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 bool blobmsg_check_name(const struct blob_attr *attr, bool name)
  34 {
  35         const struct blobmsg_hdr *hdr;
  36         uint16_t namelen;
  37
  38         if (!blob_is_extended(attr))
  39                 return !name;
  40
  41         if (blob_len(attr) < sizeof(struct blobmsg_hdr))
  42                 return false;
  43
  44         hdr = (const struct blobmsg_hdr *)blob_data(attr);
  45         if (name && !hdr->namelen)
  46                 return false;
  47
  48         namelen = blobmsg_namelen(hdr);
  49         if (blob_len(attr) < (size_t)blobmsg_hdrlen(namelen))
  50                 return false;
  51
  52         if (hdr->name[namelen] != 0)
  53                 return false;
  54
  55         return true;
  56 }
  57
  58 bool blobmsg_check_attr_len(const struct blob_attr *attr, bool name, size_t len)
  59 {
  60         const char *data;
  61         size_t data_len;
  62         int id;
  63
  64         if (len < sizeof(struct blob_attr))
  65                 return false;
  66
  67         data_len = blob_raw_len(attr);
  68         if (data_len < sizeof(struct blob_attr) || data_len > len)
  69                 return false;
  70
  71         if (!blobmsg_check_name(attr, name))
  72                 return false;
  73
  74         id = blob_id(attr);
  75         if (id > BLOBMSG_TYPE_LAST)
  76                 return false;
  77
  78         if (!blob_type[id])
  79                 return true;
  80
  81         data = blobmsg_data(attr);
  82         data_len = blobmsg_data_len(attr);
  83
  84         return blob_check_type(data, data_len, blob_type[id]);
  85 }
  86
  87 int blobmsg_check_array(const struct blob_attr *attr, int type)
  88 {
  89         return blobmsg_check_array_len(attr, type, blob_raw_len(attr));
  90 }
  91
  92 int blobmsg_check_array_len(const struct blob_attr *attr, int type,
  93                             size_t blob_len)
  94 {
  95         struct blob_attr *cur;
  96         size_t rem;
  97         bool name;
  98         int size = 0;
  99
 100         if (type > BLOBMSG_TYPE_LAST)
 101                 return -1;
 102
 103         if (!blobmsg_check_attr_len(attr, false, blob_len))
 104                 return -1;
 105
 106         switch (blobmsg_type(attr)) {
 107         case BLOBMSG_TYPE_TABLE:
 108                 name = true;
 109                 break;
 110         case BLOBMSG_TYPE_ARRAY:
 111                 name = false;
 112                 break;
 113         default:
 114                 return -1;
 115         }
 116
 117         blobmsg_for_each_attr(cur, attr, rem) {
 118                 if (type != BLOBMSG_TYPE_UNSPEC && blobmsg_type(cur) != type)
 119                         return -1;
 120
 121                 if (!blobmsg_check_attr_len(cur, name, rem))
 122                         return -1;
 123
 124                 size++;
 125         }
 126
 127         return size;
 128 }
 129
 130 bool blobmsg_check_attr_list(const struct blob_attr *attr, int type)
 131 {
 132         return blobmsg_check_array(attr, type) >= 0;
 133 }
 134
 135 bool blobmsg_check_attr_list_len(const struct blob_attr *attr, int type, size_t len)
 136 {
 137         return blobmsg_check_array_len(attr, type, len) >= 0;
 138 }
 139
 140 int blobmsg_parse_array(const struct blobmsg_policy *policy, int policy_len,
 141                         struct blob_attr **tb, void *data, unsigned int len)
 142 {
 143         struct blob_attr *attr;
 144         int i = 0;
 145
 146         memset(tb, 0, policy_len * sizeof(*tb));
 147         __blob_for_each_attr(attr, data, len) {
 148                 if (policy[i].type != BLOBMSG_TYPE_UNSPEC &&
 149                     blob_id(attr) != policy[i].type)
 150                         continue;
 151
 152                 if (!blobmsg_check_attr_len(attr, false, len))
