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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-28 09:53:30 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-28 09:53:30 +0000 |
commit | 2c7cac91ed6e7db0f6937923d2b57f97dbdbc337 (patch) | |
tree | c05dc0f8e6aa3accc84e3e5cffc933ed94941383 /lib/strlcat.c | |
parent | Initial commit. (diff) | |
download | frr-upstream.tar.xz frr-upstream.zip |
Adding upstream version 8.4.4.upstream/8.4.4upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'lib/strlcat.c')
-rw-r--r-- | lib/strlcat.c | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/lib/strlcat.c b/lib/strlcat.c new file mode 100644 index 0000000..a046822 --- /dev/null +++ b/lib/strlcat.c @@ -0,0 +1,71 @@ +/* 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. + * + * 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 + * <http://www.gnu.org/licenses/>. + */ + +/* 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 */ |