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