ubusd.c

   1 #include <sys/socket.h>
   2 #include <sys/uio.h>
   3 #include <signal.h>
   4 #include <stdio.h>
   5 #include <unistd.h>
   6 #include <fcntl.h>
   7
   8 #include <libubox/blob.h>
   9 #include <libubox/uloop.h>
  10 #include <libubox/usock.h>
  11 #include <libubox/list.h>
  12
  13 #include "ubusd.h"
  14
  15 static struct avl_tree clients;
  16
  17 static struct ubus_msg_buf *ubus_msg_unshare(struct ubus_msg_buf *ub)
  18 {
  19         ub = realloc(ub, sizeof(*ub) + ub->len);
  20         if (!ub)
  21                 return NULL;
  22
  23         ub->refcount = 1;
  24         memcpy(ub + 1, ub->data, ub->len);
  25         ub->data = (void *) (ub + 1);
  26         return ub;
  27 }
  28
  29 struct ubus_msg_buf *ubus_msg_ref(struct ubus_msg_buf *ub)
  30 {
  31         if (ub->refcount == ~0)
  32                 return ubus_msg_unshare(ub);
  33
  34         ub->refcount++;
  35         return ub;
  36 }
  37
  38 struct ubus_msg_buf *ubus_msg_new(void *data, int len, bool shared)
  39 {
  40         struct ubus_msg_buf *ub;
  41         int buflen = sizeof(*ub);
  42
  43         if (!shared)
  44                 buflen += len;
  45
  46         ub = calloc(1, buflen);
  47         if (!ub)
  48                 return NULL;
  49
  50         if (shared) {
  51                 ub->refcount = ~0;
  52                 ub->data = data;
  53         } else {
  54                 ub->refcount = 1;
  55                 ub->data = (void *) (ub + 1);
  56                 if (data)
  57                         memcpy(ub + 1, data, len);
  58         }
  59
  60         ub->len = len;
  61         return ub;
  62 }
  63
  64 void ubus_msg_free(struct ubus_msg_buf *ub)
  65 {
  66         switch (ub->refcount) {
  67         case 1:
  68         case ~0:
  69                 free(ub);
  70                 break;
  71         default:
  72                 ub->refcount--;
  73                 break;
  74         }
  75 }
  76
  77 static int ubus_msg_writev(int fd, struct ubus_msg_buf *ub, int offset)
  78 {
  79         struct iovec iov[2];
  80
  81         if (offset < sizeof(ub->hdr)) {
  82                 iov[0].iov_base = ((char *) &ub->hdr) + offset;
  83                 iov[0].iov_len = sizeof(ub->hdr) - offset;
  84                 iov[1].iov_base = (char *) ub->data;
  85                 iov[1].iov_len = ub->len;
  86                 return writev(fd, iov, 2);
  87         } else {
  88                 offset -= sizeof(ub->hdr);
  89                 return write(fd, ((char *) ub->data) + offset, ub->len - offset);
  90         }
  91 }
  92
  93 /* takes the msgbuf reference */
  94 void ubus_msg_send(struct ubus_client *cl, struct ubus_msg_buf *ub)
  95 {
  96         int written;
  97
  98         if (cl->buf_head)
  99                 goto queue;
 100
 101         written = ubus_msg_writev(cl->sock.fd, ub, 0);
 102         if (written > 0 && written < ub->len + sizeof(ub->hdr)) {
 103                 cl->buf_head_ofs = written;
 104
 105                 /* get an event once we can write to the socket again */
 106                 uloop_fd_add(&cl->sock, ULOOP_READ | ULOOP_WRITE | ULOOP_EDGE_TRIGGER);
 107                 goto queue;
 108         }
 109
 110         ubus_msg_free(ub);
 111         return;
 112
 113 queue:
 114         ub = ubus_msg_unshare(ub);
 115         ub->next = NULL;
 116         *cl->buf_tail = ub;
 117         cl->buf_tail = &ub->next;
 118 }
 119
 120 static void handle_client_disconnect(struct ubus_client *cl)
 121 {
 122         struct ubus_object *obj;
 123
 124         while (!list_empty(&cl->objects)) {
 125                 obj = list_first_entry(&cl->objects, struct ubus_object, list);
 126                 ubusd_free_object(obj);
 127         }
 128
 129         ubus_free_id(&clients, &cl->id);
 130         uloop_fd_delete(&cl->sock);
 131         close(cl->sock.fd);
 132         free(cl);
 133 }
 134
 135 static void client_cb(struct uloop_fd *sock, unsigned int events)
 136 {
 137         struct ubus_client *cl = container_of(sock, struct ubus_client, sock);
 138         struct ubus_msg_buf *ub;
 139
 140         /* first try to tx more pending data */
 141         while (cl->buf_head) {
 142                 struct ubus_msg_buf *ub = cl->buf_head;
 143                 int written;
 144
 145                 written = ubus_msg_writev(sock->fd, ub, cl->buf_head_ofs);
 146                 if (written < 0) {
 147                         switch(errno) {
 148                         case EINTR:
 149                         case EAGAIN:
 150                                 break;
 151                         default:
 152                                 goto disconnect;
 153                         }
 154                         break;
 155                 }
 156                 if (written == 0)
 157                         break;
 158
 159                 cl->buf_head_ofs += written;
 160                 if (cl->buf_head_ofs < ub->len + sizeof(ub->hdr))
