libubus-io.c

   1 /*
   2  * Copyright (C) 2011-2012 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/types.h>
  15 #include <sys/uio.h>
  16 #include <sys/socket.h>
  17
  18 #include <unistd.h>
  19 #include <fcntl.h>
  20 #include <poll.h>
  21
  22 #include <libubox/usock.h>
  23 #include <libubox/blob.h>
  24 #include <libubox/blobmsg.h>
  25
  26 #include "libubus.h"
  27 #include "libubus-internal.h"
  28
  29 #define STATIC_IOV(_var) { .iov_base = (char *) &(_var), .iov_len = sizeof(_var) }
  30
  31 static const struct blob_attr_info ubus_policy[UBUS_ATTR_MAX] = {
  32         [UBUS_ATTR_STATUS] = { .type = BLOB_ATTR_INT32 },
  33         [UBUS_ATTR_OBJID] = { .type = BLOB_ATTR_INT32 },
  34         [UBUS_ATTR_OBJPATH] = { .type = BLOB_ATTR_STRING },
  35         [UBUS_ATTR_METHOD] = { .type = BLOB_ATTR_STRING },
  36         [UBUS_ATTR_ACTIVE] = { .type = BLOB_ATTR_INT8 },
  37         [UBUS_ATTR_NO_REPLY] = { .type = BLOB_ATTR_INT8 },
  38         [UBUS_ATTR_SUBSCRIBERS] = { .type = BLOB_ATTR_NESTED },
  39 };
  40
  41 static struct blob_attr *attrbuf[UBUS_ATTR_MAX];
  42
  43 __hidden struct blob_attr **ubus_parse_msg(struct blob_attr *msg)
  44 {
  45         blob_parse(msg, attrbuf, ubus_policy, UBUS_ATTR_MAX);
  46         return attrbuf;
  47 }
  48
  49 static void wait_data(int fd, bool write)
  50 {
  51         struct pollfd pfd = { .fd = fd };
  52
  53         pfd.events = write ? POLLOUT : POLLIN;
  54         poll(&pfd, 1, 0);
  55 }
  56
  57 static int writev_retry(int fd, struct iovec *iov, int iov_len)
  58 {
  59         int len = 0;
  60
  61         do {
  62                 int cur_len = writev(fd, iov, iov_len);
  63                 if (cur_len < 0) {
  64                         switch(errno) {
  65                         case EAGAIN:
  66                                 wait_data(fd, true);
  67                                 break;
  68                         case EINTR:
  69                                 break;
  70                         default:
  71                                 return -1;
  72                         }
  73                         continue;
  74                 }
  75                 len += cur_len;
  76                 while (cur_len >= iov->iov_len) {
  77                         cur_len -= iov->iov_len;
  78                         iov_len--;
  79                         iov++;
  80                         if (!iov_len)
  81                                 return len;
  82                 }
  83                 iov->iov_len -= cur_len;
  84         } while (1);
  85
  86         /* Should never reach here */
  87         return -1;
  88 }
  89
  90 int __hidden ubus_send_msg(struct ubus_context *ctx, uint32_t seq,
  91                            struct blob_attr *msg, int cmd, uint32_t peer)
  92 {
  93         struct ubus_msghdr hdr;
  94         struct iovec iov[2] = {
  95                 STATIC_IOV(hdr)
  96         };
  97         int ret;
  98
  99         hdr.version = 0;
 100         hdr.type = cmd;
 101         hdr.seq = seq;
 102         hdr.peer = peer;
 103
 104         if (!msg) {
 105                 blob_buf_init(&b, 0);
 106                 msg = b.head;
 107         }
 108
 109         iov[1].iov_base = (char *) msg;
 110         iov[1].iov_len = blob_raw_len(msg);
 111
 112         ret = writev_retry(ctx->sock.fd, iov, ARRAY_SIZE(iov));
 113         if (ret < 0)
 114                 ctx->sock.eof = true;
 115
 116         return ret;
 117 }
 118
 119 static int recv_retry(int fd, struct iovec *iov, bool wait)
 120 {
 121         int bytes, total = 0;
 122
 123         while (iov->iov_len > 0) {
 124                 if (wait)
 125                         wait_data(fd, false);
 126
 127                 bytes = read(fd, iov->iov_base, iov->iov_len);
 128                 if (!bytes)
 129                         return -1;
 130
 131                 if (bytes < 0) {
 132                         bytes = 0;
 133                         if (uloop_cancelled)
 134                                 return 0;
 135                         if (errno == EINTR)
 136                                 continue;
 137
 138                         if (errno != EAGAIN)
 139                                 return -1;
 140                 }
 141                 if (!wait && !bytes)
 142                         return 0;
 143
