nfs-utils-1.2.2/utils/mountd/cache.c - nest-learning-thermostat/5.0.1/nfs-utils - Git at Google


 /*
  * Handle communication with knfsd internal cache
  *
  * We open /proc/net/rpc/{auth.unix.ip,nfsd.export,nfsd.fh}/channel
  * and listen for requests (using my_svc_run)
  *
  */

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

 #include <sys/types.h>
 #include <sys/select.h>
 #include <sys/stat.h>
 #include <sys/vfs.h>
 #include <time.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <errno.h>
 #include <ctype.h>
 #include <pwd.h>
 #include <grp.h>
 #include <mntent.h>
 #include "misc.h"
 #include "nfslib.h"
 #include "exportfs.h"
 #include "mountd.h"
 #include "xmalloc.h"
 #include "fsloc.h"
 #include "pseudoflavors.h"

 #ifdef USE_BLKID
 #include "blkid/blkid.h"
 #endif


 enum nfsd_fsid {
 	FSID_DEV = 0,
 	FSID_NUM,
 	FSID_MAJOR_MINOR,
 	FSID_ENCODE_DEV,
 	FSID_UUID4_INUM,
 	FSID_UUID8,
 	FSID_UUID16,
 	FSID_UUID16_INUM,
 };

 /*
  * Support routines for text-based upcalls.
  * Fields are separated by spaces.
  * Fields are either mangled to quote space tab newline slosh with slosh
  * or a hexified with a leading \x
  * Record is terminated with newline.
  *
  */
 int cache_export_ent(char *domain, struct exportent *exp, char *p);


 char *lbuf  = NULL;
 int lbuflen = 0;
 extern int use_ipaddr;

 void auth_unix_ip(FILE *f)
 {
 	/* requests are
 	 *  class IP-ADDR
 	 * Ignore if class != "nfsd"
 	 * Otherwise find domainname and write back:
 	 *
 	 *  "nfsd" IP-ADDR expiry domainname
 	 */
 	char *cp;
 	char class[20];
 	char ipaddr[20];
 	char *client = NULL;
 	struct in_addr addr;
 	struct hostent *he = NULL;
 	if (readline(fileno(f), &lbuf, &lbuflen) != 1)
 		return;

 	xlog(D_CALL, "auth_unix_ip: inbuf '%s'", lbuf);

 	cp = lbuf;

 	if (qword_get(&cp, class, 20) <= 0 ||
 	    strcmp(class, "nfsd") != 0)
 		return;

 	if (qword_get(&cp, ipaddr, 20) <= 0)
 		return;

 	if (inet_aton(ipaddr, &addr)==0)
 		return;

 	auth_reload();

 	/* addr is a valid, interesting address, find the domain name... */
 	if (!use_ipaddr) {
 		he = client_resolve(addr);
 		client = client_compose(he);
 	}

 	qword_print(f, "nfsd");
 	qword_print(f, ipaddr);
 	qword_printint(f, time(0)+30*60);
 	if (use_ipaddr)
 		qword_print(f, ipaddr);
 	else if (client)
 		qword_print(f, *client?client:"DEFAULT");
 	qword_eol(f);
 	xlog(D_CALL, "auth_unix_ip: client %p '%s'", client, client?client: "DEFAULT");

 	if (client) free(client);
 	free(he);
 }

 void auth_unix_gid(FILE *f)
 {
 	/* Request are
 	 *  uid
 	 * reply is
 	 *  uid expiry count list of group ids
 	 */
 	int uid;
 	struct passwd *pw;
 	gid_t glist[100], *groups = glist;
 	int ngroups = 100;
 	int rv, i;
 	char *cp;

 	if (readline(fileno(f), &lbuf, &lbuflen) != 1)
 		return;

 	cp = lbuf;
 	if (qword_get_int(&cp, &uid) != 0)
 		return;

 	pw = getpwuid(uid);
 	if (!pw)
 		rv = -1;
 	else {
 		rv = getgrouplist(pw->pw_name, pw->pw_gid, groups, &ngroups);
 		if (rv == -1 && ngroups >= 100) {
 			groups = malloc(sizeof(gid_t)*ngroups);
 			if (!groups)
 				rv = -1;
 			else
 				rv = getgrouplist(pw->pw_name, pw->pw_gid,
 						  groups, &ngroups);
 		}
 	}
 	qword_printint(f, uid);
 	qword_printint(f, time(0)+30*60);
 	if (rv >= 0) {
 		qword_printint(f, ngroups);
 		for (i=0; i<ngroups; i++)
 			qword_printint(f, groups[i]);
 	} else
 		qword_printint(f, 0);
 	qword_eol(f);

 	if (groups != glist)
 		free(groups);
 }

 #if USE_BLKID
 static const char *get_uuid_blkdev(char *path)
 {
 	static blkid_cache cache = NULL;
 	struct stat stb;
 	char *devname;
 	blkid_tag_iterate iter;
 	blkid_dev dev;
 	const char *type;
 	const char *val = NULL;

 	if (cache == NULL)
 		blkid_get_cache(&cache, NULL);

 	if (stat(path, &stb) != 0)
 		return NULL;
 	devname = blkid_devno_to_devname(stb.st_dev);
 	if (!devname)
 		return NULL;
 	dev = blkid_get_dev(cache, devname, BLKID_DEV_NORMAL);
 	free(devname);
 	if (!dev)
 		return NULL;
 	iter = blkid_tag_iterate_begin(dev);
 	if (!iter)
 		return NULL;
 	while (blkid_tag_next(iter, &type, &val) == 0)
 		if (strcmp(type, "UUID") == 0)
 			break;
 	blkid_tag_iterate_end(iter);
 	return val;
 }
 #else
 #define get_uuid_blkdev(path) (NULL)
 #endif

 int get_uuid(char *path, char *uuid, int uuidlen, char *u)
 {
 	/* extract hex digits from uuidstr and compose a uuid
 	 * of the given length (max 16), xoring bytes to make
 	 * a smaller uuid.  Then compare with uuid
 	 */
 	int i = 0;
 	const char *val = NULL;
 	char fsid_val[17];

 	if (path) {
 		val = get_uuid_blkdev(path);
 		if (!val) {
 			struct statfs64 st;

 			if (statfs64(path, &st))
 				return 0;
 			if (!st.f_fsid.__val[0] && !st.f_fsid.__val[1])
 				return 0;
 			snprintf(fsid_val, 17, "%08x%08x",
 				 st.f_fsid.__val[0], st.f_fsid.__val[1]);
 			val = fsid_val;
 		}
 	} else {
 		val = uuid;
 	}

 	memset(u, 0, uuidlen);
 	for ( ; *val ; val++) {
 		char c = *val;
 		if (!isxdigit(c))
 			continue;
 		if (isalpha(c)) {
 			if (isupper(c))
 				c = c - 'A' + 10;
 			else
 				c = c - 'a' + 10;
 		} else
 			c = c - '0' + 0;
 		if ((i&1) == 0)
 			c <<= 4;
 		u[i/2] ^= c;
 		i++;
 		if (i == uuidlen*2)
 			i = 0;
 	}
 	return 1;
 }

