blobmsg.h

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/*
 * Copyright (C) 2010-2012 Felix Fietkau <nbd@openwrt.org>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#ifndef __BLOBMSG_H
#define __BLOBMSG_H
 
#include <stdarg.h>
#include "blob.h"
 
#define BLOBMSG_ALIGN   2
#define BLOBMSG_PADDING(len) (((len) + (1 << BLOBMSG_ALIGN) - 1) & ~((1 << BLOBMSG_ALIGN) - 1))
 
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_BOOL = BLOBMSG_TYPE_INT8,
        BLOBMSG_TYPE_DOUBLE,
        __BLOBMSG_TYPE_LAST,
        BLOBMSG_TYPE_LAST = __BLOBMSG_TYPE_LAST - 1,
        BLOBMSG_CAST_INT64 = __BLOBMSG_TYPE_LAST,
};
 
struct blobmsg_hdr {
        uint16_t namelen;
        uint8_t name[];
} __packed;
 
struct blobmsg_policy {
        const char *name;
        enum blobmsg_type type;
};
 
static inline int blobmsg_hdrlen(unsigned int namelen)
{
        return BLOBMSG_PADDING(sizeof(struct blobmsg_hdr) + namelen + 1);
}
 
static inline void blobmsg_clear_name(struct blob_attr *attr)
{
        struct blobmsg_hdr *hdr = (struct blobmsg_hdr *) blob_data(attr);
        hdr->name[0] = 0;
}
 
static inline const char *blobmsg_name(const struct blob_attr *attr)
{
        struct blobmsg_hdr *hdr = (struct blobmsg_hdr *) blob_data(attr);
        return (const char *)(hdr + 1);
}
 
static inline int blobmsg_type(const struct blob_attr *attr)
{
        return blob_id(attr);
}
 
static uint16_t blobmsg_namelen(const struct blobmsg_hdr *hdr)
{
        return be16_to_cpu(hdr->namelen);
}
 
static inline void *blobmsg_data(const struct blob_attr *attr)
{
        struct blobmsg_hdr *hdr;
        char *data;
 
        if (!attr)
                return NULL;
 
        hdr = (struct blobmsg_hdr *) blob_data(attr);
        data = (char *) blob_data(attr);
 
        if (blob_is_extended(attr))
                data += blobmsg_hdrlen(blobmsg_namelen(hdr));
 
        return data;
}
 
static inline size_t blobmsg_data_len(const struct blob_attr *attr)
{
        uint8_t *start, *end;
 
        if (!attr)
                return 0;
 
        start = (uint8_t *) blob_data(attr);
        end = (uint8_t *) blobmsg_data(attr);
 
        return blob_len(attr) - (end - start);
}
 
static inline size_t blobmsg_len(const struct blob_attr *attr)
{
        return blobmsg_data_len(attr);
}
 
/*
 * blobmsg_check_attr: validate a list of attributes
 *
 * This method may be used with trusted data only. Providing
 * malformed blobs will cause out of bounds memory access.
 */
bool blobmsg_check_attr(const struct blob_attr *attr, bool name);
 
/*
 * blobmsg_check_attr_len: validate a list of attributes
 *
 * This method should be safer implementation of blobmsg_check_attr.
 * It will limit all memory access performed on the blob to the
 * range [attr, attr + len] (upper bound non inclusive) and is
 * thus suited for checking of untrusted blob attributes.
 */
bool blobmsg_check_attr_len(const struct blob_attr *attr, bool name, size_t len);
 
/*
 * blobmsg_check_attr_list: validate a list of attributes
 *
 * This method may be used with trusted data only. Providing
 * malformed blobs will cause out of bounds memory access.
 */
bool blobmsg_check_attr_list(const struct blob_attr *attr, int type);
 
/*
 * blobmsg_check_attr_list_len: validate a list of untrusted attributes
 *
 * This method should be safer implementation of blobmsg_check_attr_list.
 * It will limit all memory access performed on the blob to the
 * range [attr, attr + len] (upper bound non inclusive) and is
 * thus suited for checking of untrusted blob attributes.
 */
bool blobmsg_check_attr_list_len(const struct blob_attr *attr, int type, size_t len);
 
