Mirror of the official OpenWrt libubox repository https://git.openwrt.org/project/libubox
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/*
* blob - library for generating/parsing tagged binary data
*
* Copyright (C) 2010 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.
*/
#include "blob.h"
static bool
blob_buffer_grow(struct blob_buf *buf, int minlen)
{
struct blob_buf *new;
int delta = ((minlen / 256) + 1) * 256;
new = realloc(buf->buf, buf->buflen + delta);
if (new) {
buf->buf = new;
memset(buf->buf + buf->buflen, 0, delta);
buf->buflen += delta;
}
return !!new;
}
static void
blob_init(struct blob_attr *attr, int id, unsigned int len)
{
len &= BLOB_ATTR_LEN_MASK;
len |= (id << BLOB_ATTR_ID_SHIFT) & BLOB_ATTR_ID_MASK;
attr->id_len = cpu_to_be32(len);
}
static inline struct blob_attr *
offset_to_attr(struct blob_buf *buf, int offset)
{
void *ptr = (char *)buf->buf + offset - BLOB_COOKIE;
return ptr;
}
static inline int
attr_to_offset(struct blob_buf *buf, struct blob_attr *attr)
{
return (char *)attr - (char *) buf->buf + BLOB_COOKIE;
}
bool
blob_buf_grow(struct blob_buf *buf, int required)
{
int offset_head = attr_to_offset(buf, buf->head);
if ((buf->buflen + required) > BLOB_ATTR_LEN_MASK)
return false;
if (!buf->grow || !buf->grow(buf, required))
return false;
buf->head = offset_to_attr(buf, offset_head);
return true;
}
static struct blob_attr *
blob_add(struct blob_buf *buf, struct blob_attr *pos, int id, int payload)
{
int offset = attr_to_offset(buf, pos);
int required = (offset - BLOB_COOKIE + sizeof(struct blob_attr) + payload) - buf->buflen;
struct blob_attr *attr;
if (required > 0) {
if (!blob_buf_grow(buf, required))
return NULL;
attr = offset_to_attr(buf, offset);
} else {
attr = pos;
}
blob_init(attr, id, payload + sizeof(struct blob_attr));
blob_fill_pad(attr);
return attr;
}
int
blob_buf_init(struct blob_buf *buf, int id)
{
if (!buf->grow)
buf->grow = blob_buffer_grow;
buf->head = buf->buf;
if (blob_add(buf, buf->buf, id, 0) == NULL)
return -ENOMEM;
return 0;
}
void
blob_buf_free(struct blob_buf *buf)
{
free(buf->buf);
buf->buf = NULL;
buf->buflen = 0;
}
void
blob_fill_pad(struct blob_attr *attr)
{
char *buf = (char *) attr;
int len = blob_pad_len(attr);
int delta = len - blob_raw_len(attr);
if (delta > 0)
memset(buf + len - delta, 0, delta);
}
void
blob_set_raw_len(struct blob_attr *attr, unsigned int len)
{
len &= BLOB_ATTR_LEN_MASK;
attr->id_len &= ~cpu_to_be32(BLOB_ATTR_LEN_MASK);
attr->id_len |= cpu_to_be32(len);
}
struct blob_attr *
blob_new(struct blob_buf *buf, int id, int payload)
{
struct blob_attr *attr;
attr = blob_add(buf, blob_next(buf->head), id, payload);
if (!attr)
return NULL;
blob_set_raw_len(buf->head, blob_pad_len(buf->head) + blob_pad_len(attr));
return attr;
}
struct blob_attr *
blob_put_raw(struct blob_buf *buf, const void *ptr, unsigned int len)
{
struct blob_attr *attr;
if (len < sizeof(struct blob_attr) || !ptr)
return NULL;
attr = blob_add(buf, blob_next(buf->head), 0, len - sizeof(struct blob_attr));
if (!attr)
return NULL;
blob_set_raw_len(buf->head, blob_pad_len(buf->head) + len);
memcpy(attr, ptr, len);
return attr;
}
struct blob_attr *
blob_put(struct blob_buf *buf, int id, const void *ptr, unsigned int len)
{
struct blob_attr *attr;
attr = blob_new(buf, id, len);
