safec  2.1
Safe C Library - ISO TR24731 Bounds Checking Interface
strnlen_s.c
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1 /*------------------------------------------------------------------
2  * strnlen_s.c
3  *
4  * October 2008, Bo Berry
5  *
6  * Copyright (c) 2008-2011 by Cisco Systems, Inc
7  * All rights reserved.
8  *
9  * Permission is hereby granted, free of charge, to any person
10  * obtaining a copy of this software and associated documentation
11  * files (the "Software"), to deal in the Software without
12  * restriction, including without limitation the rights to use,
13  * copy, modify, merge, publish, distribute, sublicense, and/or
14  * sell copies of the Software, and to permit persons to whom the
15  * Software is furnished to do so, subject to the following
16  * conditions:
17  *
18  * The above copyright notice and this permission notice shall be
19  * included in all copies or substantial portions of the Software.
20  *
21  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
22  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
23  * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
24  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
25  * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
26  * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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29  *------------------------------------------------------------------
30  */
31 
32 #include "safeclib_private.h"
33 #include "safe_str_constraint.h"
34 #include "safe_str_lib.h"
35 
36 
66 rsize_t
67 strnlen_s (const char *dest, rsize_t dmax)
68 {
69  rsize_t count;
70 
71  if (dest == NULL) {
72  return RCNEGATE(0);
73  }
74 
75  if (dmax == 0) {
76  invoke_safe_str_constraint_handler("strnlen_s: dmax is 0",
77  NULL, ESZEROL);
78  return RCNEGATE(0);
79  }
80 
81  if (dmax > RSIZE_MAX_STR) {
82  invoke_safe_str_constraint_handler("strnlen_s: dmax exceeds max",
83  NULL, ESLEMAX);
84  return RCNEGATE(0);
85  }
86 
87  count = 0;
88  while (*dest && dmax) {
89  count++;
90  dmax--;
91  dest++;
92  }
93 
94  return RCNEGATE(count);
95 }
96 EXPORT_SYMBOL(strnlen_s)
rsize_t strnlen_s(const char *dest, rsize_t dmax)
The strnlen_s function computes the length of the string pointed to by dest.
Definition: strnlen_s.c:67
void invoke_safe_str_constraint_handler(const char *msg, void *ptr, errno_t error)
Invokes the currently set constraint handler or the default.