 /* Iterate through /etc/mtab, finding mountpoints
  * at or below a given path
  */
 static char *next_mnt(void **v, char *p)
 {
 	FILE *f;
 	struct mntent *me;
 	int l = strlen(p);
 	if (*v == NULL) {
 		f = setmntent("/etc/mtab", "r");
 		*v = f;
 	} else
 		f = *v;
 	while ((me = getmntent(f)) != NULL &&
 	       (strncmp(me->mnt_dir, p, l) != 0 ||
 		me->mnt_dir[l] != '/'))
 		;
 	if (me == NULL) {
 		endmntent(f);
 		*v = NULL;
 		return NULL;
 	}
 	return me->mnt_dir;
 }

 void nfsd_fh(FILE *f)
 {
 	/* request are:
 	 *  domain fsidtype fsid
 	 * interpret fsid, find export point and options, and write:
 	 *  domain fsidtype fsid expiry path
 	 */
 	char *cp;
 	char *dom;
 	int fsidtype;
 	int fsidlen;
 	unsigned int dev, major=0, minor=0;
 	unsigned int inode=0;
 	unsigned long long inode64;
 	unsigned int fsidnum=0;
 	char fsid[32];
 	struct exportent *found = NULL;
 	struct hostent *he = NULL;
 	struct in_addr addr;
 	char *found_path = NULL;
 	nfs_export *exp;
 	int i;
 	int dev_missing = 0;
 	int uuidlen = 0;
 	char *fhuuid = NULL;

 	if (readline(fileno(f), &lbuf, &lbuflen) != 1)
 		return;

 	xlog(D_CALL, "nfsd_fh: inbuf '%s'", lbuf);

 	cp = lbuf;

 	dom = malloc(strlen(cp));
 	if (dom == NULL)
 		return;
 	if (qword_get(&cp, dom, strlen(cp)) <= 0)
 		goto out;
 	if (qword_get_int(&cp, &fsidtype) != 0)
 		goto out;
 	if (fsidtype < 0 || fsidtype > 7)
 		goto out; /* unknown type */
 	if ((fsidlen = qword_get(&cp, fsid, 32)) <= 0)
 		goto out;
 	switch(fsidtype) {
 	case FSID_DEV: /* 4 bytes: 2 major, 2 minor, 4 inode */
 		if (fsidlen != 8)
 			goto out;
 		memcpy(&dev, fsid, 4);
 		memcpy(&inode, fsid+4, 4);
 		major = ntohl(dev)>>16;
 		minor = ntohl(dev) & 0xFFFF;
 		break;

 	case FSID_NUM: /* 4 bytes - fsid */
 		if (fsidlen != 4)
 			goto out;
 		memcpy(&fsidnum, fsid, 4);
 		break;

 	case FSID_MAJOR_MINOR: /* 12 bytes: 4 major, 4 minor, 4 inode
 		 * This format is never actually used but was
 		 * an historical accident
 		 */
 		if (fsidlen != 12)
 			goto out;
 		memcpy(&dev, fsid, 4); major = ntohl(dev);
 		memcpy(&dev, fsid+4, 4); minor = ntohl(dev);
 		memcpy(&inode, fsid+8, 4);
 		break;

 	case FSID_ENCODE_DEV: /* 8 bytes: 4 byte packed device number, 4 inode */
 		/* This is *host* endian, not net-byte-order, because
 		 * no-one outside this host has any business interpreting it
 		 */
 		if (fsidlen != 8)
 			goto out;
 		memcpy(&dev, fsid, 4);
 		memcpy(&inode, fsid+4, 4);
 		major = (dev & 0xfff00) >> 8;
 		minor = (dev & 0xff) | ((dev >> 12) & 0xfff00);
 		break;

 	case FSID_UUID4_INUM: /* 4 byte inode number and 4 byte uuid */
 		if (fsidlen != 8)
 			goto out;
 		memcpy(&inode, fsid, 4);
 		uuidlen = 4;
 		fhuuid = fsid+4;
 		break;
 	case FSID_UUID8: /* 8 byte uuid */
 		if (fsidlen != 8)
 			goto out;
 		uuidlen = 8;
 		fhuuid = fsid;
 		break;
 	case FSID_UUID16: /* 16 byte uuid */
 		if (fsidlen != 16)
 			goto out;
 		uuidlen = 16;
 		fhuuid = fsid;
 		break;
 	case FSID_UUID16_INUM: /* 8 byte inode number and 16 byte uuid */
 		if (fsidlen != 24)
 			goto out;
 		memcpy(&inode64, fsid, 8);
 		inode = inode64;
 		uuidlen = 16;
 		fhuuid = fsid+8;
 		break;
 	}

 	auth_reload();

 	/* Now determine export point for this fsid/domain */
 	for (i=0 ; i < MCL_MAXTYPES; i++) {
 		nfs_export *next_exp;
 		for (exp = exportlist[i].p_head; exp; exp = next_exp) {
 			struct stat stb;
 			char u[16];
 			char *path;

 			if (exp->m_export.e_flags & NFSEXP_CROSSMOUNT) {
 				static nfs_export *prev = NULL;
 				static void *mnt = NULL;

 				if (prev == exp) {
 					/* try a submount */
 					path = next_mnt(&mnt, exp->m_export.e_path);
 					if (!path) {
 						next_exp = exp->m_next;
 						prev = NULL;
 						continue;
 					}
 					next_exp = exp;
 				} else {
 					prev = exp;
 					mnt = NULL;
 					path = exp->m_export.e_path;
 					next_exp = exp;
 				}
 			} else {
 				path = exp->m_export.e_path;
 				next_exp = exp->m_next;
 			}

 			if (!use_ipaddr && !client_member(dom, exp->m_client->m_hostname))
 				continue;
 			if (exp->m_export.e_mountpoint &&
 			    !is_mountpoint(exp->m_export.e_mountpoint[0]?
 					   exp->m_export.e_mountpoint:
 					   exp->m_export.e_path))
 				dev_missing ++;
 			if (stat(path, &stb) != 0)
 				continue;
 			if (!S_ISDIR(stb.st_mode) && !S_ISREG(stb.st_mode)) {
 				continue;
 			}
 			switch(fsidtype){
 			case FSID_DEV:
 			case FSID_MAJOR_MINOR:
 			case FSID_ENCODE_DEV:
 				if (stb.st_ino != inode)
 					continue;
 				if (major != major(stb.st_dev) ||
 				    minor != minor(stb.st_dev))
 					continue;
 				break;
 			case FSID_NUM:
 				if (((exp->m_export.e_flags & NFSEXP_FSID) == 0 ||
 				     exp->m_export.e_fsid != fsidnum))
 					continue;
 				break;
 			case FSID_UUID4_INUM:
 			case FSID_UUID16_INUM:
 				if (stb.st_ino != inode)
 					continue;
 				goto check_uuid;
 			case FSID_UUID8:
 			case FSID_UUID16:
 				if (!is_mountpoint(path))
 					continue;
 			check_uuid:
 				if (exp->m_export.e_uuid)
 					get_uuid(NULL, exp->m_export.e_uuid,
 						 uuidlen, u);
 				else if (get_uuid(path, NULL, uuidlen, u) == 0)
 					continue;

