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