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(const struct blobmsg_policy *policy, int policy_len,
  93                   struct blob_attr **tb, void *data, int len)
  94 {
  95         struct blobmsg_hdr *hdr;
  96         struct blob_attr *attr;
  97         uint8_t *pslen;
  98         int i;
  99
 100         memset(tb, 0, policy_len * sizeof(*tb));
 101         pslen = alloca(policy_len);
 102         for (i = 0; i < policy_len; i++) {
 103                 if (!policy[i].name)
 104                         continue;
 105
 106                 pslen[i] = strlen(policy[i].name);
 107         }
 108
 109         __blob_for_each_attr(attr, data, len) {
 110                 hdr = blob_data(attr);
 111                 for (i = 0; i < policy_len; i++) {
 112                         if (!policy[i].name)
 113                                 continue;
 114
 115                         if (policy[i].type != BLOBMSG_TYPE_UNSPEC &&
 116                             blob_id(attr) != policy[i].type)
 117                                 continue;
 118
 119                         if (blobmsg_namelen(hdr) != pslen[i])
 120                                 continue;
 121
 122                         if (!blobmsg_check_attr(attr, true))
 123                                 return -1;
 124
 125                         if (tb[i])
 126                                 continue;
 127
 128                         if (strcmp(policy[i].name, (char *) hdr->name) != 0)
 129                                 continue;
 130
 131                         tb[i] = attr;
 132                 }
 133         }
 134
 135         return 0;
 136 }
 137
 138
 139 static struct blob_attr *
 140 blobmsg_new(struct blob_buf *buf, int type, const char *name, int payload_len, void **data)
 141 {
 142         struct blob_attr *attr;
 143         struct blobmsg_hdr *hdr;
 144         int attrlen, namelen;
 145         char *pad_start, *pad_end;
 146
 147         if (!name)
 148                 name = "";
 149
 150         namelen = strlen(name);
 151         attrlen = blobmsg_hdrlen(namelen) + payload_len;
 152         attr = blob_new(buf, type, attrlen);
 153         if (!attr)
 154                 return NULL;
 155
 156         hdr = blob_data(attr);
 157         hdr->namelen = cpu_to_be16(namelen);
 158         strcpy((char *) hdr->name, (const char *)name);
 159         pad_end = *data = blobmsg_data(attr);
 160         pad_start = (char *) &hdr->name[namelen];
 161         if (pad_start < pad_end)
 162                 memset(pad_start, 0, pad_end - pad_start);
 163
 164         return attr;
 165 }
 166
 167 static inline int
 168 attr_to_offset(struct blob_buf *buf, struct blob_attr *attr)
 169 {
 170         return (char *)attr - (char *) buf->buf;
 171 }
 172
 173
 174 void *
 175 blobmsg_open_nested(struct blob_buf *buf, const char *name, bool array)
 176 {
 177         struct blob_attr *head = buf->head;
 178         int type = array ? BLOBMSG_TYPE_ARRAY : BLOBMSG_TYPE_TABLE;
 179         unsigned long offset = attr_to_offset(buf, buf->head);
 180         void *data;
 181
 182         if (!name)
 183                 name = "";
 184
 185         head = blobmsg_new(buf, type, name, 0, &data);
 186         blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blobmsg_hdrlen(strlen(name)));
 187         buf->head = head;
 188         return (void *)offset;
 189 }
 190
 191 void *
 192 blobmsg_alloc_string_buffer(struct blob_buf *buf, const char *name, int maxlen)
 193 {
 194         struct blob_attr *attr;
 195         void *data_dest;
 196
 197         attr = blobmsg_new(buf, BLOBMSG_TYPE_STRING, name, maxlen, &data_dest);
 198         if (!attr)
 199                 return NULL;
 200
 201         data_dest = blobmsg_data(attr);
 202         blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blob_pad_len(attr));
 203         blob_set_raw_len(attr, blob_raw_len(attr) - maxlen);
 204
 205         return data_dest;
 206 }
 207
 208 void
 209 blobmsg_add_string_buffer(struct blob_buf *buf)
 210 {
 211         struct blob_attr *attr;
 212         int len, attrlen;
 213
 214         attr = blob_next(buf->head);
 215         len = strlen(blobmsg_data(attr)) + 1;
 216
 217         attrlen = blob_raw_len(attr) + len;
 218         blob_set_raw_len(attr, attrlen);
 219         blob_fill_pad(attr);
 220
 221         blob_set_raw_len(buf->head, blob_raw_len(buf->head) + blob_pad_len(attr));
 222 }
 223
 224 int
 225 blobmsg_add_field(struct blob_buf *buf, int type, const char *name,
 226                   const void *data, int len)
 227 {
 228         struct blob_attr *attr;
 229         void *data_dest;
 230
 231         attr = blobmsg_new(buf, type, name, len, &data_dest);
 232         if (!attr)
 233                 return -1;
 234
 235         if (len > 0)
 236                 memcpy(data_dest, data, len);
 237
 238         return 0;
 239 }