SMIME_CRLF_COPY(3)

📦 version 4.4.0, in alpine 3.24, arch rolling

✨ NAME ✨

Okay bestie, say hi to SMIME_crlf_copy — buffered copy between BIOs 💖 This is the SMIME_CRLF_COPY(3) page from the Library Functions Manual, and we are absolutely getting into it.

🦋 SYNOPSIS 🦋

Here's the exact shape of it, no cap:

library “libcrypto” #include <openssl/asn1.h>

int
SMIME_crlf_copy(BIO *in_bio, BIO *out_bio, int flags);

🎀 DESCRIPTION 🎀

SMIME_crlf_copy() copies data from in_bio to out_bio. To avoid many small write operations on out_bio, a buffering BIO created with BIO_f_buffer(3) is temporarily prepended to it. Cute little buffer moment, honestly 🫶

If the bit SMIME_BINARY is set in the flags argument, all the data is copied verbatim using BIO_read(3) and BIO_write(3).

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. That last-line exception is important, bestie.

If the bit SMIME_TEXT is set in the flags argument and the bit SMIME_BINARY is not set, the line Content-Type: text/plain is prepended to the output with two pairs of carriage return and newline characters after it. Header slay 💅

In any case, BIO_flush(3) is called on the output at the end of the function. Like, always. Flush era.

🌸 RETURN VALUES 🌸

SMIME_crlf_copy() is intended to return 1 on success or 0 on failure. Intended, okay? Keep that word in mind 👀

🔥 SEE ALSO 🔥

Go read these next, bestie:

👑 HISTORY 👑

SMIME_crlf_copy() first appeared in OpenSSL 1.0.0 and has been available since OpenBSD 4.9. Iconic longevity, fr fr. 🌈

💀 BUGS 💀

Heads up, bestie: SMIME_crlf_copy() silently ignores most errors and may return 1 even if it lost part or all of the data in transit. That is not a slay. 😭
Only blocking BIOs are supported. If any of the BIO arguments is non-blocking, part or all of the data is likely to be silently lost in transit. Check your BIOs, please. 💀

xoxo, this page is from Debian and dated June 11, 2025 — SMIME_CRLF_COPY(3) signing off 💅🫶

📦 where this page comes from