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 static uint16_t
  29 blobmsg_namelen(const struct blobmsg_hdr *hdr)
  30 {
  31         return be16_to_cpu(hdr->namelen);
  32 }
  33
  34 bool blobmsg_check_attr(const struct blob_attr *attr, bool name)
  35 {
  36         const struct blobmsg_hdr *hdr;
  37         const char *data;
  38         int id, len;
  39
  40         if (blob_len(attr) < sizeof(struct blobmsg_hdr))
  41                 return false;
  42
  43         hdr = (void *) attr->data;
  44         if (!hdr->namelen && name)
  45                 return false;
  46
  47         if (blobmsg_namelen(hdr) > blob_len(attr) - sizeof(struct blobmsg_hdr))
  48                 return false;
  49
  50         if (hdr->name[blobmsg_namelen(hdr)] != 0)
  51                 return false;
  52
  53         id = blob_id(attr);
  54         len = blobmsg_data_len(attr);
  55         data = blobmsg_data(attr);
  56
  57         if (id > BLOBMSG_TYPE_LAST)
  58                 return false;
  59
  60         if (!blob_type[id])
  61                 return true;
  62
  63         return blob_check_type(data, len, blob_type[id]);
  64 }
  65
  66 int blobmsg_check_array(const struct blob_attr *attr, int type)
  67 {
  68         struct blob_attr *cur;
  69         bool name;
  70         int rem;
  71         int size = 0;
  72
  73         switch (blobmsg_type(attr)) {
  74         case BLOBMSG_TYPE_TABLE:
  75                 name = true;
  76                 break;
  77         case BLOBMSG_TYPE_ARRAY:
  78                 name = false;
  79                 break;
  80         default:
  81                 return -1;
  82         }
  83
  84         blobmsg_for_each_attr(cur, attr, rem) {
  85                 if (type != BLOBMSG_TYPE_UNSPEC && blobmsg_type(cur) != type)
  86                         return -1;
  87
  88                 if (!blobmsg_check_attr(cur, name))
  89                         return -1;
  90
  91                 size++;
  92         }
  93
  94         return size;
  95 }
  96
  97 bool blobmsg_check_attr_list(const struct blob_attr *attr, int type)
  98 {
  99         return blobmsg_check_array(attr, type) >= 0;
 100 }
 101
 102 int blobmsg_parse_array(const struct blobmsg_policy *policy, int policy_len,
 103                         struct blob_attr **tb, void *data, unsigned int len)
 104 {
 105         struct blob_attr *attr;
 106         int i = 0;
 107
 108         memset(tb, 0, policy_len * sizeof(*tb));
 109         __blob_for_each_attr(attr, data, len) {
 110                 if (policy[i].type != BLOBMSG_TYPE_UNSPEC &&
 111                     blob_id(attr) != policy[i].type)
 112                         continue;
 113
 114                 if (!blobmsg_check_attr(attr, false))
 115                         return -1;
 116
 117                 if (tb[i])
 118                         continue;
 119
 120                 tb[i++] = attr;
 121                 if (i == policy_len)
 122                         break;
 123         }
 124
 125         return 0;
 126 }
 127
 128
 129 int blobmsg_parse(const struct blobmsg_policy *policy, int policy_len,
 130                   struct blob_attr **tb, void *data, unsigned int len)
 131 {
 132         struct blobmsg_hdr *hdr;
 133         struct blob_attr *attr;
 134         uint8_t *pslen;
 135         int i;
 136
 137         memset(tb, 0, policy_len * sizeof(*tb));
 138         if (!data || !len)
 139                 return -EINVAL;
 140         pslen = alloca(policy_len);
 141         for (i = 0; i < policy_len; i++) {
 142                 if (!policy[i].name)
 143                         continue;
 144
 145                 pslen[i] = strlen(policy[i].name);
 146         }
 147
 148         __blob_for_each_attr(attr, data, len) {
 149                 hdr = blob_data(attr);
 150                 for (i = 0; i < policy_len; i++) {
 151                         if (!policy[i].name)
 152                                 continue;
 153
 154                         if (policy[i].type != BLOBMSG_TYPE_UNSPEC &&
 155                             blob_id(attr) != policy[i].type)
 156                                 continue;
 157
 158                         if (blobmsg_namelen(hdr) != pslen[i])
 159                                 continue;
 160
 161                         if (!blobmsg_check_attr(attr, true))
 162                                 return -1;
 163
 164                         if (tb[i])
 165                                 continue;
 166
 167                         if (strcmp(policy[i].name, (char *) hdr->name) != 0)
 168                                 continue;
 169
 170                         tb[i] = attr;
 171                 }
 172         }
 173
 174         return 0;
 175 }
 176
 177
 178 static struct blob_attr *
