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         const struct blobmsg_hdr *hdr;
  52         uint16_t namelen;
  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         namelen = blobmsg_namelen(hdr);
  62         if (blob_len(attr) < (size_t)blobmsg_hdrlen(namelen))
  63                 return false;
  64
  65         if (hdr->name[namelen] != 0)
  66                 return false;
  67
  68         return true;
  69 }
  70
  71 static const char* blobmsg_check_data(const struct blob_attr *attr, size_t len, size_t *data_len)
  72 {
  73         char *limit = (char *) attr + len;
  74         const char *data;
  75
  76         *data_len = blobmsg_data_len(attr);
  77         if (*data_len > blob_raw_len(attr))
  78                 return NULL;
  79
  80         data = blobmsg_data(attr);
  81         if (data + *data_len > limit)
  82                 return NULL;
  83
  84         return data;
  85 }
  86
  87 bool blobmsg_check_attr_len(const struct blob_attr *attr, bool name, size_t len)
  88 {
  89         const char *data;
  90         size_t data_len;
  91         int id;
  92
  93         if (!blobmsg_check_name(attr, len, name))
  94                 return false;
  95
  96         id = blob_id(attr);
  97         if (id > BLOBMSG_TYPE_LAST)
  98                 return false;
  99
 100         if (!blob_type[id])
 101                 return true;
 102
 103         data = blobmsg_check_data(attr, len, &data_len);
 104         if (!data)
 105                 return false;
 106
 107         return blob_check_type(data, data_len, blob_type[id]);
 108 }
 109
 110 int blobmsg_check_array(const struct blob_attr *attr, int type)
 111 {
 112         return blobmsg_check_array_len(attr, type, blob_raw_len(attr));
 113 }
 114
 115 int blobmsg_check_array_len(const struct blob_attr *attr, int type,
 116                             size_t blob_len)
 117 {
 118         struct blob_attr *cur;
 119         size_t rem;
 120         bool name;
 121         int size = 0;
 122
 123         if (type > BLOBMSG_TYPE_LAST)
 124                 return -1;
 125
 126         if (!blobmsg_check_attr_len(attr, false, blob_len))
 127                 return -1;
 128
 129         switch (blobmsg_type(attr)) {
 130         case BLOBMSG_TYPE_TABLE:
 131                 name = true;
 132                 break;
 133         case BLOBMSG_TYPE_ARRAY:
 134                 name = false;
 135                 break;
 136         default:
 137                 return -1;
 138         }
 139
 140         blobmsg_for_each_attr(cur, attr, rem) {
 141                 if (type != BLOBMSG_TYPE_UNSPEC && blobmsg_type(cur) != type)
 142                         return -1;
 143
 144                 if (!blobmsg_check_attr_len(cur, name, rem))
 145                         return -1;
 146
 147                 size++;
 148         }
 149
 150         return size;
 151 }
 152
 153 bool blobmsg_check_attr_list(const struct blob_attr *attr, int type)
 154 {
 155         return blobmsg_check_array(attr, type) >= 0;
 156 }
 157
 158 bool blobmsg_check_attr_list_len(const struct blob_attr *attr, int type, size_t len)
 159 {
 160         return blobmsg_check_array_len(attr, type, len) >= 0;
 161 }
 162
 163 int blobmsg_parse_array(const struct blobmsg_policy *policy, int policy_len,
 164                         struct blob_attr **tb, void *data, unsigned int len)
 165 {
 166         struct blob_attr *attr;
 167         int i = 0;
 168
 169         memset(tb, 0, policy_len * sizeof(*tb));
 170         __blob_for_each_attr(attr, data, len) {
 171                 if (policy[i].type != BLOBMSG_TYPE_UNSPEC &&
 172                     blob_id(attr) != policy[i].type)
 173                         continue;
 174
 175                 if (!blobmsg_check_attr_len(attr, false, len))
 176                         return -1;
 177
 178                 if (tb[i])
 179                         continue;
 180
 181                 tb[i++] = attr;
 182                 if (i == policy_len)
 183                         break;
 184         }
 185
 186         return 0;
 187 }
 188
 189 int blobmsg_parse(const struct blobmsg_policy *policy, int policy_len,
 190                   struct blob_attr **tb, void *data, unsigned int len)
 191 {
 192         const struct blobmsg_hdr *hdr;
 193         struct blob_attr *attr;
 194         uint8_t *pslen;
 195         int i;
 196
 197         memset(tb, 0, policy_len * sizeof(*tb));
 198         if (!data || !len)
 199                 return -EINVAL;
 200         pslen = alloca(policy_len);
 201         for (i = 0; i < policy_len; i++) {
 202                 if (!policy[i].name)
 203                         continue;
 204
 205                 pslen[i] = strlen(policy[i].name);
 206         }
 207
 208         __blob_for_each_attr(attr, data, len) {
 209                 hdr = blobmsg_hdr_from_blob(attr, len);
 210                 if (!hdr)
 211                         return -1;
 212
 213                 if (!blobmsg_hdr_valid_namelen(hdr, len))
 214                         return -1;
 215
 216                 for (i = 0; i < policy_len; i++) {
 217                         if (!policy[i].name)
 218                                 continue;
 219
 220                         if (policy[i].type != BLOBMSG_TYPE_UNSPEC &&
 221                             blob_id(attr) != policy[i].type)
 222                                 continue;
 223
 224                         if (blobmsg_namelen(hdr) != pslen[i])
 225                                 continue;
 226
