3bf8d68f10
This function is like strlcpy(3), but returns -1 on truncation, which makes it much easier to test. strlcpy(3) is useful in two cases: - We don't care if the output is truncated. strlcpy(3) is fine for those, and the return value can be ignored. - Truncation is bad. In that case, we just want to signal truncation, and the length of the original string is quite useless. Return the length iff no truncation so that we can use it if necessary. This simplifies the definition of the STRLCPY() macro. Signed-off-by: Alejandro Colomar <alx@kernel.org>
64 lines
1.2 KiB
C
64 lines
1.2 KiB
C
/*
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* SPDX-FileCopyrightText: 2023, Alejandro Colomar <alx@kernel.org>
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#ifndef SHADOW_INCLUDE_LIB_STRLCPY_H_
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#define SHADOW_INCLUDE_LIB_STRLCPY_H_
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#include <config.h>
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#include <stddef.h>
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#include <string.h>
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#include "sizeof.h"
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/*
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* SYNOPSIS
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* int STRLCPY(char dst[restrict], const char *restrict src);
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*
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* ARGUMENTS
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* dst Destination buffer where to copy a string.
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* src Source string to be copied into dst.
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*
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* DESCRIPTION
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* This macro copies the string pointed to by src, into a string
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* at the buffer pointed to by dst. If the destination buffer,
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* isn't large enough to hold the copy, the resulting string is
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* truncated. The size of the buffer is calculated internally via
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* SIZEOF_ARRAY().
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*
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* RETURN VALUE
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* -1 If this call truncated the resulting string.
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*
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* strlen(dst)
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* On success.
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*
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* ERRORS
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* This function doesn't set errno.
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*/
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#define STRLCPY(dst, src) strlcpy_(dst, src, SIZEOF_ARRAY(dst))
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inline size_t strlcpy_(char *restrict dst, const char *restrict src,
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size_t size);
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inline size_t
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strlcpy_(char *restrict dst, const char *restrict src, size_t size)
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{
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size_t len;
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len = strlcpy(dst, src, size);
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return (len >= size) ? -1 : len;
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}
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#endif // include guard
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