safec  2.1
Safe C Library - ISO TR24731 Bounds Checking Interface
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strstr_s.c
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1 /*------------------------------------------------------------------
2  * strstr_s.c
3  *
4  * November 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 
68 errno_t
69 strstr_s (char *dest, rsize_t dmax,
70  const char *src, rsize_t slen, char **substring)
71 {
72  rsize_t len;
73  rsize_t dlen;
74  int i;
75 
76  if (substring == NULL) {
77  invoke_safe_str_constraint_handler("strstr_s: substring is null",
78  NULL, ESNULLP);
79  return RCNEGATE(ESNULLP);
80  }
81  *substring = NULL;
82 
83  if (dest == NULL) {
84  invoke_safe_str_constraint_handler("strstr_s: dest is null",
85  NULL, ESNULLP);
86  return RCNEGATE(ESNULLP);
87  }
88 
89  if (dmax == 0) {
90  invoke_safe_str_constraint_handler("strstr_s: dmax is 0",
91  NULL, ESZEROL);
92  return RCNEGATE(ESZEROL);
93  }
94 
95  if (dmax > RSIZE_MAX_STR) {
96  invoke_safe_str_constraint_handler("strstr_s: dmax exceeds max",
97  NULL, ESLEMAX);
98  return RCNEGATE(ESLEMAX);
99  }
100 
101  if (src == NULL) {
102  invoke_safe_str_constraint_handler("strstr_s: src is null",
103  NULL, ESNULLP);
104  return RCNEGATE(ESNULLP);
105  }
106 
107  if (slen == 0) {
108  invoke_safe_str_constraint_handler("strstr_s: slen is 0",
109  NULL, ESZEROL);
110  return RCNEGATE(ESZEROL);
111  }
112 
113  if (slen > RSIZE_MAX_STR) {
114  invoke_safe_str_constraint_handler("strstr_s: slen exceeds max",
115  NULL, ESLEMAX);
116  return RCNEGATE(ESLEMAX);
117  }
118 
119  /*
120  * src points to a string with zero length, or
121  * src equals dest, return dest
122  */
123  if (*src == '\0' || dest == src) {
124  *substring = dest;
125  return RCNEGATE(EOK);
126  }
127 
128  while (*dest && dmax) {
129  i = 0;
130  len = slen;
131  dlen = dmax;
132 
133  while (src[i] && dlen) {
134 
135  /* not a match, not a substring */
136  if (dest[i] != src[i]) {
137  break;
138  }
139 
140  /* move to the next char */
141  i++;
142  len--;
143  dlen--;
144 
145  if (src[i] == '\0' || !len) {
146  *substring = dest;
147  return RCNEGATE(EOK);
148  }
149  }
150  dest++;
151  dmax--;
152  }
153 
154  /*
155  * substring was not found, return NULL
156  */
157  *substring = NULL;
158  return RCNEGATE(ESNOTFND);
159 }
160 EXPORT_SYMBOL(strstr_s)
errno_t strstr_s(char *dest, rsize_t dmax, const char *src, rsize_t slen, char **substring)
The strstr_s() function locates the first occurrence of the substring pointed to by src which would b...
Definition: strstr_s.c:69
void invoke_safe_str_constraint_handler(const char *msg, void *ptr, errno_t error)
Invokes the currently set constraint handler or the default.