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 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 bool blobmsg_check_attr(const struct blob_attr *attr, bool name)
  27 {
  28         const struct blobmsg_hdr *hdr;
  29         const char *data;
  30         int id, len;
  31
  32         if (blob_len(attr) < sizeof(struct blobmsg_hdr))
  33                 return false;
  34
  35         hdr = (void *) attr->data;
  36         if (!hdr->namelen && name)
  37                 return false;
  38
  39         if (hdr->namelen > blob_len(attr) - sizeof(struct blobmsg_hdr))
  40                 return false;
  41
  42         if (hdr->name[hdr->namelen] != 0)
  43                 return false;
  44
  45         id = blob_id(attr);
  46         len = blobmsg_data_len(attr);
  47         data = blobmsg_data(attr);
  48
  49         if (!id || id > BLOBMSG_TYPE_LAST)
  50                 return false;
  51
  52         if (!blob_type[id])
  53                 return true;
  54
  55         return blob_check_type(data, len, blob_type[id]);
  56 }
  57
  58 int blobmsg_parse(const struct blobmsg_policy *policy, int policy_len,
  59                   struct blob_attr **tb, void *data, int len)
  60 {
  61         struct blobmsg_hdr *hdr;
  62         struct blob_attr *attr;
  63         uint8_t *pslen;
  64         int i;
  65
  66         memset(tb, 0, policy_len * sizeof(*tb));
  67         pslen = alloca(policy_len);
  68         for (i = 0; i < policy_len; i++) {
  69                 if (!policy[i].name)
  70                         continue;
  71
  72                 pslen[i] = strlen(policy[i].name);
  73         }
  74
  75         __blob_for_each_attr(attr, data, len) {
  76                 hdr = blob_data(attr);
  77                 for (i = 0; i < policy_len; i++) {
  78                         if (!policy[i].name)
  79                                 continue;
  80
  81                         if (policy[i].type != BLOBMSG_TYPE_UNSPEC &&
  82                             blob_id(attr) != policy[i].type)
  83                                 continue;
  84
  85                         if (hdr->namelen != pslen[i])
  86                                 continue;
  87
  88                         if (!blobmsg_check_attr(attr, true))
  89                                 return -1;
  90
  91                         if (tb[i])
  92                                 return -1;
  93
  94                         if (strcmp(policy[i].name, (char *) hdr->name) != 0)
  95                                 continue;
  96
  97                         tb[i] = attr;
  98                 }
  99         }
 100
 101         return 0;
 102 }
 103
 104
 105 static struct blob_attr *
 106 blobmsg_new(struct blob_buf *buf, int type, const char *name, int payload_len, void **data)
 107 {
 108         struct blob_attr *attr;
 109         struct blobmsg_hdr *hdr;
 110         int attrlen, namelen;
 111
 112         if (!name)
 113                 name = "";
 114
 115         namelen = strlen(name);
 116         attrlen = blobmsg_hdrlen(namelen) + payload_len;
 117         attr = blob_new(buf, type, attrlen);
 118         if (!attr)
 119                 return NULL;
 120
 121         hdr = blob_data(attr);
 122         hdr->namelen = namelen;
 123         strcpy((char *) hdr->name, (const char *)name);
 124         *data = blobmsg_data(attr);
 125
 126         return attr;
 127 }
 128
 129 static inline int
 130 attr_to_offset(struct blob_buf *buf, struct blob_attr *attr)
 131 {
 132         return (char *)attr - (char *) buf->buf;
 133 }
 134
 135
 136 void *
 137 blobmsg_open_nested(struct blob_buf *buf, const char *name, bool array)
 138 {
 139         struct blob_attr *head = buf->head;
 140         int type = array ? BLOBMSG_TYPE_ARRAY : BLOBMSG_TYPE_TABLE;
 141         unsigned long offset = attr_to_offset(buf, buf->head);
 142         void *data;
 143
 144         if (!name)
 145                 name = "";
 146
 147         head = blobmsg_new(buf, type, name, 0, &data);
 148         blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blobmsg_hdrlen(strlen(name)));
 149         buf->head = head;
 150         return (void *)offset;
 151 }
 152
 153 void *
 154 blobmsg_alloc_string_buffer(struct blob_buf *buf, const char *name, int maxlen)
 155 {
 156         struct blob_attr *attr;
 157         void *data_dest;
 158
 159         attr = blobmsg_new(buf, BLOBMSG_TYPE_STRING, name, maxlen, &data_dest);
 160         if (!attr)
 161                 return NULL;
 162
 163         data_dest = blobmsg_data(attr);
 164         blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blob_pad_len(attr));
 165         blob_set_raw_len(attr, blob_raw_len(attr) - maxlen);
 166
 167         return data_dest;
 168 }
 169
 170 void
 171 blobmsg_add_string_buffer(struct blob_buf *buf)
 172 {
 173         struct blob_attr *attr;
 174         int len, attrlen;
 175
 176         attr = blob_next(buf->head);
 177         len = strlen(blobmsg_data(attr)) + 1;
 178
 179         attrlen = blob_raw_len(attr) + len;
 180         blob_set_raw_len(attr, attrlen);
 181         blob_set_raw_len(buf->head, blob_raw_len(buf->head) + blob_pad_len(attr));
 182 }
 183
 184 int
 185 blobmsg_add_field(struct blob_buf *buf, int type, const char *name,
 186                   const void *data, int len)
 187 {
 188         struct blob_attr *attr;
 189         void *data_dest;
 190
 191         if (type == BLOBMSG_TYPE_ARRAY ||
 192             type == BLOBMSG_TYPE_TABLE)
 193                 return -1;
 194
 195         attr = blobmsg_new(buf, type, name, len, &data_dest);
 196         if (!attr)
 197                 return -1;
 198
 199         if (len > 0)
 200                 memcpy(data_dest, data, len);
 201
 202         return 0;
 203 }