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 (!cur_len || !iov_len)
  81                                 return len;
  82                 }
  83                 iov->iov_len -= cur_len;
  84         } while (1);
  85 }
  86
  87 int __hidden ubus_send_msg(struct ubus_context *ctx, uint32_t seq,
  88                            struct blob_attr *msg, int cmd, uint32_t peer)
  89 {
  90         struct ubus_msghdr hdr;
  91         struct iovec iov[2] = {
  92                 STATIC_IOV(hdr)
  93         };
  94
  95         hdr.version = 0;
  96         hdr.type = cmd;
  97         hdr.seq = seq;
  98         hdr.peer = peer;
  99
 100         if (!msg) {
 101                 blob_buf_init(&b, 0);
 102                 msg = b.head;
 103         }
 104
 105         iov[1].iov_base = (char *) msg;
 106         iov[1].iov_len = blob_raw_len(msg);
 107
 108         return writev_retry(ctx->sock.fd, iov, ARRAY_SIZE(iov));
 109 }
 110
 111 static bool recv_retry(int fd, struct iovec *iov, bool wait)
 112 {
 113         int bytes;
 114
 115         while (iov->iov_len > 0) {
 116                 if (wait)
 117                         wait_data(fd, false);
 118
 119                 bytes = read(fd, iov->iov_base, iov->iov_len);
 120                 if (bytes < 0) {
 121                         bytes = 0;
 122                         if (uloop_cancelled)
 123                                 return false;
 124                         if (errno == EINTR)
 125                                 continue;
 126
 127                         if (errno != EAGAIN)
 128                                 return false;
 129                 }
 130                 if (!wait && !bytes)
 131                         return false;
 132
 133                 wait = true;
 134                 iov->iov_len -= bytes;
 135                 iov->iov_base += bytes;
 136         }
 137
 138         return true;
 139 }
 140
 141 static bool ubus_validate_hdr(struct ubus_msghdr *hdr)
 142 {
 143         if (hdr->version != 0)
 144                 return false;
 145
 146         if (blob_raw_len(hdr->data) < sizeof(*hdr->data))
 147                 return false;
 148
 149         if (blob_pad_len(hdr->data) > UBUS_MAX_MSGLEN)
 150                 return false;
 151
 152         return true;
 153 }
 154
 155 static bool get_next_msg(struct ubus_context *ctx)
 156 {
 157         struct iovec iov = STATIC_IOV(ctx->msgbuf.hdr);
 158
 159         /* receive header + start attribute */
 160         iov.iov_len += sizeof(struct blob_attr);
 161         if (!recv_retry(ctx->sock.fd, &iov, false))
 162                 return false;
 163
 164         iov.iov_len = blob_len(ctx->msgbuf.hdr.data);
 165         if (iov.iov_len > 0 && !recv_retry(ctx->sock.fd, &iov, true))
 166                 return false;
 167
 168         return ubus_validate_hdr(&ctx->msgbuf.hdr);
 169 }
 170
 171 void __hidden ubus_handle_data(struct uloop_fd *u, unsigned int events)
 172 {
 173         struct ubus_context *ctx = container_of(u, struct ubus_context, sock);
 174         struct ubus_msghdr *hdr = &ctx->msgbuf.hdr;
 175
 176         while (get_next_msg(ctx)) {
 177                 ubus_process_msg(ctx, hdr);
 178                 if (uloop_cancelled)
 179                         break;
 180         }
 181
 182         if (u->eof)
 183                 ctx->connection_lost(ctx);
 184 }
 185
 186 static void
 187 ubus_refresh_state(struct ubus_context *ctx)
 188 {
 189         struct ubus_object *obj, *tmp;
 190
 191         /* clear all type IDs, they need to be registered again */
 192         avl_for_each_element(&ctx->objects, obj, avl)
 193                 obj->type->id = 0;
 194
 195         /* push out all objects again */
 196         avl_for_each_element_safe(&ctx->objects, obj, avl, tmp) {
 197                 obj->id = 0;
 198                 avl_delete(&ctx->objects, &obj->avl);
 199                 ubus_add_object(ctx, obj);
 200         }
 201 }
 202
 203 int ubus_reconnect(struct ubus_context *ctx, const char *path)
 204 {
 205         struct {
 206                 struct ubus_msghdr hdr;
 207                 struct blob_attr data;
 208         } hdr;
 209         struct blob_attr *buf;
 210         int ret = UBUS_STATUS_UNKNOWN_ERROR;
 211
 212         if (!path)
 213                 path = UBUS_UNIX_SOCKET;
 214
 215         if (ctx->sock.fd >= 0) {
 216                 if (ctx->sock.registered)
 217                         uloop_fd_delete(&ctx->sock);
 218
 219                 close(ctx->sock.fd);
 220         }
 221
 222         ctx->sock.fd = usock(USOCK_UNIX, path, NULL);
 223         if (ctx->sock.fd < 0)
 224                 return UBUS_STATUS_CONNECTION_FAILED;
 225
 226         if (read(ctx->sock.fd, &hdr, sizeof(hdr)) != sizeof(hdr))
 227                 goto out_close;
 228
 229         if (!ubus_validate_hdr(&hdr.hdr))
 230                 goto out_close;
 231
 232         if (hdr.hdr.type != UBUS_MSG_HELLO)
 233                 goto out_close;
 234
 235         buf = calloc(1, blob_raw_len(&hdr.data));
 236         if (!buf)
 237                 goto out_close;
 238
 239         memcpy(buf, &hdr.data, sizeof(hdr.data));
 240         if (read(ctx->sock.fd, blob_data(buf), blob_len(buf)) != blob_len(buf))
 241                 goto out_free;
 242
 243         ctx->local_id = hdr.hdr.peer;
 244         if (!ctx->local_id)
 245                 goto out_free;
 246
 247         ret = UBUS_STATUS_OK;
 248         fcntl(ctx->sock.fd, F_SETFL, fcntl(ctx->sock.fd, F_GETFL) | O_NONBLOCK);
 249
 250         ubus_refresh_state(ctx);
 251
 252 out_free:
 253         free(buf);
 254 out_close:
 255         if (ret)
 256                 close(ctx->sock.fd);
 257
 258         return ret;
 259 }