/**
 * collectd - src/nfs.c
 * Copyright (C) 2005,2006  Jason Pepas
 * Copyright (C) 2012,2013  Florian Forster
 *
 * 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; only version 2 of the License is applicable.
 *
 * 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, write to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 *
 * Authors:
 *   Jason Pepas <cell at ices.utexas.edu>
 *   Florian octo Forster <octo at collectd.org>
 *   Cosmin Ioiart <cioiart at gmail.com>
 **/

#include "collectd.h"
#include "common.h"
#include "plugin.h"

#if HAVE_KSTAT_H
#include <kstat.h>
#endif

/*
see /proc/net/rpc/nfs
see http://www.missioncriticallinux.com/orph/NFS-Statistics

net x x x x
rpc_stat.netcnt         Not used; always zero.
rpc_stat.netudpcnt      Not used; always zero.
rpc_stat.nettcpcnt      Not used; always zero.
rpc_stat.nettcpconn     Not used; always zero.

rpc x x x
rpc_stat.rpccnt             The number of RPC calls.
rpc_stat.rpcretrans         The number of retransmitted RPC calls.
rpc_stat.rpcauthrefresh     The number of credential refreshes.

proc2 x x x...
proc3 x x x...

Procedure   NFS Version NFS Version 3
Number      Procedures  Procedures

0           null        null
1           getattr     getattr
2           setattr     setattr
3           root        lookup
4           lookup      access
5           readlink    readlink
6           read        read
7           wrcache     write
8           write       create
9           create      mkdir
10          remove      symlink
11          rename      mknod
12          link        remove
13          symlink     rmdir
14          mkdir       rename
15          rmdir       link
16          readdir     readdir
17          fsstat      readdirplus
18                      fsstat
19                      fsinfo
20                      pathconf
21                      commit
*/

static const char *nfs2_procedures_names[] =
{
	"null",
	"getattr",
	"setattr",
	"root",
	"lookup",
	"readlink",
	"read",
	"wrcache",
	"write",
	"create",
	"remove",
	"rename",
	"link",
	"symlink",
	"mkdir",
	"rmdir",
	"readdir",
	"fsstat"
};
static size_t nfs2_procedures_names_num = STATIC_ARRAY_SIZE (nfs2_procedures_names);

static const char *nfs3_procedures_names[] =
{
	"null",
	"getattr",
	"setattr",
	"lookup",
	"access",
	"readlink",
	"read",
	"write",
	"create",
	"mkdir",
	"symlink",
	"mknod",
	"remove",
	"rmdir",
	"rename",
	"link",
	"readdir",
	"readdirplus",
	"fsstat",
	"fsinfo",
	"pathconf",
	"commit"
};
static size_t nfs3_procedures_names_num = STATIC_ARRAY_SIZE (nfs3_procedures_names);

#if HAVE_LIBKSTAT
static const char *nfs4_procedures_names[] =
{
	"null",
	"compound",
	"reserved",
	"access",
	"close",
	"commit",
	"create",
	"delegpurge",
	"delegreturn",
	"getattr",
	"getfh",
	"link",
	"lock",
	"lockt",
	"locku",
	"lookup",
	"lookupp",
	"nverify",
	"open",
	"openattr",
	"open_confirm",
	"open_downgrade",
	"putfh",
	"putpubfh",
	"putrootfh",
	"read",
	"readdir",
	"readlink",
	"remove",
	"rename",
	"renew",
	"restorefh",
	"savefh",
	"secinfo",
	"setattr",
	"setclientid",
	"setclientid_confirm",
	"verify",
	"write"
};
static size_t nfs4_procedures_names_num = STATIC_ARRAY_SIZE (nfs4_procedures_names);
#endif

#if HAVE_LIBKSTAT
extern kstat_ctl_t *kc;
static kstat_t *nfs2_ksp_client;
static kstat_t *nfs2_ksp_server;
static kstat_t *nfs3_ksp_client;
static kstat_t *nfs3_ksp_server;
static kstat_t *nfs4_ksp_client;
static kstat_t *nfs4_ksp_server;
#endif

/* Possibly TODO: NFSv4 statistics */

#if KERNEL_LINUX
static int nfs_init (void)
{
	return (0);
}
/* #endif KERNEL_LINUX */

#elif HAVE_LIBKSTAT
static int nfs_init (void)
{
	kstat_t *ksp_chain = NULL;

	nfs2_ksp_client = NULL;
	nfs2_ksp_server = NULL;
	nfs3_ksp_client = NULL;
	nfs3_ksp_server = NULL;
	nfs4_ksp_client = NULL;
	nfs4_ksp_server = NULL;

	if (kc == NULL)
		return (-1);

	for (ksp_chain = kc->kc_chain; ksp_chain != NULL;
			ksp_chain = ksp_chain->ks_next)
	{
		if (strncmp (ksp_chain->ks_module, "nfs", 3) != 0)
			continue;
		else if (strncmp (ksp_chain->ks_name, "rfsproccnt_v2", 13) == 0)
			nfs2_ksp_server = ksp_chain;
		else if (strncmp (ksp_chain->ks_name, "rfsproccnt_v3", 13) == 0)
			nfs3_ksp_server = ksp_chain;
		else if (strncmp (ksp_chain->ks_name, "rfsproccnt_v4", 13) == 0)
			nfs4_ksp_server = ksp_chain;
		else if (strncmp (ksp_chain->ks_name, "rfsreqcnt_v2", 12) == 0)
			nfs2_ksp_client = ksp_chain;
		else if (strncmp (ksp_chain->ks_name, "rfsreqcnt_v3", 12) == 0)
			nfs3_ksp_client = ksp_chain;
		else if (strncmp (ksp_chain->ks_name, "rfsreqcnt_v4", 12) == 0)
			nfs4_ksp_client = ksp_chain;
	}

