libssh2_session_callback_set - set a callback function
#include <libssh2.h> void *libssh2_session_callback_set(LIBSSH2_SESSION *session, int cbtype, void *callback);
libssh2 manual libssh2_session_callback_set(3ssh2)
NAME
libssh2_session_callback_set - set a callback function
SYNOPSIS
#include <libssh2.h>
void *libssh2_session_callback_set(LIBSSH2_SESSION *session,
int cbtype, void *callback);
DESCRIPTION
Sets a custom callback handler for a previously initialized session
object. Callbacks are triggered by the receipt of special packets at
the Transport layer. To disable a callback, set it to NULL.
session - Session instance as returned by libssh2_session_init_ex(3)
cbtype - Callback type. One of the types listed in Callback Types.
callback - Pointer to custom callback function. The prototype for this
function must match the associated callback declaration macro.
CALLBACK TYPES
LIBSSH2_CALLBACK_IGNORE
Called when a SSH_MSG_IGNORE message is received
LIBSSH2_CALLBACK_DEBUG
Called when a SSH_MSG_DEBUG message is received
LIBSSH2_CALLBACK_DISCONNECT
Called when a SSH_MSG_DISCONNECT message is received
LIBSSH2_CALLBACK_MACERROR
Called when a mismatched MAC has been detected in the transport
layer. If the function returns 0, the packet will be accepted
nonetheless.
LIBSSH2_CALLBACK_X11
Called when an X11 connection has been accepted
LIBSSH2_CALLBACK_SEND
Called when libssh2 wants to send data on the connection. Can
be set to a custom function to handle I/O your own way.
The prototype of the callback:
ssize_t sendcb(libssh2_socket_t sockfd, const void *buffer,
size_t length, int flags, void **abstract);
sockfd is the socket to write to, buffer points to the data to
send, length is the size of the data, flags is the flags that
would've been used to a send() call and abstract is a pointer to
the abstract pointer set in the libssh2_session_init_ex(3) call.
The callback returns the number of bytes sent, or -1 for error.
The special return code -EAGAIN can be returned to signal that
the send was aborted to prevent getting blocked and it needs to
be called again.
LIBSSH2_CALLBACK_RECV
Called when libssh2 wants to read data from the connection. Can
be set to a custom function to handle I/O your own way.
The prototype of the callback:
ssize_t recvcb(libssh2_socket_t sockfd, void *buffer,
size_t length, int flags, void **abstract);
sockfd is the socket to read from, buffer where to store
received data into, length is the size of the buffer, flags is
the flags that would've been used to a recv() call and abstract
is a pointer to the abstract pointer set in the libssh2_ses-
sion_init_ex(3) call.
The callback returns the number of bytes read, or -1 for error.
The special return code -EAGAIN can be returned to signal that
the read was aborted to prevent getting blocked and it needs to
be called again.
RETURN VALUE
Pointer to previous callback handler. Returns NULL if no prior callback
handler was set or the callback type was unknown.
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
+---------------+------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+------------------+
|Availability | library/libssh2 |
+---------------+------------------+
|Stability | Uncommitted |
+---------------+------------------+
SEE ALSO
libssh2_session_init_ex(3)
NOTES
Source code for open source software components in Oracle Solaris can
be found at https://www.oracle.com/downloads/opensource/solaris-source-
code-downloads.html.
This software was built from source available at
https://github.com/oracle/solaris-userland. The original community
source was downloaded from https://www.libssh2.org/download/lib-
ssh2-1.10.0.tar.gz.
Further information about this software can be found on the open source
community website at https://www.libssh2.org/.
libssh2 0.15 1 Jun 2007
libssh2_session_callback_set(3ssh2)