/*
 * blobmsg_check_array: validate array/table and return size
 *
 * Checks if all elements of an array or table are valid and have
 * the specified type. Returns the number of elements in the array
 *
 * This method may be used with trusted data only. Providing
 * malformed blobs will cause out of bounds memory access.
 */
int blobmsg_check_array(const struct blob_attr *attr, int type);
 
/*
 * blobmsg_check_array_len: validate untrusted array/table and return size
 *
 * Checks if all elements of an array or table are valid and have
 * the specified type. Returns the number of elements in the array.
 *
 * This method should be safer implementation of blobmsg_check_array.
 * It will limit all memory access performed on the blob to the
 * range [attr, attr + len] (upper bound non inclusive) and is
 * thus suited for checking of untrusted blob attributes.
 */
int blobmsg_check_array_len(const struct blob_attr *attr, int type, size_t len);
 
int blobmsg_parse(const struct blobmsg_policy *policy, int policy_len,
                  struct blob_attr **tb, void *data, unsigned int len);
int blobmsg_parse_array(const struct blobmsg_policy *policy, int policy_len,
                        struct blob_attr **tb, void *data, unsigned int len);
 
int blobmsg_add_field(struct blob_buf *buf, int type, const char *name,
                      const void *data, unsigned int len);
 
static inline int
blobmsg_parse_attr(const struct blobmsg_policy *policy, int policy_len,
                   struct blob_attr **tb, struct blob_attr *data)
{
        return blobmsg_parse(policy, policy_len, tb, blobmsg_data(data), blobmsg_len(data));
}
 
static inline int
blobmsg_parse_array_attr(const struct blobmsg_policy *policy, int policy_len,
                         struct blob_attr **tb, struct blob_attr *data)
{
        return blobmsg_parse_array(policy, policy_len, tb, blobmsg_data(data), blobmsg_len(data));
}
 
static inline int
blobmsg_add_double(struct blob_buf *buf, const char *name, double val)
{
        union {
                double d;
                uint64_t u64;
        } v;
        v.d = val;
        v.u64 = cpu_to_be64(v.u64);
        return blobmsg_add_field(buf, BLOBMSG_TYPE_DOUBLE, name, &v.u64, 8);
}
 
static inline int
blobmsg_add_u8(struct blob_buf *buf, const char *name, uint8_t val)
{
        return blobmsg_add_field(buf, BLOBMSG_TYPE_INT8, name, &val, 1);
}
 
static inline int
blobmsg_add_u16(struct blob_buf *buf, const char *name, uint16_t val)
{
        val = cpu_to_be16(val);
        return blobmsg_add_field(buf, BLOBMSG_TYPE_INT16, name, &val, 2);
}
 
static inline int
blobmsg_add_u32(struct blob_buf *buf, const char *name, uint32_t val)
{
        val = cpu_to_be32(val);
        return blobmsg_add_field(buf, BLOBMSG_TYPE_INT32, name, &val, 4);
}
 
static inline int
blobmsg_add_u64(struct blob_buf *buf, const char *name, uint64_t val)
{
        val = cpu_to_be64(val);
        return blobmsg_add_field(buf, BLOBMSG_TYPE_INT64, name, &val, 8);
}
 
static inline int
blobmsg_add_string(struct blob_buf *buf, const char *name, const char *string)
{
        return blobmsg_add_field(buf, BLOBMSG_TYPE_STRING, name, string, strlen(string) + 1);
}
 
static inline int
blobmsg_add_blob(struct blob_buf *buf, struct blob_attr *attr)
{
        return blobmsg_add_field(buf, blobmsg_type(attr), blobmsg_name(attr),
                                 blobmsg_data(attr), blobmsg_data_len(attr));
}
 
void *blobmsg_open_nested(struct blob_buf *buf, const char *name, bool array);
 
static inline void *
blobmsg_open_array(struct blob_buf *buf, const char *name)
{
        return blobmsg_open_nested(buf, name, true);
}
 
static inline void *
blobmsg_open_table(struct blob_buf *buf, const char *name)
{
        return blobmsg_open_nested(buf, name, false);
}
 
static inline void
blobmsg_close_array(struct blob_buf *buf, void *cookie)
{
        blob_nest_end(buf, cookie);
}
 
static inline void
blobmsg_close_table(struct blob_buf *buf, void *cookie)
{
        blob_nest_end(buf, cookie);
}
 
static inline int blobmsg_buf_init(struct blob_buf *buf)
{
        return blob_buf_init(buf, BLOBMSG_TYPE_TABLE);
}
 
