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 */ 29 void *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 */ 48 int 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 */ 99 #ifdef __clang__ 100 #pragma clang diagnostic push 101 #pragma clang diagnostic ignored "-Wignored-attributes" 102 #endif 103 size_t __weak strlcpy(char *dest, const char *src, size_t size) 104 { 105 size_t ret = strlen(src); 106 107 if (size) { 108 size_t len = (ret >= size) ? size - 1 : ret; 109 memcpy(dest, src, len); 110 dest[len] = '\0'; 111 } 112 return ret; 113 } 114 #ifdef __clang__ 115 #pragma clang diagnostic pop 116 #endif 117 118 /** 119 * skip_spaces - Removes leading whitespace from @str. 120 * @str: The string to be stripped. 121 * 122 * Returns a pointer to the first non-whitespace character in @str. 123 */ 124 char *skip_spaces(const char *str) 125 { 126 while (isspace(*str)) 127 ++str; 128 return (char *)str; 129 } 130 131 /** 132 * strim - Removes leading and trailing whitespace from @s. 133 * @s: The string to be stripped. 134 * 135 * Note that the first trailing whitespace is replaced with a %NUL-terminator 136 * in the given string @s. Returns a pointer to the first non-whitespace 137 * character in @s. 138 */ 139 char *strim(char *s) 140 { 141 size_t size; 142 char *end; 143 144 size = strlen(s); 145 if (!size) 146 return s; 147 148 end = s + size - 1; 149 while (end >= s && isspace(*end)) 150 end--; 151 *(end + 1) = '\0'; 152 153 return skip_spaces(s); 154 } 155 156 /** 157 * strreplace - Replace all occurrences of character in string. 158 * @s: The string to operate on. 159 * @old: The character being replaced. 160 * @new: The character @old is replaced with. 161 * 162 * Returns pointer to the nul byte at the end of @s. 163 */ 164 char *strreplace(char *s, char old, char new) 165 { 166 for (; *s; ++s) 167 if (*s == old) 168 *s = new; 169 return s; 170 } 171 172 static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes) 173 { 174 while (bytes) { 175 if (*start != value) 176 return (void *)start; 177 start++; 178 bytes--; 179 } 180 return NULL; 181 } 182 183 /** 184 * memchr_inv - Find an unmatching character in an area of memory. 185 * @start: The memory area 186 * @c: Find a character other than c 187 * @bytes: The size of the area. 188 * 189 * returns the address of the first character other than @c, or %NULL 190 * if the whole buffer contains just @c. 191 */ 192 void *memchr_inv(const void *start, int c, size_t bytes) 193 { 194 u8 value = c; 195 u64 value64; 196 unsigned int words, prefix; 197 198 if (bytes <= 16) 199 return check_bytes8(start, value, bytes); 200 201 value64 = value; 202 value64 |= value64 << 8; 203 value64 |= value64 << 16; 204 value64 |= value64 << 32; 205 206 prefix = (unsigned long)start % 8; 207 if (prefix) { 208 u8 *r; 209 210 prefix = 8 - prefix; 211 r = check_bytes8(start, value, prefix); 212 if (r) 213 return r; 214 start += prefix; 215 bytes -= prefix; 216 } 217 218 words = bytes / 8; 219 220 while (words) { 221 if (*(u64 *)start != value64) 222 return check_bytes8(start, value, 8); 223 start += 8; 224 words--; 225 } 226 227 return check_bytes8(start, value, bytes % 8); 228 } 229