 161                         break;
 162
 163                 cl->buf_head_ofs = 0;
 164                 cl->buf_head = ub->next;
 165                 if (!cl->buf_head)
 166                         cl->buf_tail = &cl->buf_head;
 167         }
 168
 169         /* prevent further ULOOP_WRITE events if we don't have data
 170          * to send anymore */
 171         if (!cl->buf_head && (events & ULOOP_WRITE))
 172                 uloop_fd_add(sock, ULOOP_READ | ULOOP_EDGE_TRIGGER);
 173
 174 retry:
 175         if (!sock->eof && cl->pending_msg_offset < sizeof(cl->hdrbuf)) {
 176                 int offset = cl->pending_msg_offset;
 177                 int bytes;
 178
 179                 bytes = read(sock->fd, (char *)&cl->hdrbuf + offset, sizeof(cl->hdrbuf) - offset);
 180                 if (bytes < 0)
 181                         goto out;
 182
 183                 cl->pending_msg_offset += bytes;
 184                 if (cl->pending_msg_offset < sizeof(cl->hdrbuf))
 185                         goto out;
 186
 187                 if (blob_len(&cl->hdrbuf.data) + sizeof(cl->hdrbuf) > UBUS_MAX_MSGLEN)
 188                         goto disconnect;
 189
 190                 cl->pending_msg = ubus_msg_new(NULL, blob_raw_len(&cl->hdrbuf.data), false);
 191                 if (!cl->pending_msg)
 192                         goto disconnect;
 193
 194                 memcpy(&cl->pending_msg->hdr, &cl->hdrbuf.hdr, sizeof(cl->hdrbuf.hdr));
 195                 memcpy(cl->pending_msg->data, &cl->hdrbuf.data, sizeof(cl->hdrbuf.data));
 196         }
 197
 198         ub = cl->pending_msg;
 199         if (ub) {
 200                 int offset = cl->pending_msg_offset - sizeof(ub->hdr);
 201                 int len = blob_raw_len(ub->data) - offset;
 202                 int bytes = 0;
 203
 204                 if (len > 0) {
 205                         bytes = read(sock->fd, (char *) ub->data + offset, len);
 206                         if (bytes <= 0)
 207                                 goto out;
 208                 }
 209
 210                 if (bytes < len) {
 211                         cl->pending_msg_offset += bytes;
 212                         goto out;
 213                 }
 214
 215                 /* accept message */
 216                 cl->pending_msg_offset = 0;
 217                 cl->pending_msg = NULL;
 218                 ubusd_receive_message(cl, ub);
 219                 goto retry;
 220         }
 221
 222 out:
 223         if (!sock->eof || cl->buf_head)
 224                 return;
 225
 226 disconnect:
 227         handle_client_disconnect(cl);
 228 }
 229
 230 struct ubus_client *ubusd_get_client_by_id(uint32_t id)
 231 {
 232         struct ubus_id *clid;
 233
 234         clid = ubus_find_id(&clients, id);
 235         if (!clid)
 236                 return NULL;
 237
 238         return container_of(clid, struct ubus_client, id);
 239 }
 240
 241 static bool get_next_connection(int fd)
 242 {
 243         struct ubus_client *cl;
 244         int client_fd;
 245
 246         client_fd = accept(fd, NULL, 0);
 247         if (client_fd < 0) {
 248                 switch (errno) {
 249                 case ECONNABORTED:
 250                 case EINTR:
 251                         return true;
 252                 default:
 253                         return false;
 254                 }
 255         }
 256
 257         cl = calloc(1, sizeof(*cl));
 258         cl->sock.fd = client_fd;
 259
 260         INIT_LIST_HEAD(&cl->objects);
 261         if (!ubus_alloc_id(&clients, &cl->id))
 262                 goto error;
 263
 264         cl->sock.cb = client_cb;
 265         uloop_fd_add(&cl->sock, ULOOP_READ | ULOOP_EDGE_TRIGGER);
 266         if (!ubusd_send_hello(cl))
 267                 goto error_free;
 268
 269         return true;
 270
 271 error_free:
 272         ubus_free_id(&clients, &cl->id);
 273 error:
 274         close(cl->sock.fd);
 275         free(cl);
 276         return true;
 277 }
 278
 279 static void server_cb(struct uloop_fd *fd, unsigned int events)
 280 {
 281         bool next;
 282
 283         do {
 284                 next = get_next_connection(fd->fd);
 285         } while (next);
 286 }
 287
 288 static struct uloop_fd server_fd = {
 289         .cb = server_cb,
 290 };
 291
 292 int main(int argc, char **argv)
 293 {
 294         int ret = 0;
 295
 296         signal(SIGPIPE, SIG_IGN);
 297
 298         ubus_init_id_tree(&clients);
 299
 300         uloop_init();
 301
 302         unlink(UBUS_UNIX_SOCKET);
 303         server_fd.fd = usock(USOCK_UNIX | USOCK_SERVER | USOCK_NONBLOCK, UBUS_UNIX_SOCKET, NULL);
 304         if (server_fd.fd < 0) {
 305                 perror("usock");
 306                 ret = -1;
 307                 goto out;
 308         }
 309         uloop_fd_add(&server_fd, ULOOP_READ | ULOOP_EDGE_TRIGGER);
 310
 311         uloop_run();
 312
 313 out:
 314         uloop_done();
 315         return ret;
 316 }