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qbipcs.h(3) libqb qbipcs.h(3)

NAME

qbipcs.h -

Server IPC API.

SYNOPSIS

#include <sys/types.h>
#include <sys/uio.h>
#include <qb/qbipc_common.h>
#include <qb/qbloop.h>

Data Structures


struct qb_ipcs_stats
struct qb_ipcs_connection_stats
struct qb_ipcs_connection_stats_2
struct qb_ipcs_poll_handlers
struct qb_ipcs_service_handlers

Typedefs


typedef struct qb_ipcs_connection qb_ipcs_connection_t
typedef struct qb_ipcs_service qb_ipcs_service_t
typedef int32_t(* qb_ipcs_dispatch_fn_t )(int32_t fd, int32_t revents, void *data)
typedef int32_t(* qb_ipcs_dispatch_add_fn )(enum qb_loop_priority p, int32_t fd, int32_t events, void *data, qb_ipcs_dispatch_fn_t fn)
typedef int32_t(* qb_ipcs_dispatch_mod_fn )(enum qb_loop_priority p, int32_t fd, int32_t events, void *data, qb_ipcs_dispatch_fn_t fn)
typedef int32_t(* qb_ipcs_dispatch_del_fn )(int32_t fd)
typedef int32_t(* qb_ipcs_job_add_fn )(enum qb_loop_priority p, void *data, qb_loop_job_dispatch_fn dispatch_fn)
typedef int32_t(* qb_ipcs_connection_accept_fn )(qb_ipcs_connection_t *c, uid_t uid, gid_t gid)
This callback is to check whether you want to accept a new connection. typedef void(* qb_ipcs_connection_created_fn )(qb_ipcs_connection_t *c)
This is called after a new connection has been created. typedef int32_t(* qb_ipcs_connection_closed_fn )(qb_ipcs_connection_t *c)
This is called after a connection has been disconnected. typedef void(* qb_ipcs_connection_destroyed_fn )(qb_ipcs_connection_t *c)
This is called just before a connection is freed. typedef int32_t(* qb_ipcs_msg_process_fn )(qb_ipcs_connection_t *c, void *data, size_t size)
This is the message processing calback.

Enumerations


enum qb_ipcs_rate_limit { QB_IPCS_RATE_FAST, QB_IPCS_RATE_NORMAL, QB_IPCS_RATE_SLOW, QB_IPCS_RATE_OFF, QB_IPCS_RATE_OFF_2 }

