]> git.decadent.org.uk Git - nfs-utils.git/blobdiff - utils/mountd/cache.c
mountd: Ensure cache downcall can handle IPv6 addresses
[nfs-utils.git] / utils / mountd / cache.c
index 5612a9edf547ed626f35d27d50ffc3e22aa88612..f70f4d6e81a7e1ee7b57061f34b7d1c6d68ba162 100644 (file)
@@ -14,6 +14,7 @@
 #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 <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
 
+/*
+ * Invoked by RPC service loop
+ */
+void   cache_set_fds(fd_set *fdset);
+int    cache_process_req(fd_set *readfds);
 
 enum nfsd_fsid {
        FSID_DEV = 0,
@@ -52,13 +62,14 @@ enum nfsd_fsid {
  * Record is terminated with newline.
  *
  */
-int cache_export_ent(char *domain, struct exportent *exp);
+static 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)
+static void auth_unix_ip(FILE *f)
 {
        /* requests are
         *  class IP-ADDR
@@ -69,49 +80,59 @@ void auth_unix_ip(FILE *f)
         */
        char *cp;
        char class[20];
-       char ipaddr[20];
-       char *client;
-       struct in_addr addr;
+       char ipaddr[INET6_ADDRSTRLEN];
+       char *client = NULL;
+       struct addrinfo *tmp = NULL;
+       struct addrinfo *ai = 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)
+       if (qword_get(&cp, ipaddr, sizeof(ipaddr)) <= 0)
                return;
 
-       if (inet_aton(ipaddr, &addr)==0)
+       tmp = host_pton(ipaddr);
+       if (tmp == NULL)
                return;
 
        auth_reload();
 
        /* addr is a valid, interesting address, find the domain name... */
-       client = client_compose(addr);
+       if (!use_ipaddr) {
+               ai = client_resolve(tmp->ai_addr);
+               client = client_compose(ai);
+               freeaddrinfo(ai);
+       }
+       freeaddrinfo(tmp);
 
-       
        qword_print(f, "nfsd");
        qword_print(f, ipaddr);
        qword_printint(f, time(0)+30*60);
-       if (client)
+       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(client);
 }
 
-void auth_unix_gid(FILE *f)
+static void auth_unix_gid(FILE *f)
 {
        /* Request are
         *  uid
         * reply is
         *  uid expiry count list of group ids
         */
-       int uid;
+       uid_t uid;
        struct passwd *pw;
        gid_t glist[100], *groups = glist;
        int ngroups = 100;
@@ -122,7 +143,7 @@ void auth_unix_gid(FILE *f)
                return;
 
        cp = lbuf;
-       if (qword_get_int(&cp, &uid) != 0)
+       if (qword_get_uint(&cp, &uid) != 0)
                return;
 
        pw = getpwuid(uid);
@@ -139,60 +160,72 @@ void auth_unix_gid(FILE *f)
                                                  groups, &ngroups);
                }
        }
-       qword_printint(f, uid);
-       qword_printint(f, time(0)+30*60);
+       qword_printuint(f, uid);
+       qword_printuint(f, time(0)+30*60);
        if (rv >= 0) {
-               qword_printint(f, ngroups);
+               qword_printuint(f, ngroups);
                for (i=0; i<ngroups; i++)
-                       qword_printint(f, groups[i]);
-       }
+                       qword_printuint(f, groups[i]);
+       } else
+               qword_printuint(f, 0);
        qword_eol(f);
+
        if (groups != glist)
                free(groups);
 }
 
-int get_uuid(char *path, char *uuid, int uuidlen, char *u)
+#if USE_BLKID
+static const char *get_uuid_blkdev(char *path)
+{
+       /* We set *safe if we know that we need the
+        * fsid from statfs too.
+        */
+       static blkid_cache cache = NULL;
+       struct stat stb;
+       char *devname;
+       blkid_tag_iterate iter;
+       blkid_dev dev;
+       const char *type;
+       const char *val, *uuid = 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)
+                       uuid = val;
+               if (strcmp(type, "TYPE") == 0 &&
+                   strcmp(val, "btrfs") == 0) {
+                       uuid = NULL;
+                       break;
+               }
+       }
+       blkid_tag_iterate_end(iter);
+       return uuid;
+}
+#else
+#define get_uuid_blkdev(path) (NULL)
+#endif
+
+static int get_uuid(const char *val, 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
+        * a smaller uuid.
         */
        int i = 0;
-       const char *val;
-
-       if (path) {
-               static blkid_cache cache = NULL;
-               struct stat stb;
-               char *devname;
-               blkid_tag_iterate iter;
-               blkid_dev dev;
-               const char *type;
-               if (cache == NULL)
-                       blkid_get_cache(&cache, NULL);
-
-               blkid_probe_all_new(cache);
-
-               if (stat(path, &stb) != 0)
-                       return 0;
-               devname = blkid_devno_to_devname(stb.st_dev);
-               if (!devname)
-                       return 0;
-               dev = blkid_get_dev(cache, devname, BLKID_DEV_NORMAL);
-               free(devname);
-               if (!dev)
-                       return 0;
-               iter = blkid_tag_iterate_begin(dev);
-               if (!iter)
-                       return 0;
-               while (blkid_tag_next(iter, &type, &val) == 0)
-                       if (strcmp(type, "UUID") == 0)
-                               break;
-               blkid_tag_iterate_end(iter);
-               if (!type)
-                       return 0;
-       } else {
-               val = uuid;
-       }
        
