73 lines
2 KiB
Text
73 lines
2 KiB
Text
=pod
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=head1 NAME
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BUF_MEM_new, BUF_MEM_free, BUF_MEM_grow, BUF_strdup - simple
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character arrays structure
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=head1 SYNOPSIS
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#include <openssl/buffer.h>
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BUF_MEM *BUF_MEM_new(void);
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void BUF_MEM_free(BUF_MEM *a);
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int BUF_MEM_grow(BUF_MEM *str, int len);
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char * BUF_strdup(const char *str);
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=head1 DESCRIPTION
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The buffer library handles simple character arrays. Buffers are used for
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various purposes in the library, most notably memory BIOs.
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The library uses the BUF_MEM structure defined in buffer.h:
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typedef struct buf_mem_st
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{
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int length; /* current number of bytes */
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char *data;
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int max; /* size of buffer */
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} BUF_MEM;
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B<length> is the current size of the buffer in bytes, B<max> is the amount of
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memory allocated to the buffer. There are three functions which handle these
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and one "miscellaneous" function.
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BUF_MEM_new() allocates a new buffer of zero size.
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BUF_MEM_free() frees up an already existing buffer. The data is zeroed
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before freeing up in case the buffer contains sensitive data.
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BUF_MEM_grow() changes the size of an already existing buffer to
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B<len>. Any data already in the buffer is preserved if it increases in
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size.
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BUF_strdup() copies a null terminated string into a block of allocated
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memory and returns a pointer to the allocated block.
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Unlike the standard C library strdup() this function uses OPENSSL_malloc() and so
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should be used in preference to the standard library strdup() because it can
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be used for memory leak checking or replacing the malloc() function.
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The memory allocated from BUF_strdup() should be freed up using the OPENSSL_free()
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function.
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=head1 RETURN VALUES
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BUF_MEM_new() returns the buffer or NULL on error.
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BUF_MEM_free() has no return value.
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BUF_MEM_grow() returns zero on error or the new size (i.e. B<len>).
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=head1 SEE ALSO
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L<bio(3)|bio(3)>
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=head1 HISTORY
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BUF_MEM_new(), BUF_MEM_free() and BUF_MEM_grow() are available in all
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versions of SSLeay and OpenSSL. BUF_strdup() was added in SSLeay 0.8.
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=cut
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