/* SPDX-License-Identifier: MIT
 * Copyright (c) 2026 Leah Rowe <leah@libreboot.org>
 *
 * String functions
 */

#include <sys/types.h>
#include <sys/stat.h>

#include <errno.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>

#include "../include/common.h"

/* scmp() - strict string comparison
 *
 * strict string comparison
 * similar to strncmp, but null and
 * unterminated inputs do not produce
 * a return value; on error, errno is
 * set and -1 is returned.
 *
 * the real return value is stored in
 * the 4th argument by pointer.
 *
 * the value at rval pointer is set,
 * only upon success. callers should
 * check the return value accordingly.
 */

int
scmp(const char *a,
    const char *b,
    size_t maxlen,
    int *rval)
{
	size_t ch;
	unsigned char ac;
	unsigned char bc;

	if (a == NULL ||
	    b == NULL ||
	    rval == NULL) {

		errno = EFAULT;
		return -1;
	}

	for (ch = 0; ch < maxlen; ch++) {

		ac = (unsigned char)a[ch];
		bc = (unsigned char)b[ch];

		if (ac != bc) {
			*rval = ac - bc;
			return 0;
		}

		if (ac == '\0') {
			*rval = 0;
			return 0;
		}
	}

	/* block unterminated strings */
	errno = EFAULT;
	return -1;
}

/* slen() - strict strict length
 *
 * strict string length calculation
 * similar to strnlen, but null and
 * unterminated inputs do not produce
 * a return value; on error, errno is
 * set and -1 is returned.
 *
 * the real return value is stored in
 * the 3rd argument by pointer.
 *
 * the value at rval pointer is set,
 * only upon success. callers should
 * check the return value accordingly.
 */

int
slen(const char *s,
    size_t maxlen,
    size_t *rval)
{
	size_t ch;

	if (s == NULL ||
	    rval == NULL) {

		errno = EFAULT;
		return -1;
	}

	for (ch = 0;
	    ch < maxlen && s[ch] != '\0';
	    ch++);

	if (ch == maxlen) {
		/* unterminated */
		errno = EFAULT;
		return -1;
	}

	*rval = ch;
	return 0;
}

/* the one for nvmutil state is in state.c */
/* this one just exits */
void
err_no_cleanup(int nvm_errval, const char *msg, ...)
{
	va_list args;

#if defined(__OpenBSD__) && defined(OpenBSD)
#if (OpenBSD) >= 509
	if (pledge("stdio", NULL) == -1)
		fprintf(stderr, "pledge failure during exit");
#endif
#endif

	if (!errno)
		errno = ECANCELED;

	fprintf(stderr, "nvmutil: ");

	va_start(args, msg);
	vfprintf(stderr, msg, args);
	va_end(args);

	fprintf(stderr, ": %s\n", strerror(errno));

	exit(EXIT_FAILURE);
}