/*
 * configfile.c -- mount configuration file manipulation 
 * Copyright (C) 2008 Red Hat, Inc <nfs@redhat.com>
 *
 * - Routines use to create mount options from the mount
 *   configuration file.
 *
 * 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 2, 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.
 *
 */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>

#include "xlog.h"
#include "mount.h"
#include "parse_opt.h"
#include "network.h"
#include "conffile.h"

#define KBYTES(x)     ((x) * (1024))
#define MEGABYTES(x)  ((x) * (1048576))
#define GIGABYTES(x)  ((x) * (1073741824))

#ifndef NFSMOUNT_GLOBAL_OPTS
#define NFSMOUNT_GLOBAL_OPTS "NFSMount_Global_Options"
#endif

#ifndef NFSMOUNT_MOUNTPOINT
#define NFSMOUNT_MOUNTPOINT "MountPoint"
#endif

#ifndef NFSMOUNT_SERVER
#define NFSMOUNT_SERVER "Server"
#endif

#ifndef MOUNTOPTS_CONFFILE
#define MOUNTOPTS_CONFFILE "/etc/nfsmount.conf"
#endif
char *conf_path = MOUNTOPTS_CONFFILE;
enum {
	MNT_NOARG=0,
	MNT_INTARG,
	MNT_STRARG,
	MNT_SPEC,
	MNT_UNSET
};
struct mnt_alias {
	char *alias;
	char *opt;
	int  argtype;
} mnt_alias_tab[] = {
	{"background", "bg", MNT_NOARG},
	{"foreground", "fg", MNT_NOARG},
	{"sloppy", "sloppy", MNT_NOARG},
};
int mnt_alias_sz = (sizeof(mnt_alias_tab)/sizeof(mnt_alias_tab[0]));

/*
 * See if the option is an alias, if so return the 
 * real mount option along with the argument type.
 */
inline static 
char *mountopts_alias(char *opt, int *argtype)
{
	int i;

	*argtype = MNT_UNSET;
	for (i=0; i < mnt_alias_sz; i++) {
		if (strcasecmp(opt, mnt_alias_tab[i].alias) != 0)
			continue;
		*argtype = mnt_alias_tab[i].argtype;
		return mnt_alias_tab[i].opt;
	}
	/* Make option names case-insensitive */
	upper2lower(opt);

	return opt;
}
/*
 * Convert numeric strings that end with 'k', 'm' or 'g'
 * into numeric strings with the real value. 
 * Meaning '8k' becomes '8094'.
 */
char *mountopts_convert(char *value)
{
	unsigned long long factor, num;
	static char buf[64];
	char *ch;

	ch = &value[strlen(value)-1];
	switch (tolower(*ch)) {
	case 'k':
		factor = KBYTES(1);
		break;
	case 'm':
		factor = MEGABYTES(1);
		break;
	case 'g':
		factor = GIGABYTES(1);
		break;
	default:
		return value;
	}
	*ch = '\0';
	if (strncmp(value, "0x", 2) == 0) {
		num = strtol(value, (char **)NULL, 16);
	} else if (strncmp(value, "0", 1) == 0) {
		num = strtol(value, (char **)NULL, 8);
	} else {
		num = strtol(value, (char **)NULL, 10);
	}
	num *= factor;
	snprintf(buf, 64, "%lld", num);

	return buf;
}

struct entry {
	SLIST_ENTRY(entry) entries;
	char *opt;
};
static SLIST_HEAD(shead, entry) head = SLIST_HEAD_INITIALIZER(head);
static int list_size;

/*
 * Add option to the link list
 */
inline static void 
add_entry(char *opt)
{
	struct entry *entry;

	entry = calloc(1, sizeof(struct entry));
	if (entry == NULL) {
		xlog_warn("Unable calloc memory for mount configs"); 
		return;
	}
	entry->opt = strdup(opt);
	if (entry->opt == NULL) {
		xlog_warn("Unable calloc memory for mount opts"); 
		free(entry);
		return;
	}
	SLIST_INSERT_HEAD(&head, entry, entries);
}
/*
 * See if the given entry exists if the link list,
 * if so return that entry
 */
inline static 
char *lookup_entry(char *opt)
{
	struct entry *entry;

	SLIST_FOREACH(entry, &head, entries) {
		if (strcasecmp(entry->opt, opt) == 0)
			return opt;
	}
	return NULL;
}
/*
 * Free all entries on the link list
 */
inline static 
void free_all(void)
{
	struct entry *entry;

	while (!SLIST_EMPTY(&head)) {
		entry = SLIST_FIRST(&head);
		SLIST_REMOVE_HEAD(&head, entries);
		free(entry->opt);
		free(entry);
	}
}
static char *versions[] = {"v2", "v3", "v4", "vers", "nfsvers", NULL};
static int 
check_vers(char *mopt, char *field)
{
	int i, found=0;

	/*
	 * First check to see if the config setting is one 
	 * of the many version settings
	 */
	for (i=0; versions[i]; i++) { 
		if (strcasestr(field, versions[i]) != NULL) {
			found++;
			break;
		}
	}
	if (!found)
		return 0;
	/*
	 * It appears the version is being set, now see
	 * if the version appears on the command 
	 */
	for (i=0; versions[i]; i++)  {
		if (strcasestr(mopt, versions[i]) != NULL)
			return 1;
	}

	return 0;
}

unsigned long config_default_vers;
unsigned long config_default_proto;
extern sa_family_t config_default_family;