 				if (memcmp(u, fhuuid, uuidlen) != 0)
 					continue;
 				break;
 			}
 			if (use_ipaddr) {
 				if (he == NULL) {
 					if (!inet_aton(dom, &addr))
 						goto out;
 					he = client_resolve(addr);
 				}
 				if (!client_check(exp->m_client, he))
 					continue;
 			}
 			/* It's a match !! */
 			if (!found) {
 				found = &exp->m_export;
 				found_path = strdup(path);
 				if (found_path == NULL)
 					goto out;
 			} else if (strcmp(found->e_path, exp->m_export.e_path)!= 0)
 			{
 				xlog(L_WARNING, "%s and %s have same filehandle for %s, using first",
 				     found_path, path, dom);
 			}
 		}
 	}
 	if (found &&
 	    found->e_mountpoint &&
 	    !is_mountpoint(found->e_mountpoint[0]?
 			   found->e_mountpoint:
 			   found->e_path)) {
 		/* Cannot export this yet
 		 * should log a warning, but need to rate limit
 		   xlog(L_WARNING, "%s not exported as %d not a mountpoint",
 		   found->e_path, found->e_mountpoint);
 		 */
 		/* FIXME we need to make sure we re-visit this later */
 		goto out;
 	}
 	if (!found && dev_missing) {
 		/* The missing dev could be what we want, so just be
 		 * quite rather than returning stale yet
 		 */
 		goto out;
 	}

 	if (found)
 		if (cache_export_ent(dom, found, found_path) < 0)
 			found = 0;

 	qword_print(f, dom);
 	qword_printint(f, fsidtype);
 	qword_printhex(f, fsid, fsidlen);
 	/* The fsid -> path lookup can be quite expensive as it
 	 * potentially stats and reads lots of devices, and some of those
 	 * might have spun-down.  The Answer is not likely to
 	 * change underneath us, and an 'exportfs -f' can always
 	 * remove this from the kernel, so use a really log
 	 * timeout.  Maybe this should be configurable on the command
 	 * line.
 	 */
 	qword_printint(f, 0x7fffffff);
 	if (found)
 		qword_print(f, found_path);
 	qword_eol(f);
  out:
 	if (found_path)
 		free(found_path);
 	if (he)
 		free(he);
 	free(dom);
 	xlog(D_CALL, "nfsd_fh: found %p path %s", found, found ? found->e_path : NULL);
 	return;
 }

 static void write_fsloc(FILE *f, struct exportent *ep, char *path)
 {
 	struct servers *servers;

 	if (ep->e_fslocmethod == FSLOC_NONE)
 		return;

 	servers = replicas_lookup(ep->e_fslocmethod, ep->e_fslocdata, path);
 	if (!servers)
 		return;
 	qword_print(f, "fsloc");
 	qword_printint(f, servers->h_num);
 	if (servers->h_num >= 0) {
 		int i;
 		for (i=0; i<servers->h_num; i++) {
 			qword_print(f, servers->h_mp[i]->h_host);
 			qword_print(f, servers->h_mp[i]->h_path);
 		}
 	}
 	qword_printint(f, servers->h_referral);
 	release_replicas(servers);
 }

 static void write_secinfo(FILE *f, struct exportent *ep, int flag_mask)
 {
 	struct sec_entry *p;

 	for (p = ep->e_secinfo; p->flav; p++)
 		; /* Do nothing */
 	if (p == ep->e_secinfo) {
 		/* There was no sec= option */
 		return;
 	}
 	qword_print(f, "secinfo");
 	qword_printint(f, p - ep->e_secinfo);
 	for (p = ep->e_secinfo; p->flav; p++) {
 		qword_printint(f, p->flav->fnum);
 		qword_printint(f, p->flags & flag_mask);
 	}

 }

 static int dump_to_cache(FILE *f, char *domain, char *path, struct exportent *exp)
 {
 	qword_print(f, domain);
 	qword_print(f, path);
 	qword_printint(f, time(0)+30*60);
 	if (exp) {
 		int different_fs = strcmp(path, exp->e_path) != 0;
 		int flag_mask = different_fs ? ~NFSEXP_FSID : ~0;

 		qword_printint(f, exp->e_flags & flag_mask);
 		qword_printint(f, exp->e_anonuid);
 		qword_printint(f, exp->e_anongid);
 		qword_printint(f, exp->e_fsid);
 		write_fsloc(f, exp, path);
 		write_secinfo(f, exp, flag_mask);
  		if (exp->e_uuid == NULL || different_fs) {
  			char u[16];
  			if (get_uuid(path, NULL, 16, u)) {
  				qword_print(f, "uuid");
  				qword_printhex(f, u, 16);
  			}
  		} else {
  			char u[16];
  			get_uuid(NULL, exp->e_uuid, 16, u);
  			qword_print(f, "uuid");
  			qword_printhex(f, u, 16);
  		}
 	}
 	return qword_eol(f);
 }

 static int is_subdirectory(char *subpath, char *path)
 {
 	int l = strlen(path);

 	return strcmp(subpath, path) == 0
 		|| (strncmp(subpath, path, l) == 0 && path[l] == '/');
 }

 static int path_matches(nfs_export *exp, char *path)
 {
 	if (exp->m_export.e_flags & NFSEXP_CROSSMOUNT)
 		return is_subdirectory(path, exp->m_export.e_path);
 	return strcmp(path, exp->m_export.e_path) == 0;
 }

 static int client_matches(nfs_export *exp, char *dom, struct hostent *he)
 {
 	if (use_ipaddr)
 		return client_check(exp->m_client, he);
 	return client_member(dom, exp->m_client->m_hostname);
 }

 static int export_matches(nfs_export *exp, char *dom, char *path, struct hostent *he)
 {
 	return path_matches(exp, path) && client_matches(exp, dom, he);
 }

 static nfs_export *lookup_export(char *dom, char *path, struct hostent *he)
 {
 	nfs_export *exp;
 	nfs_export *found = NULL;
 	int found_type = 0;
 	int i;

 	for (i=0 ; i < MCL_MAXTYPES; i++) {
 		for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {
 			if (!export_matches(exp, dom, path, he))
 				continue;
 			if (!found) {
 				found = exp;
 				found_type = i;
 				continue;
 			}

 			/* Always prefer non-V4ROOT mounts */
 			if (found->m_export.e_flags & NFSEXP_V4ROOT)
 				continue;