static inline uint8_t blobmsg_get_u8(struct blob_attr *attr)
{
        return *(uint8_t *) blobmsg_data(attr);
}
 
static inline bool blobmsg_get_bool(struct blob_attr *attr)
{
        return *(uint8_t *) blobmsg_data(attr);
}
 
static inline uint16_t blobmsg_get_u16(struct blob_attr *attr)
{
        return be16_to_cpu(*(uint16_t *) blobmsg_data(attr));
}
 
static inline uint32_t blobmsg_get_u32(struct blob_attr *attr)
{
        return be32_to_cpu(*(uint32_t *) blobmsg_data(attr));
}
 
static inline uint64_t blobmsg_get_u64(struct blob_attr *attr)
{
        uint32_t *ptr = (uint32_t *) blobmsg_data(attr);
        uint64_t tmp = ((uint64_t) be32_to_cpu(ptr[0])) << 32;
        tmp |= be32_to_cpu(ptr[1]);
        return tmp;
}
 
static inline uint64_t blobmsg_cast_u64(struct blob_attr *attr)
{
        uint64_t tmp = 0;
 
        if (blobmsg_type(attr) == BLOBMSG_TYPE_INT64)
                tmp = blobmsg_get_u64(attr);
        else if (blobmsg_type(attr) == BLOBMSG_TYPE_INT32)
                tmp = blobmsg_get_u32(attr);
        else if (blobmsg_type(attr) == BLOBMSG_TYPE_INT16)
                tmp = blobmsg_get_u16(attr);
        else if (blobmsg_type(attr) == BLOBMSG_TYPE_INT8)
                tmp = blobmsg_get_u8(attr);
 
        return tmp;
}
 
static inline int64_t blobmsg_cast_s64(struct blob_attr *attr)
{
        int64_t tmp = 0;
 
        if (blobmsg_type(attr) == BLOBMSG_TYPE_INT64)
                tmp = blobmsg_get_u64(attr);
        else if (blobmsg_type(attr) == BLOBMSG_TYPE_INT32)
                tmp = (int32_t)blobmsg_get_u32(attr);
        else if (blobmsg_type(attr) == BLOBMSG_TYPE_INT16)
                tmp = (int16_t)blobmsg_get_u16(attr);
        else if (blobmsg_type(attr) == BLOBMSG_TYPE_INT8)
                tmp = (int8_t)blobmsg_get_u8(attr);
 
        return tmp;
}
 
static inline double blobmsg_get_double(struct blob_attr *attr)
{
        union {
                double d;
                uint64_t u64;
        } v;
        v.u64 = blobmsg_get_u64(attr);
        return v.d;
}
 
static inline char *blobmsg_get_string(struct blob_attr *attr)
{
        if (!attr)
                return NULL;
 
        return (char *) blobmsg_data(attr);
}
 
void *blobmsg_alloc_string_buffer(struct blob_buf *buf, const char *name, unsigned int maxlen);
void *blobmsg_realloc_string_buffer(struct blob_buf *buf, unsigned int maxlen);
void blobmsg_add_string_buffer(struct blob_buf *buf);
 
int blobmsg_vprintf(struct blob_buf *buf, const char *name, const char *format, va_list arg);
int blobmsg_printf(struct blob_buf *buf, const char *name, const char *format, ...)
     __attribute__((format(printf, 3, 4)));
 
#define blobmsg_for_each_attr(pos, attr, rem) \
        for (rem = attr ? blobmsg_data_len(attr) : 0, \
             pos = (struct blob_attr *) (attr ? blobmsg_data(attr) : NULL); \
             rem >= sizeof(struct blob_attr) && (blob_pad_len(pos) <= rem) && \
             (blob_pad_len(pos) >= sizeof(struct blob_attr)); \
             rem -= blob_pad_len(pos), pos = blob_next(pos))
 
#define __blobmsg_for_each_attr(pos, attr, rem) \
        for (pos = (struct blob_attr *) (attr ? blobmsg_data(attr) : NULL); \
             rem >= sizeof(struct blob_attr) && (blob_pad_len(pos) <= rem) && \
             (blob_pad_len(pos) >= sizeof(struct blob_attr)); \
             rem -= blob_pad_len(pos), pos = blob_next(pos))
 
#endif