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/*
A server based on unix domain socket
Copyright (C) Amitay Isaacs 2016
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __CTDB_SOCK_DAEMON_H__
#define __CTDB_SOCK_DAEMON_H__
#include <talloc.h>
#include <tevent.h>
#include "common/logging.h"
/**
* @file sock_daemon.h
*
* @brief A framework for a server based on unix-domain sockets.
*
* This abstraction allows one to build simple servers that communicate using
* unix-domain sockets. It takes care of the common boilerplate.
*/
/**
* @brief The abstract socket daemon context
*/
struct sock_daemon_context;
/**
* @brief The abstract socket client context
*/
struct sock_client_context;
/**
* @brief The callback routines called during daemon life cycle
*
* startup() is called when the daemon starts running
* either via sock_daemon_run() or via sock_daemon_run_send()
* startup() should return 0 for success, non-zero value on failure
* On failure, sock_daemon_run() will return error.
*
* startup_send()/startup_recv() is the async version of startup()
*
* reconfigure() is called when the daemon receives SIGUSR1
* reconfigure() should return 0 for success, non-zero value on failure
* On failure, sock_daemon_run() will continue to run.
*
* reconfigure_send()/reconfigure_recv() is the async version of reconfigure()
*
* reopen_logs() is called when the daemon receives SIGHUP
* reopen_logs() should return 0 for success, non-zero value on failure
* On failure, sock_daemon_run() will continue to run.
*
* reopen_logs_send()/reopen_logs_recv() is the async version of reopen_logs()
*
* shutdown() is called when process receives SIGINT or SIGTERM or
* when wait computation has finished
*
* shutdown_send()/shutdown_recv() is the async version of shutdown()
*
* Please note that only one (sync or async) version of these functions
* will be called. If both versions are defined, then only async function
* will be called.
*
* wait_send() starts the async computation to keep running the daemon
* wait_recv() ends the async computation to keep running the daemon
*
* If wait_send()/wait_recv() is NULL, then daemon will keep running forever.
* If wait_send() returns req, then when req is over, daemon will shutdown.
*/
struct sock_daemon_funcs {
int (*startup)(void *private_data);
struct tevent_req * (*startup_send)(TALLOC_CTX *mem_ctx,
struct tevent_context *ev,
void *private_data);
bool (*startup_recv)(struct tevent_req *req, int *perr);
int (*reconfigure)(void *private_data);
struct tevent_req * (*reconfigure_send)(TALLOC_CTX *mem_ctx,
struct tevent_context *ev,
void *private_data);
bool (*reconfigure_recv)(struct tevent_req *req, int *perr);
int (*reopen_logs)(void *private_data);
struct tevent_req * (*reopen_logs_send)(TALLOC_CTX *mem_ctx,
struct tevent_context *ev,
void *private_data);
bool (*reopen_logs_recv)(struct tevent_req *req, int *perr);
void (*shutdown)(void *private_data);
struct tevent_req * (*shutdown_send)(TALLOC_CTX *mem_ctx,
struct tevent_context *ev,
void *private_data);
void (*shutdown_recv)(struct tevent_req *req);
struct tevent_req * (*wait_send)(TALLOC_CTX *mem_ctx,
struct tevent_context *ev,
void *private_data);
bool (*wait_recv)(struct tevent_req *req, int *perr);
};
/**
* @brief The callback routines called for an unix-domain socket
*
* connect() is called when there is a new connection
*
* @param[in] client The new socket client context
* @param[in] pid The pid of the new client process, or -1 if unknown
* @param[in] private_data Private data set with the socket
* @return true if connection should be accepted, false otherwise
*
*
* disconnect() is called when client closes connection
*
* @param[in] client The socket client context
* @param[in] private_data Private data associated with the socket
*
*
* read_send() starts the async computation to process data on the socket
*
* @param[in] mem_ctx Talloc memory context
* @param[in] ev Tevent context
* @param[in] client The socket client context
* @param[in] buf Data received from the client
* @param[in] buflen Length of the data
* @param[i] private_data Private data associatedwith the socket
* @return new tevent reques, or NULL on failure
*
*
* read_recv() ends the async computation to process data on the socket
*
* @param[in] req Tevent request
* @param[out] perr errno in case of failure
