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