/*
 * support/nfs/export.c
 *
 * Parse the exports file. Derived from the unfsd implementation.
 *
 * Authors:	Donald J. Becker, <becker@super.org>
 *		Rick Sladkey, <jrs@world.std.com>
 *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *		Olaf Kirch, <okir@monad.swb.de>
 *		Alexander O. Yuriev, <alex@bach.cis.temple.edu>
 *
 *		This software maybe be used for any purpose provided
 *		the above copyright notice is retained.  It is supplied
 *		as is, with no warranty expressed or implied.
 */

#include "config.h"

#include <sys/param.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <ctype.h>
#include <unistd.h>
#include "nfslib.h"
#include "exportfs.h"
#include "xmalloc.h"
#include "xlog.h"
#include "xio.h"

#define EXPORT_DEFAULT_FLAGS	\
  (NFSEXP_ASYNC|NFSEXP_READONLY|NFSEXP_ROOTSQUASH|NFSEXP_GATHERED_WRITES)

static XFILE	*efp = NULL;
static int	first;
static int	*squids = NULL, nsquids = 0,
		*sqgids = NULL, nsqgids = 0;

static int	getexport(char *exp, int len);
static int	getpath(char *path, int len);
static int	parseopts(char *cp, struct exportent *ep);
static int	parsesquash(char *list, int **idp, int *lenp, char **ep);
static int	parsenum(char **cpp);
static int	parsemaptype(char *type);
static void	freesquash(void);
static void	syntaxerr(char *msg);

void
setexportent(char *fname, char *type)
{
	if (efp)
		endexportent();
	if (!fname)
		fname = _PATH_EXPORTS;
	if (!(efp = xfopen(fname, type)))
		xlog(L_ERROR, "can't open %s for %sing",
				fname, strcmp(type, "r")? "writ" : "read");
	first = 1;
}

struct exportent *
getexportent(void)
{
	static struct exportent	ee;
	char		exp[512];
	char		rpath[MAXPATHLEN+1];
	char		*opt, *sp;
	int		ok;

	if (!efp)
		return NULL;

	freesquash();
	ee.e_flags = EXPORT_DEFAULT_FLAGS;
	ee.e_maptype = CLE_MAP_IDENT;
	ee.e_anonuid = -2;
	ee.e_anongid = -2;
	ee.e_squids = NULL;
	ee.e_sqgids = NULL;
	ee.e_nsquids = 0;
	ee.e_nsqgids = 0;

	if (first || (ok = getexport(exp, sizeof(exp))) == 0) {
		ok = getpath(ee.e_path, sizeof(ee.e_path));
		if (ok <= 0)
			return NULL;
		strncpy (ee.m_path, ee.e_path, sizeof (ee.m_path) - 1);
		ee.m_path [sizeof (ee.m_path) - 1] = '\0';
		ok = getexport(exp, sizeof(exp));
	}
	if (ok < 0) {
		xlog(L_ERROR, "expected client(options...)");
		return NULL;
	}
	first = 0;

	/* Check for default client */
	if (ok == 0)
		exp[0] = '\0';
	if ((opt = strchr(exp, '(')) != NULL) {
		*opt++ = '\0';
		if (!(sp = strchr(opt, ')')) || sp[1] != '\0') {
			syntaxerr("bad option list");
			return NULL;
		}
		*sp = '\0';
		if (parseopts(opt, &ee) < 0)
			return NULL;
	}
	if (strlen(exp) >= sizeof(ee.e_hostname)) {
		syntaxerr("client name too long");
		return NULL;
	}
	strncpy(ee.e_hostname, exp, sizeof (ee.e_hostname) - 1);
	ee.e_hostname[sizeof (ee.e_hostname) - 1] = '\0';

	/* resolve symlinks */
	if (realpath(ee.e_path, rpath) != NULL) {
		rpath[sizeof (rpath) - 1] = '\0';
		strncpy(ee.e_path, rpath, sizeof (ee.e_path) - 1);
		ee.e_path[sizeof (ee.e_path) - 1] = '\0';
		strncpy (ee.m_path, ee.e_path, sizeof (ee.m_path) - 1);
		ee.m_path [sizeof (ee.m_path) - 1] = '\0';
	}

	return &ee;
}

void
putexportent(struct exportent *ep)
{
	FILE	*fp;
	int	*id, i;

	if (!efp)
		return;

	fp = efp->x_fp;
	fprintf(fp, "%s\t%s(", ep->e_path, ep->e_hostname);
	fprintf(fp, "%s,", (ep->e_flags & NFSEXP_READONLY)? "ro" : "rw");
	fprintf(fp, "%ssync,", (ep->e_flags & NFSEXP_ASYNC)? "a" : "");
	fprintf(fp, "%swdelay,", (ep->e_flags & NFSEXP_GATHERED_WRITES)?
				"" : "no_");
	fprintf(fp, "%ssecure,", (ep->e_flags & NFSEXP_INSECURE_PORT)?
				"in" : "");
	fprintf(fp, "%sroot_squash,", (ep->e_flags & NFSEXP_ROOTSQUASH)?
				"" : "no_");
	fprintf(fp, "%sall_squash,", (ep->e_flags & NFSEXP_ALLSQUASH)?
				"" : "no_");