Functions


qb_ipcs_service_t * qb_ipcs_create (const char *name, int32_t service_id, enum qb_ipc_type type, struct qb_ipcs_service_handlers *handlers)
Create a new IPC server. void qb_ipcs_ref (qb_ipcs_service_t *s)
Increase the reference counter on the service object. void qb_ipcs_unref (qb_ipcs_service_t *s)
Decrease the reference counter on the service object. void qb_ipcs_poll_handlers_set (qb_ipcs_service_t *s, struct qb_ipcs_poll_handlers *handlers)
Set your poll callbacks. void qb_ipcs_service_context_set (qb_ipcs_service_t *s, void *context)
Associate a 'user' pointer with this service. void * qb_ipcs_service_context_get (qb_ipcs_service_t *s)
Get the context (set previously) int32_t qb_ipcs_run (qb_ipcs_service_t *s)
run the new IPC server. void qb_ipcs_destroy (qb_ipcs_service_t *s)
Destroy the IPC server. void qb_ipcs_request_rate_limit (qb_ipcs_service_t *s, enum qb_ipcs_rate_limit rl)
Limit the incoming request rate. ssize_t qb_ipcs_response_send (qb_ipcs_connection_t *c, const void *data, size_t size)
Send a response to a incoming request. ssize_t qb_ipcs_response_sendv (qb_ipcs_connection_t *c, const struct iovec *iov, size_t iov_len)
Send a response to a incoming request. ssize_t qb_ipcs_event_send (qb_ipcs_connection_t *c, const void *data, size_t size)
Send an asynchronous event message to the client. ssize_t qb_ipcs_event_sendv (qb_ipcs_connection_t *c, const struct iovec *iov, size_t iov_len)
Send an asynchronous event message to the client. void qb_ipcs_connection_ref (qb_ipcs_connection_t *c)
Increment the connection's reference counter. void qb_ipcs_connection_unref (qb_ipcs_connection_t *c)
Decrement the connection's reference counter. void qb_ipcs_disconnect (qb_ipcs_connection_t *c)
Disconnect from this client. int32_t qb_ipcs_service_id_get (qb_ipcs_connection_t *c)
Get the service id related to this connection's service. void qb_ipcs_context_set (qb_ipcs_connection_t *c, void *context)
Associate a 'user' pointer with this connection. void * qb_ipcs_context_get (qb_ipcs_connection_t *c)
Get the context (set previously) void * qb_ipcs_connection_service_context_get (qb_ipcs_connection_t *c)
Get the context previously set on the service backing this connection. int32_t qb_ipcs_connection_stats_get (qb_ipcs_connection_t *c, struct qb_ipcs_connection_stats *stats, int32_t clear_after_read)
Get the connection statistics. struct qb_ipcs_connection_stats_2 * qb_ipcs_connection_stats_get_2 (qb_ipcs_connection_t *c, int32_t clear_after_read)
Get (and allocate) the connection statistics. int32_t qb_ipcs_stats_get (qb_ipcs_service_t *pt, struct qb_ipcs_stats *stats, int32_t clear_after_read)
Get the service statistics. qb_ipcs_connection_t * qb_ipcs_connection_first_get (qb_ipcs_service_t *pt)
Get the first connection. qb_ipcs_connection_t * qb_ipcs_connection_next_get (qb_ipcs_service_t *pt, qb_ipcs_connection_t *current)
Get the next connection. void qb_ipcs_connection_auth_set (qb_ipcs_connection_t *conn, uid_t uid, gid_t gid, mode_t mode)
Set the permissions on and shared memory files so that both processes can read and write to them. int32_t qb_ipcs_connection_get_buffer_size (qb_ipcs_connection_t *conn)
Retrieve the connection ipc buffer size. void qb_ipcs_enforce_buffer_size (qb_ipcs_service_t *s, uint32_t max_buf_size)
Enforce the max buffer size clients must use from the server side.

Detailed Description

Server IPC API.

Typedef Documentation

typedef int32_t(* qb_ipcs_connection_accept_fn)(qb_ipcs_connection_t *c, uid_t uid, gid_t gid)

This callback is to check whether you want to accept a new connection. The type of checks you should do are authentication, service availability or process resource constraints.

Returns:

0 to accept or -errno to indicate a failure (sent back to the client)

Note:

If connection state data is allocated as a result of this callback being invoked, that data must be freed in the destroy callback. Just because the accept callback returns 0, that does not guarantee the create and closed callback functions will follow.

you can call qb_ipcs_connection_auth_set() within this function.

typedef int32_t(* qb_ipcs_connection_closed_fn)(qb_ipcs_connection_t *c)

This is called after a connection has been disconnected.

Note:

This callback will only be invoked if the connection is successfully created.

if you return anything but 0 this function will be repeativily called (until 0 is returned).

With SHM connections libqb will briefly trap SIGBUS during the disconnect process to guard against server crashes if the mapped file is truncated. The signal will be restored afterwards.

typedef void(* qb_ipcs_connection_created_fn)(qb_ipcs_connection_t *c)

This is called after a new connection has been created.

Note:

A client connection is not considered connected until this callback is invoked.

typedef void(* qb_ipcs_connection_destroyed_fn)(qb_ipcs_connection_t *c)

This is called just before a connection is freed.

typedef struct qb_ipcs_connection qb_ipcs_connection_t

typedef int32_t(* qb_ipcs_dispatch_add_fn)(enum qb_loop_priority p, int32_t fd, int32_t events, void *data, qb_ipcs_dispatch_fn_t fn)

typedef int32_t(* qb_ipcs_dispatch_del_fn)(int32_t fd)

typedef int32_t(* qb_ipcs_dispatch_fn_t)(int32_t fd, int32_t revents, void *data)

typedef int32_t(* qb_ipcs_dispatch_mod_fn)(enum qb_loop_priority p, int32_t fd, int32_t events, void *data, qb_ipcs_dispatch_fn_t fn)

typedef int32_t(* qb_ipcs_job_add_fn)(enum qb_loop_priority p, void *data, qb_loop_job_dispatch_fn dispatch_fn)

typedef int32_t(* qb_ipcs_msg_process_fn)(qb_ipcs_connection_t *c, void *data, size_t size)

