/*
 * stropts.c -- NFS mount using C string to pass options to kernel
 *
 * Copyright (C) 2007 Oracle.  All rights reserved.
 * Copyright (C) 2007 Chuck Lever <chuck.lever@oracle.com>
 *
 * 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 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, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 *
 */

#include <ctype.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <netdb.h>
#include <time.h>
#include <sys/socket.h>
#include <sys/mount.h>

#include "xcommon.h"
#include "mount.h"
#include "nls.h"
#include "nfs_mount.h"
#include "mount_constants.h"
#include "stropts.h"
#include "error.h"
#include "network.h"
#include "parse_opt.h"

#ifdef HAVE_RPCSVC_NFS_PROT_H
#include <rpcsvc/nfs_prot.h>
#else
#include <linux/nfs.h>
#define nfsstat nfs_stat
#endif

#ifndef NFS_PORT
#define NFS_PORT 2049
#endif

#ifndef NFS_MAXHOSTNAME
#define NFS_MAXHOSTNAME		(255)
#endif

#ifndef NFS_MAXPATHNAME
#define NFS_MAXPATHNAME		(1024)
#endif

extern int nfs_mount_data_version;
extern char *progname;
extern int verbose;

static int parse_devname(const char *spec, char **hostname)
{
	int ret = 0;
	char *dev, *pathname, *s;

	dev = xstrdup(spec);

	if (!(pathname = strchr(dev, ':'))) {
		nfs_error(_("%s: remote share not in 'host:dir' format"),
				progname);
		goto out;
	}
	*pathname = '\0';
	pathname++;

	/*
	 * We don't need a copy of the pathname, but let's
	 * sanity check it anyway.
	 */
	if (strlen(pathname) > NFS_MAXPATHNAME) {
		nfs_error(_("%s: export pathname is too long"),
				progname);
		goto out;
	}

	/*
	 * Ignore all but first hostname in replicated mounts
	 * until they can be fully supported. (mack@sgi.com)
	 */
	if ((s = strchr(dev, ','))) {
		*s = '\0';
		nfs_error(_("%s: warning: multiple hostnames not supported"),
				progname);
		nfs_error(_("%s: ignoring hostnames that follow the first one"),
				progname);
	}
	*hostname = xstrdup(dev);
	if (strlen(*hostname) > NFS_MAXHOSTNAME) {
		nfs_error(_("%s: server hostname is too long"),
				progname);
		free(*hostname);
		goto out;
	}

	ret = 1;

out:
	free(dev);
	return ret;
}

static int fill_ipv4_sockaddr(const char *hostname, struct sockaddr_in *addr)
{
	struct hostent *hp;
	addr->sin_family = AF_INET;

	if (inet_aton(hostname, &addr->sin_addr))
		return 1;
	if ((hp = gethostbyname(hostname)) == NULL) {
		nfs_error(_("%s: can't get address for %s\n"),
				progname, hostname);
		return 0;
	}
	if (hp->h_length > sizeof(struct in_addr)) {
		nfs_error(_("%s: got bad hp->h_length"), progname);
		hp->h_length = sizeof(struct in_addr);
	}
	memcpy(&addr->sin_addr, hp->h_addr, hp->h_length);
	return 1;
}

/*
 * Append the 'addr=' option to the options string to pass a resolved
 * server address to the kernel.  After a successful mount, this address
 * is also added to /etc/mtab for use when unmounting.
 *
 * If 'addr=' is already present, we strip it out.  This prevents users
 * from setting a bogus 'addr=' option themselves, and also allows bg
 * retries to recompute the server's address, in case it has changed.
 *
 * Returns 1 if 'addr=' option appended successfully;
 * otherwise zero.
 */
static int append_addr_option(struct sockaddr_in *saddr,
			   struct mount_options *options)
{
	char new_option[24];

	po_remove_all(options, "addr");

	snprintf(new_option, sizeof(new_option) - 1,
			"addr=%s", inet_ntoa(saddr->sin_addr));

	if (po_append(options, new_option) == PO_SUCCEEDED)
		return 1;
	return 0;
}

/*
 * Called to discover our address and append an appropriate 'clientaddr='
 * option to the options string.
 *
 * Returns 1 if 'clientaddr=' option created successfully or if
 * 'clientaddr=' option is already present; otherwise zero.
 */
static int append_clientaddr_option(struct sockaddr_in *saddr,
				    struct mount_options *options)
{
	struct sockaddr_in my_addr;
	char new_option[32];

	if (po_contains(options, "clientaddr") == PO_SUCCEEDED)
		return 1;

	if (!get_client_address(saddr, &my_addr))
		return 0;

	snprintf(new_option, sizeof(new_option) - 1,
			"clientaddr=%s", inet_ntoa(my_addr.sin_addr));

	if (po_append(options, new_option) == PO_SUCCEEDED)
		return 1;
	return 0;
}

/*
 * Resolve the 'mounthost=' hostname and append a new option using
 * the resulting IPv4 address.
 */
static int fix_mounthost_option(struct mount_options *options)
{
	struct sockaddr_in maddr;
	char *mounthost, new_option[32];

	mounthost = po_get(options, "mounthost");
	if (!mounthost)
		return 1;

	if (!fill_ipv4_sockaddr(mounthost, &maddr))
		return 0;

	snprintf(new_option, sizeof(new_option) - 1,
			"mountaddr=%s", inet_ntoa(maddr.sin_addr));

	if (po_append(options, new_option) == PO_SUCCEEDED)
		return 1;
	return 0;
}

/*
 * Set up mandatory mount options.
 *
 * Returns 1 if successful; otherwise zero.
 */
static int set_mandatory_options(const char *type,
				 struct sockaddr_in *saddr,
				 struct mount_options *options)
{
	if (!append_addr_option(saddr, options))
		return 0;

