1*38fd1498Szrj /* Checking strncat.
2*38fd1498Szrj Copyright (C) 1991-2018 Free Software Foundation, Inc.
3*38fd1498Szrj
4*38fd1498Szrj This file is part of GCC.
5*38fd1498Szrj
6*38fd1498Szrj GCC is free software; you can redistribute it and/or modify it under
7*38fd1498Szrj the terms of the GNU General Public License as published by the Free
8*38fd1498Szrj Software Foundation; either version 3, or (at your option) any later
9*38fd1498Szrj version.
10*38fd1498Szrj
11*38fd1498Szrj In addition to the permissions in the GNU General Public License, the
12*38fd1498Szrj Free Software Foundation gives you unlimited permission to link the
13*38fd1498Szrj compiled version of this file into combinations with other programs,
14*38fd1498Szrj and to distribute those combinations without any restriction coming
15*38fd1498Szrj from the use of this file. (The General Public License restrictions
16*38fd1498Szrj do apply in other respects; for example, they cover modification of
17*38fd1498Szrj the file, and distribution when not linked into a combine
18*38fd1498Szrj executable.)
19*38fd1498Szrj
20*38fd1498Szrj GCC is distributed in the hope that it will be useful, but WITHOUT ANY
21*38fd1498Szrj WARRANTY; without even the implied warranty of MERCHANTABILITY or
22*38fd1498Szrj FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
23*38fd1498Szrj for more details.
24*38fd1498Szrj
25*38fd1498Szrj Under Section 7 of GPL version 3, you are granted additional
26*38fd1498Szrj permissions described in the GCC Runtime Library Exception, version
27*38fd1498Szrj 3.1, as published by the Free Software Foundation.
28*38fd1498Szrj
29*38fd1498Szrj You should have received a copy of the GNU General Public License and
30*38fd1498Szrj a copy of the GCC Runtime Library Exception along with this program;
31*38fd1498Szrj see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
32*38fd1498Szrj <http://www.gnu.org/licenses/>. */
33*38fd1498Szrj
34*38fd1498Szrj
35*38fd1498Szrj #include "config.h"
36*38fd1498Szrj #include <ssp/ssp.h>
37*38fd1498Szrj #ifdef HAVE_STRING_H
38*38fd1498Szrj # include <string.h>
39*38fd1498Szrj #endif
40*38fd1498Szrj
41*38fd1498Szrj extern void __chk_fail (void) __attribute__((__noreturn__));
42*38fd1498Szrj
43*38fd1498Szrj char *
__strncat_chk(char * __restrict__ dest,const char * __restrict__ src,size_t n,size_t slen)44*38fd1498Szrj __strncat_chk (char *__restrict__ dest, const char *__restrict__ src,
45*38fd1498Szrj size_t n, size_t slen)
46*38fd1498Szrj {
47*38fd1498Szrj char c;
48*38fd1498Szrj char *s = dest;
49*38fd1498Szrj
50*38fd1498Szrj do
51*38fd1498Szrj {
52*38fd1498Szrj if (slen-- == 0)
53*38fd1498Szrj __chk_fail ();
54*38fd1498Szrj c = *dest++;
55*38fd1498Szrj }
56*38fd1498Szrj while (c != '\0');
57*38fd1498Szrj
58*38fd1498Szrj ++slen;
59*38fd1498Szrj dest -= 2;
60*38fd1498Szrj
61*38fd1498Szrj if (n >= 4)
62*38fd1498Szrj {
63*38fd1498Szrj size_t n4 = n >> 2;
64*38fd1498Szrj do
65*38fd1498Szrj {
66*38fd1498Szrj if (slen-- == 0)
67*38fd1498Szrj __chk_fail ();
68*38fd1498Szrj c = *src++;
69*38fd1498Szrj *++dest = c;
70*38fd1498Szrj if (c == '\0')
71*38fd1498Szrj return s;
72*38fd1498Szrj if (slen-- == 0)
73*38fd1498Szrj __chk_fail ();
74*38fd1498Szrj c = *src++;
75*38fd1498Szrj *++dest = c;
76*38fd1498Szrj if (c == '\0')
77*38fd1498Szrj return s;
78*38fd1498Szrj if (slen-- == 0)
79*38fd1498Szrj __chk_fail ();
80*38fd1498Szrj c = *src++;
81*38fd1498Szrj *++dest = c;
82*38fd1498Szrj if (c == '\0')
83*38fd1498Szrj return s;
84*38fd1498Szrj if (slen-- == 0)
85*38fd1498Szrj __chk_fail ();
86*38fd1498Szrj c = *src++;
87*38fd1498Szrj *++dest = c;
88*38fd1498Szrj if (c == '\0')
89*38fd1498Szrj return s;
90*38fd1498Szrj } while (--n4 > 0);
91*38fd1498Szrj n &= 3;
92*38fd1498Szrj }
93*38fd1498Szrj
94*38fd1498Szrj while (n > 0)
95*38fd1498Szrj {
96*38fd1498Szrj if (slen-- == 0)
97*38fd1498Szrj __chk_fail ();
98*38fd1498Szrj c = *src++;
99*38fd1498Szrj *++dest = c;
100*38fd1498Szrj if (c == '\0')
101*38fd1498Szrj return s;
102*38fd1498Szrj n--;
103*38fd1498Szrj }
104*38fd1498Szrj
105*38fd1498Szrj if (c != '\0')
106*38fd1498Szrj {
107*38fd1498Szrj if (slen-- == 0)
108*38fd1498Szrj __chk_fail ();
109*38fd1498Szrj *++dest = '\0';
110*38fd1498Szrj }
111*38fd1498Szrj
112*38fd1498Szrj return s;
113*38fd1498Szrj }
114