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 };
  37
  38 static struct blob_attr *attrbuf[UBUS_ATTR_MAX];
  39
  40 __hidden struct blob_attr **ubus_parse_msg(struct blob_attr *msg)
  41 {
  42         blob_parse(msg, attrbuf, ubus_policy, UBUS_ATTR_MAX);
  43         return attrbuf;
  44 }
  45
  46 static void wait_data(int fd, bool write)
  47 {
  48         struct pollfd pfd = { .fd = fd };
  49
  50         pfd.events = write ? POLLOUT : POLLIN;
  51         poll(&pfd, 1, 0);
  52 }
  53
  54 static int writev_retry(int fd, struct iovec *iov, int iov_len)
  55 {
  56         int len = 0;
  57
  58         do {
  59                 int cur_len = writev(fd, iov, iov_len);
  60                 if (cur_len < 0) {
  61                         switch(errno) {
  62                         case EAGAIN:
  63                                 wait_data(fd, true);
  64                                 break;
  65                         case EINTR:
  66                                 break;
  67                         default:
  68                                 return -1;
  69                         }
  70                         continue;
  71                 }
  72                 len += cur_len;
  73                 while (cur_len >= iov->iov_len) {
  74                         cur_len -= iov->iov_len;
  75                         iov_len--;
  76                         iov++;
  77                         if (!cur_len || !iov_len)
  78                                 return len;
  79                 }
  80                 iov->iov_len -= cur_len;
  81         } while (1);
  82 }
  83
  84 int __hidden ubus_send_msg(struct ubus_context *ctx, uint32_t seq,
  85                            struct blob_attr *msg, int cmd, uint32_t peer)
  86 {
  87         struct ubus_msghdr hdr;
  88         struct iovec iov[2] = {
  89                 STATIC_IOV(hdr)
  90         };
  91
  92         hdr.version = 0;
  93         hdr.type = cmd;
  94         hdr.seq = seq;
  95         hdr.peer = peer;
  96
  97         if (!msg) {
  98                 blob_buf_init(&b, 0);
  99                 msg = b.head;
 100         }
 101
 102         iov[1].iov_base = (char *) msg;
 103         iov[1].iov_len = blob_raw_len(msg);
 104
 105         return writev_retry(ctx->sock.fd, iov, ARRAY_SIZE(iov));
 106 }
 107
 108 static bool recv_retry(int fd, struct iovec *iov, bool wait)
 109 {
 110         int bytes;
 111
 112         while (iov->iov_len > 0) {
 113                 if (wait)
 114                         wait_data(fd, false);
 115
 116                 bytes = read(fd, iov->iov_base, iov->iov_len);
 117                 if (bytes < 0) {
 118                         bytes = 0;
 119                         if (uloop_cancelled)
 120                                 return false;
 121                         if (errno == EINTR)
 122                                 continue;
 123
 124                         if (errno != EAGAIN)
 125                                 return false;
 126                 }
 127                 if (!wait && !bytes)
 128                         return false;
 129
 130                 wait = true;
 131                 iov->iov_len -= bytes;
 132                 iov->iov_base += bytes;
 133         }
 134
 135         return true;
 136 }
 137
 138 static bool ubus_validate_hdr(struct ubus_msghdr *hdr)
 139 {
 140         if (hdr->version != 0)
 141                 return false;
 142
 143         if (blob_raw_len(hdr->data) < sizeof(*hdr->data))
 144                 return false;
 145
 146         if (blob_pad_len(hdr->data) > UBUS_MAX_MSGLEN)
 147                 return false;
 148
 149         return true;
 150 }
 151
 152 static bool get_next_msg(struct ubus_context *ctx)
 153 {
 154         struct iovec iov = STATIC_IOV(ctx->msgbuf.hdr);
 155
 156         /* receive header + start attribute */
 157         iov.iov_len += sizeof(struct blob_attr);
 158         if (!recv_retry(ctx->sock.fd, &iov, false))
 159                 return false;
 160
 161         iov.iov_len = blob_len(ctx->msgbuf.hdr.data);
 162         if (iov.iov_len > 0 && !recv_retry(ctx->sock.fd, &iov, true))
 163                 return false;
 164
 165         return ubus_validate_hdr(&ctx->msgbuf.hdr);
 166 }
 167
 168 void __hidden ubus_handle_data(struct uloop_fd *u, unsigned int events)
 169 {
 170         struct ubus_context *ctx = container_of(u, struct ubus_context, sock);
 171         struct ubus_msghdr *hdr = &ctx->msgbuf.hdr;
 172
 173         while (get_next_msg(ctx)) {
 174                 ubus_process_msg(ctx, hdr);
 175                 if (uloop_cancelled)
 176                         break;
 177         }
 178
 179         if (u->eof)
 180                 ctx->connection_lost(ctx);
 181 }
 182
 183 static void
 184 ubus_refresh_state(struct ubus_context *ctx)
 185 {
 186         struct ubus_object *obj, *tmp;
 187
 188         /* clear all type IDs, they need to be registered again */
 189         avl_for_each_element(&ctx->objects, obj, avl)
 190                 obj->type->id = 0;
 191
 192         /* push out all objects again */
 193         avl_for_each_element_safe(&ctx->objects, obj, avl, tmp) {
 194                 obj->id = 0;
 195                 avl_delete(&ctx->objects, &obj->avl);
 196                 ubus_add_object(ctx, obj);
 197         }
 198 }
 199
 200 int ubus_reconnect(struct ubus_context *ctx, const char *path)
 201 {
 202         struct {
 203                 struct ubus_msghdr hdr;
 204                 struct blob_attr data;
 205         } hdr;
 206         struct blob_attr *buf;
 207         int ret = UBUS_STATUS_UNKNOWN_ERROR;
 208
 209         if (!path)
 210                 path = UBUS_UNIX_SOCKET;
 211
 212         if (ctx->sock.fd >= 0) {
 213                 if (ctx->sock.registered)
 214                         uloop_fd_delete(&ctx->sock);
 215
 216                 close(ctx->sock.fd);
 217         }
 218
 219         ctx->sock.fd = usock(USOCK_UNIX, path, NULL);
 220         if (ctx->sock.fd < 0)
 221                 return UBUS_STATUS_CONNECTION_FAILED;
 222
 223         if (read(ctx->sock.fd, &hdr, sizeof(hdr)) != sizeof(hdr))
 224                 goto out_close;
 225
 226         if (!ubus_validate_hdr(&hdr.hdr))
 227                 goto out_close;
 228
 229         if (hdr.hdr.type != UBUS_MSG_HELLO)
 230                 goto out_close;
 231
 232         buf = calloc(1, blob_raw_len(&hdr.data));
 233         if (!buf)
 234                 goto out_close;
 235
 236         memcpy(buf, &hdr.data, sizeof(hdr.data));
 237         if (read(ctx->sock.fd, blob_data(buf), blob_len(buf)) != blob_len(buf))
 238                 goto out_free;
 239
 240         ctx->local_id = hdr.hdr.peer;
 241         if (!ctx->local_id)
 242                 goto out_free;
 243
 244         ret = UBUS_STATUS_OK;
 245         fcntl(ctx->sock.fd, F_SETFL, fcntl(ctx->sock.fd, F_GETFL) | O_NONBLOCK);
 246
 247         ubus_refresh_state(ctx);
 248
 249 out_free:
 250         free(buf);
 251 out_close:
 252         if (ret)
 253                 close(ctx->sock.fd);
 254
 255         return ret;
 256 }