This is the message processing calback. It is called with the message data.

typedef struct qb_ipcs_service qb_ipcs_service_t

Enumeration Type Documentation

enum qb_ipcs_rate_limit

Enumerator

Function Documentation

void qb_ipcs_connection_auth_set (qb_ipcs_connection_t *conn, uid_tuid, gid_tgid, mode_tmode)

Set the permissions on and shared memory files so that both processes can read and write to them.

Parameters:

conn connection instance
uid the user id to set.
gid the group id to set.
mode the mode to set.

See Also:

chmod() chown()

Note:

this must be called within the qb_ipcs_connection_accept_fn() callback.

qb_ipcs_connection_t* qb_ipcs_connection_first_get (qb_ipcs_service_t *pt)

Get the first connection.

Note:

call qb_ipcs_connection_unref() after using the connection.

Parameters:

pt service instance

Returns:

first connection

int32_t qb_ipcs_connection_get_buffer_size (qb_ipcs_connection_t *conn)

Retrieve the connection ipc buffer size. This reflects the largest size msg that can be sent or received.

Parameters:

conn connection instance

Returns:

msg size in bytes, negative value on error.

qb_ipcs_connection_t* qb_ipcs_connection_next_get (qb_ipcs_service_t *pt, qb_ipcs_connection_t *current)

Get the next connection.

Note:

call qb_ipcs_connection_unref() after using the connection.

Parameters:

pt service instance
current current connection

Returns:

next connection

void qb_ipcs_connection_ref (qb_ipcs_connection_t *c)

Increment the connection's reference counter.

Parameters:

c connection instance

void* qb_ipcs_connection_service_context_get (qb_ipcs_connection_t *c)

Get the context previously set on the service backing this connection.

Parameters:

c connection instance

Returns:

the context

See Also:

qb_ipcs_service_context_set

int32_t qb_ipcs_connection_stats_get (qb_ipcs_connection_t *c, struct qb_ipcs_connection_stats *stats, int32_tclear_after_read)

Get the connection statistics.

Deprecated

from v0.13.0 onwards, use qb_ipcs_connection_stats_get_2

Parameters:

stats (out) the statistics structure
clear_after_read clear stats after copying them into stats
c connection instance

Returns:

0 == ok; -errno to indicate a failure

struct qb_ipcs_connection_stats_2* qb_ipcs_connection_stats_get_2 (qb_ipcs_connection_t *c, int32_tclear_after_read)

Get (and allocate) the connection statistics.

Parameters:

clear_after_read clear stats after copying them into stats
c connection instance

Return values:

NULL if no memory or invalid connection
allocated statistics structure (user must free it).

void qb_ipcs_connection_unref (qb_ipcs_connection_t *c)

Decrement the connection's reference counter.

Parameters:

c connection instance

void* qb_ipcs_context_get (qb_ipcs_connection_t *c)

Get the context (set previously)

Parameters:

c connection instance

Returns:

the context

See Also:

qb_ipcs_context_set()

void qb_ipcs_context_set (qb_ipcs_connection_t *c, void *context)

Associate a 'user' pointer with this connection.

Parameters:

context the point to associate with this connection.
c connection instance

See Also:

qb_ipcs_context_get()

qb_ipcs_service_t* qb_ipcs_create (const char *name, int32_tservice_id, enum qb_ipc_typetype, struct qb_ipcs_service_handlers *handlers)

Create a new IPC server.

Parameters:

name for clients to connect to.
service_id an integer to associate with the service
type transport type.
handlers callbacks.

Returns:

the new service instance.

void qb_ipcs_destroy (qb_ipcs_service_t *s)

Destroy the IPC server.

Parameters:

s service instance to destroy

void qb_ipcs_disconnect (qb_ipcs_connection_t *c)

Disconnect from this client.

Parameters:

c connection instance

void qb_ipcs_enforce_buffer_size (qb_ipcs_service_t *s, uint32_tmax_buf_size)

Enforce the max buffer size clients must use from the server side.

