blobmsg.c

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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.
 */
#include "blobmsg.h"
 
static const int blob_type[__BLOBMSG_TYPE_LAST] = {
        [BLOBMSG_TYPE_INT8] = BLOB_ATTR_INT8,
        [BLOBMSG_TYPE_INT16] = BLOB_ATTR_INT16,
        [BLOBMSG_TYPE_INT32] = BLOB_ATTR_INT32,
        [BLOBMSG_TYPE_INT64] = BLOB_ATTR_INT64,
        [BLOBMSG_TYPE_DOUBLE] = BLOB_ATTR_DOUBLE,
        [BLOBMSG_TYPE_STRING] = BLOB_ATTR_STRING,
        [BLOBMSG_TYPE_UNSPEC] = BLOB_ATTR_BINARY,
};
 
bool blobmsg_check_attr(const struct blob_attr *attr, bool name)
{
        return blobmsg_check_attr_len(attr, name, blob_raw_len(attr));
}
 
static bool blobmsg_check_name(const struct blob_attr *attr, bool name)
{
        const struct blobmsg_hdr *hdr;
        uint16_t namelen;
 
        if (!blob_is_extended(attr))
                return !name;
 
        if (blob_len(attr) < sizeof(struct blobmsg_hdr))
                return false;
 
        hdr = (const struct blobmsg_hdr *)blob_data(attr);
        if (name && !hdr->namelen)
                return false;
 
        namelen = blobmsg_namelen(hdr);
        if (blob_len(attr) < (size_t)blobmsg_hdrlen(namelen))
                return false;
 
        if (hdr->name[namelen] != 0)
                return false;
 
        return true;
}
 
bool blobmsg_check_attr_len(const struct blob_attr *attr, bool name, size_t len)
{
        const char *data;
        size_t data_len;
        int id;
 
        if (len < sizeof(struct blob_attr))
                return false;
 
        data_len = blob_raw_len(attr);
        if (data_len < sizeof(struct blob_attr) || data_len > len)
                return false;
 
        if (!blobmsg_check_name(attr, name))
                return false;
 
        id = blob_id(attr);
        if (id > BLOBMSG_TYPE_LAST)
                return false;
 
        if (!blob_type[id])
                return true;
 
        data = blobmsg_data(attr);
        data_len = blobmsg_data_len(attr);
 
        return blob_check_type(data, data_len, blob_type[id]);
}
 
int blobmsg_check_array(const struct blob_attr *attr, int type)
{
        return blobmsg_check_array_len(attr, type, blob_raw_len(attr));
}
 
int blobmsg_check_array_len(const struct blob_attr *attr, int type,
                            size_t blob_len)
{
        struct blob_attr *cur;
        size_t rem;
        bool name;
        int size = 0;
 
        if (type > BLOBMSG_TYPE_LAST)
                return -1;
 
        if (!blobmsg_check_attr_len(attr, false, blob_len))
                return -1;
 
        switch (blobmsg_type(attr)) {
        case BLOBMSG_TYPE_TABLE:
                name = true;
                break;
        case BLOBMSG_TYPE_ARRAY:
                name = false;
                break;
        default:
                return -1;
        }
 
        blobmsg_for_each_attr(cur, attr, rem) {
                if (type != BLOBMSG_TYPE_UNSPEC && blobmsg_type(cur) != type)
                        return -1;
 
                if (!blobmsg_check_attr_len(cur, name, rem))
                        return -1;
 
                size++;
        }
 
        return size;
}
 
bool blobmsg_check_attr_list(const struct blob_attr *attr, int type)
{
        return blobmsg_check_array(attr, type) >= 0;
}
 
bool blobmsg_check_attr_list_len(const struct blob_attr *attr, int type, size_t len)
{
        return blobmsg_check_array_len(attr, type, len) >= 0;
}
 
int blobmsg_parse_array(const struct blobmsg_policy *policy, int policy_len,
                        struct blob_attr **tb, void *data, unsigned int len)
{
        struct blob_attr *attr;
        int i = 0;
 
        memset(tb, 0, policy_len * sizeof(*tb));
        __blob_for_each_attr(attr, data, len) {
                if (policy[i].type != BLOBMSG_TYPE_UNSPEC &&
                    blob_id(attr) != policy[i].type)
                        continue;
 
                if (!blobmsg_check_attr_len(attr, false, len))
                        return -1;
 
                if (tb[i])
                        continue;
 
                tb[i++] = attr;
                if (i == policy_len)
                        break;
        }
 
        return 0;
}
 
int blobmsg_parse(const struct blobmsg_policy *policy, int policy_len,
                  struct blob_attr **tb, void *data, unsigned int len)
{
        const struct blobmsg_hdr *hdr;
        struct blob_attr *attr;
        uint8_t *pslen;
        int i;
 
        memset(tb, 0, policy_len * sizeof(*tb));
        if (!data || !len)
                return -EINVAL;
        pslen = alloca(policy_len);
        for (i = 0; i < policy_len; i++) {
                if (!policy[i].name)
                        continue;
 
                pslen[i] = strlen(policy[i].name);
        }
 
        __blob_for_each_attr(attr, data, len) {
                if (!blobmsg_check_attr_len(attr, false, len))
                        return -1;
 
                if (!blob_is_extended(attr))
                        continue;
 
                hdr = blob_data(attr);
                for (i = 0; i < policy_len; i++) {
                        if (!policy[i].name)
                                continue;
 
                        if (policy[i].type != BLOBMSG_TYPE_UNSPEC &&
                            policy[i].type != BLOBMSG_CAST_INT64 &&
                            blob_id(attr) != policy[i].type)
                                continue;
 
