blobmsg.c

   1 /*
   2  * blobmsg - library for generating/parsing structured blob messages
   3  *
   4  * Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU Lesser General Public License version 2.1
   8  * as published by the Free Software Foundation
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include "blobmsg.h"
  17
  18 struct strbuf {
  19         int len;
  20         int pos;
  21         char *buf;
  22
  23         blobmsg_json_format_t custom_format;
  24         void *priv;
  25 };
  26
  27 static bool blobmsg_puts(struct strbuf *s, const char *c, int len)
  28 {
  29         if (len <= 0)
  30                 return true;
  31
  32         if (s->pos + len >= s->len) {
  33                 s->len += 16;
  34                 s->buf = realloc(s->buf, s->len);
  35                 if (!s->buf)
  36                         return false;
  37         }
  38         memcpy(s->buf + s->pos, c, len);
  39         s->pos += len;
  40         return true;
  41 }
  42
  43 static void blobmsg_format_string(struct strbuf *s, const char *str)
  44 {
  45         const char *p, *last = str, *end = str + strlen(str);
  46         char buf[8] = "\\u00";
  47
  48         blobmsg_puts(s, "\"", 1);
  49         for (p = str; *p; p++) {
  50                 char escape = '\0';
  51                 int len;
  52
  53                 switch(*p) {
  54                 case '\b':
  55                         escape = 'b';
  56                         break;
  57                 case '\n':
  58                         escape = 'n';
  59                         break;
  60                 case '\t':
  61                         escape = 't';
  62                         break;
  63                 case '\r':
  64                         escape = 'r';
  65                         break;
  66                 case '"':
  67                 case '\\':
  68                 case '/':
  69                         escape = *p;
  70                         break;
  71                 default:
  72                         if (*p < ' ')
  73                                 escape = 'u';
  74                         break;
  75                 }
  76
  77                 if (!escape)
  78                         continue;
  79
  80                 if (p > last)
  81                         blobmsg_puts(s, last, p - last);
  82                 last = p + 1;
  83                 buf[1] = escape;
  84
  85                 if (escape == 'u') {
  86                         sprintf(buf + 4, "%02x", (unsigned char) *p);
  87                         len = 4;
  88                 } else {
  89                         len = 2;
  90                 }
  91                 blobmsg_puts(s, buf, len);
  92         }
  93
  94         blobmsg_puts(s, last, end - last);
  95         blobmsg_puts(s, "\"", 1);
  96 }
  97
  98 static void blobmsg_format_json_list(struct strbuf *s, struct blob_attr *attr, int len, bool array);
  99
 100 static void blobmsg_format_element(struct strbuf *s, struct blob_attr *attr, bool array, bool head)
 101 {
 102         const char *data_str;
 103         char buf[32];
 104         void *data;
 105         int len;
 106
 107         if (!array && blobmsg_name(attr)[0]) {
 108                 blobmsg_format_string(s, blobmsg_name(attr));
 109                 blobmsg_puts(s, ":", 1);
 110         }
 111         if (head) {
 112                 data = blob_data(attr);
 113                 len = blob_len(attr);
 114         } else {
 115                 data = blobmsg_data(attr);
 116                 len = blobmsg_data_len(attr);
 117
 118                 if (s->custom_format) {
 119                         data_str = s->custom_format(s->priv, attr);
 120                         if (data_str)
 121                                 goto out;
 122                 }
 123         }
 124
 125         data_str = buf;
 126         switch(blob_id(attr)) {
 127         case BLOBMSG_TYPE_INT8:
 128                 sprintf(buf, "%d", *(uint8_t *)data);
 129                 break;
 130         case BLOBMSG_TYPE_INT16:
