blobmsg.h

   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 #ifndef __BLOBMSG_H
  17 #define __BLOBMSG_H
  18
  19 #include "blob.h"
  20
  21 #define BLOBMSG_ALIGN   2
  22 #define BLOBMSG_PADDING(len) (((len) + (1 << BLOBMSG_ALIGN) - 1) & ~((1 << BLOBMSG_ALIGN) - 1))
  23
  24 enum blobmsg_type {
  25         BLOBMSG_TYPE_UNSPEC,
  26         BLOBMSG_TYPE_ARRAY,
  27         BLOBMSG_TYPE_TABLE,
  28         BLOBMSG_TYPE_STRING,
  29         BLOBMSG_TYPE_INT64,
  30         BLOBMSG_TYPE_INT32,
  31         BLOBMSG_TYPE_INT16,
  32         BLOBMSG_TYPE_INT8,
  33         __BLOBMSG_TYPE_LAST,
  34         BLOBMSG_TYPE_LAST = __BLOBMSG_TYPE_LAST - 1,
  35         BLOBMSG_TYPE_BOOL = BLOBMSG_TYPE_INT8,
  36 };
  37
  38 struct blobmsg_hdr {
  39         uint16_t namelen;
  40         uint8_t name[];
  41 } __packed;
  42
  43 struct blobmsg_policy {
  44         const char *name;
  45         enum blobmsg_type type;
  46 };
  47
  48 static inline int blobmsg_hdrlen(int namelen)
  49 {
  50         return BLOBMSG_PADDING(sizeof(struct blobmsg_hdr) + namelen + 1);
  51 }
  52
  53 static inline const char *blobmsg_name(const struct blob_attr *attr)
  54 {
  55         struct blobmsg_hdr *hdr = (struct blobmsg_hdr *) blob_data(attr);
  56         return (const char *) hdr->name;
  57 }
  58
  59 static inline int blobmsg_type(const struct blob_attr *attr)
  60 {
  61         return blob_id(attr);
  62 }
  63
  64 static inline void *blobmsg_data(const struct blob_attr *attr)
  65 {
  66         struct blobmsg_hdr *hdr = (struct blobmsg_hdr *) blob_data(attr);
  67         return (char *) hdr + blobmsg_hdrlen(be16_to_cpu(hdr->namelen));
  68 }
  69
  70 static inline int blobmsg_data_len(const struct blob_attr *attr)
  71 {
  72         uint8_t *start, *end;
  73
  74         start = (uint8_t *) blob_data(attr);
  75         end = (uint8_t *) blobmsg_data(attr);
  76
  77         return blob_len(attr) - (end - start);
  78 }
  79
  80 bool blobmsg_check_attr(const struct blob_attr *attr, bool name);
  81 int blobmsg_parse(const struct blobmsg_policy *policy, int policy_len,
  82                   struct blob_attr **tb, void *data, int len);
  83
  84 int blobmsg_add_field(struct blob_buf *buf, int type, const char *name,
  85                       const void *data, int len);
  86
  87 static inline int
  88 blobmsg_add_u8(struct blob_buf *buf, const char *name, uint8_t val)
  89 {
  90         return blobmsg_add_field(buf, BLOBMSG_TYPE_INT8, name, &val, 1);
  91 }
  92
  93 static inline int
  94 blobmsg_add_u16(struct blob_buf *buf, const char *name, uint16_t val)
  95 {
  96         val = cpu_to_be16(val);
  97         return blobmsg_add_field(buf, BLOBMSG_TYPE_INT16, name, &val, 2);
  98 }
  99
 100 static inline int
 101 blobmsg_add_u32(struct blob_buf *buf, const char *name, uint32_t val)
 102 {
 103         val = cpu_to_be32(val);
 104         return blobmsg_add_field(buf, BLOBMSG_TYPE_INT32, name, &val, 4);
 105 }
 106
 107 static inline int
 108 blobmsg_add_u64(struct blob_buf *buf, const char *name, uint64_t val)
 109 {
 110         val = cpu_to_be64(val);
 111         return blobmsg_add_field(buf, BLOBMSG_TYPE_INT64, name, &val, 8);
 112 }
 113
 114 static inline int
 115 blobmsg_add_string(struct blob_buf *buf, const char *name, const char *string)
 116 {
 117         return blobmsg_add_field(buf, BLOBMSG_TYPE_STRING, name, string, strlen(string) + 1);
 118 }
 119
 120 void *blobmsg_open_nested(struct blob_buf *buf, const char *name, bool array);
 121
 122 static inline void *
 123 blobmsg_open_array(struct blob_buf *buf, const char *name)
 124 {
 125         return blobmsg_open_nested(buf, name, true);
 126 }
 127
 128 static inline void *
 129 blobmsg_open_table(struct blob_buf *buf, const char *name)
 130 {
 131         return blobmsg_open_nested(buf, name, false);
 132 }
 133
 134 static inline void
 135 blobmsg_close_array(struct blob_buf *buf, void *cookie)
 136 {
 137         blob_nest_end(buf, cookie);
 138 }
 139
 140 static inline void
 141 blobmsg_close_table(struct blob_buf *buf, void *cookie)
 142 {
 143         blob_nest_end(buf, cookie);
 144 }
 145
 146 static inline int blobmsg_buf_init(struct blob_buf *buf)
 147 {
 148         return blob_buf_init(buf, BLOBMSG_TYPE_TABLE);
 149 }
 150
 151 static inline uint8_t blobmsg_get_u8(struct blob_attr *attr)
 152 {
 153         return *(uint8_t *) blobmsg_data(attr);
 154 }
 155
 156 static inline bool blobmsg_get_bool(struct blob_attr *attr)
 157 {
 158         return *(uint8_t *) blobmsg_data(attr);
 159 }
 160
 161 static inline uint16_t blobmsg_get_u16(struct blob_attr *attr)
 162 {
 163         return be16_to_cpu(*(uint16_t *) blobmsg_data(attr));
 164 }
 165
 166 static inline uint32_t blobmsg_get_u32(struct blob_attr *attr)
 167 {
 168         return be32_to_cpu(*(uint32_t *) blobmsg_data(attr));
 169 }
 170
 171 static inline uint64_t blobmsg_get_u64(struct blob_attr *attr)
 172 {
 173         return be64_to_cpu(*(uint64_t *) blobmsg_data(attr));
 174 }
 175
 176 void *blobmsg_alloc_string_buffer(struct blob_buf *buf, const char *name, int maxlen);
 177 void blobmsg_add_string_buffer(struct blob_buf *buf);
 178
 179 /* blobmsg to json formatting */
 180
 181 #define blobmsg_for_each_attr(pos, attr, rem) \
 182         for (rem = blobmsg_data_len(attr), pos = blobmsg_data(attr); \
 183                  rem > 0 && (blob_pad_len(pos) <= rem) && \
 184                  (blob_pad_len(pos) >= sizeof(struct blob_attr)); \
 185                  rem -= blob_pad_len(pos), pos = blob_next(pos))
 186
 187 #endif