mirror of
git://sourceware.org/git/glibc.git
synced 2024-11-27 03:41:23 +08:00
60 lines
2.3 KiB
C
60 lines
2.3 KiB
C
|
/* Append a null-terminated string to another string, with length checking.
|
||
|
|
Copyright (C) 2023 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, see
|
||
|
|
<https://www.gnu.org/licenses/>. */
|
||
|
|
|
||
|
|
#include <stdint.h>
|
||
|
|
#include <string.h>
|
||
|
|
|
||
|
|
size_t
|
||
|
|
__strlcat (char *__restrict dest, const char *__restrict src, size_t size)
|
||
|
|
{
|
||
|
|
size_t src_length = strlen (src);
|
||
|
|
|
||
|
|
/* Our implementation strlcat supports dest == NULL if size == 0
|
||
|
|
(for consistency with snprintf and strlcpy), but strnlen does
|
||
|
|
not, so we have to cover this case explicitly. */
|
||
|
|
if (size == 0)
|
||
|
|
return src_length;
|
||
|
|
|
||
|
|
size_t dest_length = __strnlen (dest, size);
|
||
|
|
if (dest_length != size)
|
||
|
|
{
|
||
|
|
/* Copy at most the remaining number of characters in the
|
||
|
|
destination buffer. Leave for the NUL terminator. */
|
||
|
|
size_t to_copy = size - dest_length - 1;
|
||
|
|
/* But not more than what is available in the source string. */
|
||
|
|
if (to_copy > src_length)
|
||
|
|
to_copy = src_length;
|
||
|
|
|
||
|
|
char *target = dest + dest_length;
|
||
|
|
memcpy (target, src, to_copy);
|
||
|
|
target[to_copy] = '\0';
|
||
|
|
}
|
||
|
|
|
||
|
|
/* If the sum wraps around, we have more than SIZE_MAX + 2 bytes in
|
||
|
|
the two input strings (including both null terminators). If each
|
||
|
|
byte in the address space can be assigned a unique size_t value
|
||
|
|
(which the static_assert checks), then by the pigeonhole
|
||
|
|
principle, the two input strings must overlap, which is
|
||
|
|
undefined. */
|
||
|
|
_Static_assert (sizeof (uintptr_t) == sizeof (size_t),
|
||
|
|
"theoretical maximum object size covers address space");
|
||
|
|
return dest_length + src_length;
|
||
|
|
}
|
||
|
|
libc_hidden_def (__strlcat)
|
||
|
|
weak_alias (__strlcat, strlcat)
|