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                             blob_id(attr) != policy[i].type)
 199                                 continue;
 200
 201                         if (blobmsg_namelen(hdr) != pslen[i])
 202                                 continue;
 203
 204                         if (tb[i])
 205                                 continue;
 206
 207                         if (strcmp(policy[i].name, (char *) hdr->name) != 0)
 208                                 continue;
 209
 210                         tb[i] = attr;
 211                 }
 212         }
 213
 214         return 0;
 215 }
 216
 217
 218 static struct blob_attr *
 219 blobmsg_new(struct blob_buf *buf, int type, const char *name, int payload_len, void **data)
 220 {
 221         struct blob_attr *attr;
 222         struct blobmsg_hdr *hdr;
 223         int attrlen, namelen;
 224         char *pad_start, *pad_end;
 225
 226         if (!name)
 227                 name = "";
 228
 229         namelen = strlen(name);
 230         attrlen = blobmsg_hdrlen(namelen) + payload_len;
 231         attr = blob_new(buf, type, attrlen);
 232         if (!attr)
 233                 return NULL;
 234
 235         attr->id_len |= be32_to_cpu(BLOB_ATTR_EXTENDED);
 236         hdr = blob_data(attr);
 237         hdr->namelen = cpu_to_be16(namelen);
 238
 239         memcpy(hdr->name, name, namelen);
 240         hdr->name[namelen] = '\0';
 241
 242         pad_end = *data = blobmsg_data(attr);
 243         pad_start = (char *) &hdr->name[namelen];
 244         if (pad_start < pad_end)
 245                 memset(pad_start, 0, pad_end - pad_start);
 246
 247         return attr;
 248 }
 249
 250 static inline int
 251 attr_to_offset(struct blob_buf *buf, struct blob_attr *attr)
 252 {
 253         return (char *)attr - (char *) buf->buf + BLOB_COOKIE;
 254 }
 255
 256
 257 void *
 258 blobmsg_open_nested(struct blob_buf *buf, const char *name, bool array)
 259 {
 260         struct blob_attr *head;
 261         int type = array ? BLOBMSG_TYPE_ARRAY : BLOBMSG_TYPE_TABLE;
 262         unsigned long offset = attr_to_offset(buf, buf->head);
 263         void *data;
 264
 265         if (!name)
 266                 name = "";
 267
 268         head = blobmsg_new(buf, type, name, 0, &data);
 269         if (!head)
 270                 return NULL;
 271         blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blobmsg_hdrlen(strlen(name)));
 272         buf->head = head;
 273         return (void *)offset;
 274 }
 275
 276 __attribute__((format(printf, 3, 0)))
 277 int blobmsg_vprintf(struct blob_buf *buf, const char *name, const char *format, va_list arg)
 278 {
 279         va_list arg2;
 280         char cbuf;
 281         char *sbuf;
 282         int len, ret;
 283
 284         va_copy(arg2, arg);
 285         len = vsnprintf(&cbuf, sizeof(cbuf), format, arg2);
 286         va_end(arg2);
 287
 288         if (len < 0)
 289                 return -1;
 290
 291         sbuf = blobmsg_alloc_string_buffer(buf, name, len + 1);
 292         if (!sbuf)
 293                 return -1;
 294
 295         ret = vsnprintf(sbuf, len + 1, format, arg);
 296         if (ret < 0)
 297                 return -1;
 298
 299         blobmsg_add_string_buffer(buf);
 300
 301         return ret;
 302 }
 303
 304 __attribute__((format(printf, 3, 4)))
 305 int blobmsg_printf(struct blob_buf *buf, const char *name, const char *format, ...)
 306 {
 307         va_list ap;
 308         int ret;
 309
 310         va_start(ap, format);
 311         ret = blobmsg_vprintf(buf, name, format, ap);
 312         va_end(ap);
 313
 314         return ret;
 315 }
 316
 317 void *
 318 blobmsg_alloc_string_buffer(struct blob_buf *buf, const char *name, unsigned int maxlen)
 319 {
 320         struct blob_attr *attr;
 321         void *data_dest;
 322
 323         attr = blobmsg_new(buf, BLOBMSG_TYPE_STRING, name, maxlen, &data_dest);
 324         if (!attr)
 325                 return NULL;
 326
 327         blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blob_pad_len(attr));
 328         blob_set_raw_len(attr, blob_raw_len(attr) - maxlen);
 329
 330         return data_dest;
 331 }
 332
 333 void *
 334 blobmsg_realloc_string_buffer(struct blob_buf *buf, unsigned int maxlen)
 335 {
 336         struct blob_attr *attr = blob_next(buf->head);
 337         int offset = attr_to_offset(buf, blob_next(buf->head)) + blob_pad_len(attr) - BLOB_COOKIE;
 338         int required = maxlen - (buf->buflen - offset);
 339
 340         if (required <= 0)
 341                 goto out;
 342
 343         if (!blob_buf_grow(buf, required))
 344                 return NULL;
 345         attr = blob_next(buf->head);
 346
 347 out:
 348         return blobmsg_data(attr);
 349 }
 350
 351 void
 352 blobmsg_add_string_buffer(struct blob_buf *buf)
 353 {
 354         struct blob_attr *attr;
 355         int len, attrlen;
 356
 357         attr = blob_next(buf->head);
 358         len = strlen(blobmsg_data(attr)) + 1;
 359
 360         attrlen = blob_raw_len(attr) + len;
 361         blob_set_raw_len(attr, attrlen);
 362         blob_fill_pad(attr);
 363
 364         blob_set_raw_len(buf->head, blob_raw_len(buf->head) + blob_pad_len(attr));
 365 }
 366
 367 int
 368 blobmsg_add_field(struct blob_buf *buf, int type, const char *name,
 369                   const void *data, unsigned int len)
 370 {
 371         struct blob_attr *attr;
 372         void *data_dest;
 373
 374         attr = blobmsg_new(buf, type, name, len, &data_dest);
 375         if (!attr)
 376                 return -1;
 377
 378         if (len > 0)
 379                 memcpy(data_dest, data, len);
 380
 381         return 0;
 382 }