libcilkrts/runtime/sslib/strnlen_s.c

   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
  27  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  28  * OTHER DEALINGS IN THE SOFTWARE.
  29  *------------------------------------------------------------------
  30  */
  31
  32 #include "safeclib_private.h"
  33 #include "safe_str_constraint.h"
  34 #include "safe_str_lib.h"
  35
  36
  37 /**
  38  * NAME
  39  *    strnlen_s
  40  *
  41  * SYNOPSIS
  42  *    #include "safe_str_lib.h"
  43  *    rsize_t
  44  *    strnlen_s(const char *dest, rsize_t dmax)
  45  *
  46  * DESCRIPTION
  47  *    The strnlen_s function computes the length of the string pointed
  48  *    to by dest.
  49  *
  50  * SPECIFIED IN
  51  *    ISO/IEC TR 24731-1, Programming languages, environments
  52  *    and system software interfaces, Extensions to the C Library,
  53  *    Part I: Bounds-checking interfaces
  54  *
  55  * INPUT PARAMETERS
  56  *    dest      pointer to string
  57  *
  58  *    dmax      restricted maximum length.
  59  *
  60  * OUTPUT PARAMETERS
  61  *    none
  62  *
  63  * RUNTIME CONSTRAINTS
  64  *    dest shall not be a null pointer
  65  *    dmax shall not be greater than RSIZE_MAX_STR
  66  *    dmax shall not equal zero
  67  *
  68  * RETURN VALUE
  69  *    The function returns the string length, excluding  the terminating
  70  *    null character.  If dest is NULL, then strnlen_s returns 0.
  71  *
  72  *    Otherwise, the strnlen_s function returns the number of characters
  73  *    that precede the terminating null character. If there is no null
  74  *    character in the first dmax characters of dest then strnlen_s returns
  75  *    dmax. At most the first dmax characters of dest are accessed
  76  *    by strnlen_s.
  77  *
  78  * ALSO SEE
  79  *    strnterminate_s()
  80  *
  81  */
  82 rsize_t
  83 strnlen_s (const char *dest, rsize_t dmax)
  84 {
  85     rsize_t count;
  86
  87     if (dest == NULL) {
  88         return RCNEGATE(0);
  89     }
  90
  91     if (dmax == 0) {
  92         invoke_safe_str_constraint_handler("strnlen_s: dmax is 0",
  93                    NULL, ESZEROL);
  94         return RCNEGATE(0);
  95     }
  96
  97     if (dmax > RSIZE_MAX_STR) {
  98         invoke_safe_str_constraint_handler("strnlen_s: dmax exceeds max",
  99                    NULL, ESLEMAX);
 100         return RCNEGATE(0);
 101     }
 102
 103     count = 0;
 104     while (*dest && dmax) {
 105         count++;
 106         dmax--;
 107         dest++;
 108     }
 109
 110     return RCNEGATE(count);
 111 }
 112 EXPORT_SYMBOL(strnlen_s);