 227                         if (!blobmsg_check_attr_len(attr, true, len))
 228                                 return -1;
 229
 230                         if (tb[i])
 231                                 continue;
 232
 233                         if (strcmp(policy[i].name, (char *) hdr->name) != 0)
 234                                 continue;
 235
 236                         tb[i] = attr;
 237                 }
 238         }
 239
 240         return 0;
 241 }
 242
 243
 244 static struct blob_attr *
 245 blobmsg_new(struct blob_buf *buf, int type, const char *name, int payload_len, void **data)
 246 {
 247         struct blob_attr *attr;
 248         struct blobmsg_hdr *hdr;
 249         int attrlen, namelen;
 250         char *pad_start, *pad_end;
 251
 252         if (!name)
 253                 name = "";
 254
 255         namelen = strlen(name);
 256         attrlen = blobmsg_hdrlen(namelen) + payload_len;
 257         attr = blob_new(buf, type, attrlen);
 258         if (!attr)
 259                 return NULL;
 260
 261         attr->id_len |= be32_to_cpu(BLOB_ATTR_EXTENDED);
 262         hdr = blob_data(attr);
 263         hdr->namelen = cpu_to_be16(namelen);
 264
 265         memcpy(hdr->name, name, namelen);
 266         hdr->name[namelen] = '\0';
 267
 268         pad_end = *data = blobmsg_data(attr);
 269         pad_start = (char *) &hdr->name[namelen];
 270         if (pad_start < pad_end)
 271                 memset(pad_start, 0, pad_end - pad_start);
 272
 273         return attr;
 274 }
 275
 276 static inline int
 277 attr_to_offset(struct blob_buf *buf, struct blob_attr *attr)
 278 {
 279         return (char *)attr - (char *) buf->buf + BLOB_COOKIE;
 280 }
 281
 282
 283 void *
 284 blobmsg_open_nested(struct blob_buf *buf, const char *name, bool array)
 285 {
 286         struct blob_attr *head;
 287         int type = array ? BLOBMSG_TYPE_ARRAY : BLOBMSG_TYPE_TABLE;
 288         unsigned long offset = attr_to_offset(buf, buf->head);
 289         void *data;
 290
 291         if (!name)
 292                 name = "";
 293
 294         head = blobmsg_new(buf, type, name, 0, &data);
 295         if (!head)
 296                 return NULL;
 297         blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blobmsg_hdrlen(strlen(name)));
 298         buf->head = head;
 299         return (void *)offset;
 300 }
 301
 302 __attribute__((format(printf, 3, 0)))
 303 int blobmsg_vprintf(struct blob_buf *buf, const char *name, const char *format, va_list arg)
 304 {
 305         va_list arg2;
 306         char cbuf;
 307         char *sbuf;
 308         int len, ret;
 309
 310         va_copy(arg2, arg);
 311         len = vsnprintf(&cbuf, sizeof(cbuf), format, arg2);
 312         va_end(arg2);
 313
 314         if (len < 0)
 315                 return -1;
 316
 317         sbuf = blobmsg_alloc_string_buffer(buf, name, len + 1);
 318         if (!sbuf)
 319                 return -1;
 320
 321         ret = vsnprintf(sbuf, len + 1, format, arg);
 322         if (ret < 0)
 323                 return -1;
 324
 325         blobmsg_add_string_buffer(buf);
 326
 327         return ret;
 328 }
 329
 330 __attribute__((format(printf, 3, 4)))
 331 int blobmsg_printf(struct blob_buf *buf, const char *name, const char *format, ...)
 332 {
 333         va_list ap;
 334         int ret;
 335
 336         va_start(ap, format);
 337         ret = blobmsg_vprintf(buf, name, format, ap);
 338         va_end(ap);
 339
 340         return ret;
 341 }
 342
 343 void *
 344 blobmsg_alloc_string_buffer(struct blob_buf *buf, const char *name, unsigned int maxlen)
 345 {
 346         struct blob_attr *attr;
 347         void *data_dest;
 348
 349         attr = blobmsg_new(buf, BLOBMSG_TYPE_STRING, name, maxlen, &data_dest);
 350         if (!attr)
 351                 return NULL;
 352
 353         blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blob_pad_len(attr));
 354         blob_set_raw_len(attr, blob_raw_len(attr) - maxlen);
 355
 356         return data_dest;
 357 }
 358
 359 void *
 360 blobmsg_realloc_string_buffer(struct blob_buf *buf, unsigned int maxlen)
 361 {
 362         struct blob_attr *attr = blob_next(buf->head);
 363         int offset = attr_to_offset(buf, blob_next(buf->head)) + blob_pad_len(attr) - BLOB_COOKIE;
 364         int required = maxlen - (buf->buflen - offset);
 365
 366         if (required <= 0)
 367                 goto out;
 368
 369         if (!blob_buf_grow(buf, required))
 370                 return NULL;
 371         attr = blob_next(buf->head);
 372
 373 out:
 374         return blobmsg_data(attr);
 375 }
 376
 377 void
 378 blobmsg_add_string_buffer(struct blob_buf *buf)
 379 {
 380         struct blob_attr *attr;
 381         int len, attrlen;
 382
 383         attr = blob_next(buf->head);
 384         len = strlen(blobmsg_data(attr)) + 1;
 385
 386         attrlen = blob_raw_len(attr) + len;
 387         blob_set_raw_len(attr, attrlen);
 388         blob_fill_pad(attr);
 389
 390         blob_set_raw_len(buf->head, blob_raw_len(buf->head) + blob_pad_len(attr));
 391 }
 392
 393 int
 394 blobmsg_add_field(struct blob_buf *buf, int type, const char *name,
 395                   const void *data, unsigned int len)
 396 {
 397         struct blob_attr *attr;
 398         void *data_dest;
 399
 400         attr = blobmsg_new(buf, type, name, len, &data_dest);
 401         if (!attr)
 402                 return -1;
 403
 404         if (len > 0)
 405                 memcpy(data_dest, data, len);
 406
 407         return 0;
 408 }