citus/vendor/safestringlib/safeclib/stpncpy_s.c

283 lines
9.5 KiB
C

/*------------------------------------------------------------------
* stpncpy_s.c
*
* August 2014, D Wheeler
*
* Copyright (c) 2014 by Intel Corp
* 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
* stpncpy_s
*
* SYNOPSIS
* #include "safe_str_lib.h"
* char *
* stpncpy_s(char *dest, rsize_t dmax, const char *src, rsize_t smax, errno_t *err);
*
* DESCRIPTION
* The stpncpy_s function copies at most smax characters from the string
* pointed to by src, including the terminating null byte ('\0'), to the
* array pointed to by dest. Exactly smax characters are written at dest.
* If the length strlen_s(src) is smaller than smax, the remaining smax
* characters in the array pointed to by dest are filled with null bytes.
* If the length strlen_s(src) is greater than or equal to smax, the string
* pointed to by dest will contain smax characters from src plus a null
* characters (dest will be null-terminated).
*
* Therefore, dmax must be at least smax+1 in order to contain the terminator.
*
* The function returns a pointer to the end of the string in dest -
* that is to the null terminator of dest. If an error occurs,
* NULL is returned and err is set to the error encountered.
*
* 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 replaced by src.
*
* dmax restricted maximum length of dest (must be at least smax+1)
*
* src pointer to the string that will be copied
* to dest
*
* smax the maximum number of characters from src to copy into dest
*
* err the error code upon error, or EOK if successful
*
* OUTPUT PARAMETERS
* dest updated
* err updated as follows:
* EOK successful operation, the characters in src were
* copied into dest and the result is null terminated,
* and dest is returned to point to the first null at end of dest.
* On error, NULL is returned and err is set to one of hte following:
* ESNULLP NULL pointer
* ESZEROL zero length
* ESLEMAX length exceeds max limit
* ESOVRLP strings overlap
* ESNOSPC not enough space to copy src
*
* RUNTIME CONSTRAINTS
* Neither dest nor src shall be a null pointer.
* dmax shall not be greater than RSIZE_MAX_STR.
* dmax shall not equal zero.
* dmax must be at least smax+1 to allow filling dest with smax characters plus NULL.
* If src and dest overlap, copying shall be stopped; destruction of src may have occurred.
* If there is a runtime-constraint violation, then:
* if dest is not a null pointer and dmax is greater than zero and
* not greater than RSIZE_MAX_STR, then stpncpy_s shall fill dest with nulls,
* if library was compiled with SAFECLIB_STR_NULL_SLACK.
*
* RETURN VALUE
* a char pointer to the terminating null at the end of dest
* or NULL pointer on error
*
* ALSO SEE
* stpcpy_s(), strcpy_s(), strcat_s(), strncat_s(), strncpy_s()
*
*/
char *
stpncpy_s(char *dest, rsize_t dmax, const char *src, rsize_t smax, errno_t *err)
{
rsize_t orig_dmax;
char *orig_dest;
if (dest == NULL) {
invoke_safe_str_constraint_handler("stpncpy_s: dest is null",
NULL, ESNULLP);
*err = RCNEGATE(ESNULLP);
return NULL;
}
if (src == NULL) {
invoke_safe_str_constraint_handler("stpncpy_s: src is null",
NULL, ESNULLP);
*err = RCNEGATE(ESNULLP);
dest[0] = '\0';
return NULL;
}
if (dmax == 0) {
invoke_safe_str_constraint_handler("stpncpy_s: dmax is 0",
NULL, ESZEROL);
*err = RCNEGATE(ESZEROL);
return NULL;
}
if (dmax > RSIZE_MAX_STR) {
invoke_safe_str_constraint_handler("stpncpy_s: dmax exceeds max",
NULL, ESLEMAX);
*err = RCNEGATE(ESLEMAX);
return NULL;
}
