1 /*
2 * Copyright (c) Huawei Technologies Co., Ltd. 2014-2020. 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 * Author: lishunda
13 * Create: 2014-02-25
14 */
15
16 #include "securecutil.h"
17
18 /*
19 * Befor this function, the basic parameter checking has been done
20 */
SecDoCatLimit(char * strDest,size_t destMax,const char * strSrc,size_t count)21 SECUREC_INLINE errno_t SecDoCatLimit(char *strDest, size_t destMax, const char *strSrc, size_t count)
22 {
23 size_t destLen;
24 size_t srcLen;
25 SECUREC_CALC_STR_LEN(strDest, destMax, &destLen);
26 /*
27 * The strSrc is no longer optimized. The reason is that when count is small,
28 * the efficiency of strnlen is higher than that of self realization.
29 */
30 SECUREC_CALC_STR_LEN(strSrc, count, &srcLen);
31
32 if (SECUREC_CAT_STRING_IS_OVERLAP(strDest, destLen, strSrc, srcLen)) {
33 strDest[0] = '\0';
34 if (strDest + destLen <= strSrc && destLen == destMax) {
35 SECUREC_ERROR_INVALID_PARAMTER("strncat_s");
36 return EINVAL_AND_RESET;
37 }
38 SECUREC_ERROR_BUFFER_OVERLAP("strncat_s");
39 return EOVERLAP_AND_RESET;
40 }
41 if (srcLen + destLen >= destMax || strDest == strSrc) {
42 strDest[0] = '\0';
43 if (destLen == destMax) {
44 SECUREC_ERROR_INVALID_PARAMTER("strncat_s");
45 return EINVAL_AND_RESET;
46 }
47 SECUREC_ERROR_INVALID_RANGE("strncat_s");
48 return ERANGE_AND_RESET;
49 }
50 SECUREC_MEMCPY_WARP_OPT(strDest + destLen, strSrc, srcLen); /* No terminator */
51 *(strDest + destLen + srcLen) = '\0';
52 return EOK;
53 }
54
55 /*
56 * <FUNCTION DESCRIPTION>
57 * The strncat_s function appends not more than n successive characters
58 * (not including the terminating null character)
59 * from the array pointed to by strSrc to the end of the string pointed to by strDest
60 * The strncat_s function try to append the first D characters of strSrc to
61 * the end of strDest, where D is the lesser of count and the length of strSrc.
62 * If appending those D characters will fit within strDest (whose size is given
63 * as destMax) and still leave room for a null terminator, then those characters
64 * are appended, starting at the original terminating null of strDest, and a
65 * new terminating null is appended; otherwise, strDest[0] is set to the null
66 * character.
67 *
68 * <INPUT PARAMETERS>
69 * strDest Null-terminated destination string.
70 * destMax Size of the destination buffer.
71 * strSrc Null-terminated source string.
72 * count Number of character to append, or truncate.
73 *
74 * <OUTPUT PARAMETERS>
75 * strDest is updated
76 *
77 * <RETURN VALUE>
78 * EOK Success
79 * EINVAL strDest is NULL and destMax != 0 and destMax <= SECUREC_STRING_MAX_LEN
80 * EINVAL_AND_RESET (strDest unterminated and all other parameters are valid)or
81 * (strDest != NULL and strSrc is NULL and destMax != 0 and destMax <= SECUREC_STRING_MAX_LEN)
82 * ERANGE destMax is 0 and destMax > SECUREC_STRING_MAX_LEN
83 * ERANGE_AND_RESET strDest have not enough space and all other parameters are valid and not overlap
84 * EOVERLAP_AND_RESET dest buffer and source buffer are overlapped and all parameters are valid
85 *
86 * If there is a runtime-constraint violation, strDest[0] will be set to the '\0' when strDest and destMax valid
87 */
strncat_s(char * strDest,size_t destMax,const char * strSrc,size_t count)88 errno_t strncat_s(char *strDest, size_t destMax, const char *strSrc, size_t count)
89 {
90 if (destMax == 0 || destMax > SECUREC_STRING_MAX_LEN) {
91 SECUREC_ERROR_INVALID_RANGE("strncat_s");
92 return ERANGE;
93 }
94
95 if (strDest == NULL || strSrc == NULL) {
96 SECUREC_ERROR_INVALID_PARAMTER("strncat_s");
97 if (strDest != NULL) {
98 strDest[0] = '\0';
99 return EINVAL_AND_RESET;
100 }
101 return EINVAL;
102 }
103 if (count > SECUREC_STRING_MAX_LEN) {
104 #ifdef SECUREC_COMPATIBLE_WIN_FORMAT
105 if (count == (size_t)(-1)) {
106 /* Windows internal functions may pass in -1 when calling this function */
107 return SecDoCatLimit(strDest, destMax, strSrc, destMax);
108 }
109 #endif
110 strDest[0] = '\0';
111 SECUREC_ERROR_INVALID_RANGE("strncat_s");
112 return ERANGE_AND_RESET;
113 }
114 return SecDoCatLimit(strDest, destMax, strSrc, count);
115 }
116
117 #if SECUREC_IN_KERNEL
118 EXPORT_SYMBOL(strncat_s);
119 #endif
120
121