 153                         return -1;
 154
 155                 if (tb[i])
 156                         continue;
 157
 158                 tb[i++] = attr;
 159                 if (i == policy_len)
 160                         break;
 161         }
 162
 163         return 0;
 164 }
 165
 166 int blobmsg_parse(const struct blobmsg_policy *policy, int policy_len,
 167                   struct blob_attr **tb, void *data, unsigned int len)
 168 {
 169         const struct blobmsg_hdr *hdr;
 170         struct blob_attr *attr;
 171         uint8_t *pslen;
 172         int i;
 173
 174         memset(tb, 0, policy_len * sizeof(*tb));
 175         if (!data || !len)
 176                 return -EINVAL;
 177         pslen = alloca(policy_len);
 178         for (i = 0; i < policy_len; i++) {
 179                 if (!policy[i].name)
 180                         continue;
 181
 182                 pslen[i] = strlen(policy[i].name);
 183         }
 184
 185         __blob_for_each_attr(attr, data, len) {
 186                 if (!blobmsg_check_attr_len(attr, false, len))
 187                         return -1;
 188
 189                 if (!blob_is_extended(attr))
 190                         continue;
 191
 192                 hdr = blob_data(attr);
 193                 for (i = 0; i < policy_len; i++) {
 194                         if (!policy[i].name)
 195                                 continue;
 196
 197                         if (policy[i].type != BLOBMSG_TYPE_UNSPEC &&
 198                             policy[i].type != BLOBMSG_CAST_INT64 &&
 199                             blob_id(attr) != policy[i].type)
 200                                 continue;
 201
 202                         if (policy[i].type == BLOBMSG_CAST_INT64 &&
 203                             (blob_id(attr) != BLOBMSG_TYPE_INT64 &&
 204                              blob_id(attr) != BLOBMSG_TYPE_INT32 &&
 205                              blob_id(attr) != BLOBMSG_TYPE_INT16 &&
 206                              blob_id(attr) != BLOBMSG_TYPE_INT8))
 207                                 continue;
 208
 209                         if (blobmsg_namelen(hdr) != pslen[i])
 210                                 continue;
 211
 212                         if (tb[i])
 213                                 continue;
 214
 215                         if (strcmp(policy[i].name, (char *) hdr->name) != 0)
 216                                 continue;
 217
 218                         tb[i] = attr;
 219                 }
 220         }
 221
 222         return 0;
 223 }
 224
 225
 226 static struct blob_attr *
 227 blobmsg_new(struct blob_buf *buf, int type, const char *name, int payload_len, void **data)
 228 {
 229         struct blob_attr *attr;
 230         struct blobmsg_hdr *hdr;
 231         int attrlen, namelen;
 232         char *pad_start, *pad_end;
 233
 234         if (!name)
 235                 name = "";
 236
 237         namelen = strlen(name);
 238         attrlen = blobmsg_hdrlen(namelen) + payload_len;
 239         attr = blob_new(buf, type, attrlen);
 240         if (!attr)
 241                 return NULL;
 242
 243         attr->id_len |= be32_to_cpu(BLOB_ATTR_EXTENDED);
 244         hdr = blob_data(attr);
 245         hdr->namelen = cpu_to_be16(namelen);
 246
 247         memcpy(hdr->name, name, namelen);
 248         hdr->name[namelen] = '\0';
 249
 250         pad_end = *data = blobmsg_data(attr);
 251         pad_start = (char *) &hdr->name[namelen];
 252         if (pad_start < pad_end)
 253                 memset(pad_start, 0, pad_end - pad_start);
 254
 255         return attr;
 256 }
 257
 258 static inline int
 259 attr_to_offset(struct blob_buf *buf, struct blob_attr *attr)
 260 {
 261         return (char *)attr - (char *) buf->buf + BLOB_COOKIE;
 262 }
 263
 264
 265 void *