 131                 sprintf(buf, "%d", *(uint16_t *)data);
 132                 break;
 133         case BLOBMSG_TYPE_INT32:
 134                 sprintf(buf, "%d", *(uint32_t *)data);
 135                 break;
 136         case BLOBMSG_TYPE_INT64:
 137                 sprintf(buf, "%lld", *(uint64_t *)data);
 138                 break;
 139         case BLOBMSG_TYPE_STRING:
 140                 blobmsg_format_string(s, data);
 141                 return;
 142         case BLOBMSG_TYPE_ARRAY:
 143                 blobmsg_format_json_list(s, data, len, true);
 144                 return;
 145         case BLOBMSG_TYPE_TABLE:
 146                 blobmsg_format_json_list(s, data, len, false);
 147                 return;
 148         }
 149
 150 out:
 151         blobmsg_puts(s, data_str, strlen(data_str));
 152 }
 153
 154 static void blobmsg_format_json_list(struct strbuf *s, struct blob_attr *attr, int len, bool array)
 155 {
 156         struct blob_attr *pos;
 157         bool first = true;
 158         int rem = len;
 159
 160         blobmsg_puts(s, (array ? "[ " : "{ "), 2);
 161         __blob_for_each_attr(pos, attr, rem) {
 162                 if (!first)
 163                         blobmsg_puts(s, ", ", 2);
 164
 165                 blobmsg_format_element(s, pos, array, false);
 166                 first = false;
 167         }
 168         blobmsg_puts(s, (array ? " ]" : " }"), 2);
 169 }
 170
 171 char *blobmsg_format_json_with_cb(struct blob_attr *attr, bool list, blobmsg_json_format_t cb, void *priv)
 172 {
 173         struct strbuf s;
 174
 175         s.len = blob_len(attr);
 176         s.buf = malloc(s.len);
 177         s.pos = 0;
 178         s.custom_format = cb;
 179         s.priv = priv;
 180
 181         if (list)
 182                 blobmsg_format_json_list(&s, blob_data(attr), blob_len(attr), false);
 183         else
 184                 blobmsg_format_element(&s, attr, false, false);
 185
 186         if (!s.len)
 187                 return NULL;
 188
 189         s.buf = realloc(s.buf, s.pos + 1);
 190         return s.buf;
 191 }
 192
 193 static const int blob_type[__BLOBMSG_TYPE_LAST] = {
 194         [BLOBMSG_TYPE_INT8] = BLOB_ATTR_INT8,
 195         [BLOBMSG_TYPE_INT16] = BLOB_ATTR_INT16,
 196         [BLOBMSG_TYPE_INT32] = BLOB_ATTR_INT32,
 197         [BLOBMSG_TYPE_INT64] = BLOB_ATTR_INT64,
 198         [BLOBMSG_TYPE_STRING] = BLOB_ATTR_STRING,
 199 };
 200
 201 bool blobmsg_check_attr(const struct blob_attr *attr, bool name)
 202 {
 203         const struct blobmsg_hdr *hdr;
 204         const char *data;
 205         int id, len;
 206
 207         if (blob_len(attr) < sizeof(struct blobmsg_hdr))
 208                 return false;
 209
 210         hdr = (void *) attr->data;
 211         if (!hdr->namelen && name)
 212                 return false;
 213
 214         if (hdr->namelen > blob_len(attr) - sizeof(struct blobmsg_hdr))
 215                 return false;
 216
 217         if (hdr->name[hdr->namelen] != 0)
 218                 return false;
 219
 220         id = blob_id(attr);
 221         len = blobmsg_data_len(attr);
 222         data = blobmsg_data(attr);
 223
 224         if (!id || id > BLOBMSG_TYPE_LAST)
 225                 return false;
 226
 227         if (!blob_type[id])
 228                 return true;
 229
 230         return blob_check_type(data, len, blob_type[id]);
 231 }
 232
 233 int blobmsg_parse(const struct blobmsg_policy *policy, int policy_len,
 234                   struct blob_attr **tb, void *data, int len)
 235 {
 236         struct blobmsg_hdr *hdr;
 237         struct blob_attr *attr;
 238         uint8_t *pslen;
 239         int i;
 240
 241         memset(tb, 0, policy_len * sizeof(*tb));
 242         pslen = alloca(policy_len);
 243         for (i = 0; i < policy_len; i++) {
 244                 if (!policy[i].name)
 245                         continue;
 246
 247                 pslen[i] = strlen(policy[i].name);
 248         }
 249
 250         __blob_for_each_attr(attr, data, len) {
