tools/lib/string.c

   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  */
  28 void *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  */
  47 int 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  */
  98 size_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 }