);
 166
 167                 if (written < 0)
 168                         written = 0;
 169
 170                 if (written >= ub->len + sizeof(ub->hdr))
 171                         return;
 172
 173                 cl->txq_ofs = written;
 174
 175                 /* get an event once we can write to the socket again */
 176                 uloop_fd_add(&cl->sock, ULOOP_READ | ULOOP_WRITE | ULOOP_EDGE_TRIGGER);
 177         }
 178         ubus_msg_enqueue(cl, ub);
 179 }
 180
 181 static struct ubus_msg_buf *ubus_msg_head(struct ubus_client *cl)
 182 {
 183         return cl->tx_queue[cl->txq_cur];
 184 }
 185
 186 static void ubus_msg_dequeue(struct ubus_client *cl)
 187 {
 188         struct ubus_msg_buf *ub = ubus_msg_head(cl);
 189
 190         if (!ub)
 191                 return;
 192
 193         ubus_msg_free(ub);
 194         cl->txq_ofs = 0;
 195         cl->tx_queue[cl->txq_cur] = NULL;
 196         cl->txq_cur = (cl->txq_cur + 1) % ARRAY_SIZE(cl->tx_queue);
 197 }
 198
 199 static void handle_client_disconnect(struct ubus_client *cl)
 200 {
 201         while (ubus_msg_head(cl))
 202                 ubus_msg_dequeue(cl);
 203
 204         ubusd_monitor_disconnect(cl);
 205         ubusd_proto_free_client(cl);
 206         if (cl->pending_msg_fd >= 0)
 207                 close(cl->pending_msg_fd);
 208         uloop_fd_delete(&cl->sock);
 209         close(cl->sock.fd);
 210         free(cl);
 211 }
 212
 213 static void client_cb(struct uloop_fd *sock, unsigned int events)
 214 {
 215         struct ubus_client *cl = container_of(sock, struct ubus_client, sock);
 216         struct ubus_msg_buf *ub;
 217         static struct iovec iov;
 218         static struct {
 219                 struct cmsghdr h;
 220                 int fd;
 221         } fd_buf = {
 222                 .h = {
 223                         .cmsg_type = SCM_RIGHTS,
 224                         .cmsg_level = SOL_SOCKET,
 225                         .cmsg_len = sizeof(fd_buf),
 226                 }
 227         };
 228         struct msghdr msghdr = {
 229                 .msg_iov = &iov,
 230                 .msg_iovlen = 1,
 231         };
 232
 233         /* first try to tx more pending data */
 234         while ((ub = ubus_msg_head(cl))) {
 235                 int written;
 236
 237                 written = ubus_msg_writev(sock->fd, ub, cl->txq_ofs);
 238                 if (written < 0) {
 239                         switch(errno) {
 240                         case EINTR:
 241                         case EAGAIN:
 242                                 break;
 243                         default:
 244                                 goto disconnect;
 245                         }
 246                         break;
 247                 }
 248
 249                 cl->txq_ofs += written;
 250                 if (cl->txq_ofs < ub->len + sizeof(ub->hdr))
 251                         break;
 252
 253                 ubus_msg_dequeue(cl);
 254         }
 255
 256         /* prevent further ULOOP_WRITE events if we don't have data
 257          * to send anymore */
 258         if (!ubus_msg_head(cl) && (events & ULOOP_WRITE))
 259                 uloop_fd_add(sock, ULOOP_READ | ULOOP_EDGE_TRIGGER);
 260
 261 retry:
 262         if (!sock->eof && cl->pending_msg_offset < sizeof(cl->hdrbuf)) {
 263                 int offset = cl->pending_msg_offset;
 264                 int bytes;
 265
 266                 fd_buf.fd = -1;
 267
 268                 iov.iov_base = ((char *) &cl->hdrbuf) + offset;
 269                 iov.iov_len = sizeof(cl->hdrbuf) - offset;
 270
 271                 if (cl->pending_msg_fd < 0) {
 272                         msghdr.msg_control = &fd_buf;
 273                         msghdr.msg_controllen = sizeof(fd_buf);
 274                 } else {
 275                         msghdr.msg_control = NULL;
 276                         msghdr.msg_controllen = 0;
 277                 }
 278
 279                 bytes = recvmsg(sock->fd, &msghdr, 0);
 280                 if (bytes < 0)
 281                         goto out;
 282
 283                 if (fd_buf.fd >= 0)
 284                         cl->pending_msg_fd = fd_buf.fd;
 285
 286                 cl->pending_msg_offset += bytes;
 287                 if (cl->pending_msg_offset < sizeof(cl->hdrbuf))
 288                         goto out;
 289
 290                 if (blob_pad_len(&cl->hdrbuf.data) > UBUS_MAX_MSGLEN)
 291                         goto disconnect;
 292
 293                 cl->pending_msg = ubus_msg_new(NULL, blob_raw_len(&cl->hdrbuf.data), false);
