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
  24 static bool blobmsg_puts(struct strbuf *s, char *c, int len)
  25 {
  26         if (len <= 0)
  27                 return true;
  28
  29         if (s->pos + len >= s->len) {
  30                 s->len += 16;
  31                 s->buf = realloc(s->buf, s->len);
  32                 if (!s->buf)
  33                         return false;
  34         }
  35         memcpy(s->buf + s->pos, c, len);
  36         s->pos += len;
  37         return true;
  38 }
  39
  40 static void blobmsg_format_string(struct strbuf *s, char *str)
  41 {
  42         char *p, *last = str, *end = str + strlen(str);
  43         char buf[8] = "\\u00";
  44
  45         blobmsg_puts(s, "\"", 1);
  46         for (p = str; *p; p++) {
  47                 char escape = '\0';
  48                 int len;
  49
  50                 switch(*p) {
  51                 case '\b':
  52                         escape = 'b';
  53                         break;
  54                 case '\n':
  55                         escape = 'n';
  56                         break;
  57                 case '\t':
  58                         escape = 't';
  59                         break;
  60                 case '\r':
  61                         escape = 'r';
  62                         break;
  63                 case '"':
  64                 case '\\':
  65                 case '/':
  66                         escape = *p;
  67                         break;
  68                 default:
  69                         if (*p < ' ')
  70                                 escape = 'u';
  71                         break;
  72                 }
  73
  74                 if (!escape)
  75                         continue;
  76
  77                 if (p > last)
  78                         blobmsg_puts(s, last, p - last);
  79                 last = p + 1;
  80                 buf[1] = escape;
  81
  82                 if (escape == 'u') {
  83                         sprintf(buf + 4, "%02x", (unsigned char) *p);
  84                         len = 4;
  85                 } else {
  86                         len = 2;
  87                 }
  88                 blobmsg_puts(s, buf, len);
  89         }
  90
  91         blobmsg_puts(s, last, end - last);
  92         blobmsg_puts(s, "\"", 1);
  93 }
  94
  95 static void blobmsg_format_json_list(struct strbuf *s, struct blob_attr *attr, int len, bool array);
  96
  97 static void blobmsg_format_element(struct strbuf *s, struct blob_attr *attr, bool array)
  98 {
  99         char buf[32];
 100         void *data;
 101         int len;
 102
 103         if (array) {
 104                 data = blob_data(attr);
 105                 len  = blob_len(attr);
 106         } else {
 107                 blobmsg_format_string(s, blobmsg_name(attr));
 108                 blobmsg_puts(s, ":", 1);
 109                 data = blobmsg_data(attr);
 110                 len = blobmsg_data_len(attr);
 111         }
 112
 113         switch(blob_id(attr)) {
 114         case BLOBMSG_TYPE_INT8:
 115                 sprintf(buf, "%d", *(uint8_t *)data);
 116                 break;
 117         case BLOBMSG_TYPE_INT16:
 118                 sprintf(buf, "%d", *(uint16_t *)data);
 119                 break;
 120         case BLOBMSG_TYPE_INT32:
 121                 sprintf(buf, "%d", *(uint32_t *)data);
 122                 break;
 123         case BLOBMSG_TYPE_INT64:
 124                 sprintf(buf, "%lld", *(uint64_t *)data);
 125                 break;
 126         case BLOBMSG_TYPE_STRING:
 127                 blobmsg_puts(s, data, strlen(data));
 128                 return;
 129         case BLOBMSG_TYPE_ARRAY:
 130                 blobmsg_format_json_list(s, data, len, true);
 131                 return;
 132         case BLOBMSG_TYPE_TABLE:
 133                 blobmsg_format_json_list(s, data, len, false);
 134                 return;
 135         }
 136         blobmsg_puts(s, buf, strlen(buf));
 137 }
 138
 139 static void blobmsg_format_json_list(struct strbuf *s, struct blob_attr *attr, int len, bool array)
 140 {
 141         struct blob_attr *pos;
 142         bool first = true;
 143         int rem = len;
 144
 145         blobmsg_puts(s, (array ? "[ " : "{ "), 2);
 146         __blob_for_each_attr(pos, attr, rem) {
 147                 if (!first)
 148                         blobmsg_puts(s, ", ", 2);
 149
 150                 blobmsg_format_element(s, pos, array);
 151                 first = false;
 152         }
 153         blobmsg_puts(s, (array ? " ]" : " }"), 2);
 154 }
 155
 156 char *blobmsg_format_json(struct blob_attr *attr)
 157 {
 158         struct strbuf s;
 159
 160         s.len = blob_len(attr);
 161         s.buf = malloc(s.len);
 162         s.pos = 0;
 163
 164         blobmsg_format_element(&s, attr, false);
 165
 166         if (!s.len)