	return (0);
} /* int nfs_init */
#endif

static void nfs_procedures_submit (const char *plugin_instance,
		const char **type_instances,
		value_t *values, size_t values_num)
{
	value_list_t vl = VALUE_LIST_INIT;
	size_t i;

	vl.values_len = 1;
	sstrncpy (vl.host, hostname_g, sizeof (vl.host));
	sstrncpy (vl.plugin, "nfs", sizeof (vl.plugin));
	sstrncpy (vl.plugin_instance, plugin_instance,
			sizeof (vl.plugin_instance));
	sstrncpy (vl.type, "nfs_procedure", sizeof (vl.type));

	for (i = 0; i < values_num; i++)
	{
		vl.values = values + i;
		sstrncpy (vl.type_instance, type_instances[i],
				sizeof (vl.type_instance));
		plugin_dispatch_values (&vl);
	}
} /* void nfs_procedures_submit */

#if KERNEL_LINUX
static int nfs_submit_fields (int nfs_version, const char *instance,
		char **fields, size_t fields_num,
		const char **proc_names, size_t proc_names_num)
{
	char plugin_instance[DATA_MAX_NAME_LEN];
	value_t values[fields_num];
	size_t i;

	if (fields_num != proc_names_num)
	{
		WARNING ("nfs plugin: Wrong number of fields for "
				"NFSv%i %s statistics. Expected %zu, got %zu.",
				nfs_version, instance,
				proc_names_num, fields_num);
		return (EINVAL);
	}

	ssnprintf (plugin_instance, sizeof (plugin_instance), "v%i%s",
			nfs_version, instance);

	for (i = 0; i < proc_names_num; i++)
		(void) parse_value (fields[i], &values[i], DS_TYPE_DERIVE);

	nfs_procedures_submit (plugin_instance, proc_names, values,
			proc_names_num);

	return (0);
}

static void nfs_read_linux (FILE *fh, char *inst)
{
	char buffer[1024];

	char *fields[48];
	int fields_num = 0;

	if (fh == NULL)
		return;

	while (fgets (buffer, sizeof (buffer), fh) != NULL)
	{
		fields_num = strsplit (buffer,
				fields, STATIC_ARRAY_SIZE (fields));

		if (fields_num < 3)
			continue;

		if (strcmp (fields[0], "proc2") == 0)
		{
			nfs_submit_fields (/* version = */ 2, inst,
					fields + 2, (size_t) (fields_num - 2),
					nfs2_procedures_names,
					nfs2_procedures_names_num);
		}
		else if (strncmp (fields[0], "proc3", 5) == 0)
		{
			nfs_submit_fields (/* version = */ 3, inst,
					fields + 2, (size_t) (fields_num - 2),
					nfs3_procedures_names,
					nfs3_procedures_names_num);
		}
	} /* while (fgets) */
} /* void nfs_read_linux */
#endif /* KERNEL_LINUX */

#if HAVE_LIBKSTAT
static int nfs_read_kstat (kstat_t *ksp, int nfs_version, char *inst,
		char const **proc_names, size_t proc_names_num)
{
	char plugin_instance[DATA_MAX_NAME_LEN];
	value_t values[proc_names_num];
	size_t i;

	if (ksp == NULL)
		return (EINVAL);

	ssnprintf (plugin_instance, sizeof (plugin_instance), "v%i%s",
			nfs_version, inst);

	kstat_read(kc, ksp, NULL);
	for (i = 0; i < proc_names_num; i++)
	{
		/* The name passed to kstat_data_lookup() doesn't have the
		 * "const" modifier, so we need to copy the name here. */
		char name[32];
		sstrncpy (name, proc_names[i], sizeof (name));

		values[i].counter = (derive_t) get_kstat_value (ksp, name);
	}

	nfs_procedures_submit (plugin_instance, proc_names, values,
			proc_names_num);
	return (0);
}
#endif

#if KERNEL_LINUX
static int nfs_read (void)
{
	FILE *fh;

	if ((fh = fopen ("/proc/net/rpc/nfs", "r")) != NULL)
	{
		nfs_read_linux (fh, "client");
		fclose (fh);
	}

	if ((fh = fopen ("/proc/net/rpc/nfsd", "r")) != NULL)
	{
		nfs_read_linux (fh, "server");
		fclose (fh);
	}

	return (0);
}
/* #endif KERNEL_LINUX */

#elif HAVE_LIBKSTAT
static int nfs_read (void)
{
	nfs_read_kstat (nfs2_ksp_client, /* version = */ 2, "client",
			nfs2_procedures_names, nfs2_procedures_names_num);
	nfs_read_kstat (nfs2_ksp_server, /* version = */ 2, "server",
			nfs2_procedures_names, nfs2_procedures_names_num);
	nfs_read_kstat (nfs3_ksp_client, /* version = */ 3, "client",
			nfs3_procedures_names, nfs3_procedures_names_num);
	nfs_read_kstat (nfs3_ksp_server, /* version = */ 3, "server",
			nfs3_procedures_names, nfs3_procedures_names_num);
	nfs_read_kstat (nfs4_ksp_client, /* version = */ 4, "client",
			nfs4_procedures_names, nfs4_procedures_names_num);
	nfs_read_kstat (nfs4_ksp_server, /* version = */ 4, "server",
			nfs4_procedures_names, nfs4_procedures_names_num);

	return (0);
}
#endif /* HAVE_LIBKSTAT */

void module_register (void)
{
	plugin_register_init ("nfs", nfs_init);
	plugin_register_read ("nfs", nfs_read);
} /* void module_register */
