Files
lbmk/util/libreboot-utils/lib/num.c
Leah Rowe f7f1856969 libreboot-utils: move rand to own file
Signed-off-by: Leah Rowe <leah@libreboot.org>
2026-03-25 10:34:37 +00:00

128 lines
2.3 KiB
C

/* SPDX-License-Identifier: MIT
* Copyright (c) 2026 Leah Rowe <leah@libreboot.org>
*
* Numerical functions.
* NOTE: randomness was moved to rand.c
*/
/*
TODO: properly handle errno in this file
*/
#ifdef __OpenBSD__
#include <sys/param.h>
#endif
#include <sys/types.h>
#if defined(FALLBACK_RAND_1989) && \
(FALLBACK_RAND_1989) > 0
#include <sys/time.h>
#endif
#include <errno.h>
#if !((defined(__OpenBSD__) && (OpenBSD) >= 201) || \
defined(__FreeBSD__) || \
defined(__NetBSD__) || defined(__APPLE__))
#include <fcntl.h> /* if not arc4random: /dev/urandom */
#endif
#include <limits.h>
#include <stddef.h>
#include <string.h>
#if defined(FALLBACK_RAND_1989) && \
(FALLBACK_RAND_1989) > 0
#include <time.h>
#endif
#include <unistd.h>
#include "../include/common.h"
/* TODO:
* make this and errno handling more
* flexible
in particular:
hextonum could be modified to
write into a buffer instead,
with the converted numbers,
of an arbitrary length
*/
unsigned short
hextonum(char ch_s)
{
int saved_errno = errno;
/* rlong() can return error,
but preserves errno if no
error. we need to detect
this because it handles
/dev/urandom sometimes
therefore, if it's zero
at start, we know if there
was an err at the end, by
return value zero, if errno
was set; this is technically
valid, since zero is also
a valid random number!
it's an edge case that i had
to fix. i'll rewrite the code
better later. for now, it
should be ok.
*/
errno = 0;
unsigned char ch;
size_t rval;
ch = (unsigned char)ch_s;
if ((unsigned int)(ch - '0') <= 9) {
rval = ch - '0';
goto hextonum_success;
}
ch |= 0x20;
if ((unsigned int)(ch - 'a') <= 5) {
rval = ch - 'a' + 10;
goto hextonum_success;
}
if (ch == '?' || ch == 'x') {
rval = rlong();
if (errno > 0)
goto err_hextonum;
goto hextonum_success;
}
goto err_hextonum;
hextonum_success:
errno = saved_errno;
return (unsigned short)rval & 0xf;
err_hextonum:
if (errno == saved_errno)
errno = EINVAL;
else
return 17; /* 17 indicates getrandom/urandom fail */
return 16; /* invalid character */
/* caller just checks >15. */
}
void
check_bin(size_t a, const char *a_name)
{
if (a > 1)
err_no_cleanup(0, EINVAL, "%s must be 0 or 1, but is %lu",
a_name, (size_t)a);
}