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         struct blob_attr *data = ubus_msghdr_data(hdr);
 156
 157         if (hdr->version != 0)
 158                 return false;
 159
 160         if (blob_raw_len(data) < sizeof(*data))
 161                 return false;
 162
 163         if (blob_pad_len(data) > UBUS_MAX_MSGLEN)
 164                 return false;
 165
 166         return true;
 167 }
 168
 169 static bool get_next_msg(struct ubus_context *ctx)
 170 {
 171         struct iovec iov = STATIC_IOV(ctx->msgbuf.hdr);
 172         int r;
 173
 174         /* receive header + start attribute */
 175         iov.iov_len += sizeof(struct blob_attr);
 176         r = recv_retry(ctx->sock.fd, &iov, false);
 177         if (r <= 0) {
 178                 if (r < 0)
 179                         ctx->sock.eof = true;
 180
 181                 return false;
 182         }
 183
 184         iov.iov_len = blob_len(ubus_msghdr_data(&ctx->msgbuf.hdr));
 185         if (iov.iov_len > 0 && !recv_retry(ctx->sock.fd, &iov, true))
 186                 return false;
 187
 188         return ubus_validate_hdr(&ctx->msgbuf.hdr);
 189 }
 190
 191 void __hidden ubus_handle_data(struct uloop_fd *u, unsigned int events)
 192 {
 193         struct ubus_context *ctx = container_of(u, struct ubus_context, sock);
 194         struct ubus_msghdr *hdr = &ctx->msgbuf.hdr;
 195
 196         while (get_next_msg(ctx)) {
 197                 ubus_process_msg(ctx, hdr);
 198                 if (uloop_cancelled)
 199                         break;
 200         }
 201
 202         if (u->eof)
 203                 ctx->connection_lost(ctx);
 204 }
 205
 206 static void
 207 ubus_refresh_state(struct ubus_context *ctx)
 208 {
 209         struct ubus_object *obj, *tmp;
 210         struct ubus_object **objs;
 211         int n, i = 0;
 212
 213         /* clear all type IDs, they need to be registered again */
 214         avl_for_each_element(&ctx->objects, obj, avl)
 215                 if (obj->type)
 216                         obj->type->id = 0;
 217
 218         /* push out all objects again */
 219         objs = alloca(ctx->objects.count * sizeof(*objs));
 220         avl_remove_all_elements(&ctx->objects, obj, avl, tmp) {
 221                 objs[i++] = obj;
 222                 obj->id = 0;
 223         }
 224
 225         for (n = i, i = 0; i < n; i++)
 226                 ubus_add_object(ctx, objs[i]);
 227 }
 228
 229 int ubus_reconnect(struct ubus_context *ctx, const char *path)
 230 {
 231         struct {
 232                 struct ubus_msghdr hdr;
 233                 struct blob_attr data;
 234         } hdr;
 235         struct blob_attr *buf;
 236         int ret = UBUS_STATUS_UNKNOWN_ERROR;
 237
 238         if (!path)
 239                 path = UBUS_UNIX_SOCKET;
 240
 241         if (ctx->sock.fd >= 0) {
 242                 if (ctx->sock.registered)
 243                         uloop_fd_delete(&ctx->sock);
 244
 245                 close(ctx->sock.fd);
 246         }
 247
 248         ctx->sock.fd = usock(USOCK_UNIX, path, NULL);
 249         if (ctx->sock.fd < 0)
 250                 return UBUS_STATUS_CONNECTION_FAILED;
 251
 252         if (read(ctx->sock.fd, &hdr, sizeof(hdr)) != sizeof(hdr))
 253                 goto out_close;
 254
 255         if (!ubus_validate_hdr(&hdr.hdr))
 256                 goto out_close;
 257
 258         if (hdr.hdr.type != UBUS_MSG_HELLO)
 259                 goto out_close;
 260
 261         buf = calloc(1, blob_raw_len(&hdr.data));
 262         if (!buf)
 263                 goto out_close;
 264
 265         memcpy(buf, &hdr.data, sizeof(hdr.data));
 266         if (read(ctx->sock.fd, blob_data(buf), blob_len(buf)) != blob_len(buf))
 267                 goto out_free;
 268
 269         ctx->local_id = hdr.hdr.peer;
 270         if (!ctx->local_id)
 271                 goto out_free;
 272
 273         ret = UBUS_STATUS_OK;
 274         fcntl(ctx->sock.fd, F_SETFL, fcntl(ctx->sock.fd, F_GETFL) | O_NONBLOCK);
 275
 276         ubus_refresh_state(ctx);
 277
 278 out_free:
 279         free(buf);
 280 out_close:
 281         if (ret)
 282                 close(ctx->sock.fd);
 283
 284         return ret;
 285 }