 266 blobmsg_open_nested(struct blob_buf *buf, const char *name, bool array)
 267 {
 268         struct blob_attr *head;
 269         int type = array ? BLOBMSG_TYPE_ARRAY : BLOBMSG_TYPE_TABLE;
 270         unsigned long offset = attr_to_offset(buf, buf->head);
 271         void *data;
 272
 273         if (!name)
 274                 name = "";
 275
 276         head = blobmsg_new(buf, type, name, 0, &data);
 277         if (!head)
 278                 return NULL;
 279         blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blobmsg_hdrlen(strlen(name)));
 280         buf->head = head;
 281         return (void *)offset;
 282 }
 283
 284 __attribute__((format(printf, 3, 0)))
 285 int blobmsg_vprintf(struct blob_buf *buf, const char *name, const char *format, va_list arg)
 286 {
 287         va_list arg2;
 288         char cbuf;
 289         char *sbuf;
 290         int len, ret;
 291
 292         va_copy(arg2, arg);
 293         len = vsnprintf(&cbuf, sizeof(cbuf), format, arg2);
 294         va_end(arg2);
 295
 296         if (len < 0)
 297                 return -1;
 298
 299         sbuf = blobmsg_alloc_string_buffer(buf, name, len);
 300         if (!sbuf)
 301                 return -1;
 302
 303         ret = vsnprintf(sbuf, len + 1, format, arg);
 304         if (ret < 0)
 305                 return -1;
 306
 307         blobmsg_add_string_buffer(buf);
 308
 309         return ret;
 310 }
 311
 312 __attribute__((format(printf, 3, 4)))
 313 int blobmsg_printf(struct blob_buf *buf, const char *name, const char *format, ...)
 314 {
 315         va_list ap;
 316         int ret;
 317
 318         va_start(ap, format);
 319         ret = blobmsg_vprintf(buf, name, format, ap);
 320         va_end(ap);
 321
 322         return ret;
 323 }
 324
 325 void *
 326 blobmsg_alloc_string_buffer(struct blob_buf *buf, const char *name, unsigned int maxlen)
 327 {
 328         struct blob_attr *attr;
 329         void *data_dest;
 330
 331         maxlen++;
 332         attr = blobmsg_new(buf, BLOBMSG_TYPE_STRING, name, maxlen, &data_dest);
 333         if (!attr)
 334                 return NULL;
 335
 336         blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blob_pad_len(attr));
 337         blob_set_raw_len(attr, blob_raw_len(attr) - maxlen);
 338
 339         return data_dest;
 340 }
 341
 342 void *
 343 blobmsg_realloc_string_buffer(struct blob_buf *buf, unsigned int maxlen)
 344 {
 345         struct blob_attr *attr = blob_next(buf->head);
 346         int offset = attr_to_offset(buf, blob_next(buf->head)) + blob_pad_len(attr) - BLOB_COOKIE;
 347         int required = maxlen + 1 - (buf->buflen - offset);
 348
 349         if (required <= 0)
 350                 goto out;
 351
 352         if (!blob_buf_grow(buf, required))
 353                 return NULL;
 354         attr = blob_next(buf->head);
 355
 356 out:
 357         return blobmsg_data(attr);
 358 }
 359
 360 void
 361 blobmsg_add_string_buffer(struct blob_buf *buf)
 362 {
 363         struct blob_attr *attr;
 364         int len, attrlen;
 365
 366         attr = blob_next(buf->head);
 367         len = strlen(blobmsg_data(attr)) + 1;
 368
 369         attrlen = blob_raw_len(attr) + len;
 370         blob_set_raw_len(attr, attrlen);
 371         blob_fill_pad(attr);
 372
 373         blob_set_raw_len(buf->head, blob_raw_len(buf->head) + blob_pad_len(attr));
 374 }
 375
 376 int
 377 blobmsg_add_field(struct blob_buf *buf, int type, const char *name,
 378                   const void *data, unsigned int len)
 379 {
 380         struct blob_attr *attr;
 381         void *data_dest;
 382
 383         attr = blobmsg_new(buf, type, name, len, &data_dest);
 384         if (!attr)
 385                 return -1;
 386
 387         if (len > 0)
 388                 memcpy(data_dest, data, len);
 389
 390         return 0;
 391 }