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