* @return true on success, false on failure
*
*/
struct sock_socket_funcs {
bool (*connect)(struct sock_client_context *client,
pid_t pid,
void *private_data);
void (*disconnect)(struct sock_client_context *client,
void *private_data);
struct tevent_req * (*read_send)(TALLOC_CTX *mem_ctx,
struct tevent_context *ev,
struct sock_client_context *client,
uint8_t *buf, size_t buflen,
void *private_data);
bool (*read_recv)(struct tevent_req *req, int *perr);
};
/**
* @brief Async computation to send data to the client
*
* @param[in] mem_ctx Talloc memory context
* @param[in] ev Tevent context
* @param[in] client The socket client context
* @param[in] buf Data to be sent to the client
* @param[in] buflen Length of the data
* @return new tevent request, or NULL on failure
*/
struct tevent_req *sock_socket_write_send(TALLOC_CTX *mem_ctx,
struct tevent_context *ev,
struct sock_client_context *client,
uint8_t *buf, size_t buflen);
/**
* @brief Async computation end to send data to client
*
* @param[in] req Tevent request
* @param[out] perr errno in case of failure
* @return true on success, false on failure
*/
bool sock_socket_write_recv(struct tevent_req *req, int *perr);
/**
* @brief Create a new socket daemon
*
* @param[in] mem_ctx Talloc memory context
* @param[in] daemon_name Name of the daemon, used for logging
* @param[in] logging Logging setup string
* @param[in] debug_level Debug level to log at
* @param[in] funcs Socket daemon callback routines
* @param[in] private_data Private data associated with callback routines
* @param[out] result New socket daemon context
* @return 0 on success, errno on failure
*/
int sock_daemon_setup(TALLOC_CTX *mem_ctx, const char *daemon_name,
const char *logging, const char *debug_level,
struct sock_daemon_funcs *funcs,
void *private_data,
struct sock_daemon_context **result);
/**
* @brief Create and listen to the unix domain socket
*
* @param[in] sockd Socket daemon context
* @param[in] sockpath Unix domain socket path
* @param[in] funcs socket callback routines
* @param[in] private_data Private data associated with callback routines
* @return 0 on success, errno on failure
*/
int sock_daemon_add_unix(struct sock_daemon_context *sockd,
const char *sockpath,
struct sock_socket_funcs *funcs,
void *private_data);
/**
* @brief Set file descriptor for indicating startup success
*
* On successful completion, 0 (unsigned int) will be written to the fd.
*
* @param[in] sockd Socket daemon context
* @param[in] fd File descriptor
* @return true on success, false on error
*/
bool sock_daemon_set_startup_fd(struct sock_daemon_context *sockd, int fd);
/**
* @brief Async computation start to run a socket daemon
*
* @param[in] mem_ctx Talloc memory context
* @param[in] ev Tevent context
* @param[in] sockd The socket daemon context
* @param[in] pidfile PID file to create, NULL if no PID file required
* @param[in] do_fork Whether the daemon should fork on startup
* @param[in] create_session Whether the daemon should create a new session
* @param[in] pid_watch PID to watch. If PID goes away, shutdown.
* @return new tevent request, NULL on failure
*/
struct tevent_req *sock_daemon_run_send(TALLOC_CTX *mem_ctx,
struct tevent_context *ev,
struct sock_daemon_context *sockd,
const char *pidfile,
bool do_fork, bool create_session,
pid_t pid_watch);
/**
* @brief Async computation end to run a socket daemon
*
* @param[in] req Tevent request
* @param[out] perr errno in case of failure
* @return true on success, false on failure
*/
bool sock_daemon_run_recv(struct tevent_req *req, int *perr);
/**
* @brief Sync way to start a daemon
*
* @param[in] ev Tevent context
* @param[in] sockd The socket daemon context
* @param[in] pidfile PID file to create, NULL if no PID file required
* @param[in] do_fork Whether the daemon should fork on startup
* @param[in] create_session Whether the daemon should create a new session
* @param[in] pid_watch PID to watch. If PID goes away, shutdown.
* @return 0 on success, errno on failure
*
* This call will return only on shutdown of the daemon
*/
int sock_daemon_run(struct tevent_context *ev,
struct sock_daemon_context *sockd,
const char *pidfile,
bool do_fork, bool create_session,
pid_t pid_watch);
#endif /* __CTDB_SOCK_DAEMON_H__ */
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