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77008252 JJ |
1 | /* Checking strncat. |
2 | Copyright (C) 1991, 1997, 2003, 2004, 2005 Free Software Foundation, Inc. | |
3 | ||
4 | This file is part of GCC. | |
5 | ||
6 | GCC is free software; you can redistribute it and/or modify it under | |
7 | the terms of the GNU General Public License as published by the Free | |
8 | Software Foundation; either version 2, or (at your option) any later | |
9 | version. | |
10 | ||
11 | In addition to the permissions in the GNU General Public License, the | |
12 | Free Software Foundation gives you unlimited permission to link the | |
13 | compiled version of this file into combinations with other programs, | |
14 | and to distribute those combinations without any restriction coming | |
15 | from the use of this file. (The General Public License restrictions | |
16 | do apply in other respects; for example, they cover modification of | |
17 | the file, and distribution when not linked into a combine | |
18 | executable.) | |
19 | ||
20 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
21 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
22 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
23 | for more details. | |
24 | ||
25 | You should have received a copy of the GNU General Public License | |
26 | along with GCC; see the file COPYING. If not, write to the Free | |
cf398b1e KC |
27 | Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA |
28 | 02110-1301, USA. */ | |
77008252 JJ |
29 | |
30 | /* As a special exception, if you link this library with files compiled with | |
31 | GCC to produce an executable, this does not cause the resulting executable | |
32 | to be covered by the GNU General Public License. This exception does not | |
33 | however invalidate any other reasons why the executable file might be | |
34 | covered by the GNU General Public License. */ | |
35 | ||
36 | #include "config.h" | |
37 | #include <ssp/ssp.h> | |
38 | #ifdef HAVE_STRING_H | |
39 | # include <string.h> | |
40 | #endif | |
41 | ||
42 | extern void __chk_fail (void) __attribute__((__noreturn__)); | |
43 | ||
44 | char * | |
45 | __strncat_chk (char *__restrict__ dest, const char *__restrict__ src, | |
46 | size_t n, size_t slen) | |
47 | { | |
48 | char c; | |
49 | char *s = dest; | |
50 | ||
51 | do | |
52 | { | |
53 | if (slen-- == 0) | |
54 | __chk_fail (); | |
55 | c = *dest++; | |
56 | } | |
57 | while (c != '\0'); | |
58 | ||
59 | ++slen; | |
60 | dest -= 2; | |
61 | ||
62 | if (n >= 4) | |
63 | { | |
64 | size_t n4 = n >> 2; | |
65 | do | |
66 | { | |
67 | if (slen-- == 0) | |
68 | __chk_fail (); | |
69 | c = *src++; | |
70 | *++dest = c; | |
71 | if (c == '\0') | |
72 | return s; | |
73 | if (slen-- == 0) | |
74 | __chk_fail (); | |
75 | c = *src++; | |
76 | *++dest = c; | |
77 | if (c == '\0') | |
78 | return s; | |
79 | if (slen-- == 0) | |
80 | __chk_fail (); | |
81 | c = *src++; | |
82 | *++dest = c; | |
83 | if (c == '\0') | |
84 | return s; | |
85 | if (slen-- == 0) | |
86 | __chk_fail (); | |
87 | c = *src++; | |
88 | *++dest = c; | |
89 | if (c == '\0') | |
90 | return s; | |
91 | if (slen-- == 0) | |
92 | __chk_fail (); | |
93 | c = *src++; | |
94 | *++dest = c; | |
95 | if (c == '\0') | |
96 | return s; | |
97 | } while (--n4 > 0); | |
98 | n &= 3; | |
99 | } | |
100 | ||
101 | while (n > 0) | |
102 | { | |
103 | if (slen-- == 0) | |
104 | __chk_fail (); | |
105 | c = *src++; | |
106 | *++dest = c; | |
107 | if (c == '\0') | |
108 | return s; | |
109 | n--; | |
110 | } | |
111 | ||
112 | if (c != '\0') | |
113 | { | |
114 | if (slen-- == 0) | |
115 | __chk_fail (); | |
116 | *++dest = '\0'; | |
117 | } | |
118 | ||
119 | return s; | |
120 | } |