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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-09 13:16:35 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-09 13:16:35 +0000 |
commit | e2bbf175a2184bd76f6c54ccf8456babeb1a46fc (patch) | |
tree | f0b76550d6e6f500ada964a3a4ee933a45e5a6f1 /lib/strlcat.c | |
parent | Initial commit. (diff) | |
download | frr-e2bbf175a2184bd76f6c54ccf8456babeb1a46fc.tar.xz frr-e2bbf175a2184bd76f6c54ccf8456babeb1a46fc.zip |
Adding upstream version 9.1.upstream/9.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'lib/strlcat.c')
-rw-r--r-- | lib/strlcat.c | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/lib/strlcat.c b/lib/strlcat.c new file mode 100644 index 0000000..e3e29a7 --- /dev/null +++ b/lib/strlcat.c @@ -0,0 +1,58 @@ +// SPDX-License-Identifier: LGPL-2.1-or-later +/* Append a null-terminated string to another string, with length checking. + * Copyright (C) 2016 Free Software Foundation, Inc. + * This file is part of the GNU C Library. + */ + +/* adapted for Quagga from glibc patch submission originally from + * Florian Weimer <fweimer@redhat.com>, 2016-05-18 */ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#include <stdint.h> +#include <string.h> + +#ifndef HAVE_STRLCAT +#undef strlcat + +size_t strlcat(char *__restrict dest, + const char *__restrict src, size_t destsize); + +size_t strlcat(char *__restrict dest, + const char *__restrict src, size_t destsize) +{ + 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 (destsize == 0) + return src_length; + + size_t dest_length = strnlen(dest, destsize); + if (dest_length != destsize) { + /* Copy at most the remaining number of characters in the + destination buffer. Leave for the NUL terminator. */ + size_t to_copy = destsize - 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; +} +#endif /* HAVE_STRLCAT */ |