/*
 * utils/mountd/rmtab.c
 *
 * Manage the rmtab file for mountd.
 *
 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>

#include "misc.h"
#include "exportfs.h"
#include "xio.h"
#include "mountd.h"
#include "ha-callout.h"

#include <limits.h> /* PATH_MAX */
#include <errno.h>

extern int reverse_resolve;

/* If new path is a link do not destroy it but place the
 * file where the link points.
 */

static int 
slink_safe_rename(const char * oldpath, const char * newpath)
{
	int r;
	struct stat s;
	char slink_path[PATH_MAX];
	const char *real_newpath = newpath;

	if ((lstat(newpath, &s) == 0) && S_ISLNK(s.st_mode)) {
		/* New path is a symbolic link, do not destroy but follow */
		if ((r = readlink(newpath, slink_path, PATH_MAX - 1)) == -1)
			return -1;
		slink_path[r] = '\0';
		real_newpath = slink_path;
	}

	return rename(oldpath, real_newpath);
}

void
mountlist_add(char *host, const char *path)
{
	struct rmtabent	xe;
	struct rmtabent	*rep;
	int		lockid;
	long		pos;

	if ((lockid = xflock(_PATH_RMTABLCK, "a")) < 0)
		return;
	setrmtabent("r+");
	while ((rep = getrmtabent(1, &pos)) != NULL) {
		if (strcmp (rep->r_client,
			    host) == 0
		    && strcmp(rep->r_path, path) == 0) {
			rep->r_count++;
			/* PRC: do the HA callout: */
			ha_callout("mount", rep->r_client, rep->r_path, rep->r_count);
			putrmtabent(rep, &pos);
			endrmtabent();
			xfunlock(lockid);
			return;
		}
	}
	endrmtabent();
	strncpy(xe.r_client, host,
		sizeof (xe.r_client) - 1);
	xe.r_client [sizeof (xe.r_client) - 1] = '\0';
	strncpy(xe.r_path, path, sizeof (xe.r_path) - 1);
	xe.r_path [sizeof (xe.r_path) - 1] = '\0';
	xe.r_count = 1;
	if (setrmtabent("a")) {
		/* PRC: do the HA callout: */
		ha_callout("mount", xe.r_client, xe.r_path, xe.r_count);
		putrmtabent(&xe, NULL);
		endrmtabent();
	}
	xfunlock(lockid);
}

void
mountlist_del(char *hname, const char *path)
{
	struct rmtabent	*rep;
	FILE		*fp;
	int		lockid;
	int		match;

	if ((lockid = xflock(_PATH_RMTABLCK, "w")) < 0)
		return;
	if (!setrmtabent("r")) {
		xfunlock(lockid);
		return;
	}
	if (!(fp = fsetrmtabent(_PATH_RMTABTMP, "w"))) {
		endrmtabent();
		xfunlock(lockid);
		return;
	}
	while ((rep = getrmtabent(1, NULL)) != NULL) {
		match = !strcmp (rep->r_client, hname)
			&& !strcmp(rep->r_path, path);
		if (match) {
			rep->r_count--;
			/* PRC: do the HA callout: */
			ha_callout("unmount", rep->r_client, rep->r_path, rep->r_count);
		}
		if (!match || rep->r_count)
			fputrmtabent(fp, rep, NULL);
	}
	if (slink_safe_rename(_PATH_RMTABTMP, _PATH_RMTAB) < 0) {
		xlog(L_ERROR, "couldn't rename %s to %s",
				_PATH_RMTABTMP, _PATH_RMTAB);
	}
	endrmtabent();	/* close & unlink */
	fendrmtabent(fp);
	xfunlock(lockid);
}

void
mountlist_del_all(const struct sockaddr *sap)
{
	char		*hostname;
	struct rmtabent	*rep;
	FILE		*fp;
	int		lockid;

	if ((lockid = xflock(_PATH_RMTABLCK, "w")) < 0)
		return;
	hostname = host_canonname(sap);
	if (hostname == NULL) {
		char buf[INET6_ADDRSTRLEN];
		xlog(L_ERROR, "can't get hostname of %s",
			host_ntop(sap, buf, sizeof(buf)));
		goto out_unlock;
	}

	if (!setrmtabent("r"))
		goto out_free;

	if (!(fp = fsetrmtabent(_PATH_RMTABTMP, "w")))
		goto out_close;

	while ((rep = getrmtabent(1, NULL)) != NULL) {
		if (strcmp(rep->r_client, hostname) == 0 &&
		    auth_authenticate("umountall", sap, rep->r_path) != NULL)
			continue;
		fputrmtabent(fp, rep, NULL);
	}
	if (slink_safe_rename(_PATH_RMTABTMP, _PATH_RMTAB) < 0) {
		xlog(L_ERROR, "couldn't rename %s to %s",
				_PATH_RMTABTMP, _PATH_RMTAB);
	}
	fendrmtabent(fp);
out_close:
	endrmtabent();	/* close & unlink */
out_free:
	free(hostname);
out_unlock:
	xfunlock(lockid);
}

static void
mountlist_freeall(mountlist list)
{
	while (list != NULL) {
		mountlist m = list;
		list = m->ml_next;
		free(m->ml_hostname);
		free(m->ml_directory);
		free(m);
	}
}

mountlist
mountlist_list(void)
{
	static mountlist	mlist = NULL;
	static time_t		last_mtime = 0;
	mountlist		m;
	struct rmtabent		*rep;
	struct stat		stb;
	int			lockid;

	if ((lockid = xflock(_PATH_RMTABLCK, "r")) < 0)
		return NULL;
	if (stat(_PATH_RMTAB, &stb) < 0) {
		xlog(L_ERROR, "can't stat %s: %s",
				_PATH_RMTAB, strerror(errno));
		xfunlock(lockid);
		return NULL;
	}
	if (stb.st_mtime != last_mtime) {
		mountlist_freeall(mlist);
		mlist = NULL;
		last_mtime = stb.st_mtime;

		setrmtabent("r");
		while ((rep = getrmtabent(1, NULL)) != NULL) {
			m = calloc(1, sizeof(*m));
			if (m == NULL) {
				mountlist_freeall(mlist);
				mlist = NULL;
				xlog(L_ERROR, "%s: memory allocation failed",
						__func__);
				break;
			}

			if (reverse_resolve) {
				struct addrinfo *ai;
				ai = host_pton(rep->r_client);
				if (ai != NULL) {
					m->ml_hostname = host_canonname(ai->ai_addr);
					freeaddrinfo(ai);
				}
			}
			if (m->ml_hostname == NULL)
				m->ml_hostname = strdup(rep->r_client);

			m->ml_directory = strdup(rep->r_path);

			if (m->ml_hostname == NULL || m->ml_directory == NULL) {
				mountlist_freeall(mlist);
				mlist = NULL;
				xlog(L_ERROR, "%s: memory allocation failed",
						__func__);
				break;
			}

			m->ml_next = mlist;
			mlist = m;
		}
		endrmtabent();
	}
	xfunlock(lockid);

	return mlist;
}