D7net
Home
Console
Upload
information
Create File
Create Folder
About
Tools
:
/
proc
/
self
/
root
/
opt
/
cpanel
/
ea-openssl
/
etc
/
pki
/
tls
/
man
/
man3
/
Filename :
SSL_write.3
back
Copy
.\" Automatically generated by Pod::Man 4.11 (Pod::Simple 3.35) .\" .\" Standard preamble: .\" ======================================================================== .de Sp \" Vertical space (when we can't use .PP) .if t .sp .5v .if n .sp .. .de Vb \" Begin verbatim text .ft CW .nf .ne \\$1 .. .de Ve \" End verbatim text .ft R .fi .. .\" Set up some character translations and predefined strings. \*(-- will .\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left .\" double quote, and \*(R" will give a right double quote. \*(C+ will .\" give a nicer C++. Capital omega is used to do unbreakable dashes and .\" therefore won't be available. \*(C` and \*(C' expand to `' in nroff, .\" nothing in troff, for use with C<>. .tr \(*W- .ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p' .ie n \{\ . ds -- \(*W- . ds PI pi . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch . ds L" "" . ds R" "" . ds C` "" . ds C' "" 'br\} .el\{\ . ds -- \|\(em\| . ds PI \(*p . ds L" `` . ds R" '' . ds C` . ds C' 'br\} .\" .\" Escape single quotes in literal strings from groff's Unicode transform. .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" .\" If the F register is >0, we'll generate index entries on stderr for .\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index .\" entries marked with X<> in POD. Of course, you'll have to process the .\" output yourself in some meaningful fashion. .\" .\" Avoid warning from groff about undefined register 'F'. .de IX .. .nr rF 0 .if \n(.g .if rF .nr rF 1 .if (\n(rF:(\n(.g==0)) \{\ . if \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} . \} .\} .rr rF .\" .\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2). .\" Fear. Run. Save yourself. No user-serviceable parts. . \" fudge factors for nroff and troff .if n \{\ . ds #H 0 . ds #V .8m . ds #F .3m . ds #[ \f1 . ds #] \fP .\} .if t \{\ . ds #H ((1u-(\\\\n(.fu%2u))*.13m) . ds #V .6m . ds #F 0 . ds #[ \& . ds #] \& .\} . \" simple accents for nroff and troff .if n \{\ . ds ' \& . ds ` \& . ds ^ \& . ds , \& . ds ~ ~ . ds / .\} .if t \{\ . ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u" . ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u' . ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u' . ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u' . ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u' . ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u' .\} . \" troff and (daisy-wheel) nroff accents .ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V' .ds 8 \h'\*(#H'\(*b\h'-\*(#H' .ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#] .ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H' .ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u' .ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#] .ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#] .ds ae a\h'-(\w'a'u*4/10)'e .ds Ae A\h'-(\w'A'u*4/10)'E . \" corrections for vroff .if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u' .if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u' . \" for low resolution devices (crt and lpr) .if \n(.H>23 .if \n(.V>19 \ \{\ . ds : e . ds 8 ss . ds o a . ds d- d\h'-1'\(ga . ds D- D\h'-1'\(hy . ds th \o'bp' . ds Th \o'LP' . ds ae ae . ds Ae AE .\} .rm #[ #] #H #V #F C .\" ======================================================================== .\" .IX Title "SSL_write 3" .TH SSL_write 3 "2019-12-20" "1.0.2u" "OpenSSL" .\" For nroff, turn off justification. Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH "NAME" SSL_write \- write bytes to a TLS/SSL connection. .SH "SYNOPSIS" .IX Header "SYNOPSIS" .Vb 1 \& #include <openssl/ssl.h> \& \& int SSL_write(SSL *ssl, const void *buf, int num); .Ve .SH "DESCRIPTION" .IX Header "DESCRIPTION" \&\fBSSL_write()\fR writes \fBnum\fR bytes from the buffer \fBbuf\fR into the specified \&\fBssl\fR connection. .SH "NOTES" .IX Header "NOTES" If necessary, \fBSSL_write()\fR will negotiate a \s-1TLS/SSL\s0 session, if not already explicitly performed by \fBSSL_connect\fR\|(3) or \&\fBSSL_accept\fR\|(3). If the peer requests a re-negotiation, it will be performed transparently during the \fBSSL_write()\fR operation. The behaviour of \fBSSL_write()\fR depends on the underlying \s-1BIO.