blobmsg.c

   1 /*
   2  * Copyright (C) 2010-2012 Felix Fietkau <nbd@openwrt.org>
   3  *
   4  * Permission to use, copy, modify, and/or distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16 #include "blobmsg.h"
  17
  18 static const int blob_type[__BLOBMSG_TYPE_LAST] = {
  19         [BLOBMSG_TYPE_INT8] = BLOB_ATTR_INT8,
  20         [BLOBMSG_TYPE_INT16] = BLOB_ATTR_INT16,
  21         [BLOBMSG_TYPE_INT32] = BLOB_ATTR_INT32,
  22         [BLOBMSG_TYPE_INT64] = BLOB_ATTR_INT64,
  23         [BLOBMSG_TYPE_DOUBLE] = BLOB_ATTR_DOUBLE,
  24         [BLOBMSG_TYPE_STRING] = BLOB_ATTR_STRING,
  25         [BLOBMSG_TYPE_UNSPEC] = BLOB_ATTR_BINARY,
  26 };
  27
  28 bool blobmsg_check_attr(const struct blob_attr *attr, bool name)
  29 {
  30         return blobmsg_check_attr_len(attr, name, blob_raw_len(attr));
  31 }
  32
  33 static const struct blobmsg_hdr* blobmsg_hdr_from_blob(const struct blob_attr *attr, size_t len)
  34 {
  35         if (len < sizeof(struct blob_attr) + sizeof(struct blobmsg_hdr))
  36                 return NULL;
  37
  38         return blob_data(attr);
  39 }
  40
  41 static bool blobmsg_hdr_valid_namelen(const struct blobmsg_hdr *hdr, size_t len)
  42 {
  43         if (len < sizeof(struct blob_attr) + sizeof(struct blobmsg_hdr) + blobmsg_namelen(hdr) + 1)
  44                 return false;
  45
  46         return true;
  47 }
  48
  49 static bool blobmsg_check_name(const struct blob_attr *attr, size_t len, bool name)
  50 {
  51         char *limit = (char *) attr + len;
  52         const struct blobmsg_hdr *hdr;
  53
  54         hdr = blobmsg_hdr_from_blob(attr, len);
  55         if (!hdr)
  56                 return false;
  57
  58         if (name && !hdr->namelen)
  59                 return false;
  60
  61         if (name && !blobmsg_hdr_valid_namelen(hdr, len))
  62                 return false;
  63
  64         if ((char *) hdr->name + blobmsg_namelen(hdr) + 1 > limit)
  65                 return false;
  66
  67         if (blobmsg_namelen(hdr) > (blob_len(attr) - sizeof(struct blobmsg_hdr)))
  68                 return false;
  69
  70         if (hdr->name[blobmsg_namelen(hdr)] != 0)
  71                 return false;
  72
  73         return true;
  74 }
  75
  76 static const char* blobmsg_check_data(const struct blob_attr *attr, size_t len, size_t *data_len)
  77 {
  78         char *limit = (char *) attr + len;
  79         const char *data;
  80
  81         *data_len = blobmsg_data_len(attr);
  82         if (*data_len > blob_raw_len(attr))
  83                 return NULL;
  84
  85         data = blobmsg_data(attr);
  86         if (data + *data_len > limit)
  87                 return NULL;
  88
  89         return data;
  90 }
  91
  92 bool blobmsg_check_attr_len(const struct blob_attr *attr, bool name, size_t len)
  93 {
  94         const char *data;
  95         size_t data_len;
  96         int id;
  97
  98         if (!blobmsg_check_name(attr, len, name))
  99                 return false;
 100
 101         id = blob_id(attr);
 102         if (id > BLOBMSG_TYPE_LAST)
 103                 return false;
 104
 105         if (!blob_type[id])
 106                 return true;
 107
 108         data = blobmsg_check_data(attr, len, &data_len);
 109         if (!data)
 110                 return false;
 111
 112         return blob_check_type(data, data_len, blob_type[id]);
 113 }
 114
 115 int blobmsg_check_array(const struct blob_attr *attr, int type)
 116 {
 117         return blobmsg_check_array_len(attr, type, blobmsg_len(attr));
 118 }
 119
 120 int blobmsg_check_array_len(const struct blob_attr *attr, int type, size_t len)
 121 {
 122         struct blob_attr *cur;
 123         bool name;
 124         int size = 0;
 125
 126         if (type > BLOBMSG_TYPE_LAST)
 127                 return -1;
 128
 129         if (!blobmsg_check_attr_len(attr, false, len))
 130                 return -1;
 131
 132         switch (blobmsg_type(attr)) {
 133         case BLOBMSG_TYPE_TABLE:
 134                 name = true;
 135                 break;
 136         case BLOBMSG_TYPE_ARRAY:
 137                 name = false;
 138                 break;
 139         default:
 140                 return -1;
 141         }
 142
 143         __blobmsg_for_each_attr(cur, attr, len) {