 			/* If one is a CROSSMOUNT, then prefer the longest path */
 			if (((found->m_export.e_flags & NFSEXP_CROSSMOUNT) ||
 			     (exp->m_export.e_flags & NFSEXP_CROSSMOUNT)) &&
 			    strlen(found->m_export.e_path) !=
 			    strlen(exp->m_export.e_path)) {

 				if (strlen(exp->m_export.e_path) >
 				    strlen(found->m_export.e_path)) {
 					found = exp;
 					found_type = i;
 				}
 				continue;

 			} else if (found_type == i && found->m_warned == 0) {
 				xlog(L_WARNING, "%s exported to both %s and %s, "
 				     "arbitrarily choosing options from first",
 				     path, found->m_client->m_hostname, exp->m_client->m_hostname,
 				     dom);
 				found->m_warned = 1;
 			}
 		}
 	}
 	return found;
 }

 void nfsd_export(FILE *f)
 {
 	/* requests are:
 	 *  domain path
 	 * determine export options and return:
 	 *  domain path expiry flags anonuid anongid fsid
 	 */

 	char *cp;
 	char *dom, *path;
 	nfs_export *found = NULL;
 	struct in_addr addr;
 	struct hostent *he = NULL;


 	if (readline(fileno(f), &lbuf, &lbuflen) != 1)
 		return;

 	xlog(D_CALL, "nfsd_export: inbuf '%s'", lbuf);

 	cp = lbuf;
 	dom = malloc(strlen(cp));
 	path = malloc(strlen(cp));

 	if (!dom || !path)
 		goto out;

 	if (qword_get(&cp, dom, strlen(lbuf)) <= 0)
 		goto out;
 	if (qword_get(&cp, path, strlen(lbuf)) <= 0)
 		goto out;

 	auth_reload();

 	if (use_ipaddr) {
 		if (!inet_aton(dom, &addr))
 			goto out;
 		he = client_resolve(addr);
 	}

 	found = lookup_export(dom, path, he);

 	if (found) {
 		if (dump_to_cache(f, dom, path, &found->m_export) < 0) {
 			xlog(L_WARNING,
 			     "Cannot export %s, possibly unsupported filesystem"
 			     " or fsid= required", path);
 			dump_to_cache(f, dom, path, NULL);
 		}
 	} else {
 		dump_to_cache(f, dom, path, NULL);
 	}
  out:
 	xlog(D_CALL, "nfsd_export: found %p path %s", found, path ? path : NULL);
 	if (dom) free(dom);
 	if (path) free(path);
 	if (he) free(he);
 }


 struct {
 	char *cache_name;
 	void (*cache_handle)(FILE *f);
 	FILE *f;
 } cachelist[] = {
 	{ "auth.unix.ip", auth_unix_ip},
 	{ "auth.unix.gid", auth_unix_gid},
 	{ "nfsd.export", nfsd_export},
 	{ "nfsd.fh", nfsd_fh},
 	{ NULL, NULL }
 };

 extern int manage_gids;
 void cache_open(void)
 {
 	int i;
 	for (i=0; cachelist[i].cache_name; i++ ) {
 		char path[100];
 		if (!manage_gids && cachelist[i].cache_handle == auth_unix_gid)
 			continue;
 		sprintf(path, "/proc/net/rpc/%s/channel", cachelist[i].cache_name);
 		cachelist[i].f = fopen(path, "r+");
 	}
 }

 void cache_set_fds(fd_set *fdset)
 {
 	int i;
 	for (i=0; cachelist[i].cache_name; i++) {
 		if (cachelist[i].f)
 			FD_SET(fileno(cachelist[i].f), fdset);
 	}
 }

 int cache_process_req(fd_set *readfds)
 {
 	int i;
 	int cnt = 0;
 	for (i=0; cachelist[i].cache_name; i++) {
 		if (cachelist[i].f != NULL &&
 		    FD_ISSET(fileno(cachelist[i].f), readfds)) {
 			cnt++;
 			cachelist[i].cache_handle(cachelist[i].f);
 			FD_CLR(fileno(cachelist[i].f), readfds);
 		}
 	}
 	return cnt;
 }


 /*
  * Give IP->domain and domain+path->options to kernel
  * % echo nfsd $IP  $[now+30*60] $domain > /proc/net/rpc/auth.unix.ip/channel
  * % echo $domain $path $[now+30*60] $options $anonuid $anongid $fsid > /proc/net/rpc/nfsd.export/channel
  */

 int cache_export_ent(char *domain, struct exportent *exp, char *path)
 {
 	int err;
 	FILE *f = fopen("/proc/net/rpc/nfsd.export/channel", "w");
 	if (!f)
 		return -1;

 	err = dump_to_cache(f, domain, exp->e_path, exp);
 	if (err) {
 		xlog(L_WARNING,
 		     "Cannot export %s, possibly unsupported filesystem or"
 		     " fsid= required", exp->e_path);
 	}

 	while (err == 0 && (exp->e_flags & NFSEXP_CROSSMOUNT) && path) {
 		/* really an 'if', but we can break out of
 		 * a 'while' more easily */
 		/* Look along 'path' for other filesystems
 		 * and export them with the same options
 		 */
 		struct stat stb;
 		int l = strlen(exp->e_path);
 		int dev;

 		if (strlen(path) <= l || path[l] != '/' ||
 		    strncmp(exp->e_path, path, l) != 0)
 			break;
 		if (stat(exp->e_path, &stb) != 0)
 			break;
 		dev = stb.st_dev;
 		while(path[l] == '/') {
 			char c;
 			/* errors for submount should fail whole filesystem */
 			int err2;

 			l++;
 			while (path[l] != '/' && path[l])
 				l++;
 			c = path[l];
 			path[l] = 0;
 			err2 = lstat(path, &stb);
 			path[l] = c;
 			if (err2 < 0)
 				break;
 			if (stb.st_dev == dev)
 				continue;
 			dev = stb.st_dev;
 			path[l] = 0;
 			dump_to_cache(f, domain, path, exp);
 			path[l] = c;
 		}
 		break;
 	}

 	fclose(f);
 	return err;
 }

 int cache_export(nfs_export *exp, char *path)
 {
 	int err;
 	FILE *f;

 	f = fopen("/proc/net/rpc/auth.unix.ip/channel", "w");
 	if (!f)
 		return -1;

 	qword_print(f, "nfsd");
 	qword_print(f, inet_ntoa(exp->m_client->m_addrlist[0]));
 	qword_printint(f, time(0)+30*60);
 	qword_print(f, exp->m_client->m_hostname);
 	err = qword_eol(f);

 	fclose(f);

 	err = cache_export_ent(exp->m_client->m_hostname, &exp->m_export, path)
 		|| err;
 	return err;
 }

