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