 251                 hdr = blob_data(attr);
 252                 for (i = 0; i < policy_len; i++) {
 253                         if (!policy[i].name)
 254                                 continue;
 255
 256                         if (policy[i].type != BLOBMSG_TYPE_UNSPEC &&
 257                             blob_id(attr) != policy[i].type)
 258                                 continue;
 259
 260                         if (hdr->namelen != pslen[i])
 261                                 continue;
 262
 263                         if (!blobmsg_check_attr(attr, true))
 264                                 return -1;
 265
 266                         if (tb[i])
 267                                 return -1;
 268
 269                         if (strcmp(policy[i].name, (char *) hdr->name) != 0)
 270                                 continue;
 271
 272                         tb[i] = attr;
 273                 }
 274         }
 275
 276         return 0;
 277 }
 278
 279
 280 static struct blob_attr *
 281 blobmsg_new(struct blob_buf *buf, int type, const char *name, int payload_len, void **data)
 282 {
 283         struct blob_attr *attr;
 284         struct blobmsg_hdr *hdr;
 285         int attrlen, namelen;
 286
 287         if (!name)
 288                 name = "";
 289
 290         namelen = strlen(name);
 291         attrlen = blobmsg_hdrlen(namelen) + payload_len;
 292         attr = blob_new(buf, type, attrlen);
 293         if (!attr)
 294                 return NULL;
 295
 296         hdr = blob_data(attr);
 297         hdr->namelen = namelen;
 298         strcpy((char *) hdr->name, (const char *)name);
 299         *data = blobmsg_data(attr);
 300
 301         return attr;
 302 }
 303
 304 static inline int
 305 attr_to_offset(struct blob_buf *buf, struct blob_attr *attr)
 306 {
 307         return (char *)attr - (char *) buf->buf;
 308 }
 309
 310
 311 void *
 312 blobmsg_open_nested(struct blob_buf *buf, const char *name, bool array)
 313 {
 314         struct blob_attr *head = buf->head;
 315         int type = array ? BLOBMSG_TYPE_ARRAY : BLOBMSG_TYPE_TABLE;
 316         unsigned long offset = attr_to_offset(buf, buf->head);
 317         void *data;
 318
 319         if (!name)
 320                 name = "";
 321
 322         head = blobmsg_new(buf, type, name, 0, &data);
 323         blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blobmsg_hdrlen(strlen(name)));
 324         buf->head = head;
 325         return (void *)offset;
 326 }
 327
 328 void *
 329 blobmsg_alloc_string_buffer(struct blob_buf *buf, const char *name, int maxlen)
 330 {
 331         struct blob_attr *attr;
 332         void *data_dest;
 333
 334         attr = blobmsg_new(buf, BLOBMSG_TYPE_STRING, name, maxlen, &data_dest);
 335         if (!attr)
 336                 return NULL;
 337
 338         data_dest = blobmsg_data(attr);
 339         blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blob_pad_len(attr));
 340         blob_set_raw_len(attr, blob_raw_len(attr) - maxlen);
 341
 342         return data_dest;
 343 }
 344
 345 void
 346 blobmsg_add_string_buffer(struct blob_buf *buf)
 347 {
 348         struct blob_attr *attr;
 349         int len, attrlen;
 350
 351         attr = blob_next(buf->head);
 352         len = strlen(blobmsg_data(attr)) + 1;
 353
 354         attrlen = blob_raw_len(attr) + len;
 355         blob_set_raw_len(attr, attrlen);
 356         blob_set_raw_len(buf->head, blob_raw_len(buf->head) + blob_pad_len(attr));
 357 }
 358
 359 int
 360 blobmsg_add_field(struct blob_buf *buf, int type, const char *name,
 361                   const void *data, int len)
 362 {
 363         struct blob_attr *attr;
 364         void *data_dest;
 365
 366         if (type == BLOBMSG_TYPE_ARRAY ||
 367             type == BLOBMSG_TYPE_TABLE)
 368                 return -1;
 369
 370         attr = blobmsg_new(buf, type, name, len, &data_dest);
 371         if (!attr)
 372                 return -1;
 373
 374         if (len > 0)
 375                 memcpy(data_dest, data, len);
 376
 377         return 0;
 378 }