Commit 3d42833d authored by Tomas Mraz's avatar Tomas Mraz Committed by Matt Caswell
Browse files

Add documentation for the BIO_s_mem pecularities 



Reviewed-by: default avatarBernd Edlinger <bernd.edlinger@hotmail.de>
Reviewed-by: default avatarMatt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/8649)
parent d34bce03

doc/man3/BIO_s_mem.pod

+16 −0
Original line number Diff line number Diff line
@@ -88,6 +88,22 @@ 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.



Switching the memory BIO from read write to read only is not supported and

can give undefined results including a program crash. There are two notable

exceptions to the rule. The first one is to assign a static memory buffer

immediately after BIO creation and set the BIO as read only.



The other supported sequence is to start with read write BIO then temporarily

switch it to read only and call BIO_reset() on the read only BIO immediately

before switching it back to read write. Before the BIO is freed it must be

switched back to the read write mode.



Calling BIO_get_mem_ptr() on read only BIO will return a BUF_MEM that

contains only the remaining data to be read. If the close status of the

BIO is set to BIO_NOCLOSE, before freeing the BUF_MEM the data pointer

in it must be set to NULL as the data pointer does not point to an

allocated memory.



=head1 BUGS



There should be an option to set the maximum size of a memory BIO.