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_STRING] = BLOB_ATTR_STRING,
  24         [BLOBMSG_TYPE_UNSPEC] = BLOB_ATTR_BINARY,
  25 };
  26
  27 static uint16_t
  28 blobmsg_namelen(const struct blobmsg_hdr *hdr)
  29 {
  30         return be16_to_cpu(hdr->namelen);
  31 }
  32
  33 bool blobmsg_check_attr(const struct blob_attr *attr, bool name)
  34 {
  35         const struct blobmsg_hdr *hdr;
  36         const char *data;
  37         int id, len;
  38
  39         if (blob_len(attr) < sizeof(struct blobmsg_hdr))
  40                 return false;
  41
  42         hdr = (void *) attr->data;
  43         if (!hdr->namelen && name)
  44                 return false;
  45
  46         if (blobmsg_namelen(hdr) > blob_len(attr) - sizeof(struct blobmsg_hdr))
  47                 return false;
  48
  49         if (hdr->name[blobmsg_namelen(hdr)] != 0)
  50                 return false;
  51
  52         id = blob_id(attr);
  53         len = blobmsg_data_len(attr);
  54         data = blobmsg_data(attr);
  55
  56         if (id > BLOBMSG_TYPE_LAST)
  57                 return false;
  58
  59         if (!blob_type[id])
  60                 return true;
  61
  62         return blob_check_type(data, len, blob_type[id]);
  63 }
  64
  65 int blobmsg_check_array(const struct blob_attr *attr, int type)
  66 {
  67         struct blob_attr *cur;
  68         bool name;
  69         int rem;
  70         int size = 0;
  71
  72         switch (blobmsg_type(attr)) {
  73         case BLOBMSG_TYPE_TABLE:
  74                 name = true;
  75                 break;
  76         case BLOBMSG_TYPE_ARRAY:
  77                 name = false;
  78                 break;
  79         default:
  80                 return -1;
  81         }
  82
  83         blobmsg_for_each_attr(cur, attr, rem) {
  84                 if (type != BLOBMSG_TYPE_UNSPEC && blobmsg_type(cur) != type)
  85                         return -1;
  86
  87                 if (!blobmsg_check_attr(cur, name))
  88                         return -1;
  89
  90                 size++;
  91         }
  92
  93         return size;
  94 }
  95
  96 bool blobmsg_check_attr_list(const struct blob_attr *attr, int type)
  97 {
  98         return blobmsg_check_array(attr, type) >= 0;
  99 }
 100
 101 int blobmsg_parse_array(const struct blobmsg_policy *policy, int policy_len,
 102                         struct blob_attr **tb, void *data, unsigned int len)
 103 {
 104         struct blob_attr *attr;
 105         int i = 0;
 106
 107         memset(tb, 0, policy_len * sizeof(*tb));
 108         __blob_for_each_attr(attr, data, len) {
 109                 if (policy[i].type != BLOBMSG_TYPE_UNSPEC &&
 110                     blob_id(attr) != policy[i].type)
 111                         continue;
 112
 113                 if (!blobmsg_check_attr(attr, false))
 114                         return -1;
 115
 116                 if (tb[i])
 117                         continue;
 118
 119                 tb[i++] = attr;
 120                 if (i == policy_len)
 121                         break;
 122         }
 123
 124         return 0;
 125 }
 126
 127
 128 int blobmsg_parse(const struct blobmsg_policy *policy, int policy_len,
 129                   struct blob_attr **tb, void *data, unsigned int len)
 130 {
 131         struct blobmsg_hdr *hdr;
 132         struct blob_attr *attr;
 133         uint8_t *pslen;
 134         int i;
 135
 136         memset(tb, 0, policy_len * sizeof(*tb));
 137         pslen = alloca(policy_len);
 138         for (i = 0; i < policy_len; i++) {
 139                 if (!policy[i].name)
 140                         continue;
 141
 142                 pslen[i] = strlen(policy[i].name);
 143         }
 144
 145         __blob_for_each_attr(attr, data, len) {
 146                 hdr = blob_data(attr);
 147                 for (i = 0; i < policy_len; i++) {
 148                         if (!policy[i].name)
 149                                 continue;
 150
 151                         if (policy[i].type != BLOBMSG_TYPE_UNSPEC &&
 152                             blob_id(attr) != policy[i].type)
 153                                 continue;
 154
 155                         if (blobmsg_namelen(hdr) != pslen[i])
 156                                 continue;
 157
 158                         if (!blobmsg_check_attr(attr, true))
 159                                 return -1;
 160
 161                         if (tb[i])
 162                                 continue;
 163
 164                         if (strcmp(policy[i].name, (char *) hdr->name) != 0)
 165                                 continue;
 166
 167                         tb[i] = attr;
