about summary refs log tree commit diff
path: root/debug/strncpy_chk.c
blob: bdede7738b04bf199ea594c3831c111fa3b846b1 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
/* Copyright (C) 1991, 1997, 2003, 2004 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <string.h>
#include <memcopy.h>


char *
__strncpy_chk (s1, s2, n, s1len)
     char *s1;
     const char *s2;
     size_t n;
     size_t s1len;
{
  reg_char c;
  char *s = s1;

  if (__builtin_expect (s1len < n, 0))
    __chk_fail ();

  --s1;

  if (n >= 4)
    {
      size_t n4 = n >> 2;

      for (;;)
	{
	  c = *s2++;
	  *++s1 = c;
	  if (c == '\0')
	    break;
	  c = *s2++;
	  *++s1 = c;
	  if (c == '\0')
	    break;
	  c = *s2++;
	  *++s1 = c;
	  if (c == '\0')
	    break;
	  c = *s2++;
	  *++s1 = c;
	  if (c == '\0')
	    break;
	  if (--n4 == 0)
	    goto last_chars;
	}
      n = n - (s1 - s) - 1;
      if (n == 0)
	return s;
      goto zero_fill;
    }

 last_chars:
  n &= 3;
  if (n == 0)
    return s;

  do
    {
      c = *s2++;
      *++s1 = c;
      if (--n == 0)
	return s;
    }
  while (c != '\0');

 zero_fill:
  do
    *++s1 = '\0';
  while (--n > 0);

  return s;
}