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libubox组件（2）——blob/blobmsg

时间：2016-06-24 19:02:29      阅读：4488      评论：0      收藏：0      [点我收藏+]

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一：blob相关接口

1.数据结构

   1:  struct blob_attr {
   2:      uint32_t id_len;    /** 高1位为extend标志，高7位存储id，
   3:                           *  低24位存储data的内存大小+结构大小(blob_attr) */
   4:      char data[];
   5:  } __packed;
   6:   实际使用中每个blob_attr的长度包含：结构长度(4)+数据长度+对齐特性= id_len+pad_len
   7:  struct blob_attr_info {
   8:      unsigned int type;
   9:      unsigned int minlen;
  10:      unsigned int maxlen;
  11:      bool (*validate)(const struct blob_attr_info *, struct blob_attr *);
  12:  };
  13:   
  14:  struct blob_buf {
  15:      struct blob_attr *head;
  16:      bool (*grow)(struct blob_buf *buf, int minlen);
  17:      int buflen;
  18:      void *buf;
  19:  };

2. 存储结构

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3.获取BLOB属性信息

   1:  /**
   2:   * 返回指向BLOB属性数据区指针
   3:   */
   4:  static inline void * blob_data(const struct blob_attr *attr)
   5:   
   6:  /**
   7:   * 返回BLOB属性ID
   8:   */
   9:  static inline unsigned int blob_id(const struct blob_attr *attr)
  10:   
  11:  /**
  12:   * 判断BLOB属性扩展标志是否为真
  13:   */
  14:  static inline bool blob_is_extended(const struct blob_attr *attr)
  15:   
  16:  /**
  17:   * 返回BLOB属性有效存储空间大小
  18:   */
  19:  static inline unsigned int blob_len(const struct blob_attr *attr)
  20:   
  21:  /*
  22:   * 返回BLOB属性完全存储空间大小(包括头部)
  23:   */
  24:  static inline unsigned int blob_raw_len(const struct blob_attr *attr)
  25:   
  26:  /*
  27:   * 返回BLOB属性填补后存储空间大小(包括头部)
  28:   */
  29:  static inline unsigned int blob_pad_len(const struct blob_attr *attr)
 
4.获取BLOB数据信息
   1:  static inline uint8_t blob_get_u8(const struct blob_attr *attr)
   2:   
   3:  static inline uint16_t blob_get_u16(const struct blob_attr *attr)
   4:   
   5:  static inline uint32_t blob_get_u32(const struct blob_attr *attr)
   6:   
   7:  static inline uint64_t blob_get_u64(const struct blob_attr *attr)
   8:   
   9:  static inline int8_t blob_get_int8(const struct blob_attr *attr)
  10:   
  11:  static inline int16_t blob_get_int16(const struct blob_attr *attr)
  12:   
  13:  static inline int32_t blob_get_int32(const struct blob_attr *attr)
  14:   
  15:  static inline int64_t blob_get_int64(const struct blob_attr *attr)
  16:   
  17:  static inline const char * blob_get_string(const struct blob_attr *attr)
 
 
5.设置BLOB数据信息
   1:  static inline struct blob_attr *
   2:  blob_put_string(struct blob_buf *buf, int id, const char *str)
   3:   
   4:  static inline struct blob_attr *
   5:  blob_put_u8(struct blob_buf *buf, int id, uint8_t val)
   6:   
   7:  static inline struct blob_attr *
   8:  blob_put_u16(struct blob_buf *buf, int id, uint16_t val)
   9:   
  10:  static inline struct blob_attr *
  11:  blob_put_u32(struct blob_buf *buf, int id, uint32_t val)
  12:   
  13:  static inline struct blob_attr *
  14:  blob_put_u64(struct blob_buf *buf, int id, uint64_t val)
  15:   
  16:  #define blob_put_int8   blob_put_u8
  17:  #define blob_put_int16  blob_put_u16
  18:  #define blob_put_int32  blob_put_u32
  19:  #define blob_put_int64  blob_put_u64
  20:   
  21:  struct blob_attr *
  22:  blob_put(struct blob_buf *buf, int id, const void *ptr, unsigned int len)
  23:   
  24:  /**
  25:   * ptr - 指向struct blob_attr
  26:   */
  27:  struct blob_attr *
  28:  blob_put_raw(struct blob_buf *buf, const void *ptr, unsigned int len)

6. 遍历

#define __blob_for_each_attr(pos, attr, rem)
#define blob_for_each_attr(pos, attr, rem)
 
7. 复制
struct blob_attr * blob_memdup(struct blob_attr *attr)

8. 数据类型判断

   1:  enum {
   2:      BLOB_ATTR_UNSPEC,
   3:      BLOB_ATTR_NESTED,  /** 嵌套 */
   4:      BLOB_ATTR_BINARY,
   5:      BLOB_ATTR_STRING,
   6:      BLOB_ATTR_INT8,
   7:      BLOB_ATTR_INT16,
   8:      BLOB_ATTR_INT32,
   9:      BLOB_ATTR_INT64,
  10:      BLOB_ATTR_LAST
  11:  };
  12:  bool blob_check_type(const void *ptr, unsigned int len, int type)