 144                 if (type != BLOBMSG_TYPE_UNSPEC && blobmsg_type(cur) != type)
 145                         return -1;
 146
 147                 if (!blobmsg_check_attr_len(cur, name, len))
 148                         return -1;
 149
 150                 size++;
 151         }
 152
 153         return size;
 154 }
 155
 156 bool blobmsg_check_attr_list(const struct blob_attr *attr, int type)
 157 {
 158         return blobmsg_check_array(attr, type) >= 0;
 159 }
 160
 161 bool blobmsg_check_attr_list_len(const struct blob_attr *attr, int type, size_t len)
 162 {
 163         return blobmsg_check_array_len(attr, type, len) >= 0;
 164 }
 165
 166 int blobmsg_parse_array(const struct blobmsg_policy *policy, int policy_len,
 167                         struct blob_attr **tb, void *data, unsigned int len)
 168 {
 169         struct blob_attr *attr;
 170         int i = 0;
 171
 172         memset(tb, 0, policy_len * sizeof(*tb));
 173         __blob_for_each_attr(attr, data, len) {
 174                 if (policy[i].type != BLOBMSG_TYPE_UNSPEC &&
 175                     blob_id(attr) != policy[i].type)
 176                         continue;
 177
 178                 if (!blobmsg_check_attr_len(attr, false, len))
 179                         return -1;
 180
 181                 if (tb[i])
 182                         continue;
 183
 184                 tb[i++] = attr;
 185                 if (i == policy_len)
 186                         break;
 187         }
 188
 189         return 0;
 190 }
 191
 192 int blobmsg_parse(const struct blobmsg_policy *policy, int policy_len,
 193                   struct blob_attr **tb, void *data, unsigned int len)
 194 {
 195         const struct blobmsg_hdr *hdr;
 196         struct blob_attr *attr;
 197         uint8_t *pslen;
 198         int i;
 199
 200         memset(tb, 0, policy_len * sizeof(*tb));
 201         if (!data || !len)
 202                 return -EINVAL;
 203         pslen = alloca(policy_len);
 204         for (i = 0; i < policy_len; i++) {
 205                 if (!policy[i].name)
 206                         continue;
 207
 208                 pslen[i] = strlen(policy[i].name);
 209         }
 210
 211         __blob_for_each_attr(attr, data, len) {
 212                 hdr = blobmsg_hdr_from_blob(attr, len);
 213                 if (!hdr)
 214                         return -1;
 215
 216                 if (!blobmsg_hdr_valid_namelen(hdr, len))
 217                         return -1;
 218
 219                 for (i = 0; i < policy_len; i++) {
 220                         if (!policy[i].name)
 221                                 continue;
 222
 223                         if (policy[i].type != BLOBMSG_TYPE_UNSPEC &&
 224                             blob_id(attr) != policy[i].type)
 225                                 continue;
 226
 227                         if (blobmsg_namelen(hdr) != pslen[i])
 228                                 continue;
 229
 230                         if (!blobmsg_check_attr_len(attr, true, len))
 231                                 return -1;
 232
 233                         if (tb[i])
 234                                 continue;
 235
 236                         if (strcmp(policy[i].name, (char *) hdr->name) != 0)
 237                                 continue;
 238
 239                         tb[i] = attr;
 240                 }
 241         }
 242
 243         return 0;
 244 }
 245
 246
 247 static struct blob_attr *
 248 blobmsg_new(struct blob_buf *buf, int type, const char *name, int payload_len, void **data)
 249 {
 250         struct blob_attr *attr;
 251         struct blobmsg_hdr *hdr;
 252         int attrlen, namelen;
 253         char *pad_start, *pad_end;
 254
 255         if (!name)
 256                 name = "";
 257
 258         namelen = strlen(name);
 259         attrlen = blobmsg_hdrlen(namelen) + payload_len;
 260         attr = blob_new(buf, type, attrlen);
 261         if (!attr)
 262                 return NULL;
 263
 264         attr->id_len |= be32_to_cpu(BLOB_ATTR_EXTENDED);
 265         hdr = blob_data(attr);
 266         hdr->namelen = cpu_to_be16(namelen);
 267
 268         memcpy(hdr->name, name, namelen);
 269         hdr->name[namelen] = '\0';
 270
