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77008252 | 1 | /* Checking strncat. |
a945c346 | 2 | Copyright (C) 1991-2024 Free Software Foundation, Inc. |
77008252 JJ |
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 | |
748086b7 | 8 | Software Foundation; either version 3, or (at your option) any later |
77008252 JJ |
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 | ||
748086b7 JJ |
25 | Under Section 7 of GPL version 3, you are granted additional |
26 | permissions described in the GCC Runtime Library Exception, version | |
27 | 3.1, as published by the Free Software Foundation. | |
28 | ||
29 | You should have received a copy of the GNU General Public License and | |
30 | a copy of the GCC Runtime Library Exception along with this program; | |
31 | see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
32 | <http://www.gnu.org/licenses/>. */ | |
77008252 | 33 | |
77008252 JJ |
34 | |
35 | #include "config.h" | |
36 | #include <ssp/ssp.h> | |
37 | #ifdef HAVE_STRING_H | |
38 | # include <string.h> | |
39 | #endif | |
40 | ||
41 | extern void __chk_fail (void) __attribute__((__noreturn__)); | |
42 | ||
43 | char * | |
44 | __strncat_chk (char *__restrict__ dest, const char *__restrict__ src, | |
45 | size_t n, size_t slen) | |
46 | { | |
47 | char c; | |
48 | char *s = dest; | |
49 | ||
50 | do | |
51 | { | |
52 | if (slen-- == 0) | |
53 | __chk_fail (); | |
54 | c = *dest++; | |
55 | } | |
56 | while (c != '\0'); | |
57 | ||
58 | ++slen; | |
59 | dest -= 2; | |
60 | ||
61 | if (n >= 4) | |
62 | { | |
63 | size_t n4 = n >> 2; | |
64 | do | |
65 | { | |
66 | if (slen-- == 0) | |
67 | __chk_fail (); | |
68 | c = *src++; | |
69 | *++dest = c; | |
70 | if (c == '\0') | |
71 | return s; | |
72 | if (slen-- == 0) | |
73 | __chk_fail (); | |
74 | c = *src++; | |
75 | *++dest = c; | |
76 | if (c == '\0') | |
77 | return s; | |
78 | if (slen-- == 0) | |
79 | __chk_fail (); | |
80 | c = *src++; | |
81 | *++dest = c; | |
82 | if (c == '\0') | |
83 | return s; | |
84 | if (slen-- == 0) | |
85 | __chk_fail (); | |
86 | c = *src++; | |
87 | *++dest = c; | |
88 | if (c == '\0') | |
89 | return s; | |
77008252 JJ |
90 | } while (--n4 > 0); |
91 | n &= 3; | |
92 | } | |
93 | ||
94 | while (n > 0) | |
95 | { | |
96 | if (slen-- == 0) | |
97 | __chk_fail (); | |
98 | c = *src++; | |
99 | *++dest = c; | |
100 | if (c == '\0') | |
101 | return s; | |
102 | n--; | |
103 | } | |
104 | ||
105 | if (c != '\0') | |
106 | { | |
107 | if (slen-- == 0) | |
108 | __chk_fail (); | |
109 | *++dest = '\0'; | |
110 | } | |
111 | ||
112 | return s; | |
113 | } |