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/ctype.h>
 21#include <linux/compiler.h>
 22
 23/**
 24 * memdup - duplicate region of memory
 25 *
 26 * @src: memory region to duplicate
 27 * @len: memory region length
 28 */
 29void *memdup(const void *src, size_t len)
 30{
 31	void *p = malloc(len);
 32
 33	if (p)
 34		memcpy(p, src, len);
 35
 36	return p;
 37}
 38
 39/**
 40 * strtobool - convert common user inputs into boolean values
 41 * @s: input string
 42 * @res: result
 43 *
 44 * This routine returns 0 iff the first character is one of 'Yy1Nn0', or
 45 * [oO][NnFf] for "on" and "off". Otherwise it will return -EINVAL.  Value
 46 * pointed to by res is updated upon finding a match.
 47 */
 48int strtobool(const char *s, bool *res)
 49{
 50	if (!s)
 51		return -EINVAL;
 52
 53	switch (s[0]) {
 54	case 'y':
 55	case 'Y':
 56	case '1':
 57		*res = true;
 58		return 0;
 59	case 'n':
 60	case 'N':
 61	case '0':
 62		*res = false;
 63		return 0;
 64	case 'o':
 65	case 'O':
 66		switch (s[1]) {
 67		case 'n':
 68		case 'N':
 69			*res = true;
 70			return 0;
 71		case 'f':
 72		case 'F':
 73			*res = false;
 74			return 0;
 75		default:
 76			break;
 77		}
 78	default:
 79		break;
 80	}
 81
 82	return -EINVAL;
 83}
 84
 85/**
 86 * strlcpy - Copy a C-string into a sized buffer
 87 * @dest: Where to copy the string to
 88 * @src: Where to copy the string from
 89 * @size: size of destination buffer
 90 *
 91 * Compatible with *BSD: the result is always a valid
 92 * NUL-terminated string that fits in the buffer (unless,
 93 * of course, the buffer size is zero). It does not pad
 94 * out the result like strncpy() does.
 95 *
 96 * If libc has strlcpy() then that version will override this
 97 * implementation:
 98 */
 99size_t __weak strlcpy(char *dest, const char *src, size_t size)
100{
101	size_t ret = strlen(src);
102
103	if (size) {
104		size_t len = (ret >= size) ? size - 1 : ret;
105		memcpy(dest, src, len);
106		dest[len] = '\0';
107	}
108	return ret;
109}
110
111/**
112 * skip_spaces - Removes leading whitespace from @str.
113 * @str: The string to be stripped.
114 *
115 * Returns a pointer to the first non-whitespace character in @str.
116 */
117char *skip_spaces(const char *str)
118{
119	while (isspace(*str))
120		++str;
121	return (char *)str;
122}
123
124/**
125 * strim - Removes leading and trailing whitespace from @s.
126 * @s: The string to be stripped.
127 *
128 * Note that the first trailing whitespace is replaced with a %NUL-terminator
129 * in the given string @s. Returns a pointer to the first non-whitespace
130 * character in @s.
131 */
132char *strim(char *s)
133{
134	size_t size;
135	char *end;
136
137	size = strlen(s);
138	if (!size)
139		return s;
140
141	end = s + size - 1;
142	while (end >= s && isspace(*end))
143		end--;
144	*(end + 1) = '\0';
145
146	return skip_spaces(s);
147}
148
149/**
150 * strreplace - Replace all occurrences of character in string.
151 * @s: The string to operate on.
152 * @old: The character being replaced.
153 * @new: The character @old is replaced with.
154 *
155 * Returns pointer to the nul byte at the end of @s.
156 */
157char *strreplace(char *s, char old, char new)
158{
159	for (; *s; ++s)
160		if (*s == old)
161			*s = new;
162	return s;
163}