mountd: Add lookup_export_parent()
[nfs-utils.git] / utils / mountd / cache.c
1
2 /*
3  * Handle communication with knfsd internal cache
4  *
5  * We open /proc/net/rpc/{auth.unix.ip,nfsd.export,nfsd.fh}/channel
6  * and listen for requests (using my_svc_run)
7  * 
8  */
9
10 #ifdef HAVE_CONFIG_H
11 #include <config.h>
12 #endif
13
14 #include <sys/types.h>
15 #include <sys/select.h>
16 #include <sys/stat.h>
17 #include <sys/vfs.h>
18 #include <time.h>
19 #include <netinet/in.h>
20 #include <arpa/inet.h>
21 #include <unistd.h>
22 #include <fcntl.h>
23 #include <errno.h>
24 #include <ctype.h>
25 #include <pwd.h>
26 #include <grp.h>
27 #include <mntent.h>
28 #include "misc.h"
29 #include "nfslib.h"
30 #include "exportfs.h"
31 #include "mountd.h"
32 #include "xmalloc.h"
33 #include "fsloc.h"
34 #include "pseudoflavors.h"
35
36 #ifdef USE_BLKID
37 #include "blkid/blkid.h"
38 #endif
39
40 /*
41  * Invoked by RPC service loop
42  */
43 void    cache_set_fds(fd_set *fdset);
44 int     cache_process_req(fd_set *readfds);
45
46 enum nfsd_fsid {
47         FSID_DEV = 0,
48         FSID_NUM,
49         FSID_MAJOR_MINOR,
50         FSID_ENCODE_DEV,
51         FSID_UUID4_INUM,
52         FSID_UUID8,
53         FSID_UUID16,
54         FSID_UUID16_INUM,
55 };
56
57 /*
58  * Support routines for text-based upcalls.
59  * Fields are separated by spaces.
60  * Fields are either mangled to quote space tab newline slosh with slosh
61  * or a hexified with a leading \x
62  * Record is terminated with newline.
63  *
64  */
65 static int cache_export_ent(char *domain, struct exportent *exp, char *p);
66
67 #define INITIAL_MANAGED_GROUPS 100
68
69 char *lbuf  = NULL;
70 int lbuflen = 0;
71 extern int use_ipaddr;
72
73 static void auth_unix_ip(FILE *f)
74 {
75         /* requests are
76          *  class IP-ADDR
77          * Ignore if class != "nfsd"
78          * Otherwise find domainname and write back:
79          *
80          *  "nfsd" IP-ADDR expiry domainname
81          */
82         char *cp;
83         char class[20];
84         char ipaddr[INET6_ADDRSTRLEN];
85         char *client = NULL;
86         struct addrinfo *tmp = NULL;
87         if (readline(fileno(f), &lbuf, &lbuflen) != 1)
88                 return;
89
90         xlog(D_CALL, "auth_unix_ip: inbuf '%s'", lbuf);
91
92         cp = lbuf;
93
94         if (qword_get(&cp, class, 20) <= 0 ||
95             strcmp(class, "nfsd") != 0)
96                 return;
97
98         if (qword_get(&cp, ipaddr, sizeof(ipaddr)) <= 0)
99                 return;
100
101         tmp = host_pton(ipaddr);
102         if (tmp == NULL)
103                 return;
104
105         auth_reload();
106
107         /* addr is a valid, interesting address, find the domain name... */
108         if (!use_ipaddr) {
109                 struct addrinfo *ai = NULL;
110
111                 ai = client_resolve(tmp->ai_addr);
112                 if (ai == NULL)
113                         goto out;
114                 client = client_compose(ai);
115                 freeaddrinfo(ai);
116                 if (!client)
117                         goto out;
118         }
119         qword_print(f, "nfsd");
120         qword_print(f, ipaddr);
121         qword_printuint(f, time(0) + DEFAULT_TTL);
122         if (use_ipaddr)
123                 qword_print(f, ipaddr);
124         else if (client)
125                 qword_print(f, *client?client:"DEFAULT");
126         qword_eol(f);
127         xlog(D_CALL, "auth_unix_ip: client %p '%s'", client, client?client: "DEFAULT");
128
129         free(client);
130 out:
131         freeaddrinfo(tmp);
132
133 }
134
135 static void auth_unix_gid(FILE *f)
136 {
137         /* Request are
138          *  uid
139          * reply is
140          *  uid expiry count list of group ids
141          */
142         uid_t uid;
143         struct passwd *pw;
144         static gid_t *groups = NULL;
145         static int groups_len = 0;
146         gid_t *more_groups;
147         int ngroups;
148         int rv, i;
149         char *cp;
150
151         if (groups_len == 0) {
152                 groups = malloc(sizeof(gid_t) * INITIAL_MANAGED_GROUPS);
153                 if (!groups)
154                         return;
155
156                 groups_len = INITIAL_MANAGED_GROUPS;
157         }
158
159         ngroups = groups_len;
160
161         if (readline(fileno(f), &lbuf, &lbuflen) != 1)