        memset(u, 0, uuidlen);
        for ( ; *val ; val++) {
@@ -215,9 +248,87 @@ int get_uuid(char *path, char *uuid, int uuidlen, char *u)
        }
        return 1;
 }
-       
 
-void nfsd_fh(FILE *f)
+static int uuid_by_path(char *path, int type, int uuidlen, char *uuid)
+{
+       /* get a uuid for the filesystem found at 'path'.
+        * There are several possible ways of generating the
+        * uuids (types).
+        * Type 0 is used for new filehandles, while other types
+        * may be used to interpret old filehandle - to ensure smooth
+        * forward migration.
+        * We return 1 if a uuid was found (and it might be worth 
+        * trying the next type) or 0 if no more uuid types can be
+        * extracted.
+        */
+
+       /* Possible sources of uuid are
+        * - blkid uuid
+        * - statfs64 uuid
+        *
+        * On some filesystems (e.g. vfat) the statfs64 uuid is simply an
+        * encoding of the device that the filesystem is mounted from, so
+        * it we be very bad to use that (as device numbers change).  blkid
+        * must be preferred.
+        * On other filesystems (e.g. btrfs) the statfs64 uuid contains
+        * important info that the blkid uuid cannot contain:  This happens
+        * when multiple subvolumes are exported (they have the same
+        * blkid uuid but different statfs64 uuids).
+        * We rely on get_uuid_blkdev *knowing* which is which and not returning
+        * a uuid for filesystems where the statfs64 uuid is better.
+        *
+        */
+       struct statfs64 st;
+       char fsid_val[17];
+       const char *blkid_val;
+       const char *val;
+
+       blkid_val = get_uuid_blkdev(path);
+
+       if (statfs64(path, &st) == 0 &&
+           (st.f_fsid.__val[0] || st.f_fsid.__val[1]))
+               snprintf(fsid_val, 17, "%08x%08x",
+                        st.f_fsid.__val[0], st.f_fsid.__val[1]);
+       else
+               fsid_val[0] = 0;
+
+       if (blkid_val && (type--) == 0)
+               val = blkid_val;
+       else if (fsid_val[0] && (type--) == 0)
+               val = fsid_val;
+       else
+               return 0;
+
+       get_uuid(val, uuidlen, uuid);
+       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;
+}
+
+static void nfsd_fh(FILE *f)
 {
        /* request are:
         *  domain fsidtype fsid
@@ -234,6 +345,8 @@ void nfsd_fh(FILE *f)
        unsigned int fsidnum=0;
        char fsid[32];
        struct exportent *found = NULL;
+       struct addrinfo *ai = NULL;
+       char *found_path = NULL;
        nfs_export *exp;
        int i;
        int dev_missing = 0;
@@ -243,8 +356,10 @@ void nfsd_fh(FILE *f)
        if (readline(fileno(f), &lbuf, &lbuflen) != 1)
                return;
 
-       cp = lbuf;
+       xlog(D_CALL, "nfsd_fh: inbuf '%s'", lbuf);
 
+       cp = lbuf;
+       
        dom = malloc(strlen(cp));
        if (dom == NULL)
                return;
@@ -328,19 +443,49 @@ void nfsd_fh(FILE *f)
 
