转载：https://segmentfault.com/a/1190000002391970
BLOB二进制对象(blob.c/h)
数据结构
全选 struct blob_attr { uint32_t id_len;
/** 高1位为extend标志，高7位存储id， * 低24位存储data的内存大小 */ char data[];
} __packed;
struct blob_attr_info { unsigned int type;
unsigned int minlen;
unsigned int maxlen;
bool (*validate)(const struct blob_attr_info *, struct blob_attr *);
};
struct blob_buf { struct blob_attr *head;
bool (*grow)(struct blob_buf *buf, int minlen);
int buflen;
void *buf;
};
存储结构
文章图片
接口说明
获取BLOB属性信息 /**
* 返回指向BLOB属性数据区指针
*/
static inline void * blob_data(const struct blob_attr *attr)/**
* 返回BLOB属性ID
*/
static inline unsigned int blob_id(const struct blob_attr *attr)/**
* 判断BLOB属性扩展标志是否为真
*/
static inline bool blob_is_extended(const struct blob_attr *attr)/**
* 返回BLOB属性有效存储空间大小
*/
static inline unsigned int blob_len(const struct blob_attr *attr)/*
* 返回BLOB属性完全存储空间大小(包括头部)
*/
static inline unsigned int blob_raw_len(const struct blob_attr *attr)/*
* 返回BLOB属性填补后存储空间大小(包括头部)
*/
static inline unsigned int blob_pad_len(const struct blob_attr *attr)
获取BLOB数据信息
static inline uint8_t blob_get_u8(const struct blob_attr *attr)static inline uint16_t blob_get_u16(const struct blob_attr *attr)static inline uint32_t blob_get_u32(const struct blob_attr *attr)static inline uint64_t blob_get_u64(const struct blob_attr *attr)static inline int8_t blob_get_int8(const struct blob_attr *attr)static inline int16_t blob_get_int16(const struct blob_attr *attr)static inline int32_t blob_get_int32(const struct blob_attr *attr)static inline int64_t blob_get_int64(const struct blob_attr *attr)static inline const char * blob_get_string(const struct blob_attr *attr)
设置BLOB数据信息
static inline struct blob_attr *
blob_put_string(struct blob_buf *buf, int id, const char *str)static inline struct blob_attr *
blob_put_u8(struct blob_buf *buf, int id, uint8_t val)static inline struct blob_attr *
blob_put_u16(struct blob_buf *buf, int id, uint16_t val)static inline struct blob_attr *
blob_put_u32(struct blob_buf *buf, int id, uint32_t val)static inline struct blob_attr *
blob_put_u64(struct blob_buf *buf, int id, uint64_t val)#define blob_put_int8blob_put_u8
#define blob_put_int16blob_put_u16
#define blob_put_int32blob_put_u32
#define blob_put_int64blob_put_u64struct blob_attr *
blob_put(struct blob_buf *buf, int id, const void *ptr, unsigned int len)/**
* ptr - 指向struct blob_attr
*/
struct blob_attr *
blob_put_raw(struct blob_buf *buf, const void *ptr, unsigned int len)
遍历
#define __blob_for_each_attr(pos, attr, rem)
#define blob_for_each_attr(pos, attr, rem)
复制
struct blob_attr * blob_memdup(struct blob_attr *attr)
数据类型判断
enum {
BLOB_ATTR_UNSPEC,
BLOB_ATTR_NESTED,/** 嵌套 */
BLOB_ATTR_BINARY,
BLOB_ATTR_STRING,
BLOB_ATTR_INT8,
BLOB_ATTR_INT16,
BLOB_ATTR_INT32,
BLOB_ATTR_INT64,
BLOB_ATTR_LAST
};
bool blob_check_type(const void *ptr, unsigned int len, int type)
嵌套操作
void * blob_nest_start(struct blob_buf *buf, int id)
Void blob_nest_end(struct blob_buf *buf, void *cookie)
判断
bool blob_attr_equal(const struct blob_attr *a1, const struct blob_attr *a2)
初始/销毁
/**
* 初始化BLOB buffer
*/
int blob_buf_init(struct blob_buf *buf, int id)/**
* 销毁BLOB buffer
*/
void blob_buf_free(struct blob_buf *buf)
解析BLOB
/**
* 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
*
* @paramattr 输入BLOB属性串
* @paramdata 输出BLOB属性数组
* @paraminfo 属性过滤策略
* @parammax data数组大小
*/
int blob_parse(struct blob_attr *attr, struct blob_attr **data,
const struct blob_attr_info *info, int max)
BLOB消息对象(blobmsg.c/h) 数据结构
struct blobmsg_hdr {
uint16_t namelen;
uint8_t name[];
} __packed;
struct blobmsg_policy {
const char *name;
enum blobmsg_type type;
};
存储结构
文章图片
消息类型
enum blobmsg_type {
BLOBMSG_TYPE_UNSPEC,
BLOBMSG_TYPE_ARRAY,
BLOBMSG_TYPE_TABLE,
BLOBMSG_TYPE_STRING,
BLOBMSG_TYPE_INT64,
BLOBMSG_TYPE_INT32,
BLOBMSG_TYPE_INT16,
BLOBMSG_TYPE_INT8,
__BLOBMSG_TYPE_LAST,
BLOBMSG_TYPE_LAST = __BLOBMSG_TYPE_LAST - 1,
BLOBMSG_TYPE_BOOL = BLOBMSG_TYPE_INT8,
};
接口说明
基本操作
/**
* 根据BLOB消息名字长度计算出blobmsg头部大小
*/
static inline int blobmsg_hdrlen(unsigned int namelen)/**
* 获取BLOB消息名字
*/
static inline const char *blobmsg_name(const struct blob_attr *attr)/**
* 获取BLOB消息类型
*/
static inline int blobmsg_type(const struct blob_attr *attr)/**
* 获取BLOB消息数据内容
*/
static inline void *blobmsg_data(const struct blob_attr *attr)/**
* 获取BLOB消息数据内容大小
*/
static inline int blobmsg_data_len(const struct blob_attr *attr)
static inline int blobmsg_len(const struct blob_attr *attr)
数据类型判断
/**
* 判断BLOBMSG属性类型是否合法
*/
bool blobmsg_check_attr(const struct blob_attr *attr, bool name)
设置
int blobmsg_add_field(struct blob_buf *buf, int type, const char *name,
const void *data, unsigned int len)static inline int
blobmsg_add_u8(struct blob_buf *buf, const char *name, uint8_t val)static inline int
blobmsg_add_u16(struct blob_buf *buf, const char *name, uint16_t val)static inline int
blobmsg_add_u32(struct blob_buf *buf, const char *name, uint32_t val)static inline int
blobmsg_add_u64(struct blob_buf *buf, const char *name, uint64_t val)static inline int
blobmsg_add_string(struct blob_buf *buf, const char *name, const char *string)static inline int
blobmsg_add_blob(struct blob_buf *buf, struct blob_attr *attr)/**
* 格式化设备BLOGMSG
*/
void blobmsg_printf(struct blob_buf *buf, const char *name, const char *format, ...)