if (!attr)
return NULL;
if (ptr)
memcpy(blob_data(attr), ptr, len);
return attr;
}
void *
blob_nest_start(struct blob_buf *buf, int id)
{
unsigned long offset = attr_to_offset(buf, buf->head);
buf->head = blob_new(buf, id, 0);
if (!buf->head)
return NULL;
return (void *) offset;
}
void
blob_nest_end(struct blob_buf *buf, void *cookie)
{
struct blob_attr *attr = offset_to_attr(buf, (unsigned long) cookie);
blob_set_raw_len(attr, blob_pad_len(attr) + blob_len(buf->head));
buf->head = attr;
}
static const size_t blob_type_minlen[BLOB_ATTR_LAST] = {
[BLOB_ATTR_STRING] = 1,
[BLOB_ATTR_INT8] = sizeof(uint8_t),
[BLOB_ATTR_INT16] = sizeof(uint16_t),
[BLOB_ATTR_INT32] = sizeof(uint32_t),
[BLOB_ATTR_INT64] = sizeof(uint64_t),
[BLOB_ATTR_DOUBLE] = sizeof(double),
};
bool
blob_check_type(const void *ptr, unsigned int len, int type)
{
const char *data = ptr;
if (type >= BLOB_ATTR_LAST)
return false;
if (type >= BLOB_ATTR_INT8 && type <= BLOB_ATTR_INT64) {
if (len != blob_type_minlen[type])
return false;
} else {
if (len < blob_type_minlen[type])
return false;
}
if (type == BLOB_ATTR_STRING && data[len - 1] != 0)
return false;
return true;
}
static int
blob_parse_attr(struct blob_attr *attr, size_t attr_len, struct blob_attr **data, const struct blob_attr_info *info, int max)
{
int id;
size_t len;
int found = 0;
size_t data_len;
if (!attr || attr_len < sizeof(struct blob_attr))
return 0;
id = blob_id(attr);
if (id >= max)
return 0;
len = blob_raw_len(attr);
if (len > attr_len || len < sizeof(struct blob_attr))
return 0;
data_len = blob_len(attr);
if (data_len > len)
return 0;
if (info) {
int type = info[id].type;
if (type < BLOB_ATTR_LAST) {
if (!blob_check_type(blob_data(attr), data_len, type))
return 0;
}
if (info[id].minlen && len < info[id].minlen)
return 0;
if (info[id].maxlen && len > info[id].maxlen)
return 0;
if (info[id].validate && !info[id].validate(&info[id], attr))
return 0;
}
if (!data[id])
found++;
data[id] = attr;
return found;
}
int
blob_parse_untrusted(struct blob_attr *attr, size_t attr_len, struct blob_attr **data, const struct blob_attr_info *info, int max)
{
struct blob_attr *pos;
size_t len = 0;
int found = 0;
size_t rem;
if (!attr || attr_len < sizeof(struct blob_attr))
return 0;
len = blob_raw_len(attr);
if (attr_len < len)
return 0;
memset(data, 0, sizeof(struct blob_attr *) * max);
blob_for_each_attr_len(pos, attr, len, rem) {
found += blob_parse_attr(pos, rem, data, info, max);
}
return found;
}
/* use only on trusted input, otherwise consider blob_parse_untrusted */
int
blob_parse(struct blob_attr *attr, struct blob_attr **data, const struct blob_attr_info *info, int max)
{
struct blob_attr *pos;
int found = 0;
size_t rem;
memset(data, 0, sizeof(struct blob_attr *) * max);
blob_for_each_attr(pos, attr, rem) {
found += blob_parse_attr(pos, rem, data, info, max);
}
return found;
}
bool
blob_attr_equal(const struct blob_attr *a1, const struct blob_attr *a2)
{
if (!a1 && !a2)
return true;
if (!a1 || !a2)
return false;
if (blob_pad_len(a1) != blob_pad_len(a2))
return false;
return !memcmp(a1, a2, blob_pad_len(a1));
}
struct blob_attr *
blob_memdup(struct blob_attr *attr)
{
struct blob_attr *ret;
int size = blob_pad_len(attr);
ret = malloc(size);
if (!ret)
return NULL;
memcpy(ret, attr, size);
return ret;
}