Note:

Setting this will force client connections to use at least max_buf_size bytes as their buffer size. If this value is not set on the server, the clients enforce their own buffer sizes.

Parameters:

s ipc server instance
max_buf_size represented in bytes

ssize_t qb_ipcs_event_send (qb_ipcs_connection_t *c, const void *data, size_tsize)

Send an asynchronous event message to the client.

Parameters:

c connection instance
data the message to send
size the size of the message

Returns:

size sent or -errno for errors

Note:

the data must include a qb_ipc_response_header at the top of the message. The client will read the size field to determine how much to recv.

When send returns -EMSGSIZE, this means the msg is too large and will never succeed. To determine the max msg size a client can be sent, use qb_ipcs_connection_get_buffer_size()

ssize_t qb_ipcs_event_sendv (qb_ipcs_connection_t *c, const struct iovec *iov, size_tiov_len)

Send an asynchronous event message to the client.

Parameters:

c connection instance
iov the iovec struct that points to the message to send
iov_len the number of iovecs.

Returns:

size sent or -errno for errors

Note:

the iov[0] must be a qb_ipc_response_header. The client will read the size field to determine how much to recv.

When send returns -EMSGSIZE, this means the msg is too large and will never succeed. To determine the max msg size a client can be sent, use qb_ipcs_connection_get_buffer_size()

void qb_ipcs_poll_handlers_set (qb_ipcs_service_t *s, struct qb_ipcs_poll_handlers *handlers)

Set your poll callbacks.

Parameters:

s service instance
handlers the handlers that you want ipcs to use.

void qb_ipcs_ref (qb_ipcs_service_t *s)

Increase the reference counter on the service object.

Parameters:

s service instance

void qb_ipcs_request_rate_limit (qb_ipcs_service_t *s, enum qb_ipcs_rate_limitrl)

Limit the incoming request rate.

Parameters:

s service instance
rl the new rate

ssize_t qb_ipcs_response_send (qb_ipcs_connection_t *c, const void *data, size_tsize)

Send a response to a incoming request.

Parameters:

c connection instance
data the message to send
size the size of the message

Returns:

size sent or -errno for errors

Note:

the data must include a qb_ipc_response_header at the top of the message. The client will read the size field to determine how much to recv.

ssize_t qb_ipcs_response_sendv (qb_ipcs_connection_t *c, const struct iovec *iov, size_tiov_len)

Send a response to a incoming request.

Parameters:

c connection instance
iov the iovec struct that points to the message to send
iov_len the number of iovecs.

Returns:

size sent or -errno for errors

Note:

the iov[0] must be a qb_ipc_response_header. The client will read the size field to determine how much to recv.

When send returns -EMSGSIZE, this means the msg is too large and will never succeed. To determine the max msg size a client can be sent, use qb_ipcs_connection_get_buffer_size()

int32_t qb_ipcs_run (qb_ipcs_service_t *s)

run the new IPC server.

Parameters:

s service instance

Returns:

0 == ok; -errno to indicate a failure. Service is destroyed on failure.

void* qb_ipcs_service_context_get (qb_ipcs_service_t *s)

Get the context (set previously)

Parameters:

s service instance

Returns:

the context

See Also:

qb_ipcs_service_context_set()

void qb_ipcs_service_context_set (qb_ipcs_service_t *s, void *context)

Associate a 'user' pointer with this service.

Parameters:

s service instance
context the pointer to associate with this service.

See Also:

qb_ipcs_service_context_get()

int32_t qb_ipcs_service_id_get (qb_ipcs_connection_t *c)

Get the service id related to this connection's service. (as passed into qb_ipcs_create()

Returns:

service id.

int32_t qb_ipcs_stats_get (qb_ipcs_service_t *pt, struct qb_ipcs_stats *stats, int32_tclear_after_read)

Get the service statistics.

Parameters:

stats (out) the statistics structure
clear_after_read clear stats after copying them into stats
pt service instance

Returns:

0 == ok; -errno to indicate a failure

void qb_ipcs_unref (qb_ipcs_service_t *s)

Decrease the reference counter on the service object.

Parameters:

s service instance

Author

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Wed Apr 1 2020 Version 1.0.1