| Current File : //usr/include/mpath_cmd.h |
/*
* Copyright (C) 2015 Red Hat, Inc.
*
* This file is part of the device-mapper multipath userspace tools.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2.1
* 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef LIB_MPATH_CMD_H
#define LIB_MPATH_CMD_H
/*
* This should be sufficient for json output for >10000 maps,
* and >60000 paths.
*/
#define MAX_REPLY_LEN (32 * 1024 * 1024)
#ifdef __cplusplus
extern "C" {
#endif
#define DEFAULT_SOCKET "/org/kernel/linux/storage/multipathd"
#define DEFAULT_REPLY_TIMEOUT 4000
/*
* DESCRIPTION:
* Same as mpath_connect() (see below) except for the "nonblocking"
* parameter.
* If "nonblocking" is set, connects in non-blocking mode. This is
* useful to avoid blocking if the listening socket's backlog is
* exceeded. In this case, errno will be set to EAGAIN.
* In case of success, the returned file descriptor is in in blocking
* mode, even if "nonblocking" was true.
*
* RETURNS:
* A file descriptor on success. -1 on failure (with errno set).
*/
int __mpath_connect(int nonblocking);
/*
* DESCRIPTION:
* Connect to the running multipathd daemon. On systems with the
* multipathd.socket systemd unit file installed, this command will
* start multipathd if it is not already running. This function
* must be run before any of the others in this library
*
* RETURNS:
* A file descriptor on success. -1 on failure (with errno set).
*/
int mpath_connect(void);
/*
* DESCRIPTION:
* Disconnect from the multipathd daemon. This function must be
* run after after processing all the multipath commands.
*
* RETURNS:
* 0 on success. -1 on failure (with errno set).
*/
int mpath_disconnect(int fd);
/*
* DESCRIPTION
* Send multipathd a command and return the reply. This function
* does the same as calling mpath_send_cmd() and then
* mpath_recv_reply()
*
* RETURNS:
* 0 on successs, and reply will either be NULL (if there was no
* reply data), or point to the reply string, which must be freed by
* the caller. -1 on failure (with errno set).
*/
int mpath_process_cmd(int fd, const char *cmd, char **reply,
unsigned int timeout);
/*
* DESCRIPTION:
* Send a command to multipathd
*
* RETURNS:
* 0 on success. -1 on failure (with errno set)
*/
int mpath_send_cmd(int fd, const char *cmd);
/*
* DESCRIPTION:
* Return a reply from multipathd for a previously sent command.
* This is equivalent to calling mpath_recv_reply_len(), allocating
* a buffer of the appropriate size, and then calling
* mpath_recv_reply_data() with that buffer.
*
* RETURNS:
* 0 on success, and reply will either be NULL (if there was no
* reply data), or point to the reply string, which must be freed by
* the caller, -1 on failure (with errno set).
*/
int mpath_recv_reply(int fd, char **reply, unsigned int timeout);
/*
* DESCRIPTION:
* Return the size of the upcoming reply data from the sent multipath
* command. This must be called before calling mpath_recv_reply_data().
*
* RETURNS:
* The required size of the reply data buffer on success. -1 on
* failure (with errno set).
*/
ssize_t mpath_recv_reply_len(int fd, unsigned int timeout);
/*
* DESCRIPTION:
* Return the reply data from the sent multipath command.
* mpath_recv_reply_len must be called first. reply must point to a
* buffer of len size.
*
* RETURNS:
* 0 on success, and reply will contain the reply data string. -1
* on failure (with errno set).
*/
int mpath_recv_reply_data(int fd, char *reply, size_t len,
unsigned int timeout);
#ifdef __cplusplus
}
#endif
#endif /* LIB_MPATH_CMD_H */