libubus: fix crash on reconnect with objects that have no type
[project/ubus.git] / 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 if (obj->type)
194 obj->type->id = 0;
195
196 /* push out all objects again */
197 avl_for_each_element_safe(&ctx->objects, obj, avl, tmp) {
198 obj->id = 0;
199 avl_delete(&ctx->objects, &obj->avl);
200 ubus_add_object(ctx, obj);
201 }
202 }
203
204 int ubus_reconnect(struct ubus_context *ctx, const char *path)
205 {
206 struct {
207 struct ubus_msghdr hdr;
208 struct blob_attr data;
209 } hdr;
210 struct blob_attr *buf;
211 int ret = UBUS_STATUS_UNKNOWN_ERROR;
212
213 if (!path)
214 path = UBUS_UNIX_SOCKET;
215
216 if (ctx->sock.fd >= 0) {
217 if (ctx->sock.registered)
218 uloop_fd_delete(&ctx->sock);
219
220 close(ctx->sock.fd);
221 }
222
223 ctx->sock.fd = usock(USOCK_UNIX, path, NULL);
224 if (ctx->sock.fd < 0)
225 return UBUS_STATUS_CONNECTION_FAILED;
226
227 if (read(ctx->sock.fd, &hdr, sizeof(hdr)) != sizeof(hdr))
228 goto out_close;
229
230 if (!ubus_validate_hdr(&hdr.hdr))
231 goto out_close;
232
233 if (hdr.hdr.type != UBUS_MSG_HELLO)
234 goto out_close;
235
236 buf = calloc(1, blob_raw_len(&hdr.data));
237 if (!buf)
238 goto out_close;
239
240 memcpy(buf, &hdr.data, sizeof(hdr.data));
241 if (read(ctx->sock.fd, blob_data(buf), blob_len(buf)) != blob_len(buf))
242 goto out_free;
243
244 ctx->local_id = hdr.hdr.peer;
245 if (!ctx->local_id)
246 goto out_free;
247
248 ret = UBUS_STATUS_OK;
249 fcntl(ctx->sock.fd, F_SETFL, fcntl(ctx->sock.fd, F_GETFL) | O_NONBLOCK);
250
251 ubus_refresh_state(ctx);
252
253 out_free:
254 free(buf);
255 out_close:
256 if (ret)
257 close(ctx->sock.fd);
258
259 return ret;
260 }