 271         pad_end = *data = blobmsg_data(attr);
 272         pad_start = (char *) &hdr->name[namelen];
 273         if (pad_start < pad_end)
 274                 memset(pad_start, 0, pad_end - pad_start);
 275
 276         return attr;
 277 }
 278
 279 static inline int
 280 attr_to_offset(struct blob_buf *buf, struct blob_attr *attr)
 281 {
 282         return (char *)attr - (char *) buf->buf + BLOB_COOKIE;
 283 }
 284
 285
 286 void *
 287 blobmsg_open_nested(struct blob_buf *buf, const char *name, bool array)
 288 {
 289         struct blob_attr *head;
 290         int type = array ? BLOBMSG_TYPE_ARRAY : BLOBMSG_TYPE_TABLE;
 291         unsigned long offset = attr_to_offset(buf, buf->head);
 292         void *data;
 293
 294         if (!name)
 295                 name = "";
 296
 297         head = blobmsg_new(buf, type, name, 0, &data);
 298         if (!head)
 299                 return NULL;
 300         blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blobmsg_hdrlen(strlen(name)));
 301         buf->head = head;
 302         return (void *)offset;
 303 }
 304
 305 __attribute__((format(printf, 3, 0)))
 306 int blobmsg_vprintf(struct blob_buf *buf, const char *name, const char *format, va_list arg)
 307 {
 308         va_list arg2;
 309         char cbuf;
 310         char *sbuf;
 311         int len, ret;
 312
 313         va_copy(arg2, arg);
 314         len = vsnprintf(&cbuf, sizeof(cbuf), format, arg2);
 315         va_end(arg2);
 316
 317         if (len < 0)
 318                 return -1;
 319
 320         sbuf = blobmsg_alloc_string_buffer(buf, name, len + 1);
 321         if (!sbuf)
 322                 return -1;
 323
 324         ret = vsnprintf(sbuf, len + 1, format, arg);
 325         if (ret < 0)
 326                 return -1;
 327
 328         blobmsg_add_string_buffer(buf);
 329
 330         return ret;
 331 }
 332
 333 __attribute__((format(printf, 3, 4)))
 334 int blobmsg_printf(struct blob_buf *buf, const char *name, const char *format, ...)
 335 {
 336         va_list ap;
 337         int ret;
 338
 339         va_start(ap, format);
 340         ret = blobmsg_vprintf(buf, name, format, ap);
 341         va_end(ap);
 342
 343         return ret;
 344 }
 345
 346 void *
 347 blobmsg_alloc_string_buffer(struct blob_buf *buf, const char *name, unsigned int maxlen)
 348 {
 349         struct blob_attr *attr;
 350         void *data_dest;
 351
 352         attr = blobmsg_new(buf, BLOBMSG_TYPE_STRING, name, maxlen, &data_dest);
 353         if (!attr)
 354                 return NULL;
 355
 356         blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blob_pad_len(attr));
 357         blob_set_raw_len(attr, blob_raw_len(attr) - maxlen);
 358
 359         return data_dest;
 360 }
 361
 362 void *
 363 blobmsg_realloc_string_buffer(struct blob_buf *buf, unsigned int maxlen)
 364 {
 365         struct blob_attr *attr = blob_next(buf->head);
 366         int offset = attr_to_offset(buf, blob_next(buf->head)) + blob_pad_len(attr) - BLOB_COOKIE;
 367         int required = maxlen - (buf->buflen - offset);
 368
 369         if (required <= 0)
 370                 goto out;
 371
 372         if (!blob_buf_grow(buf, required))
 373                 return NULL;
 374         attr = blob_next(buf->head);
 375
 376 out:
 377         return blobmsg_data(attr);
 378 }
 379
 380 void
 381 blobmsg_add_string_buffer(struct blob_buf *buf)
 382 {
 383         struct blob_attr *attr;
 384         int len, attrlen;
 385
 386         attr = blob_next(buf->head);
 387         len = strlen(blobmsg_data(attr)) + 1;
 388
 389         attrlen = blob_raw_len(attr) + len;
 390         blob_set_raw_len(attr, attrlen);
 391         blob_fill_pad(attr);
 392
 393         blob_set_raw_len(buf->head, blob_raw_len(buf->head) + blob_pad_len(attr));
 394 }
 395
 396 int
 397 blobmsg_add_field(struct blob_buf *buf, int type, const char *name,
 398                   const void *data, unsigned int len)
 399 {
 400         struct blob_attr *attr;
 401         void *data_dest;
 402
 403         attr = blobmsg_new(buf, type, name, len, &data_dest);
 404         if (!attr)
 405                 return -1;
 406
 407         if (len > 0)
 408                 memcpy(data_dest, data, len);
 409
 410         return 0;
 411 }