.\" $OpenBSD: SMIME_crlf_copy.3,v 1.3 2023/05/01 07:28:11 tb Exp $
.\"
.\" Copyright (c) 2021 Ingo Schwarze <schwarze@openbsd.org>
.\"
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.Dd $Mdocdate: May 1 2023 $
.Dt SMIME_CRLF_COPY 3
.Os
.Sh NAME
.Nm SMIME_crlf_copy
.Nd buffered copy between BIOs
.Sh SYNOPSIS
.Ft int
.Fo SMIME_crlf_copy
.Fa "BIO *in_bio"
.Fa "BIO *out_bio"
.Fa "int flags"
.Fc
.Sh DESCRIPTION
.Fn SMIME_crlf_copy
copies data from
.Fa in_bio
to
.Fa out_bio .
To avoid many small write operations on
.Fa out_bio ,
a buffering BIO created with
.Xr BIO_f_buffer 3
is temporarily prepended to it.
.Pp
If the bit
.Dv SMIME_BINARY
is set in the
.Fa flags
argument, all the data is copied verbatim using
.Xr BIO_read 3
and
.Xr BIO_write 3 .
.Pp
Otherwise, the data is read as text.
All trailing carriage return and newline characters are discarded
from every input line and a single pair of carriage return and
newline characters is appended to mark the end of every output line,
except that the last output line will end without such a pair if
the last input line does not have a newline character at the end.
.Pp
If the bit
.Dv SMIME_TEXT
is set in the
.Fa flags
argument and the bit
.Dv SMIME_BINARY
is not set, the line
.Qq Content-Type: text/plain
is prepended to the output
with two pairs of carriage return and newline characters after it.
.Pp
In any case,
.Xr BIO_flush 3
is called on the output at the end of the function.
.Sh RETURN VALUES
.Fn SMIME_crlf_copy
is intended to return 1 on success or 0 on failure.
.Sh SEE ALSO
.Xr BIO_f_buffer 3 ,
.Xr BIO_flush 3 ,
.Xr BIO_new 3 ,
.Xr BIO_push 3 ,
.Xr BIO_read 3 ,
.Xr SMIME_text 3 ,
.Xr SMIME_write_ASN1 3
.Sh HISTORY
.Fn SMIME_crlf_copy
first appeared in OpenSSL 1.0.0 and has been available since
.Ox 4.9 .
.Sh BUGS
.Fn SMIME_crlf_copy
silently ignores most errors and may return 1
even if it lost part or all of the data in transit.
.Pp
Only blocking BIOs are supported.
If any of the
.Vt BIO
arguments is non-blocking, part or all of the data is likely
to be silently lost in transit.