 144                 wait = true;
 145                 iov->iov_len -= bytes;
 146                 iov->iov_base += bytes;
 147                 total += bytes;
 148         }
 149
 150         return total;
 151 }
 152
 153 static bool ubus_validate_hdr(struct ubus_msghdr *hdr)
 154 {
 155         if (hdr->version != 0)
 156                 return false;
 157
 158         if (blob_raw_len(hdr->data) < sizeof(*hdr->data))
 159                 return false;
 160
 161         if (blob_pad_len(hdr->data) > UBUS_MAX_MSGLEN)
 162                 return false;
 163
 164         return true;
 165 }
 166
 167 static bool get_next_msg(struct ubus_context *ctx)
 168 {
 169         struct iovec iov = STATIC_IOV(ctx->msgbuf.hdr);
 170         int r;
 171
 172         /* receive header + start attribute */
 173         iov.iov_len += sizeof(struct blob_attr);
 174         r = recv_retry(ctx->sock.fd, &iov, false);
 175         if (r <= 0) {
 176                 if (r < 0)
 177                         ctx->sock.eof = true;
 178
 179                 return false;
 180         }
 181
 182         iov.iov_len = blob_len(ctx->msgbuf.hdr.data);
 183         if (iov.iov_len > 0 && !recv_retry(ctx->sock.fd, &iov, true))
 184                 return false;
 185
 186         return ubus_validate_hdr(&ctx->msgbuf.hdr);
 187 }
 188
 189 void __hidden ubus_handle_data(struct uloop_fd *u, unsigned int events)
 190 {
 191         struct ubus_context *ctx = container_of(u, struct ubus_context, sock);
 192         struct ubus_msghdr *hdr = &ctx->msgbuf.hdr;
 193
 194         while (get_next_msg(ctx)) {
 195                 ubus_process_msg(ctx, hdr);
 196                 if (uloop_cancelled)
 197                         break;
 198         }
 199
 200         if (u->eof)
 201                 ctx->connection_lost(ctx);
 202 }
 203
 204 static void
 205 ubus_refresh_state(struct ubus_context *ctx)
 206 {
 207         struct ubus_object *obj, *tmp;
 208         struct ubus_object **objs;
 209         int n, i = 0;
 210
 211         /* clear all type IDs, they need to be registered again */
 212         avl_for_each_element(&ctx->objects, obj, avl)
 213                 if (obj->type)
 214                         obj->type->id = 0;
 215
 216         /* push out all objects again */
 217         objs = alloca(ctx->objects.count * sizeof(*objs));
 218         avl_remove_all_elements(&ctx->objects, obj, avl, tmp) {
 219                 objs[i++] = obj;
 220                 obj->id = 0;
 221         }
 222
 223         for (n = i, i = 0; i < n; i++)
 224                 ubus_add_object(ctx, objs[i]);
 225 }
 226
 227 int ubus_reconnect(struct ubus_context *ctx, const char *path)
 228 {
 229         struct {
 230                 struct ubus_msghdr hdr;
 231                 struct blob_attr data;
 232         } hdr;
 233         struct blob_attr *buf;
 234         int ret = UBUS_STATUS_UNKNOWN_ERROR;
 235
 236         if (!path)
 237                 path = UBUS_UNIX_SOCKET;
 238
 239         if (ctx->sock.fd >= 0) {
 240                 if (ctx->sock.registered)
 241                         uloop_fd_delete(&ctx->sock);
 242
 243                 close(ctx->sock.fd);
 244         }
 245
 246         ctx->sock.fd = usock(USOCK_UNIX, path, NULL);
 247         if (ctx->sock.fd < 0)
 248                 return UBUS_STATUS_CONNECTION_FAILED;
 249
 250         if (read(ctx->sock.fd, &hdr, sizeof(hdr)) != sizeof(hdr))
 251                 goto out_close;
 252
 253         if (!ubus_validate_hdr(&hdr.hdr))
 254                 goto out_close;
 255
 256         if (hdr.hdr.type != UBUS_MSG_HELLO)
 257                 goto out_close;
 258
 259         buf = calloc(1, blob_raw_len(&hdr.data));
 260         if (!buf)
 261                 goto out_close;
 262
 263         memcpy(buf, &hdr.data, sizeof(hdr.data));
 264         if (read(ctx->sock.fd, blob_data(buf), blob_len(buf)) != blob_len(buf))
 265                 goto out_free;
 266
 267         ctx->local_id = hdr.hdr.peer;
 268         if (!ctx->local_id)
 269                 goto out_free;
 270
 271         ret = UBUS_STATUS_OK;
 272         fcntl(ctx->sock.fd, F_SETFL, fcntl(ctx->sock.fd, F_GETFL) | O_NONBLOCK);
 273
 274         ubus_refresh_state(ctx);
 275
 276 out_free:
 277         free(buf);
 278 out_close:
 279         if (ret)
 280                 close(ctx->sock.fd);
 281
 282         return ret;
 283 }