 /* Get a filehandle.
  * {
  *   echo $domain $path $length
  *   read filehandle <&0
  * } <> /proc/fs/nfsd/filehandle
  */
 struct nfs_fh_len *
 cache_get_filehandle(nfs_export *exp, int len, char *p)
 {
 	FILE *f = fopen("/proc/fs/nfsd/filehandle", "r+");
 	char buf[200];
 	char *bp = buf;
 	int failed;
 	static struct nfs_fh_len fh;

 	if (!f)
 		f = fopen("/proc/fs/nfs/filehandle", "r+");
 	if (!f)
 		return NULL;

 	qword_print(f, exp->m_client->m_hostname);
 	qword_print(f, p);
 	qword_printint(f, len);
 	failed = qword_eol(f);

 	if (!failed)
 		failed = (fgets(buf, sizeof(buf), f) == NULL);
 	fclose(f);
 	if (failed)
 		return NULL;
 	memset(fh.fh_handle, 0, sizeof(fh.fh_handle));
 	fh.fh_size = qword_get(&bp, (char *)fh.fh_handle, NFS3_FHSIZE);
 	return &fh;
 }

	/*
	* Handle communication with knfsd internal cache
	*
	* We open /proc/net/rpc/{auth.unix.ip,nfsd.export,nfsd.fh}/channel
	* and listen for requests (using my_svc_run)
	*
	*/

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

	#include <sys/types.h>
	#include <sys/select.h>
	#include <sys/stat.h>
	#include <sys/vfs.h>
	#include <time.h>
	#include <netinet/in.h>
	#include <arpa/inet.h>
	#include <unistd.h>
	#include <fcntl.h>
	#include <errno.h>
	#include <ctype.h>
	#include <pwd.h>
	#include <grp.h>
	#include <mntent.h>
	#include "misc.h"
	#include "nfslib.h"
	#include "exportfs.h"
	#include "mountd.h"
	#include "xmalloc.h"
	#include "fsloc.h"
	#include "pseudoflavors.h"

	#ifdef USE_BLKID
	#include "blkid/blkid.h"
	#endif


	enum nfsd_fsid {
	FSID_DEV = 0,
	FSID_NUM,
	FSID_MAJOR_MINOR,
	FSID_ENCODE_DEV,
	FSID_UUID4_INUM,
	FSID_UUID8,
	FSID_UUID16,
	FSID_UUID16_INUM,
	};

	/*
	* Support routines for text-based upcalls.
	* Fields are separated by spaces.
	* Fields are either mangled to quote space tab newline slosh with slosh
	* or a hexified with a leading \x
	* Record is terminated with newline.
	*
	*/
	int cache_export_ent(char domain, struct exportent exp, char *p);


	char *lbuf = NULL;
	int lbuflen = 0;
	extern int use_ipaddr;

	void auth_unix_ip(FILE *f)
	{
	/* requests are
	* class IP-ADDR
	* Ignore if class != "nfsd"
	* Otherwise find domainname and write back:
	*
	* "nfsd" IP-ADDR expiry domainname
	*/
	char *cp;
	char class[20];
	char ipaddr[20];
	char *client = NULL;
	struct in_addr addr;
	struct hostent *he = NULL;
	if (readline(fileno(f), &lbuf, &lbuflen) != 1)
	return;

	xlog(D_CALL, "auth_unix_ip: inbuf '%s'", lbuf);

	cp = lbuf;

	if (qword_get(&cp, class, 20) <= 0 \|\|
	strcmp(class, "nfsd") != 0)
	return;

	if (qword_get(&cp, ipaddr, 20) <= 0)
	return;

	if (inet_aton(ipaddr, &addr)==0)
	return;

	auth_reload();

	/* addr is a valid, interesting address, find the domain name... */
	if (!use_ipaddr) {
	he = client_resolve(addr);
	client = client_compose(he);
	}

	qword_print(f, "nfsd");
	qword_print(f, ipaddr);
	qword_printint(f, time(0)+30*60);
	if (use_ipaddr)
	qword_print(f, ipaddr);
	else if (client)
	qword_print(f, *client?client:"DEFAULT");
	qword_eol(f);
	xlog(D_CALL, "auth_unix_ip: client %p '%s'", client, client?client: "DEFAULT");

	if (client) free(client);
	free(he);
	}

	void auth_unix_gid(FILE *f)
	{
	/* Request are
	* uid
	* reply is
	* uid expiry count list of group ids
	*/
	int uid;
	struct passwd *pw;
	gid_t glist[100], *groups = glist;
	int ngroups = 100;
	int rv, i;
	char *cp;

	if (readline(fileno(f), &lbuf, &lbuflen) != 1)
	return;

	cp = lbuf;
	if (qword_get_int(&cp, &uid) != 0)
	return;

	pw = getpwuid(uid);
	if (!pw)
	rv = -1;
	else {
	rv = getgrouplist(pw->pw_name, pw->pw_gid, groups, &ngroups);
	if (rv == -1 && ngroups >= 100) {
	groups = malloc(sizeof(gid_t)*ngroups);
	if (!groups)
	rv = -1;
	else
	rv = getgrouplist(pw->pw_name, pw->pw_gid,
	groups, &ngroups);
	}
	}
	qword_printint(f, uid);
	qword_printint(f, time(0)+30*60);
	if (rv >= 0) {
	qword_printint(f, ngroups);
	for (i=0; i<ngroups; i++)
	qword_printint(f, groups[i]);
	} else
	qword_printint(f, 0);
	qword_eol(f);

	if (groups != glist)
	free(groups);
	}

	#if USE_BLKID
	static const char get_uuid_blkdev(char path)
	{
	static blkid_cache cache = NULL;
	struct stat stb;
	char *devname;
	blkid_tag_iterate iter;
	blkid_dev dev;
	const char *type;
	const char *val = NULL;

	if (cache == NULL)
	blkid_get_cache(&cache, NULL);

	if (stat(path, &stb) != 0)
	return NULL;
	devname = blkid_devno_to_devname(stb.st_dev);
	if (!devname)
	return NULL;
	dev = blkid_get_dev(cache, devname, BLKID_DEV_NORMAL);
	free(devname);
	if (!dev)
	return NULL;
	iter = blkid_tag_iterate_begin(dev);
	if (!iter)
	return NULL;
	while (blkid_tag_next(iter, &type, &val) == 0)
	if (strcmp(type, "UUID") == 0)
	break;
	blkid_tag_iterate_end(iter);
	return val;
	}
	#else
	#define get_uuid_blkdev(path) (NULL)
	#endif

	int get_uuid(char path, char uuid, int uuidlen, char *u)
	{
	/* extract hex digits from uuidstr and compose a uuid
	* of the given length (max 16), xoring bytes to make
	* a smaller uuid. Then compare with uuid
	*/
	int i = 0;
	const char *val = NULL;
	char fsid_val[17];

	if (path) {
	val = get_uuid_blkdev(path);
	if (!val) {
	struct statfs64 st;

	if (statfs64(path, &st))
	return 0;
	if (!st.f_fsid.__val[0] && !st.f_fsid.__val[1])
	return 0;
	snprintf(fsid_val, 17, "%08x%08x",
	st.f_fsid.__val[0], st.f_fsid.__val[1]);
	val = fsid_val;
	}
	} else {
	val = uuid;
	}

	memset(u, 0, uuidlen);
	for ( ; *val ; val++) {
	char c = *val;
	if (!isxdigit(c))
	continue;
	if (isalpha(c)) {
	if (isupper(c))
	c = c - 'A' + 10;
	else
	c = c - 'a' + 10;
	} else
	c = c - '0' + 0;
	if ((i&1) == 0)
	c <<= 4;
	u[i/2] ^= c;
	i++;
	if (i == uuidlen*2)
	i = 0;
	}
	return 1;
	}