9.嵌套操作

   1:  void * blob_nest_start(struct blob_buf *buf, int id)
   2:  Void blob_nest_end(struct blob_buf *buf, void *cookie)

10.判断

bool blob_attr_equal(const struct blob_attr *a1, const struct blob_attr *a2)

11.初始/销毁，解析

   1:  /**
   2:   * 初始化BLOB buffer
   3:   */
   4:  int blob_buf_init(struct blob_buf *buf, int id)
   5:   
   6:  /**
   7:   * 销毁BLOB buffer
   8:   */
   9:  void blob_buf_free(struct blob_buf *buf)
  10:   
  11:  /**
  12:   * 从attr串中根据info策略过滤，得到的结果存储在data属性数组中
  13:   *
  14:   * @param  attr 输入BLOB属性串
  15:   * @param  data 输出BLOB属性数组
  16:   * @param  info 属性过滤策略
  17:   * @param  max data数组大小
  18:   */
  19:  int blob_parse(struct blob_attr *attr, struct blob_attr **data, 
  20:                 const struct blob_attr_info *info, int max)
 
 
二：blobmsg相关接口
1.数据结构
   1:  struct blobmsg_hdr {
   2:      uint16_t namelen;
   3:      uint8_t name[];
   4:  } __packed;
   5:   
   6:  struct blobmsg_policy {
   7:      const char *name;
   8:      enum blobmsg_type type;
   9:  };
 
2.存储结构
技术分享
3.消息类型
   1:  enum blobmsg_type {
   2:      BLOBMSG_TYPE_UNSPEC,
   3:      BLOBMSG_TYPE_ARRAY,
   4:      BLOBMSG_TYPE_TABLE,
   5:      BLOBMSG_TYPE_STRING,
   6:      BLOBMSG_TYPE_INT64,
   7:      BLOBMSG_TYPE_INT32,
   8:      BLOBMSG_TYPE_INT16,
   9:      BLOBMSG_TYPE_INT8,
  10:      __BLOBMSG_TYPE_LAST,
  11:      BLOBMSG_TYPE_LAST = __BLOBMSG_TYPE_LAST - 1,
  12:      BLOBMSG_TYPE_BOOL = BLOBMSG_TYPE_INT8,
  13:  };

4.基本操作

   1:  /**
   2:   * 根据BLOB消息名字长度计算出blobmsg头部大小
   3:   */
   4:  static inline int blobmsg_hdrlen(unsigned int namelen)
   5:   
   6:  /**
   7:   * 获取BLOB消息名字
   8:   */
   9:  static inline const char *blobmsg_name(const struct blob_attr *attr)
  10:   
  11:  /**
  12:   * 获取BLOB消息类型
  13:   */
  14:  static inline int blobmsg_type(const struct blob_attr *attr)
  15:   
  16:  /**
  17:   * 获取BLOB消息数据内容
  18:   */
  19:  static inline void *blobmsg_data(const struct blob_attr *attr)
  20:   
  21:  /**
  22:   * 获取BLOB消息数据内容大小
  23:   */
  24:  static inline int blobmsg_data_len(const struct blob_attr *attr)
  25:  static inline int blobmsg_len(const struct blob_attr *attr)
  26:  数据类型判断
  27:   
  28:  /**
  29:   * 判断BLOBMSG属性类型是否合法
  30:   */
  31:  bool blobmsg_check_attr(const struct blob_attr *attr, bool name)
  32:  设置
  33:   
  34:  int blobmsg_add_field(struct blob_buf *buf, int type, const char *name,
  35:                        const void *data, unsigned int len)
  36:   
  37:  static inline int
  38:  blobmsg_add_u8(struct blob_buf *buf, const char *name, uint8_t val)
  39:   
  40:  static inline int
  41:  blobmsg_add_u16(struct blob_buf *buf, const char *name, uint16_t val)
  42:   
  43:  static inline int
  44:  blobmsg_add_u32(struct blob_buf *buf, const char *name, uint32_t val)
  45:   
  46:  static inline int
  47:  blobmsg_add_u64(struct blob_buf *buf, const char *name, uint64_t val)
  48:   
  49:  static inline int
  50:  blobmsg_add_string(struct blob_buf *buf, const char *name, const char *string)
  51:   
  52:  static inline int
  53:  blobmsg_add_blob(struct blob_buf *buf, struct blob_attr *attr)
  54:   
  55:  /**
  56:   * 格式化设备BLOGMSG
  57:   */
  58:  void blobmsg_printf(struct blob_buf *buf, const char *name, const char *format, ...)
  59:  获取
  60:   
  61:  static inline uint8_t blobmsg_get_u8(struct blob_attr *attr)
  62:  static inline bool blobmsg_get_bool(struct blob_attr *attr)
  63:  static inline uint16_t blobmsg_get_u16(struct blob_attr *attr)
  64:  static inline uint32_t blobmsg_get_u32(struct blob_attr *attr)
  65:  static inline uint64_t blobmsg_get_u64(struct blob_attr *attr)
  66:  static inline char *blobmsg_get_string(struct blob_attr *attr)
  67:  创建
  68:   
  69:  /**
  70:   * 创建BLOBMSG，返回数据区开始地址
  71:   */
  72:  void *blobmsg_alloc_string_buffer(struct blob_buf *buf, const char *name, 
  73:  unsigned int maxlen)
  74:   
  75:  /**
  76:   * 扩大BLOGMSG，返回数据区开始地址
  77:   */
  78:  void *blobmsg_realloc_string_buffer(struct blob_buf *buf, unsigned int maxlen)
  79:   
  80:  void blobmsg_add_string_buffer(struct blob_buf *buf)
  81:  遍历
  82:   
  83:  #define blobmsg_for_each_attr(pos, attr, rem)
  84:  嵌套
  85:   
  86:  static inline void * blobmsg_open_array(struct blob_buf *buf, const char *name)
  87:  static inline void blobmsg_close_array(struct blob_buf *buf, void *cookie)
  88:   
  89:  static inline void *blobmsg_open_table(struct blob_buf *buf, const char *name)
  90:  static inline void blobmsg_close_table(struct blob_buf *buf, void *cookie)
  91:  解析BLOGMSG
  92:   
  93:  /**
  94:   * 从data BLOGMSG串中根据policy策略过滤，得到的结果存储在tb BLOGATTR数组中
  95:   *
  96:   * @param  policy 过滤策略
  97:   * @param  policy_len 策略个数
  98:   * @param  tb 返回属性数据
  99:   * @param  len data属性个数
 100:   */
 101:  int blobmsg_parse(const struct blobmsg_policy *policy, int policy_len,
 102:                    struct blob_attr **tb, void *data, unsigned int len)
 