 167                 return NULL;
 168
 169         s.buf = realloc(s.buf, s.pos + 1);
 170         return s.buf;
 171 }
 172
 173 bool blobmsg_check_attr(const struct blob_attr *attr, bool name)
 174 {
 175         const struct blobmsg_hdr *hdr;
 176
 177         if (blob_len(attr) < sizeof(struct blobmsg_hdr))
 178                 return false;
 179
 180         hdr = (void *) attr->data;
 181         if (!hdr->namelen && name)
 182                 return false;
 183
 184         if (hdr->namelen > blob_len(attr) - sizeof(struct blobmsg_hdr))
 185                 return false;
 186
 187         if (hdr->name[hdr->namelen] != 0)
 188                 return false;
 189
 190         return true;
 191 }
 192
 193 int blobmsg_parse(const struct blobmsg_policy *policy, int policy_len,
 194                   struct blob_attr **tb, void *data, int len)
 195 {
 196         struct blobmsg_hdr *hdr;
 197         struct blob_attr *attr;
 198         uint8_t *pslen;
 199         int i;
 200
 201         memset(tb, 0, policy_len * sizeof(*tb));
 202         pslen = alloca(policy_len);
 203         for (i = 0; i < policy_len; i++) {
 204                 if (!policy[i].name)
 205                         continue;
 206
 207                 pslen[i] = strlen(policy[i].name);
 208         }
 209
 210         __blob_for_each_attr(attr, data, len) {
 211                 hdr = blob_data(attr);
 212                 for (i = 0; i < policy_len; i++) {
 213                         if (!policy[i].name)
 214                                 continue;
 215
 216                         if (policy[i].type != BLOBMSG_TYPE_UNSPEC &&
 217                             blob_id(attr) != policy[i].type)
 218                                 continue;
 219
 220                         if (hdr->namelen != pslen[i])
 221                                 continue;
 222
 223                         if (!blobmsg_check_attr(attr, true))
 224                                 return -1;
 225
 226                         if (tb[i])
 227                                 return -1;
 228
 229                         if (strcmp(policy[i].name, (char *) hdr->name) != 0)
 230                                 continue;
 231
 232                         tb[i] = attr;
 233                 }
 234         }
 235
 236         return 0;
 237 }
 238
 239
 240 static struct blob_attr *
 241 blobmsg_new(struct blob_buf *buf, int type, const char *name, int payload_len, void **data)
 242 {
 243         struct blob_attr *attr;
 244         struct blobmsg_hdr *hdr;
 245         int attrlen, namelen;
 246
 247         if (blob_id(buf->head) == BLOBMSG_TYPE_ARRAY && !name) {
 248                 attr = blob_new(buf, type, payload_len);
 249                 *data = blob_data(attr);
 250                 return attr;
 251         }
 252
 253         if (blob_id(buf->head) != BLOBMSG_TYPE_TABLE || !name)
 254                 return NULL;
 255
 256         namelen = strlen(name);
 257         attrlen = blobmsg_hdrlen(namelen) + payload_len;
 258         attr = blob_new(buf, type, attrlen);
 259         if (!attr)
 260                 return NULL;
 261
 262         hdr = blob_data(attr);
 263         hdr->namelen = namelen;
 264         strcpy((char *) hdr->name, (const char *)name);
 265         *data = blobmsg_data(attr);
 266
 267         return attr;
 268 }
 269
 270 static inline int
 271 attr_to_offset(struct blob_buf *buf, struct blob_attr *attr)
 272 {
 273         return (char *)attr - (char *) buf->buf;
 274 }
 275
 276
 277 void *
 278 blobmsg_open_nested(struct blob_buf *buf, const char *name, bool array)
 279 {
 280         struct blob_attr *head = buf->head;
 281         int type = array ? BLOBMSG_TYPE_ARRAY : BLOBMSG_TYPE_TABLE;
 282         unsigned long offset = attr_to_offset(buf, buf->head);
 283         void *data;
 284
 285         if (blob_id(head) == BLOBMSG_TYPE_ARRAY && !name)
 286                 return blob_nest_start(buf, type);
 287
 288         if (blob_id(head) == BLOBMSG_TYPE_TABLE && name) {
 289                 head = blobmsg_new(buf, type, name, 0, &data);
 290                 blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blobmsg_hdrlen(strlen(name)));
 291                 buf->head = head;
 292                 return (void *)offset;
 293         }
 294
 295         return NULL;
 296 }
 297
 298 int
 299 blobmsg_add_field(struct blob_buf *buf, int type, const char *name,
 300                   const void *data, int len)
 301 {
 302         struct blob_attr *attr;
 303         void *data_dest;
 304
 305         if (type == BLOBMSG_TYPE_ARRAY ||
 306             type == BLOBMSG_TYPE_TABLE)
 307                 return -1;
 308
 309         attr = blobmsg_new(buf, type, name, len, &data_dest);
 310         if (!attr)
 311                 return -1;
 312
 313         if (len > 0)
 314                 memcpy(data_dest, data, len);
 315
 316         return 0;
 317 }