	fprintf(fp, "mapping=");
	switch (ep->e_maptype) {
	case CLE_MAP_IDENT:
		fprintf(fp, "identity,");
		break;
	case CLE_MAP_UGIDD:
		fprintf(fp, "ugidd,");
		break;
	case CLE_MAP_FILE:
		fprintf(fp, "file,");
		break;
	default:
		xlog(L_ERROR, "unknown mapping type for %s:%s",
					ep->e_hostname, ep->e_path);
	}
	if ((id = ep->e_squids) != NULL) {
		fprintf(fp, "squash_uids=");
		for (i = 0; i < ep->e_nsquids; i += 2)
			if (id[i] != id[i+1])
				fprintf(fp, "%d-%d,", id[i], id[i+1]);
			else
				fprintf(fp, "%d,", id[i]);
	}
	if ((id = ep->e_sqgids) != NULL) {
		fprintf(fp, "squash_gids=");
		for (i = 0; i < ep->e_nsquids; i += 2)
			if (id[i] != id[i+1])
				fprintf(fp, "%d-%d,", id[i], id[i+1]);
			else
				fprintf(fp, "%d,", id[i]);
	}
	fprintf(fp, "anonuid=%d,anongid=%d)\n", ep->e_anonuid, ep->e_anongid);
}

void
endexportent(void)
{
	if (efp)
		xfclose(efp);
	efp = NULL;
	freesquash();
}

void
dupexportent(struct exportent *dst, struct exportent *src)
{
	int	n;

	*dst = *src;
	if ((n = src->e_nsquids) != 0) {
		dst->e_squids = (int *) xmalloc(n * sizeof(int));
		memcpy(dst->e_squids, src->e_squids, n * sizeof(int));
	}
	if ((n = src->e_nsqgids) != 0) {
		dst->e_sqgids = (int *) xmalloc(n * sizeof(int));
		memcpy(dst->e_sqgids, src->e_sqgids, n * sizeof(int));
	}
}

struct exportent *
mkexportent(char *hname, char *path, char *options)
{
	static struct exportent	ee;

	ee.e_flags = EXPORT_DEFAULT_FLAGS;
	ee.e_maptype = CLE_MAP_IDENT;
	ee.e_anonuid = -2;
	ee.e_anongid = -2;
	ee.e_squids = NULL;
	ee.e_sqgids = NULL;
	ee.e_nsquids = 0;
	ee.e_nsqgids = 0;

	if (strlen(hname) >= sizeof(ee.e_hostname)) {
		xlog(L_WARNING, "client name %s too long", hname);
		return NULL;
	}
	strncpy(ee.e_hostname, hname, sizeof (ee.e_hostname) - 1);
	ee.e_hostname[sizeof (ee.e_hostname) - 1] = '\0';
	if (strlen(path) >= sizeof(ee.e_path)) {
		xlog(L_WARNING, "path name %s too long", path);
		return NULL;
	}
	strncpy(ee.e_path, path, sizeof (ee.e_path));
	ee.e_path[sizeof (ee.e_path) - 1] = '\0';
	strncpy (ee.m_path, ee.e_path, sizeof (ee.m_path) - 1);
	ee.m_path [sizeof (ee.m_path) - 1] = '\0';
	if (options && parseopts(options, &ee) < 0)
		return NULL;
	return &ee;
}

int
updateexportent(struct exportent *eep, char *options)
{
	if (options && parseopts(options, eep) < 0)
		return 0;
	return 1;
}

/*
 * Parse option string pointed to by s and set mount options accordingly.
 */
static int
parseopts(char *cp, struct exportent *ep)
{
	char 	*opt;

	squids = ep->e_squids; nsquids = ep->e_nsquids;
	sqgids = ep->e_sqgids; nsqgids = ep->e_nsqgids;

	while (isblank(*cp))
		cp++;
	while (*cp) {
		opt = cp;
		while (*cp && *cp != ',')
			cp++;
		if (*cp)
			*cp++ = '\0';