	/* Iterate through /etc/mtab, finding mountpoints
	* at or below a given path
	*/
	static char next_mnt(void v, char p)
	{
	FILE *f;
	struct mntent *me;
	int l = strlen(p);
	if (*v == NULL) {
	f = setmntent("/etc/mtab", "r");
	*v = f;
	} else
	f = *v;
	while ((me = getmntent(f)) != NULL &&
	(strncmp(me->mnt_dir, p, l) != 0 \|\|
	me->mnt_dir[l] != '/'))
	;
	if (me == NULL) {
	endmntent(f);
	*v = NULL;
	return NULL;
	}
	return me->mnt_dir;
	}

	void nfsd_fh(FILE *f)
	{
	/* request are:
	* domain fsidtype fsid
	* interpret fsid, find export point and options, and write:
	* domain fsidtype fsid expiry path
	*/
	char *cp;
	char *dom;
	int fsidtype;
	int fsidlen;
	unsigned int dev, major=0, minor=0;
	unsigned int inode=0;
	unsigned long long inode64;
	unsigned int fsidnum=0;
	char fsid[32];
	struct exportent *found = NULL;
	struct hostent *he = NULL;
	struct in_addr addr;
	char *found_path = NULL;
	nfs_export *exp;
	int i;
	int dev_missing = 0;
	int uuidlen = 0;
	char *fhuuid = NULL;

	if (readline(fileno(f), &lbuf, &lbuflen) != 1)
	return;

	xlog(D_CALL, "nfsd_fh: inbuf '%s'", lbuf);

	cp = lbuf;

	dom = malloc(strlen(cp));
	if (dom == NULL)
	return;
	if (qword_get(&cp, dom, strlen(cp)) <= 0)
	goto out;
	if (qword_get_int(&cp, &fsidtype) != 0)
	goto out;
	if (fsidtype < 0 \|\| fsidtype > 7)
	goto out; /* unknown type */
	if ((fsidlen = qword_get(&cp, fsid, 32)) <= 0)
	goto out;
	switch(fsidtype) {
	case FSID_DEV: /* 4 bytes: 2 major, 2 minor, 4 inode */
	if (fsidlen != 8)
	goto out;
	memcpy(&dev, fsid, 4);
	memcpy(&inode, fsid+4, 4);
	major = ntohl(dev)>>16;
	minor = ntohl(dev) & 0xFFFF;
	break;

	case FSID_NUM: /* 4 bytes - fsid */
	if (fsidlen != 4)
	goto out;
	memcpy(&fsidnum, fsid, 4);
	break;

	case FSID_MAJOR_MINOR: /* 12 bytes: 4 major, 4 minor, 4 inode
	* This format is never actually used but was
	* an historical accident
	*/
	if (fsidlen != 12)
	goto out;
	memcpy(&dev, fsid, 4); major = ntohl(dev);
	memcpy(&dev, fsid+4, 4); minor = ntohl(dev);
	memcpy(&inode, fsid+8, 4);
	break;

	case FSID_ENCODE_DEV: /* 8 bytes: 4 byte packed device number, 4 inode */
	/* This is host endian, not net-byte-order, because
	* no-one outside this host has any business interpreting it
	*/
	if (fsidlen != 8)
	goto out;
	memcpy(&dev, fsid, 4);
	memcpy(&inode, fsid+4, 4);
	major = (dev & 0xfff00) >> 8;
	minor = (dev & 0xff) \| ((dev >> 12) & 0xfff00);
	break;

	case FSID_UUID4_INUM: /* 4 byte inode number and 4 byte uuid */
	if (fsidlen != 8)
	goto out;
	memcpy(&inode, fsid, 4);
	uuidlen = 4;
	fhuuid = fsid+4;
	break;
	case FSID_UUID8: /* 8 byte uuid */
	if (fsidlen != 8)
	goto out;
	uuidlen = 8;
	fhuuid = fsid;
	break;
	case FSID_UUID16: /* 16 byte uuid */
	if (fsidlen != 16)
	goto out;
	uuidlen = 16;
	fhuuid = fsid;
	break;
	case FSID_UUID16_INUM: /* 8 byte inode number and 16 byte uuid */
	if (fsidlen != 24)
	goto out;
	memcpy(&inode64, fsid, 8);
	inode = inode64;
	uuidlen = 16;
	fhuuid = fsid+8;
	break;
	}

	auth_reload();

	/* Now determine export point for this fsid/domain */
	for (i=0 ; i < MCL_MAXTYPES; i++) {
	nfs_export *next_exp;
	for (exp = exportlist[i].p_head; exp; exp = next_exp) {
	struct stat stb;
	char u[16];
	char *path;

	if (exp->m_export.e_flags & NFSEXP_CROSSMOUNT) {
	static nfs_export *prev = NULL;
	static void *mnt = NULL;

	if (prev == exp) {
	/* try a submount */
	path = next_mnt(&mnt, exp->m_export.e_path);
	if (!path) {
	next_exp = exp->m_next;
	prev = NULL;
	continue;
	}
	next_exp = exp;
	} else {
	prev = exp;
	mnt = NULL;
	path = exp->m_export.e_path;
	next_exp = exp;
	}
	} else {
	path = exp->m_export.e_path;
	next_exp = exp->m_next;
	}

	if (!use_ipaddr && !client_member(dom, exp->m_client->m_hostname))
	continue;
	if (exp->m_export.e_mountpoint &&
	!is_mountpoint(exp->m_export.e_mountpoint[0]?
	exp->m_export.e_mountpoint:
	exp->m_export.e_path))
	dev_missing ++;
	if (stat(path, &stb) != 0)
	continue;
	if (!S_ISDIR(stb.st_mode) && !S_ISREG(stb.st_mode)) {
	continue;
	}
	switch(fsidtype){
	case FSID_DEV:
	case FSID_MAJOR_MINOR:
	case FSID_ENCODE_DEV:
	if (stb.st_ino != inode)
	continue;
	if (major != major(stb.st_dev) \|\|
	minor != minor(stb.st_dev))
	continue;
	break;
	case FSID_NUM:
	if (((exp->m_export.e_flags & NFSEXP_FSID) == 0 \|\|
	exp->m_export.e_fsid != fsidnum))
	continue;
	break;
	case FSID_UUID4_INUM:
	case FSID_UUID16_INUM:
	if (stb.st_ino != inode)
	continue;
	goto check_uuid;
	case FSID_UUID8:
	case FSID_UUID16:
	if (!is_mountpoint(path))
	continue;
	check_uuid:
	if (exp->m_export.e_uuid)
	get_uuid(NULL, exp->m_export.e_uuid,
	uuidlen, u);
	else if (get_uuid(path, NULL, uuidlen, u) == 0)
	continue;