if (smax > RSIZE_MAX_STR) {
invoke_safe_str_constraint_handler("stpncpy_s: smax exceeds max",
NULL, ESLEMAX);
*err = RCNEGATE(ESLEMAX);
return NULL;
}
if (dmax < (smax+1)) {
invoke_safe_str_constraint_handler("stpncpy_s: dmax too short for smax",
NULL, ESNOSPC);
*err = RCNEGATE(ESNOSPC);
dest[0] = '\0';
return NULL;
}
/* dmwheel1: Add check to prevent destruction of overlap into destination */
if ((src < dest) && ((src+smax) >= dest)) {
invoke_safe_str_constraint_handler("stpncpy_s: src+smax overlaps into dest",
NULL, ESOVRLP);
*err = RCNEGATE(ESOVRLP);
dest[0] = '\0';
return NULL;
}
/* dmwheel1: Add check to prevent destruction of overlap into source */
if ((dest < src) && ((dest+smax) >= src)) {
invoke_safe_str_constraint_handler("stpncpy_s: dest+smax overlaps into src",
NULL, ESOVRLP);
*err = RCNEGATE(ESOVRLP);
dest[0] = '\0';
return NULL;
}
#ifdef SAFECLIB_STR_NULL_SLACK
/* dmwheel1: Add check to prevent destruction of overlap into destination */
if ((src < dest) && ((src+dmax) >= dest)) {
invoke_safe_str_constraint_handler("stpncpy_s: src+dmax overlaps into dest",
NULL, ESOVRLP);
*err = RCNEGATE(ESOVRLP);
return NULL;
}
/* dmwheel1: Add check to prevent destruction of overlap into source */
if ((dest < src) && ((dest+dmax) >= src)) {
invoke_safe_str_constraint_handler("stpncpy_s: dest+dmax overlaps into src",
NULL, ESOVRLP);
*err = RCNEGATE(ESOVRLP);
return NULL;
}
#endif
if (src == NULL) {
#ifdef SAFECLIB_STR_NULL_SLACK
/* null string to clear data */
while (dmax) { *dest = '\0'; dmax--; dest++; }
#else
*dest = '\0';
#endif
invoke_safe_str_constraint_handler("stpncpy_s: src is null",
NULL, ESNULLP);
*err = RCNEGATE(ESNULLP);
return NULL;
}
/* hold base of dest in case src was not copied */
orig_dmax = dmax;
orig_dest = dest;
if (dest == src) {
/* look for the terminating null character, or return err if not found in dmax bytes */
while (dmax > 0) {
if (*dest == '\0') {
/* add nulls to complete smax */
char *filler = dest; /* don't change dest, because we need to return it */
while (smax) { *filler = '\0'; dmax--; smax--; filler++; }
#ifdef SAFECLIB_STR_NULL_SLACK
/* null dmax slack to clear any data */
while (dmax) { *filler = '\0'; dmax--; filler++; }
#endif
*err = RCNEGATE(EOK);
return dest;
}
dmax--;
dest++;
if (--smax == 0) {
/* we have copied smax characters, add null terminator */
*dest = '\0';
}
}
/* null terminator not found in src before end of dmax */
handle_error(orig_dest, orig_dmax, "stpncpy_s: not enough space for src",
ESNOSPC);
*err = RCNEGATE(ESNOSPC);
return NULL;
}
/* All checks for buffer overlaps were made, just do the copies */
while (dmax > 0) {
*dest = *src; /* Copy the data into the destination */
/* Check for maximum copy from source */
if (smax == 0) {
/* we have copied smax characters, add null terminator */
*dest = '\0';
}
/* Check for end of copying */
if (*dest == '\0') {
/* add nulls to complete smax, if fewer than smax characters
* were in src when the NULL was encountered */
char *filler = dest; /* don't change dest, because we need to return it */
while (smax) { *filler = '\0'; dmax--; smax--; filler++; }
#ifdef SAFECLIB_STR_NULL_SLACK
/* null dmax slack to clear any data */
while (dmax) { *filler = '\0'; dmax--; filler++; }
#endif
*err = RCNEGATE(EOK);
return dest;
}
dmax--;
smax--;
dest++;
src++;
}
/*
* Ran out of space in dest, and did not find the null terminator in src
*/
handle_error(orig_dest, orig_dmax, "stpncpy_s: not enough space for src",
ESNOSPC);
*err = RCNEGATE(ESNOSPC);
return NULL;
}
EXPORT_SYMBOL(stpncpy_s)