1 /*
2 * Copyright (c) Huawei Technologies Co., Ltd. 2014-2021. All rights reserved.
3 * Licensed under Mulan PSL v2.
4 * You can use this software according to the terms and conditions of the Mulan PSL v2.
5 * You may obtain a copy of Mulan PSL v2 at:
6 * http://license.coscl.org.cn/MulanPSL2
7 * THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
8 * EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
9 * MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
10 * See the Mulan PSL v2 for more details.
11 * Description: strncat_s function
12 * Create: 2014-02-25
13 */
14
15 #include "securecutil.h"
16
17 /*
18 * Befor this function, the basic parameter checking has been done
19 */
SecDoCatLimit(char * strDest,size_t destMax,const char * strSrc,size_t count)20 SECUREC_INLINE errno_t SecDoCatLimit(char *strDest, size_t destMax, const char *strSrc, size_t count)
21 {
22 size_t destLen;
23 size_t srcLen;
24 SECUREC_CALC_STR_LEN(strDest, destMax, &destLen);
25 /*
26 * The strSrc is no longer optimized. The reason is that when count is small,
27 * the efficiency of strnlen is higher than that of self realization.
28 */
29 SECUREC_CALC_STR_LEN(strSrc, count, &srcLen);
30
31 if (SECUREC_CAT_STRING_IS_OVERLAP(strDest, destLen, strSrc, srcLen)) {
32 strDest[0] = '\0';
33 if (strDest + destLen <= strSrc && destLen == destMax) {
34 SECUREC_ERROR_INVALID_PARAMTER("strncat_s");
35 return EINVAL_AND_RESET;
36 }
37 SECUREC_ERROR_BUFFER_OVERLAP("strncat_s");
38 return EOVERLAP_AND_RESET;
39 }
40 if (srcLen + destLen >= destMax || strDest == strSrc) {
41 strDest[0] = '\0';
42 if (destLen == destMax) {
43 SECUREC_ERROR_INVALID_PARAMTER("strncat_s");
44 return EINVAL_AND_RESET;
45 }
46 SECUREC_ERROR_INVALID_RANGE("strncat_s");
47 return ERANGE_AND_RESET;
48 }
49 SECUREC_MEMCPY_WARP_OPT(strDest + destLen, strSrc, srcLen); /* No terminator */
50 *(strDest + destLen + srcLen) = '\0';
51 return EOK;
52 }
53
54 /*
55 * <FUNCTION DESCRIPTION>
56 * The strncat_s function appends not more than n successive characters
57 * (not including the terminating null character)
58 * from the array pointed to by strSrc to the end of the string pointed to by strDest
59 * The strncat_s function try to append the first D characters of strSrc to
60 * the end of strDest, where D is the lesser of count and the length of strSrc.
61 * If appending those D characters will fit within strDest (whose size is given
62 * as destMax) and still leave room for a null terminator, then those characters
63 * are appended, starting at the original terminating null of strDest, and a
64 * new terminating null is appended; otherwise, strDest[0] is set to the null
65 * character.
66 *
67 * <INPUT PARAMETERS>
68 * strDest Null-terminated destination string.
69 * destMax Size of the destination buffer.
70 * strSrc Null-terminated source string.
71 * count Number of character to append, or truncate.
72 *
73 * <OUTPUT PARAMETERS>
74 * strDest is updated
75 *
76 * <RETURN VALUE>
77 * EOK Success
78 * EINVAL strDest is NULL and destMax != 0 and destMax <= SECUREC_STRING_MAX_LEN
79 * EINVAL_AND_RESET (strDest unterminated and all other parameters are valid)or
80 * (strDest != NULL and strSrc is NULL and destMax != 0 and destMax <= SECUREC_STRING_MAX_LEN)
81 * ERANGE destMax is 0 and destMax > SECUREC_STRING_MAX_LEN
82 * ERANGE_AND_RESET strDest have not enough space and all other parameters are valid and not overlap
83 * EOVERLAP_AND_RESET dest buffer and source buffer are overlapped and all parameters are valid
84 *
85 * If there is a runtime-constraint violation, strDest[0] will be set to the '\0' when strDest and destMax valid
86 */
strncat_s(char * strDest,size_t destMax,const char * strSrc,size_t count)87 errno_t strncat_s(char *strDest, size_t destMax, const char *strSrc, size_t count)
88 {
89 if (destMax == 0 || destMax > SECUREC_STRING_MAX_LEN) {
90 SECUREC_ERROR_INVALID_RANGE("strncat_s");
91 return ERANGE;
92 }
93
94 if (strDest == NULL || strSrc == NULL) {
95 SECUREC_ERROR_INVALID_PARAMTER("strncat_s");
96 if (strDest != NULL) {
97 strDest[0] = '\0';
98 return EINVAL_AND_RESET;
99 }
100 return EINVAL;
101 }
102 if (count > SECUREC_STRING_MAX_LEN) {
103 #ifdef SECUREC_COMPATIBLE_WIN_FORMAT
104 if (count == (size_t)(-1)) {
105 /* Windows internal functions may pass in -1 when calling this function */
106 return SecDoCatLimit(strDest, destMax, strSrc, destMax);
107 }
108 #endif
109 strDest[0] = '\0';
110 SECUREC_ERROR_INVALID_RANGE("strncat_s");
111 return ERANGE_AND_RESET;
112 }
113 return SecDoCatLimit(strDest, destMax, strSrc, count);
114 }
115
116 #if SECUREC_EXPORT_KERNEL_SYMBOL
117 EXPORT_SYMBOL(strncat_s);
118 #endif
119
120