 179 blobmsg_new(struct blob_buf *buf, int type, const char *name, int payload_len, void **data)
 180 {
 181         struct blob_attr *attr;
 182         struct blobmsg_hdr *hdr;
 183         int attrlen, namelen;
 184         char *pad_start, *pad_end;
 185
 186         if (!name)
 187                 name = "";
 188
 189         namelen = strlen(name);
 190         attrlen = blobmsg_hdrlen(namelen) + payload_len;
 191         attr = blob_new(buf, type, attrlen);
 192         if (!attr)
 193                 return NULL;
 194
 195         attr->id_len |= be32_to_cpu(BLOB_ATTR_EXTENDED);
 196         hdr = blob_data(attr);
 197         hdr->namelen = cpu_to_be16(namelen);
 198         strcpy((char *) hdr->name, (const char *)name);
 199         pad_end = *data = blobmsg_data(attr);
 200         pad_start = (char *) &hdr->name[namelen];
 201         if (pad_start < pad_end)
 202                 memset(pad_start, 0, pad_end - pad_start);
 203
 204         return attr;
 205 }
 206
 207 static inline int
 208 attr_to_offset(struct blob_buf *buf, struct blob_attr *attr)
 209 {
 210         return (char *)attr - (char *) buf->buf + BLOB_COOKIE;
 211 }
 212
 213
 214 void *
 215 blobmsg_open_nested(struct blob_buf *buf, const char *name, bool array)
 216 {
 217         struct blob_attr *head;
 218         int type = array ? BLOBMSG_TYPE_ARRAY : BLOBMSG_TYPE_TABLE;
 219         unsigned long offset = attr_to_offset(buf, buf->head);
 220         void *data;
 221
 222         if (!name)
 223                 name = "";
 224
 225         head = blobmsg_new(buf, type, name, 0, &data);
 226         if (!head)
 227                 return NULL;
 228         blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blobmsg_hdrlen(strlen(name)));
 229         buf->head = head;
 230         return (void *)offset;
 231 }
 232
 233 int
 234 blobmsg_vprintf(struct blob_buf *buf, const char *name, const char *format, va_list arg)
 235 {
 236         va_list arg2;
 237         char cbuf;
 238         char *sbuf;
 239         int len, ret;
 240
 241         va_copy(arg2, arg);
 242         len = vsnprintf(&cbuf, sizeof(cbuf), format, arg2);
 243         va_end(arg2);
 244
 245         sbuf = blobmsg_alloc_string_buffer(buf, name, len + 1);
 246         if (!sbuf)
 247                 return -1;
 248         ret = vsprintf(sbuf, format, arg);
 249         blobmsg_add_string_buffer(buf);
 250
 251         return ret;
 252 }
 253
 254 int
 255 blobmsg_printf(struct blob_buf *buf, const char *name, const char *format, ...)
 256 {
 257         va_list ap;
 258         int ret;
 259
 260         va_start(ap, format);
 261         ret = blobmsg_vprintf(buf, name, format, ap);
 262         va_end(ap);
 263
 264         return ret;
 265 }
 266
 267 void *
 268 blobmsg_alloc_string_buffer(struct blob_buf *buf, const char *name, unsigned int maxlen)
 269 {
 270         struct blob_attr *attr;
 271         void *data_dest;
 272
 273         attr = blobmsg_new(buf, BLOBMSG_TYPE_STRING, name, maxlen, &data_dest);
 274         if (!attr)
 275                 return NULL;
 276
 277         blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blob_pad_len(attr));
 278         blob_set_raw_len(attr, blob_raw_len(attr) - maxlen);
 279
 280         return data_dest;
 281 }
 282
 283 void *
 284 blobmsg_realloc_string_buffer(struct blob_buf *buf, unsigned int maxlen)
 285 {
 286         struct blob_attr *attr = blob_next(buf->head);
 287         int offset = attr_to_offset(buf, blob_next(buf->head)) + blob_pad_len(attr) - BLOB_COOKIE;
 288         int required = maxlen - (buf->buflen - offset);
 289
 290         if (required <= 0)
 291                 goto out;
 292
 293         if (!blob_buf_grow(buf, required))
 294                 return NULL;
 295         attr = blob_next(buf->head);
 296
 297 out:
 298         return blobmsg_data(attr);
 299 }
 300
 301 void
 302 blobmsg_add_string_buffer(struct blob_buf *buf)
 303 {
 304         struct blob_attr *attr;
 305         int len, attrlen;
 306
 307         attr = blob_next(buf->head);
 308         len = strlen(blobmsg_data(attr)) + 1;
 309
 310         attrlen = blob_raw_len(attr) + len;
 311         blob_set_raw_len(attr, attrlen);
 312         blob_fill_pad(attr);
 313
 314         blob_set_raw_len(buf->head, blob_raw_len(buf->head) + blob_pad_len(attr));
 315 }
 316
 317 int
 318 blobmsg_add_field(struct blob_buf *buf, int type, const char *name,
 319                   const void *data, unsigned int len)
 320 {
 321         struct blob_attr *attr;
 322         void *data_dest;
 323
 324         attr = blobmsg_new(buf, type, name, len, &data_dest);
 325         if (!attr)
 326                 return -1;
 327
 328         if (len > 0)
 329                 memcpy(data_dest, data, len);
 330
 331         return 0;
 332 }