citus/vendor/safestringlib/safeclib/strncat_s.c

266 lines
8.0 KiB
C

/*------------------------------------------------------------------
* strncat_s.c
*
* October 2008, Bo Berry
*
* Copyright (c) 2008-2011 by Cisco Systems, Inc
* All rights reserved.
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*------------------------------------------------------------------
*/
#include "safeclib_private.h"
#include "safe_str_constraint.h"
#include "safe_str_lib.h"
/**
* NAME
* strncat_s
*
* SYNOPSIS
* #include "safe_str_lib.h"
* errno_t
* strncat_s(char *dest, rsize_t dmax, const char *src, rsize_t slen)
*
* DESCRIPTION
* The strncat_s function appends a copy of the string pointed
* to by src (including the terminating null character) to the
* end of the string pointed to by dest. The initial character
* from src overwrites the null character at the end of dest.
*
* All elements following the terminating null character (if
* any) written by strncat_s in the array of dmax characters
* pointed to by dest take unspecified values when strncat_s returns.
*
* SPECIFIED IN
* ISO/IEC TR 24731, Programming languages, environments
* and system software interfaces, Extensions to the C Library,
* Part I: Bounds-checking interfaces
*
* INPUT PARAMETERS
* dest pointer to string that will be extended by src
* if dmax allows. The string is null terminated.
* If the resulting concatenated string is less
* than dmax, the remaining slack space is nulled.
*
* dmax restricted maximum length of the resulting dest,
* including the null
*
* src pointer to the string that will be concatenaed
* to string dest
*
* slen maximum characters to append
*
* OUTPUT PARAMETERS
* dest updated string
*
* RUNTIME CONSTRAINTS
* Neither dest nor src shall be a null pointer
* dmax shall not equal zero
* dmax shall not be greater than RSIZE_STR_MAX
* dmax shall be greater than strnlen_s(src,m).
* Copying shall not takeplace between objects that overlap
* If there is a runtime-constraint violation, then if dest is
* not a null pointer and dmax is greater than zero and not
* greater thanRSIZE_MAX, then strncat_s sets dest[0] to the
* null character.
*
* RETURN VALUE
* EOK successful operation, all the characters from src
* were appended to dest and the result in dest is
* null terminated.
* ESNULLP NULL pointer
* ESZEROL zero length
* ESLEMAX length exceeds max limit
* ESUNTERM dest not terminated
*
*
*/
errno_t
strncat_s (char *dest, rsize_t dmax, const char *src, rsize_t slen)
{
rsize_t orig_dmax;
char *orig_dest;
const char *overlap_bumper;
if (dest == NULL) {
invoke_safe_str_constraint_handler("strncat_s: dest is null",
NULL, ESNULLP);
return RCNEGATE(ESNULLP);
}
if (src == NULL) {
invoke_safe_str_constraint_handler("strncat_s: src is null",
NULL, ESNULLP);
return RCNEGATE(ESNULLP);
}
if (slen > RSIZE_MAX_STR) {
invoke_safe_str_constraint_handler("strncat_s: slen exceeds max",
NULL, ESLEMAX);
return RCNEGATE(ESLEMAX);
}
if (dmax == 0) {
invoke_safe_str_constraint_handler("strncat_s: dmax is 0",
NULL, ESZEROL);
return RCNEGATE(ESZEROL);
}
if (dmax > RSIZE_MAX_STR) {
invoke_safe_str_constraint_handler("strncat_s: dmax exceeds max",
NULL, ESLEMAX);
return RCNEGATE(ESLEMAX);
}
/* hold base of dest in case src was not copied */
orig_dmax = dmax;
orig_dest = dest;
if (dest < src) {
overlap_bumper = src;
/* Find the end of dest */
while (*dest != '\0') {
if (dest == overlap_bumper) {
handle_error(orig_dest, orig_dmax, "strncat_s: "
"overlapping objects",
ESOVRLP);
return RCNEGATE(ESOVRLP);
}
dest++;
dmax--;
if (dmax == 0) {
handle_error(orig_dest, orig_dmax, "strncat_s: "
"dest unterminated",
ESUNTERM);
return RCNEGATE(ESUNTERM);
}
}
while (dmax > 0) {
if (dest == overlap_bumper) {
handle_error(orig_dest, orig_dmax, "strncat_s: "
"overlapping objects",
ESOVRLP);
return RCNEGATE(ESOVRLP);
}
/*
* Copying truncated before the source null is encountered
*/
if (slen == 0) {
#ifdef SAFECLIB_STR_NULL_SLACK
/* null remaining string */
while (dmax) { *dest = '\0'; dmax--; dest++; }
#else
*dest = '\0';
#endif
return RCNEGATE(EOK);
}
*dest = *src;
if (*dest == '\0') {
#ifdef SAFECLIB_STR_NULL_SLACK
/* null slack to clear data */
while (dmax) { *dest = '\0'; dmax--; dest++; }
#endif
return RCNEGATE(EOK);
}
dmax--;
slen--;
dest++;
src++;
}
} else {
overlap_bumper = dest;
/* Find the end of dest */
while (*dest != '\0') {
/*
* NOTE: no need to check for overlap here since src comes first
* in memory and we're not incrementing src here.
*/
dest++;
dmax--;
if (dmax == 0) {
handle_error(orig_dest, orig_dmax, "strncat_s: "
"dest unterminated",
ESUNTERM);
return RCNEGATE(ESUNTERM);
}
}
while (dmax > 0) {
if (src == overlap_bumper) {
handle_error(orig_dest, orig_dmax, "strncat_s: "
"overlapping objects",
ESOVRLP);
return RCNEGATE(ESOVRLP);
}
/*
* Copying truncated
*/
if (slen == 0) {
#ifdef SAFECLIB_STR_NULL_SLACK
/* null remaining string */
while (dmax) { *dest = '\0'; dmax--; dest++; }
#else
*dest = '\0';
#endif
return RCNEGATE(EOK);
}
*dest = *src;
if (*dest == '\0') {
#ifdef SAFECLIB_STR_NULL_SLACK
/* null slack to clear any data */
while (dmax) { *dest = '\0'; dmax--; dest++; }
#endif
return RCNEGATE(EOK);
}
dmax--;
slen--;
dest++;
src++;
}
}
/*
* the entire src was not copied, so the string will be nulled.
*/
handle_error(orig_dest, orig_dmax, "strncat_s: not enough "
"space for src",
ESNOSPC);
return RCNEGATE(ESNOSPC);
}
EXPORT_SYMBOL(strncat_s)