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/* See LICENSE file for copyright and license details. */
#include "../common.h"
#include <stdio.h>
/**
* Calculate a Keccak-family hashsum of a file,
* the content of the file is assumed non-sensitive
*
* @param fd The file descriptor of the file to hash
* @param state The hashing state, should not be initialised unless
* `spec` is `NULL` (memory leak otherwise)
* @param spec Specifications for the hashing algorithm; or `NULL`
* if `spec` is already initialised
* @param suffix The data suffix, see `libkeccak_digest`
* @param hashsum Output array for the hashsum, have an allocation size of
* at least `((spec->output + 7) / 8) * sizeof(char)`, may be `NULL`
* @return Zero on success, -1 on error
*/
int
libkeccak_generalised_sum_fd(int fd, struct libkeccak_state *restrict state, const struct libkeccak_spec *restrict spec,
const char *restrict suffix, void *restrict hashsum)
{
ssize_t got;
size_t offset;
#ifndef _WIN32
struct stat attr;
#endif
size_t blksize = 4096;
unsigned char *restrict chunk;
size_t chunksize, extrasize, extrachunks;
size_t chunks, chunkmod;
if (spec && libkeccak_state_initialise(state, spec) < 0)
return -1;
chunksize = libkeccak_zerocopy_chunksize(state);
extrasize = ((suffix ? strlen(suffix) : 0) + 2 + 7) >> 3;
extrachunks = (extrasize + (chunksize - 1)) / chunksize;
#ifndef _WIN32
if (fstat(fd, &attr) == 0)
if (attr.st_blksize > 0)
blksize = (size_t)attr.st_blksize;
#endif
chunks = blksize / chunksize;
chunkmod = blksize % chunksize;
if (chunkmod) {
blksize -= chunkmod;
blksize += chunksize;
chunks += 1;
}
if (chunks < extrachunks + 1)
blksize = (extrachunks + 1) * chunksize;
#if ALLOCA_LIMIT > 0
if (blksize > (size_t)ALLOCA_LIMIT) {
blksize = (size_t)ALLOCA_LIMIT;
blksize -= blksize % chunksize;
if (!blksize)
blksize = chunksize;
}
# if defined(__clang__)
/* We are using a limit so it's just like declaring an array
* in a function, except we might use less of the stack. */
# pragma clang diagnostic push
# pragma clang diagnostic ignored "-Walloca"
# endif
chunk = alloca(blksize);
# if defined(__clang__)
# pragma clang diagnostic pop
# endif
#else
chunk = malloc(blksize);
if (!chunk)
return -1;
#endif
offset = 0;
for (;;) {
got = read(fd, &chunk[offset], blksize - offset);
if (got <= 0) {
if (!got)
break;
if (errno == EINTR)
continue;
goto fail;
}
offset += (size_t)got;
if (offset == blksize) {
libkeccak_zerocopy_update(state, chunk, blksize);
offset = 0;
}
}
if (extrasize > blksize - offset) {
chunkmod = offset % chunksize;
libkeccak_zerocopy_update(state, chunk, offset - chunkmod);
__builtin_memcpy(chunk, &chunk[offset - chunkmod], chunkmod * sizeof(char));
offset = chunkmod;
}
libkeccak_zerocopy_digest(state, chunk, offset, 0, suffix, hashsum);
return 0;
fail:
#if ALLOCA_LIMIT <= 0
free(chunk);
#endif
return -1;
}
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