	if (memcmp(u, fhuuid, uuidlen) != 0)
	continue;
	break;
	}
	if (use_ipaddr) {
	if (he == NULL) {
	if (!inet_aton(dom, &addr))
	goto out;
	he = client_resolve(addr);
	}
	if (!client_check(exp->m_client, he))
	continue;
	}
	/* It's a match !! */
	if (!found) {
	found = &exp->m_export;
	found_path = strdup(path);
	if (found_path == NULL)
	goto out;
	} else if (strcmp(found->e_path, exp->m_export.e_path)!= 0)
	{
	xlog(L_WARNING, "%s and %s have same filehandle for %s, using first",
	found_path, path, dom);
	}
	}
	}
	if (found &&
	found->e_mountpoint &&
	!is_mountpoint(found->e_mountpoint[0]?
	found->e_mountpoint:
	found->e_path)) {
	/* Cannot export this yet
	* should log a warning, but need to rate limit
	xlog(L_WARNING, "%s not exported as %d not a mountpoint",
	found->e_path, found->e_mountpoint);
	*/
	/* FIXME we need to make sure we re-visit this later */
	goto out;
	}
	if (!found && dev_missing) {
	/* The missing dev could be what we want, so just be
	* quite rather than returning stale yet
	*/
	goto out;
	}

	if (found)
	if (cache_export_ent(dom, found, found_path) < 0)
	found = 0;

	qword_print(f, dom);
	qword_printint(f, fsidtype);
	qword_printhex(f, fsid, fsidlen);
	/* The fsid -> path lookup can be quite expensive as it
	* potentially stats and reads lots of devices, and some of those
	* might have spun-down. The Answer is not likely to
	* change underneath us, and an 'exportfs -f' can always
	* remove this from the kernel, so use a really log
	* timeout. Maybe this should be configurable on the command
	* line.
	*/
	qword_printint(f, 0x7fffffff);
	if (found)
	qword_print(f, found_path);
	qword_eol(f);
	out:
	if (found_path)
	free(found_path);
	if (he)
	free(he);
	free(dom);
	xlog(D_CALL, "nfsd_fh: found %p path %s", found, found ? found->e_path : NULL);
	return;
	}

	static void write_fsloc(FILE f, struct exportent ep, char *path)
	{
	struct servers *servers;

	if (ep->e_fslocmethod == FSLOC_NONE)
	return;

	servers = replicas_lookup(ep->e_fslocmethod, ep->e_fslocdata, path);
	if (!servers)
	return;
	qword_print(f, "fsloc");
	qword_printint(f, servers->h_num);
	if (servers->h_num >= 0) {
	int i;
	for (i=0; i<servers->h_num; i++) {
	qword_print(f, servers->h_mp[i]->h_host);
	qword_print(f, servers->h_mp[i]->h_path);
	}
	}
	qword_printint(f, servers->h_referral);
	release_replicas(servers);
	}

	static void write_secinfo(FILE f, struct exportent ep, int flag_mask)
	{
	struct sec_entry *p;

	for (p = ep->e_secinfo; p->flav; p++)
	; /* Do nothing */
	if (p == ep->e_secinfo) {
	/* There was no sec= option */
	return;
	}
	qword_print(f, "secinfo");
	qword_printint(f, p - ep->e_secinfo);
	for (p = ep->e_secinfo; p->flav; p++) {
	qword_printint(f, p->flav->fnum);
	qword_printint(f, p->flags & flag_mask);
	}

	}

	static int dump_to_cache(FILE f, char domain, char path, struct exportent exp)
	{
	qword_print(f, domain);
	qword_print(f, path);
	qword_printint(f, time(0)+30*60);
	if (exp) {
	int different_fs = strcmp(path, exp->e_path) != 0;
	int flag_mask = different_fs ? ~NFSEXP_FSID : ~0;

	qword_printint(f, exp->e_flags & flag_mask);
	qword_printint(f, exp->e_anonuid);
	qword_printint(f, exp->e_anongid);
	qword_printint(f, exp->e_fsid);
	write_fsloc(f, exp, path);
	write_secinfo(f, exp, flag_mask);
	if (exp->e_uuid == NULL \|\| different_fs) {
	char u[16];
	if (get_uuid(path, NULL, 16, u)) {
	qword_print(f, "uuid");
	qword_printhex(f, u, 16);
	}
	} else {
	char u[16];
	get_uuid(NULL, exp->e_uuid, 16, u);
	qword_print(f, "uuid");
	qword_printhex(f, u, 16);
	}
	}
	return qword_eol(f);
	}

	static int is_subdirectory(char subpath, char path)
	{
	int l = strlen(path);

	return strcmp(subpath, path) == 0
	\|\| (strncmp(subpath, path, l) == 0 && path[l] == '/');
	}

	static int path_matches(nfs_export exp, char path)
	{
	if (exp->m_export.e_flags & NFSEXP_CROSSMOUNT)
	return is_subdirectory(path, exp->m_export.e_path);
	return strcmp(path, exp->m_export.e_path) == 0;
	}

	static int client_matches(nfs_export exp, char dom, struct hostent *he)
	{
	if (use_ipaddr)
	return client_check(exp->m_client, he);
	return client_member(dom, exp->m_client->m_hostname);
	}

	static int export_matches(nfs_export exp, char dom, char path, struct hostent he)
	{
	return path_matches(exp, path) && client_matches(exp, dom, he);
	}

	static nfs_export lookup_export(char dom, char path, struct hostent he)
	{
	nfs_export *exp;
	nfs_export *found = NULL;
	int found_type = 0;
	int i;

	for (i=0 ; i < MCL_MAXTYPES; i++) {
	for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {
	if (!export_matches(exp, dom, path, he))
	continue;
	if (!found) {
	found = exp;
	found_type = i;
	continue;
	}

	/* Always prefer non-V4ROOT mounts */
	if (found->m_export.e_flags & NFSEXP_V4ROOT)
	continue;

	/* If one is a CROSSMOUNT, then prefer the longest path */
	if (((found->m_export.e_flags & NFSEXP_CROSSMOUNT) \|\|
	(exp->m_export.e_flags & NFSEXP_CROSSMOUNT)) &&
	strlen(found->m_export.e_path) !=
	strlen(exp->m_export.e_path)) {

	if (strlen(exp->m_export.e_path) >
	strlen(found->m_export.e_path)) {
	found = exp;
	found_type = i;
	}
	continue;

