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, bool head)
  98 {
  99         char buf[32];
 100         void *data;
 101         int len;
 102
 103         if (!array) {
 104                 blobmsg_format_string(s, blobmsg_name(attr));
 105                 blobmsg_puts(s, ":", 1);
 106         }
 107         if (head) {
 108                 data = blob_data(attr);
 109                 len = blob_len(attr);
 110         } else {
 111                 data = blobmsg_data(attr);
 112                 len = blobmsg_data_len(attr);
 113         }
 114
 115         switch(blob_id(attr)) {
 116         case BLOBMSG_TYPE_INT8:
 117                 sprintf(buf, "%d", *(uint8_t *)data);
 118                 break;
 119         case BLOBMSG_TYPE_INT16:
 120                 sprintf(buf, "%d", *(uint16_t *)data);
 121                 break;
 122         case BLOBMSG_TYPE_INT32:
 123                 sprintf(buf, "%d", *(uint32_t *)data);
 124                 break;
 125         case BLOBMSG_TYPE_INT64:
 126                 sprintf(buf, "%lld", *(uint64_t *)data);
 127                 break;
 128         case BLOBMSG_TYPE_STRING:
 129                 blobmsg_puts(s, data, strlen(data));
 130                 return;
 131         case BLOBMSG_TYPE_ARRAY:
 132                 blobmsg_format_json_list(s, data, len, true);
 133                 return;
 134         case BLOBMSG_TYPE_TABLE:
 135                 blobmsg_format_json_list(s, data, len, false);
 136                 return;
 137         }
 138         blobmsg_puts(s, buf, strlen(buf));
 139 }
 140
 141 static void blobmsg_format_json_list(struct strbuf *s, struct blob_attr *attr, int len, bool array)
 142 {
 143         struct blob_attr *pos;
 144         bool first = true;
 145         int rem = len;
 146
 147         blobmsg_puts(s, (array ? "[ " : "{ "), 2);
 148         __blob_for_each_attr(pos, attr, rem) {
 149                 if (!first)
 150                         blobmsg_puts(s, ", ", 2);
 151
 152                 blobmsg_format_element(s, pos, array, false);
 153                 first = false;
 154         }
 155         blobmsg_puts(s, (array ? " ]" : " }"), 2);
 156 }
 157
 158 char *blobmsg_format_json(struct blob_attr *attr, bool named)
 159 {
 160         struct strbuf s;
 161
 162         s.len = blob_len(attr);
 163         s.buf = malloc(s.len);
 164         s.pos = 0;
 165
 166         blobmsg_format_json_list(&s, blob_data(attr), blob_len(attr), !named);
 167
 168         if (!s.len)
 169                 return NULL;
 170
 171         s.buf = realloc(s.buf, s.pos + 1);
 172         return s.buf;
 173 }
 174
 175 bool blobmsg_check_attr(const struct blob_attr *attr, bool name)
 176 {
 177         const struct blobmsg_hdr *hdr;
 178
 179         if (blob_len(attr) < sizeof(struct blobmsg_hdr))
 180                 return false;
 181
 182         hdr = (void *) attr->data;
 183         if (!hdr->namelen && name)
 184                 return false;
 185
 186         if (hdr->namelen > blob_len(attr) - sizeof(struct blobmsg_hdr))
 187                 return false;
 188
 189         if (hdr->name[hdr->namelen] != 0)
 190                 return false;
 191
 192         return true;
 193 }
 194
 195 int blobmsg_parse(const struct blobmsg_policy *policy, int policy_len,
 196                   struct blob_attr **tb, void *data, int len)
 197 {
 198         struct blobmsg_hdr *hdr;
 199         struct blob_attr *attr;
 200         uint8_t *pslen;
 201         int i;
 202
 203         memset(tb, 0, policy_len * sizeof(*tb));
 204         pslen = alloca(policy_len);
 205         for (i = 0; i < policy_len; i++) {
 206                 if (!policy[i].name)
 207                         continue;
 208
 209                 pslen[i] = strlen(policy[i].name);
 210         }
 211
 212         __blob_for_each_attr(attr, data, len) {
 213                 hdr = blob_data(attr);
 214                 for (i = 0; i < policy_len; i++) {
 215                         if (!policy[i].name)
 216                                 continue;
 217
 218                         if (policy[i].type != BLOBMSG_TYPE_UNSPEC &&
 219                             blob_id(attr) != policy[i].type)
 220                                 continue;
 221
 222                         if (hdr->namelen != pslen[i])
 223                                 continue;
 224
 225                         if (!blobmsg_check_attr(attr, true))
 226                                 return -1;
 227
 228                         if (tb[i])
 229                                 return -1;
 230
 231                         if (strcmp(policy[i].name, (char *) hdr->name) != 0)
 232                                 continue;
 233
 234                         tb[i] = attr;
 235                 }
 236         }
 237
 238         return 0;
 239 }
 240
 241
 242 static struct blob_attr *
 243 blobmsg_new(struct blob_buf *buf, int type, const char *name, int payload_len, void **data)
 244 {
 245         struct blob_attr *attr;
 246         struct blobmsg_hdr *hdr;
 247         int attrlen, namelen;
 248
 249         if (!name)
 250                 name = "";
 251
 252         namelen = strlen(name);
 253         attrlen = blobmsg_hdrlen(namelen) + payload_len;
 254         attr = blob_new(buf, type, attrlen);
 255         if (!attr)
 256                 return NULL;
 257
 258         hdr = blob_data(attr);
 259         hdr->namelen = namelen;
 260         strcpy((char *) hdr->name, (const char *)name);
 261         *data = blobmsg_data(attr);
 262
 263         return attr;
 264 }
 265
 266 static inline int
 267 attr_to_offset(struct blob_buf *buf, struct blob_attr *attr)
 268 {
 269         return (char *)attr - (char *) buf->buf;
 270 }
 271
 272
 273 void *
 274 blobmsg_open_nested(struct blob_buf *buf, const char *name, bool array)
 275 {
 276         struct blob_attr *head = buf->head;
 277         int type = array ? BLOBMSG_TYPE_ARRAY : BLOBMSG_TYPE_TABLE;
 278         unsigned long offset = attr_to_offset(buf, buf->head);
 279         void *data;
 280
 281         if (!name)
 282                 name = "";
 283
 284         head = blobmsg_new(buf, type, name, 0, &data);
 285         blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blobmsg_hdrlen(strlen(name)));
 286         buf->head = head;
 287         return (void *)offset;
 288 }
 289
 290 int
 291 blobmsg_add_field(struct blob_buf *buf, int type, const char *name,
 292                   const void *data, int len)
 293 {
 294         struct blob_attr *attr;
 295         void *data_dest;
 296
 297         if (type == BLOBMSG_TYPE_ARRAY ||
 298             type == BLOBMSG_TYPE_TABLE)
 299                 return -1;
 300
 301         attr = blobmsg_new(buf, type, name, len, &data_dest);
 302         if (!attr)
 303                 return -1;
 304
 305         if (len > 0)
 306                 memcpy(data_dest, data, len);
 307
 308         return 0;
 309 }