162                 return;
163
164         cp = lbuf;
165         if (qword_get_uint(&cp, &uid) != 0)
166                 return;
167
168         pw = getpwuid(uid);
169         if (!pw)
170                 rv = -1;
171         else {
172                 rv = getgrouplist(pw->pw_name, pw->pw_gid, groups, &ngroups);
173                 if (rv == -1 && ngroups >= groups_len) {
174                         more_groups = realloc(groups, sizeof(gid_t)*ngroups);
175                         if (!more_groups)
176                                 rv = -1;
177                         else {
178                                 groups = more_groups;
179                                 groups_len = ngroups;
180                                 rv = getgrouplist(pw->pw_name, pw->pw_gid,
181                                                   groups, &ngroups);
182                         }
183                 }
184         }
185         qword_printuint(f, uid);
186         qword_printuint(f, time(0) + DEFAULT_TTL);
187         if (rv >= 0) {
188                 qword_printuint(f, ngroups);
189                 for (i=0; i<ngroups; i++)
190                         qword_printuint(f, groups[i]);
191         } else
192                 qword_printuint(f, 0);
193         qword_eol(f);
194 }
195
196 #if USE_BLKID
197 static const char *get_uuid_blkdev(char *path)
198 {
199         /* We set *safe if we know that we need the
200          * fsid from statfs too.
201          */
202         static blkid_cache cache = NULL;
203         struct stat stb;
204         char *devname;
205         blkid_tag_iterate iter;
206         blkid_dev dev;
207         const char *type;
208         const char *val, *uuid = NULL;
209
210         if (cache == NULL)
211                 blkid_get_cache(&cache, NULL);
212
213         if (stat(path, &stb) != 0)
214                 return NULL;
215         devname = blkid_devno_to_devname(stb.st_dev);
216         if (!devname)
217                 return NULL;
218         dev = blkid_get_dev(cache, devname, BLKID_DEV_NORMAL);
219         free(devname);
220         if (!dev)
221                 return NULL;
222         iter = blkid_tag_iterate_begin(dev);
223         if (!iter)
224                 return NULL;
225         while (blkid_tag_next(iter, &type, &val) == 0) {
226                 if (strcmp(type, "UUID") == 0)
227                         uuid = val;
228                 if (strcmp(type, "TYPE") == 0 &&
229                     strcmp(val, "btrfs") == 0) {
230                         uuid = NULL;
231                         break;
232                 }
233         }
234         blkid_tag_iterate_end(iter);
235         return uuid;
236 }
237 #else
238 #define get_uuid_blkdev(path) (NULL)
239 #endif
240
241 static int get_uuid(const char *val, int uuidlen, char *u)
242 {
243         /* extract hex digits from uuidstr and compose a uuid
244          * of the given length (max 16), xoring bytes to make
245          * a smaller uuid.
246          */
247         int i = 0;
248         
249         memset(u, 0, uuidlen);
250         for ( ; *val ; val++) {
251                 char c = *val;
252                 if (!isxdigit(c))
253                         continue;
254                 if (isalpha(c)) {
255                         if (isupper(c))
256                                 c = c - 'A' + 10;
257                         else
258                                 c = c - 'a' + 10;
259                 } else
260                         c = c - '0' + 0;
261                 if ((i&1) == 0)
262                         c <<= 4;
263                 u[i/2] ^= c;
264                 i++;
265                 if (i == uuidlen*2)
266                         i = 0;
267         }
268         return 1;
269 }
270
271 static int uuid_by_path(char *path, int type, int uuidlen, char *uuid)
272 {
273         /* get a uuid for the filesystem found at 'path'.
274          * There are several possible ways of generating the
275          * uuids (types).
276          * Type 0 is used for new filehandles, while other types
277          * may be used to interpret old filehandle - to ensure smooth
278          * forward migration.
279          * We return 1 if a uuid was found (and it might be worth 
280          * trying the next type) or 0 if no more uuid types can be
281          * extracted.