        /* Now determine export point for this fsid/domain */
        for (i=0 ; i < MCL_MAXTYPES; i++) {
-               for (exp = exportlist[i]; exp; exp = exp->m_next) {
+               nfs_export *next_exp;
+               for (exp = exportlist[i].p_head; exp; exp = next_exp) {
                        struct stat stb;
-                       char u[16];                     
+                       char u[16];
+                       char *path;
+                       int type;
+
+                       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 (!client_member(dom, exp->m_client->m_hostname))
+                       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(exp->m_export.e_path, &stb) != 0)
+                       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:
@@ -363,27 +508,45 @@ void nfsd_fh(FILE *f)
                                goto check_uuid;
                        case FSID_UUID8:
                        case FSID_UUID16:
-                               if (!is_mountpoint(exp->m_export.e_path))
+                               if (!is_mountpoint(path))
                                        continue;
                        check_uuid:
                                if (exp->m_export.e_uuid)
-                                       get_uuid(NULL, exp->m_export.e_uuid,
+                                       get_uuid(exp->m_export.e_uuid,
                                                 uuidlen, u);
-                               else if (get_uuid(exp->m_export.e_path, NULL,
-                                                 uuidlen, u) == 0)
-                                       continue;
+                               else
+                                       for (type = 0;
+                                            uuid_by_path(path, type, uuidlen, u);
+                                            type++)
+                                               if (memcmp(u, fhuuid, uuidlen) == 0)
+                                                       break;
 
                                if (memcmp(u, fhuuid, uuidlen) != 0)
                                        continue;
                                break;
                        }
+                       if (use_ipaddr) {
+                               if (ai == NULL) {
+                                       struct addrinfo *tmp;
+                                       tmp = host_pton(dom);
+                                       if (tmp == NULL)
+                                               goto out;
+                                       ai = client_resolve(tmp->ai_addr);
+                                       freeaddrinfo(tmp);
+                               }
+                               if (!client_check(exp->m_client, ai))
+                                       continue;
+                       }
                        /* It's a match !! */
-                       if (!found)
+                       if (!found) {
                                found = &exp->m_export;
-                       else if (strcmp(found->e_path, exp->m_export.e_path)!= 0)
+                               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->e_path, exp->m_export.e_path, dom);
+                                    found_path, path, dom);
                        }
                }
        }
@@ -408,7 +571,8 @@ void nfsd_fh(FILE *f)
        }
 
        if (found)
-               cache_export_ent(dom, found);
+               if (cache_export_ent(dom, found, found_path) < 0)
+                       found = 0;
 
        qword_print(f, dom);
        qword_printint(f, fsidtype);
@@ -423,21 +587,25 @@ void nfsd_fh(FILE *f)
         */
        qword_printint(f, 0x7fffffff);
        if (found)
-               qword_print(f, found->e_path);
+               qword_print(f, found_path);
        qword_eol(f);
  out:
+       if (found_path)
+               free(found_path);
+       freeaddrinfo(ai);
        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)
+static void write_fsloc(FILE *f, struct exportent *ep)
 {
        struct servers *servers;
 
        if (ep->e_fslocmethod == FSLOC_NONE)
                return;
 
-       servers = replicas_lookup(ep->e_fslocmethod, ep->e_fslocdata, path);
+       servers = replicas_lookup(ep->e_fslocmethod, ep->e_fslocdata);
        if (!servers)
                return;
        qword_print(f, "fsloc");
@@ -453,32 +621,133 @@ static void write_fsloc(FILE *f, struct exportent *ep, char *path)
        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) {
-               qword_printint(f, exp->e_flags);
+               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);
-               if (exp->e_uuid == NULL) {
+               write_fsloc(f, exp);
+               write_secinfo(f, exp, flag_mask);
+               if (exp->e_uuid == NULL || different_fs) {
                        char u[16];
-                       if (get_uuid(exp->e_path, NULL, 16, u)) {
+                       if (uuid_by_path(path, 0, 16, u)) {
                                qword_print(f, "uuid");
                                qword_printhex(f, u, 16);
                        }
-               } else if (exp->e_uuid) {
+               } else {
+                       char u[16];
+                       get_uuid(exp->e_uuid, 16, u);
                        qword_print(f, "uuid");
-                       qword_printhex(f, exp->e_uuid, 16);
+                       qword_printhex(f, u, 16);
                }
        }
        return qword_eol(f);
 }
 
-void nfsd_export(FILE *f)
+static int is_subdirectory(char *child, char *parent)
+{
+       int l = strlen(parent);
+
+       return strcmp(child, parent) == 0
+               || (strncmp(child, parent, l) == 0 && child[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 addrinfo *ai)
+{
+       if (use_ipaddr)
+               return client_check(exp->m_client, ai);
+       return client_member(dom, exp->m_client->m_hostname);
+}
+
+static int
+export_matches(nfs_export *exp, char *dom, char *path, struct addrinfo *ai)
+{
+       return path_matches(exp, path) && client_matches(exp, dom, ai);
+}
+
+static nfs_export *
+lookup_export(char *dom, char *path, struct addrinfo *ai)
+{
+       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, ai))
+                               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;
+}
+
+static void nfsd_export(FILE *f)
 {
        /* requests are:
         *  domain path
@@ -487,15 +756,15 @@ void nfsd_export(FILE *f)
         */
 
        char *cp;
-       int i;
        char *dom, *path;
-       nfs_export *exp, *found = NULL;
-       int found_type = 0;
-
+       nfs_export *found = NULL;
+       struct addrinfo *ai = 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));
@@ -510,35 +779,33 @@ void nfsd_export(FILE *f)
 
        auth_reload();
 
