From aa4d426b4d3527d7e166df1a05058c9a4a0f6683 Mon Sep 17 00:00:00 2001 From: Wojtek Kosior Date: Fri, 30 Apr 2021 00:33:56 +0200 Subject: initial/final commit --- openssl-1.1.0h/doc/crypto/BIO_s_mem.pod | 124 ++++++++++++++++++++++++++++++++ 1 file changed, 124 insertions(+) create mode 100644 openssl-1.1.0h/doc/crypto/BIO_s_mem.pod (limited to 'openssl-1.1.0h/doc/crypto/BIO_s_mem.pod') diff --git a/openssl-1.1.0h/doc/crypto/BIO_s_mem.pod b/openssl-1.1.0h/doc/crypto/BIO_s_mem.pod new file mode 100644 index 0000000..eb67cbe --- /dev/null +++ b/openssl-1.1.0h/doc/crypto/BIO_s_mem.pod @@ -0,0 +1,124 @@ +=pod + +=head1 NAME + +BIO_s_secmem, +BIO_s_mem, BIO_set_mem_eof_return, BIO_get_mem_data, BIO_set_mem_buf, +BIO_get_mem_ptr, BIO_new_mem_buf - memory BIO + +=head1 SYNOPSIS + + #include + + const BIO_METHOD * BIO_s_mem(void); + const BIO_METHOD * BIO_s_secmem(void); + + BIO_set_mem_eof_return(BIO *b, int v) + long BIO_get_mem_data(BIO *b, char **pp) + BIO_set_mem_buf(BIO *b, BUF_MEM *bm, int c) + BIO_get_mem_ptr(BIO *b, BUF_MEM **pp) + + BIO *BIO_new_mem_buf(const void *buf, int len); + +=head1 DESCRIPTION + +BIO_s_mem() return the memory BIO method function. + +A memory BIO is a source/sink BIO which uses memory for its I/O. Data +written to a memory BIO is stored in a BUF_MEM structure which is extended +as appropriate to accommodate the stored data. + +BIO_s_secmem() is like BIO_s_mem() except that the secure heap is used +for buffer storage. + +Any data written to a memory BIO can be recalled by reading from it. +Unless the memory BIO is read only any data read from it is deleted from +the BIO. + +Memory BIOs support BIO_gets() and BIO_puts(). + +If the BIO_CLOSE flag is set when a memory BIO is freed then the underlying +BUF_MEM structure is also freed. + +Calling BIO_reset() on a read write memory BIO clears any data in it if the +flag BIO_FLAGS_NONCLEAR_RST is not set. On a read only BIO or if the flag +BIO_FLAGS_NONCLEAR_RST is set it restores the BIO to its original state and +the data can be read again. + +BIO_eof() is true if no data is in the BIO. + +BIO_ctrl_pending() returns the number of bytes currently stored. + +BIO_set_mem_eof_return() sets the behaviour of memory BIO B when it is +empty. If the B is zero then an empty memory BIO will return EOF (that is +it will return zero and BIO_should_retry(b) will be false. If B is non +zero then it will return B when it is empty and it will set the read retry +flag (that is BIO_read_retry(b) is true). To avoid ambiguity with a normal +positive return value B should be set to a negative value, typically -1. + +BIO_get_mem_data() sets *B to a pointer to the start of the memory BIOs data +and returns the total amount of data available. It is implemented as a macro. + +BIO_set_mem_buf() sets the internal BUF_MEM structure to B and sets the +close flag to B, that is B should be either BIO_CLOSE or BIO_NOCLOSE. +It is a macro. + +BIO_get_mem_ptr() places the underlying BUF_MEM structure in *B. It is +a macro. + +BIO_new_mem_buf() creates a memory BIO using B bytes of data at B, +if B is -1 then the B is assumed to be nul terminated and its +length is determined by B. The BIO is set to a read only state and +as a result cannot be written to. This is useful when some data needs to be +made available from a static area of memory in the form of a BIO. The +supplied data is read directly from the supplied buffer: it is B copied +first, so the supplied area of memory must be unchanged until the BIO is freed. + +=head1 NOTES + +Writes to memory BIOs will always succeed if memory is available: that is +their size can grow indefinitely. + +Every read from a read write memory BIO will remove the data just read with +an internal copy operation, if a BIO contains a lot of data and it is +read in small chunks the operation can be very slow. The use of a read only +memory BIO avoids this problem. If the BIO must be read write then adding +a buffering BIO to the chain will speed up the process. + +Calling BIO_set_mem_buf() on a BIO created with BIO_new_secmem() will +give undefined results, including perhaps a program crash. + +=head1 BUGS + +There should be an option to set the maximum size of a memory BIO. + +=head1 EXAMPLE + +Create a memory BIO and write some data to it: + + BIO *mem = BIO_new(BIO_s_mem()); + BIO_puts(mem, "Hello World\n"); + +Create a read only memory BIO: + + char data[] = "Hello World"; + BIO *mem; + mem = BIO_new_mem_buf(data, -1); + +Extract the BUF_MEM structure from a memory BIO and then free up the BIO: + + BUF_MEM *bptr; + BIO_get_mem_ptr(mem, &bptr); + BIO_set_close(mem, BIO_NOCLOSE); /* So BIO_free() leaves BUF_MEM alone */ + BIO_free(mem); + +=head1 COPYRIGHT + +Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved. + +Licensed under the OpenSSL license (the "License"). You may not use +this file except in compliance with the License. You can obtain a copy +in the file LICENSE in the source distribution or at +L. + +=cut -- cgit v1.2.3