\s0 .PP For the transparent negotiation to succeed, the \fBssl\fR must have been initialized to client or server mode. This is being done by calling \&\fBSSL_set_connect_state\fR\|(3) or \fBSSL_set_accept_state()\fR before the first call to an \fBSSL_read\fR\|(3) or \fBSSL_write()\fR function. .PP If the underlying \s-1BIO\s0 is \fBblocking\fR, \fBSSL_write()\fR will only return, once the write operation has been finished or an error occurred, except when a renegotiation take place, in which case a \s-1SSL_ERROR_WANT_READ\s0 may occur. This behaviour can be controlled with the \s-1SSL_MODE_AUTO_RETRY\s0 flag of the \&\fBSSL_CTX_set_mode\fR\|(3) call. .PP If the underlying \s-1BIO\s0 is \fBnon-blocking\fR, \fBSSL_write()\fR will also return, when the underlying \s-1BIO\s0 could not satisfy the needs of \fBSSL_write()\fR to continue the operation. In this case a call to \&\fBSSL_get_error\fR\|(3) with the return value of \fBSSL_write()\fR will yield \fB\s-1SSL_ERROR_WANT_READ\s0\fR or \&\fB\s-1SSL_ERROR_WANT_WRITE\s0\fR. As at any time a re-negotiation is possible, a call to \fBSSL_write()\fR can also cause read operations! The calling process then must repeat the call after taking appropriate action to satisfy the needs of \fBSSL_write()\fR. The action depends on the underlying \s-1BIO.\s0 When using a non-blocking socket, nothing is to be done, but \fBselect()\fR can be used to check for the required condition. When using a buffering \s-1BIO,\s0 like a \s-1BIO\s0 pair, data must be written into or retrieved out of the \s-1BIO\s0 before being able to continue. .PP \&\fBSSL_write()\fR will only return with success, when the complete contents of \fBbuf\fR of length \fBnum\fR has been written. This default behaviour can be changed with the \s-1SSL_MODE_ENABLE_PARTIAL_WRITE\s0 option of \&\fBSSL_CTX_set_mode\fR\|(3). When this flag is set, \&\fBSSL_write()\fR will also return with success, when a partial write has been successfully completed. In this case the \fBSSL_write()\fR operation is considered completed. The bytes are sent and a new \fBSSL_write()\fR operation with a new buffer (with the already sent bytes removed) must be started. A partial write is performed with the size of a message block, which is 16kB for SSLv3/TLSv1. .SH "WARNING" .IX Header "WARNING" When an \fBSSL_write()\fR operation has to be repeated because of \&\fB\s-1SSL_ERROR_WANT_READ\s0\fR or \fB\s-1SSL_ERROR_WANT_WRITE\s0\fR, it must be repeated with the same arguments. .PP When calling \fBSSL_write()\fR with num=0 bytes to be sent the behaviour is undefined. .SH "RETURN VALUES" .IX Header "RETURN VALUES" The following return values can occur: .IP "> 0" 4 .IX Item "> 0" The write operation was successful, the return value is the number of bytes actually written to the \s-1TLS/SSL\s0 connection. .IP "<= 0" 4 .IX Item "<= 0" The write operation was not successful, because either the connection was closed, an error occurred or action must be taken by the calling process. Call \fBSSL_get_error()\fR with the return value \fBret\fR to find out the reason. .Sp SSLv2 (deprecated) does not support a shutdown alert protocol, so it can only be detected, whether the underlying connection was closed. It cannot be checked, why the closure happened. .Sp Old documentation indicated a difference between 0 and \-1, and that \-1 was retryable. You should instead call \fBSSL_get_error()\fR to find out if it's retryable. .SH "SEE ALSO" .IX Header "SEE ALSO" \&\fBSSL_get_error\fR\|(3), \fBSSL_read\fR\|(3), \&\fBSSL_CTX_set_mode\fR\|(3), \fBSSL_CTX_new\fR\|(3), \&\fBSSL_connect\fR\|(3), \fBSSL_accept\fR\|(3) \&\fBSSL_set_connect_state\fR\|(3), \&\fBssl\fR\|(3), \fBbio\fR\|(3)