	if (strncmp(type, "nfs4", 4) == 0) {
		if (!append_clientaddr_option(saddr, options))
			return 0;
	} else {
		if (!fix_mounthost_option(options))
			return 0;
	}

	return 1;
}

/*
 * nfsmount_s - Mount an NFSv2 or v3 file system using C string options
 *
 * @spec:	C string hostname:path specifying remoteshare to mount
 * @node:	C string pathname of local mounted on directory
 * @flags:	MS_ style flags
 * @extra_opts:	pointer to C string containing fs-specific mount options
 *		(possibly also a return argument)
 * @fake:	flag indicating whether to carry out the whole operation
 * @child:	one if this is a backgrounded mount
 *
 * XXX: need to handle bg, fg, and retry options.
 */
int nfsmount_s(const char *spec, const char *node, int flags,
		char **extra_opts, int fake, int child)
{
	struct mount_options *options = NULL;
	struct sockaddr_in saddr;
	char *hostname;
	int err, retval = EX_FAIL;

	if (!parse_devname(spec, &hostname))
		goto out;
	err = fill_ipv4_sockaddr(hostname, &saddr);
	free(hostname);
	if (!err)
		goto out;

	options = po_split(*extra_opts);
	if (!options) {
		nfs_error(_("%s: internal option parsing error"), progname);
		goto out;
	}

	if (!append_addr_option(&saddr, options))
		goto out;

	if (!fix_mounthost_option(options))
		goto out;

	if (po_join(options, extra_opts) == PO_FAILED) {
		nfs_error(_("%s: internal option parsing error"), progname);
		goto out;
	}

	if (verbose)
		printf(_("%s: text-based options: '%s'\n"),
			progname, *extra_opts);

	if (!fake) {
		if (mount(spec, node, "nfs",
				flags & ~(MS_USER|MS_USERS), *extra_opts)) {
			mount_error(spec, node, errno);
			goto out;
		}
	}

	retval = EX_SUCCESS;

out:
	po_destroy(options);
	return retval;
}

/*
 * nfs4mount_s - Mount an NFSv4 file system using C string options
 *
 * @spec:	C string hostname:path specifying remoteshare to mount
 * @node:	C string pathname of local mounted on directory
 * @flags:	MS_ style flags
 * @extra_opts:	pointer to C string containing fs-specific mount options
 *		(possibly also a return argument)
 * @fake:	flag indicating whether to carry out the whole operation
 * @child:	one if this is a backgrounded mount
 *
 * XXX: need to handle bg, fg, and retry options.
 *
 */
int nfs4mount_s(const char *spec, const char *node, int flags,
		char **extra_opts, int fake, int child)
{
	struct mount_options *options = NULL;
	struct sockaddr_in saddr;
	char *hostname;
	int err, retval = EX_FAIL;

	if (!parse_devname(spec, &hostname))
		goto out;
	err = fill_ipv4_sockaddr(hostname, &saddr);
	free(hostname);
	if (!err)
		goto out;

	options = po_split(*extra_opts);
	if (!options) {
		nfs_error(_("%s: internal option parsing error"), progname);
		goto out;
	}

	if (!append_addr_option(&saddr, options))
		goto out;

	if (!append_clientaddr_option(&saddr, options))
		goto out;

	if (po_join(options, extra_opts) == PO_FAILED) {
		nfs_error(_("%s: internal option parsing error"), progname);
		goto out;
	}

	if (verbose)
		printf(_("%s: text-based options: '%s'\n"),
			progname, *extra_opts);

	if (!fake) {
		if (mount(spec, node, "nfs4",
				flags & ~(MS_USER|MS_USERS), *extra_opts)) {
			mount_error(spec, node, errno);
			goto out;
		}
	}

	retval = EX_SUCCESS;

out:
	po_destroy(options);
	return retval;
}

/**
 * nfsmount_string - Mount an NFS file system using C string options
 * @spec: C string specifying remote share to mount ("hostname:path")
 * @node: C string pathname of local mounted-on directory
 * @type: C string that represents file system type ("nfs" or "nfs4")
 * @flags: MS_ style mount flags
 * @extra_opts:	pointer to C string containing fs-specific mount options
 *		(input and output argument)
 * @fake: flag indicating whether to carry out the whole operation
 * @child: one if this is a mount daemon (bg)
 */
int nfsmount_string(const char *spec, const char *node, const char *type,
		    int flags, char **extra_opts, int fake, int child)
{
	struct mount_options *options = NULL;
	struct sockaddr_in saddr;
	char *hostname;
	int err, retval = EX_FAIL;

	if (!parse_devname(spec, &hostname))
		goto out;
	err = fill_ipv4_sockaddr(hostname, &saddr);
	free(hostname);
	if (!err)
		goto out;

	options = po_split(*extra_opts);
	if (!options) {
		nfs_error(_("%s: internal option parsing error"), progname);
		goto out;
	}

	if (!set_mandatory_options(type, &saddr, options))
		goto out;

	if (po_join(options, extra_opts) == PO_FAILED) {
		nfs_error(_("%s: internal option parsing error"), progname);
		goto out;
	}

	if (verbose)
		printf(_("%s: text-based options: '%s'\n"),
			progname, *extra_opts);

	if (!fake) {
		if (mount(spec, node, type,
				flags & ~(MS_USER|MS_USERS), *extra_opts)) {
			mount_error(spec, node, errno);
			goto out;
		}
	}

	retval = EX_SUCCESS;

out:
	po_destroy(options);
	return retval;
}