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/* See LICENSE file for copyright and license details. */
#include "common.h"
int
libsha2_sum_fd(int fd, enum libsha2_algorithm algorithm, void *restrict hashsum)
{
struct libsha2_state state;
ssize_t r;
#ifndef _WIN32
struct stat attr;
#endif
size_t blksize = 4096;
char *restrict chunk;
if (libsha2_init(&state, algorithm) < 0)
return -1;
#ifndef _WIN32
if (fstat(fd, &attr) == 0 && attr.st_blksize > 0)
blksize = (size_t)(attr.st_blksize);
#endif
#if ALLOCA_LIMIT > 0
if (blksize > (size_t)ALLOCA_LIMIT) {
blksize = (size_t)ALLOCA_LIMIT;
blksize -= blksize % sizeof(((struct libsha2_state)NULL)->chunk);
if (!blksize)
blksize = sizeof(((struct libsha2_state)NULL)->chunk);
}
# 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
for (;;) {
r = read(fd, chunk, blksize);
if (r <= 0) {
if (!r)
break;
if (errno == EINTR)
continue;
#if ALLOCA_LIMIT <= 0
free(chunk);
#endif
return -1;
}
libsha2_update(&state, chunk, (size_t)r * 8);
}
libsha2_digest(&state, NULL, 0, hashsum);
#if ALLOCA_LIMIT <= 0
free(chunk);
#endif
return 0;
}
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