-       /* now find flags for this export point in this domain */
-       for (i=0 ; i < MCL_MAXTYPES; i++) {
-               for (exp = exportlist[i]; exp; exp = exp->m_next) {
-                       if (!client_member(dom, exp->m_client->m_hostname))
-                               continue;
-                       if (strcmp(path, exp->m_export.e_path))
-                               continue;
-                       if (!found) {
-                               found = exp;
-                               found_type = i;
-                       } 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;
-                       }
-               }
+       if (use_ipaddr) {
+               struct addrinfo *tmp;
+               tmp = host_pton(dom);
+               if (tmp == NULL)
+                       goto out;
+               ai = client_resolve(tmp->ai_addr);
+               freeaddrinfo(tmp);
+                       goto out;
        }
 
+       found = lookup_export(dom, path, ai);
+
        if (found) {
-               dump_to_cache(f, dom, path, &found->m_export);
-               mountlist_add(dom, path);
+               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);
+       freeaddrinfo(ai);
 }
 
 
@@ -547,14 +814,19 @@ struct {
        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 }
+       { "auth.unix.ip", auth_unix_ip, NULL},
+       { "auth.unix.gid", auth_unix_gid, NULL},
+       { "nfsd.export", nfsd_export, NULL},
+       { "nfsd.fh", nfsd_fh, NULL},
+       { NULL, NULL, NULL }
 };
 
 extern int manage_gids;
+
+/**
+ * cache_open - prepare communications channels with kernel RPC caches
+ *
+ */
 void cache_open(void) 
 {
        int i;
@@ -567,6 +839,10 @@ void cache_open(void)
        }
 }
 
+/**
+ * cache_set_fds - prepare cache file descriptors for one iteration of the service loop
+ * @fdset: pointer to fd_set to prepare
+ */
 void cache_set_fds(fd_set *fdset)
 {
        int i;
@@ -576,6 +852,10 @@ void cache_set_fds(fd_set *fdset)
        }
 }
 
+/**
+ * cache_process_req - process any active cache file descriptors during service loop iteration
+ * @fdset: pointer to fd_set to examine for activity
+ */
 int cache_process_req(fd_set *readfds) 
 {
        int i;
@@ -598,7 +878,7 @@ int cache_process_req(fd_set *readfds)
  * % 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)
+static int cache_export_ent(char *domain, struct exportent *exp, char *path)
 {
        int err;
        FILE *f = fopen("/proc/net/rpc/nfsd.export/channel", "w");
@@ -606,13 +886,64 @@ int cache_export_ent(char *domain, struct exportent *exp)
                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;
+               size_t l = strlen(exp->e_path);
+               __dev_t 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);
-       mountlist_add(domain, exp->e_path);
        return err;
 }
 
-int cache_export(nfs_export *exp)
+/**
+ * cache_export - Inform kernel of a new nfs_export
+ * @exp: target nfs_export
+ * @path: NUL-terminated C string containing export path
+ */
+int cache_export(nfs_export *exp, char *path)
 {
+       char buf[INET6_ADDRSTRLEN];
        int err;
        FILE *f;
 
@@ -620,20 +951,29 @@ int cache_export(nfs_export *exp)
        if (!f)
                return -1;
 
+
        qword_print(f, "nfsd");
-       qword_print(f, inet_ntoa(exp->m_client->m_addrlist[0]));
+       qword_print(f,
+               host_ntop(get_addrlist(exp->m_client, 0), buf, sizeof(buf)));
        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)
+       err = cache_export_ent(exp->m_client->m_hostname, &exp->m_export, path)
                || err;
        return err;
 }
 
-/* Get a filehandle.
+/**
+ * cache_get_filehandle - given an nfs_export, get its root filehandle
+ * @exp: target nfs_export
+ * @len: length of requested file handle
+ * @p: NUL-terminated C string containing export path
+ *
+ * Returns pointer to NFS file handle of root directory of export
+ *
  * { 
  *   echo $domain $path $length 
  *   read filehandle <&0
@@ -667,4 +1007,3 @@ cache_get_filehandle(nfs_export *exp, int len, char *p)
        fh.fh_size = qword_get(&bp, (char *)fh.fh_handle, NFS3_FHSIZE);
        return &fh;
 }
-