		/* process keyword */
		if (strcmp(opt, "ro") == 0)
			ep->e_flags |= NFSEXP_READONLY;
		else if (strcmp(opt, "rw") == 0)
			ep->e_flags &= ~NFSEXP_READONLY;
		else if (!strcmp(opt, "secure"))
			ep->e_flags &= ~NFSEXP_INSECURE_PORT;
		else if (!strcmp(opt, "insecure"))
			ep->e_flags |= NFSEXP_INSECURE_PORT;
		else if (!strcmp(opt, "sync"))
			ep->e_flags &= ~NFSEXP_ASYNC;
		else if (!strcmp(opt, "async"))
			ep->e_flags |= NFSEXP_ASYNC;
		else if (!strcmp(opt, "wdelay"))
			ep->e_flags |= NFSEXP_GATHERED_WRITES;
		else if (!strcmp(opt, "no_wdelay"))
			ep->e_flags &= ~NFSEXP_GATHERED_WRITES;
		else if (strcmp(opt, "root_squash") == 0)
			ep->e_flags |= NFSEXP_ROOTSQUASH;
		else if (!strcmp(opt, "no_root_squash"))
			ep->e_flags &= ~NFSEXP_ROOTSQUASH;
		else if (strcmp(opt, "all_squash") == 0)
			ep->e_flags |= NFSEXP_ALLSQUASH;
		else if (strcmp(opt, "no_all_squash") == 0)
			ep->e_flags &= ~NFSEXP_ALLSQUASH;
		else if (strncmp(opt, "mapping=", 8) == 0)
			ep->e_maptype = parsemaptype(opt+8);
		else if (strcmp(opt, "map_identity") == 0)	/* old style */
			ep->e_maptype = CLE_MAP_IDENT;
		else if (strcmp(opt, "map_daemon") == 0)	/* old style */
			ep->e_maptype = CLE_MAP_UGIDD;
		else if (strncmp(opt, "anonuid=", 8) == 0)
			ep->e_anonuid = atoi(opt+8);
		else if (strncmp(opt, "anongid=", 8) == 0)
			ep->e_anongid = atoi(opt+8);
		else if (strncmp(opt, "squash_uids=", 12) == 0) {
			if (parsesquash(opt+12, &squids, &nsquids, &cp) < 0)
				return -1;
		} else if (strncmp(opt, "squash_gids=", 12) == 0) {
			if (parsesquash(opt+12, &sqgids, &nsqgids, &cp) < 0)
				return -1;
		} else {
			xlog(L_ERROR,
				"Unknown keyword \"%s\" in export file\n",
				opt);
			ep->e_flags |= NFSEXP_ALLSQUASH | NFSEXP_READONLY;
			return -1;
		}
		while (isblank(*cp))
			cp++;
	}

	ep->e_squids = squids;
	ep->e_sqgids = sqgids;
	ep->e_nsquids = nsquids;
	ep->e_nsqgids = nsqgids;

	return 1;
}

static int
parsesquash(char *list, int **idp, int *lenp, char **ep)
{
	char	*cp = list;
	int	id0, id1;
	int	len = *lenp;
	int	*id = *idp;

	if (**ep)
	    *--(*ep) = ',';

	do {
		id0 = parsenum(&cp);
		if (*cp == '-') {
			cp++;
			id1 = parsenum(&cp);
		} else {
			id1 = id0;
		}
		if (id0 == -1 || id1 == -1) {
			syntaxerr("uid/gid -1 not permitted");
			return -1;
		}
		if ((len % 8) == 0)
			id = (int *) xrealloc(id, (len + 8) * sizeof(*id));
		id[len++] = id0;
		id[len++] = id1;
		if (!*cp || *cp == ')' || (*cp == ',' && !isdigit(cp[1])))
			break;
		if (*cp != ',') {
			syntaxerr("bad uid/gid list");
			return -1;
		}
		cp++;
	} while(1);

	if (*cp == ',') *ep = cp+1;
	
	*lenp = len;
	*idp = id;
	return 1;
}

static void
freesquash(void)
{
	if (squids) {
		xfree (squids);
		squids = NULL;
		nsquids = 0;
	}
	if (sqgids) {
		xfree (sqgids);
		sqgids = NULL;
		nsqgids = 0;
	}
}

static int
parsenum(char **cpp)
{
	char	*cp = *cpp, c;
	int	num = 0;

	if (**cpp == '-')
		(*cpp)++;
	while (isdigit(**cpp))
		(*cpp)++;
	c = **cpp; **cpp = '\0'; num = atoi(cp); **cpp = c;
	return num;
}

static int
parsemaptype(char *type)
{
	if (!strcmp(type, "identity"))
		return CLE_MAP_IDENT;
	if (!strcmp(type, "ugidd"))
		return CLE_MAP_UGIDD;
	if (!strcmp(type, "file"))
		return CLE_MAP_FILE;
	syntaxerr("invalid map type");
	return CLE_MAP_IDENT;	/* default */
}

static int
getpath(char *path, int len)
{
	xskip(efp, " \t\n");
	return xgettok(efp, 0, path, len);
}

static int
getexport(char *exp, int len)
{
	int	ok;

	xskip(efp, " \t");
	if ((ok = xgettok(efp, 0, exp, len)) < 0)
		xlog(L_ERROR, "error parsing export entry");
	return ok;
}

static void
syntaxerr(char *msg)
{
	xlog(L_ERROR, "syntax error in exports file (line %d): %s",
				efp->x_line, msg);
}