                        if (policy[i].type == BLOBMSG_CAST_INT64 &&
                            (blob_id(attr) != BLOBMSG_TYPE_INT64 &&
                             blob_id(attr) != BLOBMSG_TYPE_INT32 &&
                             blob_id(attr) != BLOBMSG_TYPE_INT16 &&
                             blob_id(attr) != BLOBMSG_TYPE_INT8))
                                continue;
 
                        if (blobmsg_namelen(hdr) != pslen[i])
                                continue;
 
                        if (tb[i])
                                continue;
 
                        if (strcmp(policy[i].name, (char *) hdr->name) != 0)
                                continue;
 
                        tb[i] = attr;
                }
        }
 
        return 0;
}
 
 
static struct blob_attr *
blobmsg_new(struct blob_buf *buf, int type, const char *name, int payload_len, void **data)
{
        struct blob_attr *attr;
        struct blobmsg_hdr *hdr;
        int attrlen, namelen;
        char *pad_start, *pad_end;
 
        if (!name)
                name = "";
 
        namelen = strlen(name);
        attrlen = blobmsg_hdrlen(namelen) + payload_len;
        attr = blob_new(buf, type, attrlen);
        if (!attr)
                return NULL;
 
        attr->id_len |= be32_to_cpu(BLOB_ATTR_EXTENDED);
        hdr = blob_data(attr);
        hdr->namelen = cpu_to_be16(namelen);
 
        memcpy(hdr->name, name, namelen);
        hdr->name[namelen] = '\0';
 
        pad_end = *data = blobmsg_data(attr);
        pad_start = (char *) &hdr->name[namelen];
        if (pad_start < pad_end)
                memset(pad_start, 0, pad_end - pad_start);
 
        return attr;
}
 
static inline int
attr_to_offset(struct blob_buf *buf, struct blob_attr *attr)
{
        return (char *)attr - (char *) buf->buf + BLOB_COOKIE;
}
 
 
void *
blobmsg_open_nested(struct blob_buf *buf, const char *name, bool array)
{
        struct blob_attr *head;
        int type = array ? BLOBMSG_TYPE_ARRAY : BLOBMSG_TYPE_TABLE;
        unsigned long offset = attr_to_offset(buf, buf->head);
        void *data;
 
        if (!name)
                name = "";
 
        head = blobmsg_new(buf, type, name, 0, &data);
        if (!head)
                return NULL;
        blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blobmsg_hdrlen(strlen(name)));
        buf->head = head;
        return (void *)offset;
}
 
__attribute__((format(printf, 3, 0)))
int blobmsg_vprintf(struct blob_buf *buf, const char *name, const char *format, va_list arg)
{
        va_list arg2;
        char cbuf;
        char *sbuf;
        int len, ret;
 
        va_copy(arg2, arg);
        len = vsnprintf(&cbuf, sizeof(cbuf), format, arg2);
        va_end(arg2);
 
        if (len < 0)
                return -1;
 
        sbuf = blobmsg_alloc_string_buffer(buf, name, len);
        if (!sbuf)
                return -1;
 
        ret = vsnprintf(sbuf, len + 1, format, arg);
        if (ret < 0)
                return -1;
 
        blobmsg_add_string_buffer(buf);
 
        return ret;
}
 
__attribute__((format(printf, 3, 4)))
int blobmsg_printf(struct blob_buf *buf, const char *name, const char *format, ...)
{
        va_list ap;
        int ret;
 
        va_start(ap, format);
        ret = blobmsg_vprintf(buf, name, format, ap);
        va_end(ap);
 
        return ret;
}
 
void *
blobmsg_alloc_string_buffer(struct blob_buf *buf, const char *name, unsigned int maxlen)
{
        struct blob_attr *attr;
        void *data_dest;
 
        maxlen++;
        attr = blobmsg_new(buf, BLOBMSG_TYPE_STRING, name, maxlen, &data_dest);
        if (!attr)
                return NULL;
 
        blob_set_raw_len(buf->head, blob_pad_len(buf->head) - blob_pad_len(attr));
        blob_set_raw_len(attr, blob_raw_len(attr) - maxlen);
 
        return data_dest;
}
 
void *
blobmsg_realloc_string_buffer(struct blob_buf *buf, unsigned int maxlen)
{
        struct blob_attr *attr = blob_next(buf->head);
        int offset = attr_to_offset(buf, blob_next(buf->head)) + blob_pad_len(attr) - BLOB_COOKIE;
        int required = maxlen + 1 - (buf->buflen - offset);
 
        if (required <= 0)
                goto out;
 
        if (!blob_buf_grow(buf, required))
                return NULL;
        attr = blob_next(buf->head);
 
out:
        return blobmsg_data(attr);
}
 
void
blobmsg_add_string_buffer(struct blob_buf *buf)
{
        struct blob_attr *attr;
        int len, attrlen;
 
        attr = blob_next(buf->head);
        len = strlen(blobmsg_data(attr)) + 1;
 
        attrlen = blob_raw_len(attr) + len;
        blob_set_raw_len(attr, attrlen);
        blob_fill_pad(attr);
 
        blob_set_raw_len(buf->head, blob_raw_len(buf->head) + blob_pad_len(attr));
}
 
int
blobmsg_add_field(struct blob_buf *buf, int type, const char *name,
                  const void *data, unsigned int len)
{
        struct blob_attr *attr;
        void *data_dest;
 
        attr = blobmsg_new(buf, type, name, len, &data_dest);
        if (!attr)
                return -1;
 
        if (len > 0)
                memcpy(data_dest, data, len);
 
        return 0;
}