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, bool name)
  65 {
  66         struct blob_attr *cur;
  67         int rem;
  68
  69         blobmsg_for_each_attr(cur, attr, rem) {
  70                 if (blobmsg_type(cur) != type)
  71                         return false;
  72
  73                 if (!blobmsg_check_attr(cur, name))
  74                         return false;
  75         }
  76
  77         return true;
  78 }
  79
  80 int blobmsg_parse(const struct blobmsg_policy *policy, int policy_len,
  81                   struct blob_attr **tb, void *data, int len)
  82 {
  83         struct blobmsg_hdr *hdr;
  84         struct blob_attr *attr;
  85         uint8_t *pslen;
  86         int i;
  87
  88         memset(tb, 0, policy_len * sizeof(*tb));
  89         pslen = alloca(policy_len);
  90         for (i = 0; i < policy_len; i++) {
  91                 if (!policy[i].name)
  92                         continue;
  93
  94                 pslen[i] = strlen(policy[i].name);
  95         }
  96
  97         __blob_for_each_attr(attr, data, len) {
  98                 hdr = blob_data(attr);
  99                 for (i = 0; i < policy_len; i++) {
 100                         if (!policy[i].name)
 101                                 continue;
 102
 103                         if (policy[i].type != BLOBMSG_TYPE_UNSPEC &&
 104                             blob_id(attr) != policy[i].type)
 105                                 continue;
 106
 107                         if (blobmsg_namelen(hdr) != pslen[i])
 108                                 continue;
 109
 110                         if (!blobmsg_check_attr(attr, true))
 111                                 return -1;
 112
 113                         if (tb[i])
 114                                 continue;
 115
 116                         if (strcmp(policy[i].name, (char *) hdr->name) != 0)
 117                                 continue;
 118
 119                         tb[i] = attr;
 120                 }
 121         }
 122
 123         return 0;
 124 }
 125
 126
 127 static struct blob_attr *
 128 blobmsg_new(struct blob_buf *buf, int type, const char *name, int payload_len, void **data)
 129 {
 130         struct blob_attr *attr;
 131         struct blobmsg_hdr *hdr;
 132         int attrlen, namelen;
 133         char *pad_start, *pad_end;
 134
 135         if (!name)
 136                 name = "";
 137
 138         namelen = strlen(name);
 139         attrlen = blobmsg_hdrlen(namelen) + payload_len;
 140         attr = blob_new(buf, type, attrlen);
 141         if (!attr)
 142                 return NULL;
 143
 144         hdr = blob_data(attr);
 145         hdr->namelen = cpu_to_be16(namelen);
 146         strcpy((char *) hdr->name, (const char *)name);
 147         pad_end = *data = blobmsg_data(attr);
 148         pad_start = (char *) &hdr->name[namelen];
 149         if (pad_start < pad_end)
 150                 memset(pad_start, 0, pad_end - pad_start);
 151
 152         return attr;
 153 }
 154
 155 static inline int
 156 attr_to_offset(struct blob_buf *buf, struct blob_attr *attr)
 157 {
 158         return (char *)attr - (char *) buf->buf;
 159 }
 160
 161
 162 void *
 163 blobmsg_open_nested(struct blob_buf *buf, const char *name, bool array)
 164 {
 165         struct blob_attr *head = buf->head;
 166         int type = array ? BLOBMSG_TYPE_ARRAY : BLOBMSG_TYPE_TABLE;
 167         unsigned long offset = attr_to_offset(buf, buf->head);
 168         void *data;
 169
 170         if (!name)
 171                 name = "";
 172
 173         head = blobmsg_new(buf, type, name, 0, &data);
 174         blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blobmsg_hdrlen(strlen(name)));
 175         buf->head = head;
 176         return (void *)offset;
 177 }
 178
 179 void *
 180 blobmsg_alloc_string_buffer(struct blob_buf *buf, const char *name, int maxlen)
 181 {
 182         struct blob_attr *attr;
 183         void *data_dest;
 184
 185         attr = blobmsg_new(buf, BLOBMSG_TYPE_STRING, name, maxlen, &data_dest);
 186         if (!attr)
 187                 return NULL;
 188
 189         data_dest = blobmsg_data(attr);
 190         blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blob_pad_len(attr));
 191         blob_set_raw_len(attr, blob_raw_len(attr) - maxlen);
 192
 193         return data_dest;
 194 }
 195
 196 void
 197 blobmsg_add_string_buffer(struct blob_buf *buf)
 198 {
 199         struct blob_attr *attr;
 200         int len, attrlen;
 201
 202         attr = blob_next(buf->head);
 203         len = strlen(blobmsg_data(attr)) + 1;
 204
 205         attrlen = blob_raw_len(attr) + len;
 206         blob_set_raw_len(attr, attrlen);
 207         blob_fill_pad(attr);
 208
 209         blob_set_raw_len(buf->head, blob_raw_len(buf->head) + blob_pad_len(attr));
 210 }
 211
 212 int
 213 blobmsg_add_field(struct blob_buf *buf, int type, const char *name,
 214                   const void *data, int len)
 215 {
 216         struct blob_attr *attr;
 217         void *data_dest;
 218
 219         attr = blobmsg_new(buf, type, name, len, &data_dest);
 220         if (!attr)
 221                 return -1;
 222
 223         if (len > 0)
 224                 memcpy(data_dest, data, len);
 225
 226         return 0;
 227 }