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 };
  39
  40 static struct blob_attr *attrbuf[UBUS_ATTR_MAX];
  41
  42 __hidden struct blob_attr **ubus_parse_msg(struct blob_attr *msg)
  43 {
  44         blob_parse(msg, attrbuf, ubus_policy, UBUS_ATTR_MAX);
  45         return attrbuf;
  46 }
  47
  48 static void wait_data(int fd, bool write)
  49 {
  50         struct pollfd pfd = { .fd = fd };
  51
  52         pfd.events = write ? POLLOUT : POLLIN;
  53         poll(&pfd, 1, 0);
  54 }
  55
  56 static int writev_retry(int fd, struct iovec *iov, int iov_len)
  57 {
  58         int len = 0;
  59
  60         do {
  61                 int cur_len = writev(fd, iov, iov_len);
  62                 if (cur_len < 0) {
  63                         switch(errno) {
  64                         case EAGAIN:
  65                                 wait_data(fd, true);
  66                                 break;
  67                         case EINTR:
  68                                 break;
  69                         default:
  70                                 return -1;
  71                         }
  72                         continue;
  73                 }
  74                 len += cur_len;
  75                 while (cur_len >= iov->iov_len) {
  76                         cur_len -= iov->iov_len;
  77                         iov_len--;
  78                         iov++;
  79                         if (!cur_len || !iov_len)
  80                                 return len;
  81                 }
  82                 iov->iov_len -= cur_len;
  83         } while (1);
  84 }
  85
  86 int __hidden ubus_send_msg(struct ubus_context *ctx, uint32_t seq,
  87                            struct blob_attr *msg, int cmd, uint32_t peer)
  88 {
  89         struct ubus_msghdr hdr;
  90         struct iovec iov[2] = {
  91                 STATIC_IOV(hdr)
  92         };
  93
  94         hdr.version = 0;
  95         hdr.type = cmd;
  96         hdr.seq = seq;
  97         hdr.peer = peer;
  98
  99         if (!msg) {
 100                 blob_buf_init(&b, 0);
 101                 msg = b.head;
 102         }
 103
 104         iov[1].iov_base = (char *) msg;
 105         iov[1].iov_len = blob_raw_len(msg);
 106
 107         return writev_retry(ctx->sock.fd, iov, ARRAY_SIZE(iov));
 108 }
 109
 110 static bool recv_retry(int fd, struct iovec *iov, bool wait)
 111 {
 112         int bytes;
 113
 114         while (iov->iov_len > 0) {
 115                 if (wait)
 116                         wait_data(fd, false);
 117
 118                 bytes = read(fd, iov->iov_base, iov->iov_len);
 119                 if (bytes < 0) {
 120                         bytes = 0;
 121                         if (uloop_cancelled)
 122                                 return false;
 123                         if (errno == EINTR)
 124                                 continue;
 125
 126                         if (errno != EAGAIN)
 127                                 return false;
 128                 }
 129                 if (!wait && !bytes)
 130                         return false;
 131
 132                 wait = true;
 133                 iov->iov_len -= bytes;
 134                 iov->iov_base += bytes;
 135         }
 136
 137         return true;
 138 }
 139
 140 static bool ubus_validate_hdr(struct ubus_msghdr *hdr)
 141 {
 142         if (hdr->version != 0)
 143                 return false;
 144
 145         if (blob_raw_len(hdr->data) < sizeof(*hdr->data))
 146                 return false;
 147
 148         if (blob_pad_len(hdr->data) > UBUS_MAX_MSGLEN)
 149                 return false;
 150
 151         return true;
 152 }
 153
 154 static bool get_next_msg(struct ubus_context *ctx)
 155 {
 156         struct iovec iov = STATIC_IOV(ctx->msgbuf.hdr);
 157
 158         /* receive header + start attribute */
 159         iov.iov_len += sizeof(struct blob_attr);
 160         if (!recv_retry(ctx->sock.fd, &iov, false))
 161                 return false;
 162
 163         iov.iov_len = blob_len(ctx->msgbuf.hdr.data);
 164         if (iov.iov_len > 0 && !recv_retry(ctx->sock.fd, &iov, true))
 165                 return false;
 166
 167         return ubus_validate_hdr(&ctx->msgbuf.hdr);
 168 }
 169
 170 void __hidden ubus_handle_data(struct uloop_fd *u, unsigned int events)
 171 {
 172         struct ubus_context *ctx = container_of(u, struct ubus_context, sock);
 173         struct ubus_msghdr *hdr = &ctx->msgbuf.hdr;
 174
 175         while (get_next_msg(ctx)) {
 176                 ubus_process_msg(ctx, hdr);
 177                 if (uloop_cancelled)
 178                         break;
 179         }
 180
 181         if (u->eof)
 182                 ctx->connection_lost(ctx);
 183 }
 184
 185 static void
 186 ubus_refresh_state(struct ubus_context *ctx)
 187 {
 188         struct ubus_object *obj, *tmp;
 189
 190         /* clear all type IDs, they need to be registered again */
 191         avl_for_each_element(&ctx->objects, obj, avl)
 192                 obj->type->id = 0;
 193
 194         /* push out all objects again */
 195         avl_for_each_element_safe(&ctx->objects, obj, avl, tmp) {
 196                 obj->id = 0;
 197                 avl_delete(&ctx->objects, &obj->avl);
 198                 ubus_add_object(ctx, obj);
 199         }
 200 }
 201
 202 int ubus_reconnect(struct ubus_context *ctx, const char *path)
 203 {
 204         struct {
 205                 struct ubus_msghdr hdr;
 206                 struct blob_attr data;
 207         } hdr;
 208         struct blob_attr *buf;
 209         int ret = UBUS_STATUS_UNKNOWN_ERROR;
 210
 211         if (!path)
 212                 path = UBUS_UNIX_SOCKET;
 213
 214         if (ctx->sock.fd >= 0) {
 215                 if (ctx->sock.registered)
 216                         uloop_fd_delete(&ctx->sock);
 217
 218                 close(ctx->sock.fd);
 219         }
 220
 221         ctx->sock.fd = usock(USOCK_UNIX, path, NULL);
 222         if (ctx->sock.fd < 0)
 223                 return UBUS_STATUS_CONNECTION_FAILED;
 224
 225         if (read(ctx->sock.fd, &hdr, sizeof(hdr)) != sizeof(hdr))
 226                 goto out_close;
 227
 228         if (!ubus_validate_hdr(&hdr.hdr))
 229                 goto out_close;
 230
 231         if (hdr.hdr.type != UBUS_MSG_HELLO)
 232                 goto out_close;
 233
 234         buf = calloc(1, blob_raw_len(&hdr.data));
 235         if (!buf)
 236                 goto out_close;
 237
 238         memcpy(buf, &hdr.data, sizeof(hdr.data));
 239         if (read(ctx->sock.fd, blob_data(buf), blob_len(buf)) != blob_len(buf))
 240                 goto out_free;
 241
 242         ctx->local_id = hdr.hdr.peer;
 243         if (!ctx->local_id)
 244                 goto out_free;
 245
 246         ret = UBUS_STATUS_OK;
 247         fcntl(ctx->sock.fd, F_SETFL, fcntl(ctx->sock.fd, F_GETFL) | O_NONBLOCK);
 248
 249         ubus_refresh_state(ctx);
 250
 251 out_free:
 252         free(buf);
 253 out_close:
 254         if (ret)
 255                 close(ctx->sock.fd);
 256
 257         return ret;
 258 }