 294                 if (!cl->pending_msg)
 295                         goto disconnect;
 296
 297                 cl->hdrbuf.hdr.seq = be16_to_cpu(cl->hdrbuf.hdr.seq);
 298                 cl->hdrbuf.hdr.peer = be32_to_cpu(cl->hdrbuf.hdr.peer);
 299
 300                 memcpy(&cl->pending_msg->hdr, &cl->hdrbuf.hdr, sizeof(cl->hdrbuf.hdr));
 301                 memcpy(cl->pending_msg->data, &cl->hdrbuf.data, sizeof(cl->hdrbuf.data));
 302         }
 303
 304         ub = cl->pending_msg;
 305         if (ub) {
 306                 int offset = cl->pending_msg_offset - sizeof(ub->hdr);
 307                 int len = blob_raw_len(ub->data) - offset;
 308                 int bytes = 0;
 309
 310                 if (len > 0) {
 311                         bytes = read(sock->fd, (char *) ub->data + offset, len);
 312                         if (bytes <= 0)
 313                                 goto out;
 314                 }
 315
 316                 if (bytes < len) {
 317                         cl->pending_msg_offset += bytes;
 318                         goto out;
 319                 }
 320
 321                 /* accept message */
 322                 ub->fd = cl->pending_msg_fd;
 323                 cl->pending_msg_fd = -1;
 324                 cl->pending_msg_offset = 0;
 325                 cl->pending_msg = NULL;
 326                 ubusd_monitor_message(cl, ub, false);
 327                 ubusd_proto_receive_message(cl, ub);
 328                 goto retry;
 329         }
 330
 331 out:
 332         if (!sock->eof || ubus_msg_head(cl))
 333                 return;
 334
 335 disconnect:
 336         handle_client_disconnect(cl);
 337 }
 338
 339 static bool get_next_connection(int fd)
 340 {
 341         struct ubus_client *cl;
 342         int client_fd;
 343
 344         client_fd = accept(fd, NULL, 0);
 345         if (client_fd < 0) {
 346                 switch (errno) {
 347                 case ECONNABORTED:
 348                 case EINTR:
 349                         return true;
 350                 default:
 351                         return false;
 352                 }
 353         }
 354
 355         cl = ubusd_proto_new_client(client_fd, client_cb);
 356         if (cl)
 357                 uloop_fd_add(&cl->sock, ULOOP_READ | ULOOP_EDGE_TRIGGER);
 358         else
 359                 close(client_fd);
 360
 361         return true;
 362 }
 363
 364 static void server_cb(struct uloop_fd *fd, unsigned int events)
 365 {
 366         bool next;
 367
 368         do {
 369                 next = get_next_connection(fd->fd);
 370         } while (next);
 371 }
 372
 373 static struct uloop_fd server_fd = {
 374         .cb = server_cb,
 375 };
 376
 377 static int usage(const char *progname)
 378 {
 379         fprintf(stderr, "Usage: %s [<options>]\n"
 380                 "Options: \n"
 381                 "  -A <path>:           Set the path to ACL files\n"
 382                 "  -s <socket>:         Set the unix domain socket to listen on\n"
 383                 "\n", progname);
 384         return 1;
 385 }
 386
 387 static void sighup_handler(int sig)
 388 {
 389         ubusd_acl_load();
 390 }
 391
 392 int main(int argc, char **argv)
 393 {
 394         const char *ubus_socket = UBUS_UNIX_SOCKET;
 395         int ret = 0;
 396         int ch;
 397
 398         signal(SIGPIPE, SIG_IGN);
 399         signal(SIGHUP, sighup_handler);
 400
 401         openlog("ubusd", LOG_PID, LOG_DAEMON);
 402         uloop_init();
 403
 404         while ((ch = getopt(argc, argv, "A:s:")) != -1) {
 405                 switch (ch) {
 406                 case 's':
 407                         ubus_socket = optarg;
 408                         break;
 409                 case 'A':
 410                         ubusd_acl_dir = optarg;
 411                         break;
 412                 default:
 413                         return usage(argv[0]);
 414                 }
 415         }
 416
 417         unlink(ubus_socket);
 418         umask(0111);
 419         server_fd.fd = usock(USOCK_UNIX | USOCK_SERVER | USOCK_NONBLOCK, ubus_socket, NULL);
 420         if (server_fd.fd < 0) {
 421                 perror("usock");
 422                 ret = -1;
 423                 goto out;
 424         }
 425         uloop_fd_add(&server_fd, ULOOP_READ | ULOOP_EDGE_TRIGGER);
 426         ubusd_acl_load();
 427
 428         uloop_run();
 429         unlink(ubus_socket);
 430
 431 out:
 432         uloop_done();
 433         return ret;
 434 }