/*
 * Check to see if a default value is being set.
 * If so, set the appropriate global value which will 
 * be used as the initial value in the server negation.
 */
static int 
default_value(char *mopt)
{
	struct mount_options *options = NULL;
	int dftlen = strlen("default");
	char *field;

	if (strncasecmp(mopt, "default", dftlen) != 0)
		return 0;

	field = mopt + dftlen;
	if (strncasecmp(field, "proto", strlen("proto")) == 0) {
		if ((options = po_split(field)) != NULL) {
			if (!nfs_nfs_protocol(options, &config_default_proto)) {
				xlog_warn("Unable to set default protocol : %s", 
					strerror(errno));
			}
			if (!nfs_nfs_proto_family(options, &config_default_family)) {
				xlog_warn("Unable to set default family : %s", 
					strerror(errno));
			}
		} else {
			xlog_warn("Unable to alloc memory for default protocol");
		}
	} else if (strncasecmp(field, "vers", strlen("vers")) == 0) {
		if ((options = po_split(field)) != NULL) {
			if (!nfs_nfs_version(options, &config_default_vers)) {
				xlog_warn("Unable to set default version: %s", 
					strerror(errno));
				
			}
		} else {
			xlog_warn("Unable to alloc memory for default version");
		}
	} else 
		xlog_warn("Invalid default setting: '%s'", mopt);

	if (options)
		po_destroy(options);

	return 1;
}
/*
 * Parse the given section of the configuration 
 * file to if there are any mount options set.
 * If so, added them to link list.
 */
static void 
conf_parse_mntopts(char *section, char *arg, char *opts)
{
	struct conf_list *list;
	struct conf_list_node *node;
	char buf[BUFSIZ], *value, *field;
	char *nvalue, *ptr;
	int argtype;

	list = conf_get_tag_list(section);
	TAILQ_FOREACH(node, &list->fields, link) {
		/*
		 * Do not overwrite options if already exists 
		 */
		snprintf(buf, BUFSIZ, "%s=", node->field);
		if (opts && strcasestr(opts, buf) != NULL)
			continue;
		/* 
		 * Protocol verions can be set in a number of ways
		 */
		if (opts && check_vers(opts, node->field))
			continue;

		if (lookup_entry(node->field) != NULL)
			continue;
		buf[0] = '\0';
		value = conf_get_section(section, arg, node->field);
		if (value == NULL)
			continue;
		field = mountopts_alias(node->field, &argtype);
		if (strcasecmp(value, "false") == 0) {
			if (argtype != MNT_NOARG)
				snprintf(buf, BUFSIZ, "no%s", field);
		} else if (strcasecmp(value, "true") == 0) {
			snprintf(buf, BUFSIZ, "%s", field);
		} else {
			nvalue = strdup(value);
			ptr = mountopts_convert(nvalue);
			snprintf(buf, BUFSIZ, "%s=%s", field, ptr);
			free(nvalue);
		}
		if (buf[0] == '\0')
			continue;
		/* 
		 * Keep a running tally of the list size adding 
		 * one for the ',' that will be appened later
		 */
		list_size += strlen(buf) + 1;
		add_entry(buf);
	}
	conf_free_list(list);
}

/*
 * Concatenate options from the configuration file with the 
 * given options by building a link list of options from the
 * different sections in the conf file. Options that exists 
 * in the either the given options or link list are not 
 * overwritten so it matter which when each section is
 * parsed. 
 */
char *conf_get_mntopts(char *spec, char *mount_point, 
	char *mount_opts)
{
	struct entry *entry;
	char *ptr, *server, *config_opts;
	int optlen = 0;

	SLIST_INIT(&head);
	list_size = 0;
	/*
	 * First see if there are any mount options relative 
	 * to the mount point.
	 */
	conf_parse_mntopts(NFSMOUNT_MOUNTPOINT, mount_point, mount_opts);

	/* 
	 * Next, see if there are any mount options relative
	 * to the server
	 */
	server = strdup(spec);
	if (server == NULL) {
		xlog_warn("conf_get_mountops: Unable calloc memory for server"); 
		free_all();
		return mount_opts;
	}
	if ((ptr = strchr(server, ':')) != NULL)
		*ptr='\0';
	conf_parse_mntopts(NFSMOUNT_SERVER, server, mount_opts);
	free(server);

	/*
	 * Finally process all the global mount options. 
	 */
	conf_parse_mntopts(NFSMOUNT_GLOBAL_OPTS, NULL, mount_opts);

	/*
	 * If no mount options were found in the configuration file
	 * just return what was passed in .
	 */
	if (SLIST_EMPTY(&head))
		return mount_opts;

	/*
	 * Found options in the configuration file. So
	 * concatenate the configuration options with the 
	 * options that were passed in
	 */
	if (mount_opts)
		optlen = strlen(mount_opts);

	/* list_size + optlen + ',' + '\0' */
	config_opts = calloc(1, (list_size+optlen+2));
	if (server == NULL) {
		xlog_warn("conf_get_mountops: Unable calloc memory for config_opts"); 
		free_all();
		return mount_opts;
	}

	if (mount_opts) {
		strcpy(config_opts, mount_opts);
		strcat(config_opts, ",");
	}
	SLIST_FOREACH(entry, &head, entries) {
		if (default_value(entry->opt))
			continue;
		strcat(config_opts, entry->opt);
		strcat(config_opts, ",");
	}
	if ((ptr = strrchr(config_opts, ',')) != NULL)
		*ptr = '\0';

	free_all();
	if (mount_opts)
		free(mount_opts);

	return config_opts;
}