获取
static inline uint8_t blobmsg_get_u8(struct blob_attr *attr)
static inline bool blobmsg_get_bool(struct blob_attr *attr)
static inline uint16_t blobmsg_get_u16(struct blob_attr *attr)
static inline uint32_t blobmsg_get_u32(struct blob_attr *attr)
static inline uint64_t blobmsg_get_u64(struct blob_attr *attr)
static inline char *blobmsg_get_string(struct blob_attr *attr)
创建
/**
* 创建BLOBMSG，返回数据区开始地址
*/
void *blobmsg_alloc_string_buffer(struct blob_buf *buf, const char *name,
unsigned int maxlen)/**
* 扩大BLOGMSG，返回数据区开始地址
*/
void *blobmsg_realloc_string_buffer(struct blob_buf *buf, unsigned int maxlen)void blobmsg_add_string_buffer(struct blob_buf *buf)
遍历
#define blobmsg_for_each_attr(pos, attr, rem)
嵌套
static inline void * blobmsg_open_array(struct blob_buf *buf, const char *name)
static inline void blobmsg_close_array(struct blob_buf *buf, void *cookie)static inline void *blobmsg_open_table(struct blob_buf *buf, const char *name)
static inline void blobmsg_close_table(struct blob_buf *buf, void *cookie)
解析BLOGMSG
/**
* 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
*
* @parampolicy 过滤策略
* @parampolicy_len 策略个数
* @paramtb 返回属性数据
* @paramlen data属性个数
*/
int blobmsg_parse(const struct blobmsg_policy *policy, int policy_len,
struct blob_attr **tb, void *data, unsigned int len)
例子 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'
定义参数列表:
enum {
POLICY_ATTR_NAME,/** name */
POLICY_ATTR_ENABLE,/** enable */
POLICY_ATTR_DNS,/** dns */
__POLICY_ATTR_MAX
};
static const struct blobmsg_policy policy_attrs[__POLICY_ATTR_MAX] = {
[POLICY_ATTR_NAME] = { .name = "name", .type = BLOBMSG_TYPE_STRING },
[POLICY_ATTR_ENABLE] = { .name = "enable", .type = BLOBMSG_TYPE_BOOL },
[POLICY_ATTR_DNS] = { .name = "dns", .type = BLOBMSG_TYPE_ARRAY },
};
/** 定义BLOBMSG_TYPE_ARRAY类型参数的实际数据类型 */
static const struct uci_blob_param_info policy_attr_info[__POLICY_ATTR_MAX] = {
[POLICY_ATTR_DNS] = { .type = BLOBMSG_TYPE_STRING },
};
static const struct uci_blob_param_list policy_attr_list = {
.n_params = __POLICY_ATTR_MAX,
.params = policy_attrs,
.info = policy_attr_info,
};
【BLOB二进制对象(blob.c/h)】 转化为BLOB:
static struct uci_context *g_uci_ctx;
static struct blob_buf *b;
void
transform(const char *config)
{
struct uci_context *ctx = g_uci_ctx;
struct uci_package *p = NULL;
if (!ctx) {
ctx = uci_alloc_context();
g_uci_ctx = ctx;
uci_set_confdir(ctx, NULL);
} else {
p = uci_lookup_package(ctx, config);
if (p)
uci_unload(ctx, p);
}if (uci_load(ctx, config, &p))
return;
struct uci_element *e;
struct blob_attr *config = NULL;
uci_foreach_element(&p->sectons, e) {
struct uci_section *s = uci_to_section(e);
blob_buf_init(&b, 0);
uci_to_blob(&b, s, &policy_attr_list);
config = blob_memdup(b.head);
/**
* do something with `config`
* free(config), when not use it
*/
}
}
使用转化后的blob_attr
void
foo(blob_attr *confg)
{
struct blob_attr *tb[__POLICY_ATTR_MAX];
blobmsg_parse(policy_attrs, __POLICY_ATTR_MAX, tb,
blob_data(config), blob_len(config));
/**
* do something with *tb[]
*/
}
