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/* Generates a random, valid protobuf message. Useful to seed
* external fuzzers such as afl-fuzz.
*/
#include <pb_encode.h>
#include <pb_common.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <time.h>
#include "alltypes_static.pb.h"
static uint64_t random_seed;
/* Uses xorshift64 here instead of rand() for both speed and
* reproducibility across platforms. */
static uint32_t rand_word()
{
random_seed ^= random_seed >> 12;
random_seed ^= random_seed << 25;
random_seed ^= random_seed >> 27;
return random_seed * 2685821657736338717ULL;
}
/* Fills a buffer with random data. */
static void rand_fill(uint8_t *buf, size_t count)
{
while (count--)
{
*buf++ = rand_word() & 0xff;
}
}
/* Check that size/count fields do not exceed their max size.
* Otherwise we would have to loop pretty long in generate_message().
* Note that there may still be a few encoding errors from submessages.
*/
static void limit_sizes(alltypes_static_AllTypes *msg)
{
pb_field_iter_t iter;
pb_field_iter_begin(&iter, alltypes_static_AllTypes_fields, msg);
while (pb_field_iter_next(&iter))
{
if (PB_LTYPE(iter.pos->type) == PB_LTYPE_BYTES)
{
((pb_bytes_array_t*)iter.pData)->size %= iter.pos->data_size - PB_BYTES_ARRAY_T_ALLOCSIZE(0);
}
if (PB_HTYPE(iter.pos->type) == PB_HTYPE_REPEATED)
{
*((pb_size_t*)iter.pSize) %= iter.pos->array_size;
}
if (PB_HTYPE(iter.pos->type) == PB_HTYPE_ONEOF)
{
/* Set the oneof to this message type with 50% chance. */
if (rand_word() & 1)
{
*((pb_size_t*)iter.pSize) = iter.pos->tag;
}
}
}
}
static void generate_message()
{
alltypes_static_AllTypes msg;
uint8_t buf[8192];
pb_ostream_t stream = {0};
do {
if (stream.errmsg)
fprintf(stderr, "Encoder error: %s\n", stream.errmsg);
stream = pb_ostream_from_buffer(buf, sizeof(buf));
rand_fill((void*)&msg, sizeof(msg));
limit_sizes(&msg);
} while (!pb_encode(&stream, alltypes_static_AllTypes_fields, &msg));
fwrite(buf, 1, stream.bytes_written, stdout);
}
int main(int argc, char **argv)
{
if (argc > 1)
{
random_seed = atol(argv[1]);
}
else
{
random_seed = time(NULL);
}
fprintf(stderr, "Random seed: %llu\n", (long long unsigned)random_seed);
generate_message();
return 0;
}
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