 168                 }
 169         }
 170
 171         return 0;
 172 }
 173
 174
 175 static struct blob_attr *
 176 blobmsg_new(struct blob_buf *buf, int type, const char *name, int payload_len, void **data)
 177 {
 178         struct blob_attr *attr;
 179         struct blobmsg_hdr *hdr;
 180         int attrlen, namelen;
 181         char *pad_start, *pad_end;
 182
 183         if (!name)
 184                 name = "";
 185
 186         namelen = strlen(name);
 187         attrlen = blobmsg_hdrlen(namelen) + payload_len;
 188         attr = blob_new(buf, type, attrlen);
 189         if (!attr)
 190                 return NULL;
 191
 192         attr->id_len |= be32_to_cpu(BLOB_ATTR_EXTENDED);
 193         hdr = blob_data(attr);
 194         hdr->namelen = cpu_to_be16(namelen);
 195         strcpy((char *) hdr->name, (const char *)name);
 196         pad_end = *data = blobmsg_data(attr);
 197         pad_start = (char *) &hdr->name[namelen];
 198         if (pad_start < pad_end)
 199                 memset(pad_start, 0, pad_end - pad_start);
 200
 201         return attr;
 202 }
 203
 204 static inline int
 205 attr_to_offset(struct blob_buf *buf, struct blob_attr *attr)
 206 {
 207         return (char *)attr - (char *) buf->buf + BLOB_COOKIE;
 208 }
 209
 210
 211 void *
 212 blobmsg_open_nested(struct blob_buf *buf, const char *name, bool array)
 213 {
 214         struct blob_attr *head;
 215         int type = array ? BLOBMSG_TYPE_ARRAY : BLOBMSG_TYPE_TABLE;
 216         unsigned long offset = attr_to_offset(buf, buf->head);
 217         void *data;
 218
 219         if (!name)
 220                 name = "";
 221
 222         head = blobmsg_new(buf, type, name, 0, &data);
 223         if (!head)
 224                 return NULL;
 225         blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blobmsg_hdrlen(strlen(name)));
 226         buf->head = head;
 227         return (void *)offset;
 228 }
 229
 230 void
 231 blobmsg_vprintf(struct blob_buf *buf, const char *name, const char *format, va_list arg)
 232 {
 233         va_list arg2;
 234         char cbuf;
 235         int len;
 236
 237         va_copy(arg2, arg);
 238         len = vsnprintf(&cbuf, sizeof(cbuf), format, arg2);
 239         va_end(arg2);
 240
 241         vsprintf(blobmsg_alloc_string_buffer(buf, name, len + 1), format, arg);
 242         blobmsg_add_string_buffer(buf);
 243 }
 244
 245 void
 246 blobmsg_printf(struct blob_buf *buf, const char *name, const char *format, ...)
 247 {
 248         va_list ap;
 249
 250         va_start(ap, format);
 251         blobmsg_vprintf(buf, name, format, ap);
 252         va_end(ap);
 253 }
 254
 255 void *
 256 blobmsg_alloc_string_buffer(struct blob_buf *buf, const char *name, unsigned int maxlen)
 257 {
 258         struct blob_attr *attr;
 259         void *data_dest;
 260
 261         attr = blobmsg_new(buf, BLOBMSG_TYPE_STRING, name, maxlen, &data_dest);
 262         if (!attr)
 263                 return NULL;
 264
 265         blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blob_pad_len(attr));
 266         blob_set_raw_len(attr, blob_raw_len(attr) - maxlen);
 267
 268         return data_dest;
 269 }
 270
 271 void *
 272 blobmsg_realloc_string_buffer(struct blob_buf *buf, unsigned int maxlen)
 273 {
 274         struct blob_attr *attr = blob_next(buf->head);
 275         int offset = attr_to_offset(buf, blob_next(buf->head)) + blob_pad_len(attr) - BLOB_COOKIE;
 276         int required = maxlen - (buf->buflen - offset);
 277
 278         if (required <= 0)
 279                 goto out;
 280
 281         blob_buf_grow(buf, required);
 282         attr = blob_next(buf->head);
 283
 284 out:
 285         return blobmsg_data(attr);
 286 }
 287
 288 void
 289 blobmsg_add_string_buffer(struct blob_buf *buf)
 290 {
 291         struct blob_attr *attr;
 292         int len, attrlen;
 293
 294         attr = blob_next(buf->head);
 295         len = strlen(blobmsg_data(attr)) + 1;
 296
 297         attrlen = blob_raw_len(attr) + len;
 298         blob_set_raw_len(attr, attrlen);
 299         blob_fill_pad(attr);
 300
 301         blob_set_raw_len(buf->head, blob_raw_len(buf->head) + blob_pad_len(attr));
 302 }
 303
 304 int
 305 blobmsg_add_field(struct blob_buf *buf, int type, const char *name,
 306                   const void *data, unsigned int len)
 307 {
 308         struct blob_attr *attr;
 309         void *data_dest;
 310
 311         attr = blobmsg_new(buf, type, name, len, &data_dest);
 312         if (!attr)
 313                 return -1;
 314
 315         if (len > 0)
 316                 memcpy(data_dest, data, len);
 317
 318         return 0;
 319 }