282          */
283
284         /* Possible sources of uuid are
285          * - blkid uuid
286          * - statfs64 uuid
287          *
288          * On some filesystems (e.g. vfat) the statfs64 uuid is simply an
289          * encoding of the device that the filesystem is mounted from, so
290          * it we be very bad to use that (as device numbers change).  blkid
291          * must be preferred.
292          * On other filesystems (e.g. btrfs) the statfs64 uuid contains
293          * important info that the blkid uuid cannot contain:  This happens
294          * when multiple subvolumes are exported (they have the same
295          * blkid uuid but different statfs64 uuids).
296          * We rely on get_uuid_blkdev *knowing* which is which and not returning
297          * a uuid for filesystems where the statfs64 uuid is better.
298          *
299          */
300         struct statfs64 st;
301         char fsid_val[17];
302         const char *blkid_val;
303         const char *val;
304
305         blkid_val = get_uuid_blkdev(path);
306
307         if (statfs64(path, &st) == 0 &&
308             (st.f_fsid.__val[0] || st.f_fsid.__val[1]))
309                 snprintf(fsid_val, 17, "%08x%08x",
310                          st.f_fsid.__val[0], st.f_fsid.__val[1]);
311         else
312                 fsid_val[0] = 0;
313
314         if (blkid_val && (type--) == 0)
315                 val = blkid_val;
316         else if (fsid_val[0] && (type--) == 0)
317                 val = fsid_val;
318         else
319                 return 0;
320
321         get_uuid(val, uuidlen, uuid);
322         return 1;
323 }
324
325 /* Iterate through /etc/mtab, finding mountpoints
326  * at or below a given path
327  */
328 static char *next_mnt(void **v, char *p)
329 {
330         FILE *f;
331         struct mntent *me;
332         int l = strlen(p);
333         if (*v == NULL) {
334                 f = setmntent("/etc/mtab", "r");
335                 *v = f;
336         } else
337                 f = *v;
338         while ((me = getmntent(f)) != NULL &&
339                (strncmp(me->mnt_dir, p, l) != 0 ||
340                 me->mnt_dir[l] != '/'))
341                 ;
342         if (me == NULL) {
343                 endmntent(f);
344                 *v = NULL;
345                 return NULL;
346         }
347         return me->mnt_dir;
348 }
349
350 /* True iff e1 is a child of e2 and e2 has crossmnt set: */
351 static bool subexport(struct exportent *e1, struct exportent *e2)
352 {
353         char *p1 = e1->e_path, *p2 = e2->e_path;
354         int l2 = strlen(p2);
355
356         return e2->e_flags & NFSEXP_CROSSMOUNT
357                && strncmp(p1, p2, l2) == 0
358                && p1[l2] == '/';
359 }
360
361 struct parsed_fsid {
362         int fsidtype;
363         /* We could use a union for this, but it would be more
364          * complicated; why bother? */
365         unsigned int inode;
366         unsigned int minor;
367         unsigned int major;
368         unsigned int fsidnum;
369         int uuidlen;
370         char *fhuuid;
371 };
372
373 int parse_fsid(int fsidtype, int fsidlen, char *fsid, struct parsed_fsid *parsed)
374 {
375         unsigned int dev;
376         unsigned long long inode64;
377
378         parsed->fsidtype = fsidtype;
379         switch(fsidtype) {
380         case FSID_DEV: /* 4 bytes: 2 major, 2 minor, 4 inode */
381                 if (fsidlen != 8)
382                         return -1;
383                 memcpy(&dev, fsid, 4);
384                 memcpy(&parsed->inode, fsid+4, 4);
385                 parsed->major = ntohl(dev)>>16;
386                 parsed->minor = ntohl(dev) & 0xFFFF;
387                 break;
388
389         case FSID_NUM: /* 4 bytes - fsid */
390                 if (fsidlen != 4)
391                         return -1;
392                 memcpy(&parsed->fsidnum, fsid, 4);
393                 break;
394
395         case FSID_MAJOR_MINOR: /* 12 bytes: 4 major, 4 minor, 4 inode 
396                  * This format is never actually used but was
397                  * an historical accident
398                  */
399                 if (fsidlen != 12)
400                         return -1;
401                 memcpy(&dev, fsid, 4);
402                 parsed->major = ntohl(dev);
403                 memcpy(&dev, fsid+4, 4);
404                 parsed->minor = ntohl(dev);
405                 memcpy(&parsed->inode, fsid+8, 4);
406                 break;
407
408         case FSID_ENCODE_DEV: /* 8 bytes: 4 byte packed device number, 4 inode */
