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d614a753 | 1 | /* Copyright (C) 1991-2020 Free Software Foundation, Inc. |
b5cc329c UD |
2 | This file is part of the GNU C Library. |
3 | ||
4 | The GNU C Library is free software; you can redistribute it and/or | |
5 | modify it under the terms of the GNU Lesser General Public | |
6 | License as published by the Free Software Foundation; either | |
7 | version 2.1 of the License, or (at your option) any later version. | |
8 | ||
9 | The GNU C Library is distributed in the hope that it will be useful, | |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
12 | Lesser General Public License for more details. | |
13 | ||
14 | You should have received a copy of the GNU Lesser General Public | |
59ba27a6 | 15 | License along with the GNU C Library; if not, see |
5a82c748 | 16 | <https://www.gnu.org/licenses/>. */ |
b5cc329c UD |
17 | |
18 | #include <string.h> | |
19 | ||
20 | #include <memcopy.h> | |
21 | ||
22 | ||
23 | char * | |
9d46370c | 24 | __strncat_chk (char *s1, const char *s2, size_t n, size_t s1len) |
b5cc329c | 25 | { |
50f81fd7 | 26 | char c; |
b5cc329c UD |
27 | char *s = s1; |
28 | ||
29 | /* Find the end of S1. */ | |
30 | do | |
31 | { | |
a1ffb40e | 32 | if (__glibc_unlikely (s1len-- == 0)) |
b5cc329c UD |
33 | __chk_fail (); |
34 | c = *s1++; | |
35 | } | |
36 | while (c != '\0'); | |
37 | ||
38 | /* Make S1 point before next character, so we can increment | |
39 | it while memory is read (wins on pipelined cpus). */ | |
40 | ++s1len; | |
41 | s1 -= 2; | |
42 | ||
43 | if (n >= 4) | |
44 | { | |
45 | size_t n4 = n >> 2; | |
46 | do | |
47 | { | |
a1ffb40e | 48 | if (__glibc_unlikely (s1len-- == 0)) |
b5cc329c UD |
49 | __chk_fail (); |
50 | c = *s2++; | |
51 | *++s1 = c; | |
52 | if (c == '\0') | |
53 | return s; | |
a1ffb40e | 54 | if (__glibc_unlikely (s1len-- == 0)) |
b5cc329c UD |
55 | __chk_fail (); |
56 | c = *s2++; | |
57 | *++s1 = c; | |
58 | if (c == '\0') | |
59 | return s; | |
a1ffb40e | 60 | if (__glibc_unlikely (s1len-- == 0)) |
b5cc329c UD |
61 | __chk_fail (); |
62 | c = *s2++; | |
63 | *++s1 = c; | |
64 | if (c == '\0') | |
65 | return s; | |
a1ffb40e | 66 | if (__glibc_unlikely (s1len-- == 0)) |
b5cc329c UD |
67 | __chk_fail (); |
68 | c = *s2++; | |
69 | *++s1 = c; | |
70 | if (c == '\0') | |
71 | return s; | |
72 | } while (--n4 > 0); | |
73 | n &= 3; | |
74 | } | |
75 | ||
76 | while (n > 0) | |
77 | { | |
a1ffb40e | 78 | if (__glibc_unlikely (s1len-- == 0)) |
b5cc329c UD |
79 | __chk_fail (); |
80 | c = *s2++; | |
81 | *++s1 = c; | |
82 | if (c == '\0') | |
83 | return s; | |
84 | n--; | |
85 | } | |
86 | ||
87 | if (c != '\0') | |
88 | { | |
a1ffb40e | 89 | if (__glibc_unlikely (s1len-- == 0)) |
b5cc329c UD |
90 | __chk_fail (); |
91 | *++s1 = '\0'; | |
92 | } | |
93 | ||
94 | return s; | |
95 | } |