	} else if (found_type == i && found->m_warned == 0) {
	xlog(L_WARNING, "%s exported to both %s and %s, "
	"arbitrarily choosing options from first",
	path, found->m_client->m_hostname, exp->m_client->m_hostname,
	dom);
	found->m_warned = 1;
	}
	}
	}
	return found;
	}

	void nfsd_export(FILE *f)
	{
	/* requests are:
	* domain path
	* determine export options and return:
	* domain path expiry flags anonuid anongid fsid
	*/

	char *cp;
	char dom, path;
	nfs_export *found = NULL;
	struct in_addr addr;
	struct hostent *he = NULL;


	if (readline(fileno(f), &lbuf, &lbuflen) != 1)
	return;

	xlog(D_CALL, "nfsd_export: inbuf '%s'", lbuf);

	cp = lbuf;
	dom = malloc(strlen(cp));
	path = malloc(strlen(cp));

	if (!dom \|\| !path)
	goto out;

	if (qword_get(&cp, dom, strlen(lbuf)) <= 0)
	goto out;
	if (qword_get(&cp, path, strlen(lbuf)) <= 0)
	goto out;

	auth_reload();

	if (use_ipaddr) {
	if (!inet_aton(dom, &addr))
	goto out;
	he = client_resolve(addr);
	}

	found = lookup_export(dom, path, he);

	if (found) {
	if (dump_to_cache(f, dom, path, &found->m_export) < 0) {
	xlog(L_WARNING,
	"Cannot export %s, possibly unsupported filesystem"
	" or fsid= required", path);
	dump_to_cache(f, dom, path, NULL);
	}
	} else {
	dump_to_cache(f, dom, path, NULL);
	}
	out:
	xlog(D_CALL, "nfsd_export: found %p path %s", found, path ? path : NULL);
	if (dom) free(dom);
	if (path) free(path);
	if (he) free(he);
	}


	struct {
	char *cache_name;
	void (cache_handle)(FILE f);
	FILE *f;
	} cachelist[] = {
	{ "auth.unix.ip", auth_unix_ip},
	{ "auth.unix.gid", auth_unix_gid},
	{ "nfsd.export", nfsd_export},
	{ "nfsd.fh", nfsd_fh},
	{ NULL, NULL }
	};

	extern int manage_gids;
	void cache_open(void)
	{
	int i;
	for (i=0; cachelist[i].cache_name; i++ ) {
	char path[100];
	if (!manage_gids && cachelist[i].cache_handle == auth_unix_gid)
	continue;
	sprintf(path, "/proc/net/rpc/%s/channel", cachelist[i].cache_name);
	cachelist[i].f = fopen(path, "r+");
	}
	}

	void cache_set_fds(fd_set *fdset)
	{
	int i;
	for (i=0; cachelist[i].cache_name; i++) {
	if (cachelist[i].f)
	FD_SET(fileno(cachelist[i].f), fdset);
	}
	}

	int cache_process_req(fd_set *readfds)
	{
	int i;
	int cnt = 0;
	for (i=0; cachelist[i].cache_name; i++) {
	if (cachelist[i].f != NULL &&
	FD_ISSET(fileno(cachelist[i].f), readfds)) {
	cnt++;
	cachelist[i].cache_handle(cachelist[i].f);
	FD_CLR(fileno(cachelist[i].f), readfds);
	}
	}
	return cnt;
	}


	/*
	* Give IP->domain and domain+path->options to kernel
	* % echo nfsd $IP $[now+30*60] $domain > /proc/net/rpc/auth.unix.ip/channel
	* % echo $domain $path $[now+30*60] $options $anonuid $anongid $fsid > /proc/net/rpc/nfsd.export/channel
	*/

	int cache_export_ent(char domain, struct exportent exp, char *path)
	{
	int err;
	FILE *f = fopen("/proc/net/rpc/nfsd.export/channel", "w");
	if (!f)
	return -1;

	err = dump_to_cache(f, domain, exp->e_path, exp);
	if (err) {
	xlog(L_WARNING,
	"Cannot export %s, possibly unsupported filesystem or"
	" fsid= required", exp->e_path);
	}

	while (err == 0 && (exp->e_flags & NFSEXP_CROSSMOUNT) && path) {
	/* really an 'if', but we can break out of
	* a 'while' more easily */
	/* Look along 'path' for other filesystems
	* and export them with the same options
	*/
	struct stat stb;
	int l = strlen(exp->e_path);
	int dev;

	if (strlen(path) <= l \|\| path[l] != '/' \|\|
	strncmp(exp->e_path, path, l) != 0)
	break;
	if (stat(exp->e_path, &stb) != 0)
	break;
	dev = stb.st_dev;
	while(path[l] == '/') {
	char c;
	/* errors for submount should fail whole filesystem */
	int err2;

	l++;
	while (path[l] != '/' && path[l])
	l++;
	c = path[l];
	path[l] = 0;
	err2 = lstat(path, &stb);
	path[l] = c;
	if (err2 < 0)
	break;
	if (stb.st_dev == dev)
	continue;
	dev = stb.st_dev;
	path[l] = 0;
	dump_to_cache(f, domain, path, exp);
	path[l] = c;
	}
	break;
	}

	fclose(f);
	return err;
	}

	int cache_export(nfs_export exp, char path)
	{
	int err;
	FILE *f;

	f = fopen("/proc/net/rpc/auth.unix.ip/channel", "w");
	if (!f)
	return -1;

	qword_print(f, "nfsd");
	qword_print(f, inet_ntoa(exp->m_client->m_addrlist[0]));
	qword_printint(f, time(0)+30*60);
	qword_print(f, exp->m_client->m_hostname);
	err = qword_eol(f);

	fclose(f);

	err = cache_export_ent(exp->m_client->m_hostname, &exp->m_export, path)
	\|\| err;
	return err;
	}

	/* Get a filehandle.
	* {
	* echo $domain $path $length
	* read filehandle <&0
	* } <> /proc/fs/nfsd/filehandle
	*/
	struct nfs_fh_len *
	cache_get_filehandle(nfs_export exp, int len, char p)
	{
	FILE *f = fopen("/proc/fs/nfsd/filehandle", "r+");
	char buf[200];
	char *bp = buf;
	int failed;
	static struct nfs_fh_len fh;

	if (!f)
	f = fopen("/proc/fs/nfs/filehandle", "r+");
	if (!f)
	return NULL;

	qword_print(f, exp->m_client->m_hostname);
	qword_print(f, p);
	qword_printint(f, len);
	failed = qword_eol(f);

	if (!failed)
	failed = (fgets(buf, sizeof(buf), f) == NULL);
	fclose(f);
	if (failed)
	return NULL;
	memset(fh.fh_handle, 0, sizeof(fh.fh_handle));
	fh.fh_size = qword_get(&bp, (char *)fh.fh_handle, NFS3_FHSIZE);
	return &fh;
	}