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         pslen = alloca(policy_len);
 139         for (i = 0; i < policy_len; i++) {
 140                 if (!policy[i].name)
 141                         continue;
 142
 143                 pslen[i] = strlen(policy[i].name);
 144         }
 145
 146         __blob_for_each_attr(attr, data, len) {
 147                 hdr = blob_data(attr);
 148                 for (i = 0; i < policy_len; i++) {
 149                         if (!policy[i].name)
 150                                 continue;
 151
 152                         if (policy[i].type != BLOBMSG_TYPE_UNSPEC &&
 153                             blob_id(attr) != policy[i].type)
 154                                 continue;
 155
 156                         if (blobmsg_namelen(hdr) != pslen[i])
 157                                 continue;
 158
 159                         if (!blobmsg_check_attr(attr, true))
 160                                 return -1;
 161
 162                         if (tb[i])
 163                                 continue;
 164
 165                         if (strcmp(policy[i].name, (char *) hdr->name) != 0)
 166                                 continue;
 167
 168                         tb[i] = attr;
 169                 }
 170         }
 171
 172         return 0;
 173 }
 174
 175
 176 static struct blob_attr *
 177 blobmsg_new(struct blob_buf *buf, int type, const char *name, int payload_len, void **data)
 178 {
 179         struct blob_attr *attr;
 180         struct blobmsg_hdr *hdr;
 181         int attrlen, namelen;
 182         char *pad_start, *pad_end;
 183
 184         if (!name)
 185                 name = "";
 186
 187         namelen = strlen(name);
 188         attrlen = blobmsg_hdrlen(namelen) + payload_len;
 189         attr = blob_new(buf, type, attrlen);
 190         if (!attr)
 191                 return NULL;
 192
 193         attr->id_len |= be32_to_cpu(BLOB_ATTR_EXTENDED);
 194         hdr = blob_data(attr);
 195         hdr->namelen = cpu_to_be16(namelen);
 196         strcpy((char *) hdr->name, (const char *)name);
 197         pad_end = *data = blobmsg_data(attr);
 198         pad_start = (char *) &hdr->name[namelen];
 199         if (pad_start < pad_end)
 200                 memset(pad_start, 0, pad_end - pad_start);
 201
 202         return attr;
 203 }
 204
 205 static inline int
 206 attr_to_offset(struct blob_buf *buf, struct blob_attr *attr)
 207 {
 208         return (char *)attr - (char *) buf->buf + BLOB_COOKIE;
 209 }
 210
 211
 212 void *
 213 blobmsg_open_nested(struct blob_buf *buf, const char *name, bool array)
 214 {
 215         struct blob_attr *head;
 216         int type = array ? BLOBMSG_TYPE_ARRAY : BLOBMSG_TYPE_TABLE;
 217         unsigned long offset = attr_to_offset(buf, buf->head);
 218         void *data;
 219
 220         if (!name)
 221                 name = "";
 222
 223         head = blobmsg_new(buf, type, name, 0, &data);
 224         if (!head)
 225                 return NULL;
 226         blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blobmsg_hdrlen(strlen(name)));
 227         buf->head = head;
 228         return (void *)offset;
 229 }
 230
 231 int
 232 blobmsg_vprintf(struct blob_buf *buf, const char *name, const char *format, va_list arg)
 233 {
 234         va_list arg2;
 235         char cbuf;
 236         char *sbuf;
 237         int len, ret;
 238
 239         va_copy(arg2, arg);
 240         len = vsnprintf(&cbuf, sizeof(cbuf), format, arg2);
 241         va_end(arg2);
 242
 243         sbuf = blobmsg_alloc_string_buffer(buf, name, len + 1);
 244         if (!sbuf)
 245                 return -1;
 246         ret = vsprintf(sbuf, format, arg);
 247         blobmsg_add_string_buffer(buf);
 248
 249         return ret;
 250 }
 251
 252 int
 253 blobmsg_printf(struct blob_buf *buf, const char *name, const char *format, ...)
 254 {
 255         va_list ap;
 256         int ret;
 257
 258         va_start(ap, format);
 259         ret = blobmsg_vprintf(buf, name, format, ap);
 260         va_end(ap);
 261
 262         return ret;
 263 }
 264
 265 void *
 266 blobmsg_alloc_string_buffer(struct blob_buf *buf, const char *name, unsigned int maxlen)
 267 {
 268         struct blob_attr *attr;
 269         void *data_dest;
 270
 271         attr = blobmsg_new(buf, BLOBMSG_TYPE_STRING, name, maxlen, &data_dest);
 272         if (!attr)
 273                 return NULL;
 274
 275         blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blob_pad_len(attr));
 276         blob_set_raw_len(attr, blob_raw_len(attr) - maxlen);
 277
 278         return data_dest;
 279 }
 280
 281 void *
 282 blobmsg_realloc_string_buffer(struct blob_buf *buf, unsigned int maxlen)
 283 {
 284         struct blob_attr *attr = blob_next(buf->head);
 285         int offset = attr_to_offset(buf, blob_next(buf->head)) + blob_pad_len(attr) - BLOB_COOKIE;
 286         int required = maxlen - (buf->buflen - offset);
 287
 288         if (required <= 0)
 289                 goto out;
 290
 291         if (!blob_buf_grow(buf, required))
 292                 return NULL;
 293         attr = blob_next(buf->head);
 294
 295 out:
 296         return blobmsg_data(attr);
 297 }
 298
 299 void
 300 blobmsg_add_string_buffer(struct blob_buf *buf)
 301 {
 302         struct blob_attr *attr;
 303         int len, attrlen;
 304
 305         attr = blob_next(buf->head);
 306         len = strlen(blobmsg_data(attr)) + 1;
 307
 308         attrlen = blob_raw_len(attr) + len;
 309         blob_set_raw_len(attr, attrlen);
 310         blob_fill_pad(attr);
 311
 312         blob_set_raw_len(buf->head, blob_raw_len(buf->head) + blob_pad_len(attr));
 313 }
 314
 315 int
 316 blobmsg_add_field(struct blob_buf *buf, int type, const char *name,
 317                   const void *data, unsigned int len)
 318 {
 319         struct blob_attr *attr;
 320         void *data_dest;
 321
 322         attr = blobmsg_new(buf, type, name, len, &data_dest);
 323         if (!attr)
 324                 return -1;
 325
 326         if (len > 0)
 327                 memcpy(data_dest, data, len);
 328
 329         return 0;
 330 }