 
三：实例操作
把UCI转化为BLOB

UCI配置文件:
/etc/config/test

config policy test
    option name ‘test‘
    option enable ‘1‘
    option dns ‘1.1.1.1 2.2.2.2‘
 
 
   1:  定义参数列表:
   2:   
   3:  enum {
   4:      POLICY_ATTR_NAME,       /** name */
   5:      POLICY_ATTR_ENABLE,     /** enable */
   6:      POLICY_ATTR_DNS,        /** dns */
   7:      __POLICY_ATTR_MAX
   8:  };
   9:   
  10:  static const struct blobmsg_policy policy_attrs[__POLICY_ATTR_MAX] = {
  11:      [POLICY_ATTR_NAME] = { .name = "name", .type = BLOBMSG_TYPE_STRING },
  12:      [POLICY_ATTR_ENABLE] = { .name = "enable", .type = BLOBMSG_TYPE_BOOL },
  13:      [POLICY_ATTR_DNS] = { .name = "dns", .type = BLOBMSG_TYPE_ARRAY },
  14:  };
  15:   
  16:  /** 定义BLOBMSG_TYPE_ARRAY类型参数的实际数据类型 */
  17:  static const struct uci_blob_param_info policy_attr_info[__POLICY_ATTR_MAX] = {
  18:      [POLICY_ATTR_DNS] = { .type = BLOBMSG_TYPE_STRING },
  19:  };
  20:   
  21:  static const struct uci_blob_param_list policy_attr_list = {
  22:      .n_params = __POLICY_ATTR_MAX,
  23:      .params = policy_attrs,
  24:      .info = policy_attr_info,
  25:  };
  26:  转化为BLOB:
  27:   
  28:  static struct uci_context *g_uci_ctx;
  29:  static struct blob_buf *b;
  30:   
  31:  void
  32:  transform(const char *config)
  33:  {
  34:      struct uci_context *ctx = g_uci_ctx;
  35:      struct uci_package *p = NULL;
  36:   
  37:      if (!ctx) {
  38:          ctx = uci_alloc_context();
  39:          g_uci_ctx = ctx;
  40:          uci_set_confdir(ctx, NULL);
  41:      } else {
  42:          p = uci_lookup_package(ctx, config);
  43:          if (p)
  44:              uci_unload(ctx, p);
  45:      }
  46:   
  47:      if (uci_load(ctx, config, &p))
  48:          return;    
  49:   
  50:      struct uci_element *e;
  51:      struct blob_attr *config = NULL;
  52:      uci_foreach_element(&p->sectons, e) {
  53:          struct uci_section *s = uci_to_section(e);
  54:   
  55:          blob_buf_init(&b, 0);
  56:          uci_to_blob(&b, s, &policy_attr_list);
  57:          config = blob_memdup(b.head);
  58:   
  59:          /**
  60:           * do something with `config` 
  61:           * free(config), when not use it
  62:           */
  63:      }
  64:  }
  65:  使用转化后的blob_attr
  66:   
  67: void
  68:  foo(blob_attr *confg)
  69:  {
  70:      struct blob_attr *tb[__POLICY_ATTR_MAX];
  71:   
  72:      blobmsg_parse(policy_attrs, __POLICY_ATTR_MAX, tb,
  73:              blob_data(config), blob_len(config));
  74:   
  75:      /**
  76:       * do something with *tb[] 
  77:       */
  78:  }
 

libubox组件（2）——blob/blobmsg

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原文地址：http://www.cnblogs.com/xuyh/p/5615096.html
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