1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 *  linux/tools/lib/string.c
  4 *
  5 *  Copied from linux/lib/string.c, where it is:
  6 *
  7 *  Copyright (C) 1991, 1992  Linus Torvalds
  8 *
  9 *  More specifically, the first copied function was strtobool, which
 10 *  was introduced by:
 11 *
 12 *  d0f1fed29e6e ("Add a strtobool function matching semantics of existing in kernel equivalents")
 13 *  Author: Jonathan Cameron <jic23@cam.ac.uk>
 14 */
 15
 16#include <stdlib.h>
 17#include <string.h>
 18#include <errno.h>
 19#include <linux/string.h>
 20#include <linux/compiler.h>
 21
 22/**
 23 * memdup - duplicate region of memory
 24 *
 25 * @src: memory region to duplicate
 26 * @len: memory region length
 27 */
 28void *memdup(const void *src, size_t len)
 29{
 30	void *p = malloc(len);
 31
 32	if (p)
 33		memcpy(p, src, len);
 34
 35	return p;
 36}
 37
 38/**
 39 * strtobool - convert common user inputs into boolean values
 40 * @s: input string
 41 * @res: result
 42 *
 43 * This routine returns 0 iff the first character is one of 'Yy1Nn0', or
 44 * [oO][NnFf] for "on" and "off". Otherwise it will return -EINVAL.  Value
 45 * pointed to by res is updated upon finding a match.
 46 */
 47int strtobool(const char *s, bool *res)
 48{
 49	if (!s)
 50		return -EINVAL;
 51
 52	switch (s[0]) {
 53	case 'y':
 54	case 'Y':
 55	case '1':
 56		*res = true;
 57		return 0;
 58	case 'n':
 59	case 'N':
 60	case '0':
 61		*res = false;
 62		return 0;
 63	case 'o':
 64	case 'O':
 65		switch (s[1]) {
 66		case 'n':
 67		case 'N':
 68			*res = true;
 69			return 0;
 70		case 'f':
 71		case 'F':
 72			*res = false;
 73			return 0;
 74		default:
 75			break;
 76		}
 77	default:
 78		break;
 79	}
 80
 81	return -EINVAL;
 82}
 83
 84/**
 85 * strlcpy - Copy a C-string into a sized buffer
 86 * @dest: Where to copy the string to
 87 * @src: Where to copy the string from
 88 * @size: size of destination buffer
 89 *
 90 * Compatible with *BSD: the result is always a valid
 91 * NUL-terminated string that fits in the buffer (unless,
 92 * of course, the buffer size is zero). It does not pad
 93 * out the result like strncpy() does.
 94 *
 95 * If libc has strlcpy() then that version will override this
 96 * implementation:
 97 */
 98size_t __weak strlcpy(char *dest, const char *src, size_t size)
 99{
100	size_t ret = strlen(src);
101
102	if (size) {
103		size_t len = (ret >= size) ? size - 1 : ret;
104		memcpy(dest, src, len);
105		dest[len] = '\0';
106	}
107	return ret;
108}