409                 /* This is *host* endian, not net-byte-order, because
410                  * no-one outside this host has any business interpreting it
411                  */
412                 if (fsidlen != 8)
413                         return -1;
414                 memcpy(&dev, fsid, 4);
415                 memcpy(&parsed->inode, fsid+4, 4);
416                 parsed->major = (dev & 0xfff00) >> 8;
417                 parsed->minor = (dev & 0xff) | ((dev >> 12) & 0xfff00);
418                 break;
419
420         case FSID_UUID4_INUM: /* 4 byte inode number and 4 byte uuid */
421                 if (fsidlen != 8)
422                         return -1;
423                 memcpy(&parsed->inode, fsid, 4);
424                 parsed->uuidlen = 4;
425                 parsed->fhuuid = fsid+4;
426                 break;
427         case FSID_UUID8: /* 8 byte uuid */
428                 if (fsidlen != 8)
429                         return -1;
430                 parsed->uuidlen = 8;
431                 parsed->fhuuid = fsid;
432                 break;
433         case FSID_UUID16: /* 16 byte uuid */
434                 if (fsidlen != 16)
435                         return -1;
436                 parsed->uuidlen = 16;
437                 parsed->fhuuid = fsid;
438                 break;
439         case FSID_UUID16_INUM: /* 8 byte inode number and 16 byte uuid */
440                 if (fsidlen != 24)
441                         return -1;
442                 memcpy(&inode64, fsid, 8);
443                 parsed->inode = inode64;
444                 parsed->uuidlen = 16;
445                 parsed->fhuuid = fsid+8;
446                 break;
447         }
448         return 0;
449 }
450
451 static bool match_fsid(struct parsed_fsid *parsed, nfs_export *exp, char *path)
452 {
453         struct stat stb;
454         int type;
455         char u[16];
456
457         if (stat(path, &stb) != 0)
458                 return false;
459         if (!S_ISDIR(stb.st_mode) && !S_ISREG(stb.st_mode))
460                 return false;
461
462         switch (parsed->fsidtype) {
463         case FSID_DEV:
464         case FSID_MAJOR_MINOR:
465         case FSID_ENCODE_DEV:
466                 if (stb.st_ino != parsed->inode)
467                         return false;
468                 if (parsed->major != major(stb.st_dev) ||
469                     parsed->minor != minor(stb.st_dev))
470                         return false;
471                 return true;
472         case FSID_NUM:
473                 if (((exp->m_export.e_flags & NFSEXP_FSID) == 0 ||
474                      exp->m_export.e_fsid != parsed->fsidnum))
475                         return false;
476                 return true;
477         case FSID_UUID4_INUM:
478         case FSID_UUID16_INUM:
479                 if (stb.st_ino != parsed->inode)
480                         return false;
481                 goto check_uuid;
482         case FSID_UUID8:
483         case FSID_UUID16:
484                 if (!is_mountpoint(path))
485                         return false;
486         check_uuid:
487                 if (exp->m_export.e_uuid)
488                         get_uuid(exp->m_export.e_uuid, parsed->uuidlen, u);
489                 else
490                         for (type = 0;
491                              uuid_by_path(path, type, parsed->uuidlen, u);
492                              type++)
493                                 if (memcmp(u, parsed->fhuuid, parsed->uuidlen) == 0)
494                                         return true;
495
496                 if (memcmp(u, parsed->fhuuid, parsed->uuidlen) != 0)
497                         return false;
498                 return true;
499         }
500         /* Well, unreachable, actually: */
501         return false;
502 }
503
504 struct addrinfo *lookup_client_addr(char *dom)
505 {
506         struct addrinfo *ret;
507         struct addrinfo *tmp;
508
509         dom++; /* skip initial "$" */
510
511         tmp = host_pton(dom);
512         if (tmp == NULL)
513                 return NULL;
514         ret = client_resolve(tmp->ai_addr);
515         freeaddrinfo(tmp);
516         return ret;
517 }
518
519 static void nfsd_fh(FILE *f)
520 {
521         /* request are:
522          *  domain fsidtype fsid
523          * interpret fsid, find export point and options, and write:
524          *  domain fsidtype fsid expiry path
525          */
526         char *cp;
527         char *dom;
528         int fsidtype;
529         int fsidlen;
530         char fsid[32];
531         struct parsed_fsid parsed;
532         struct exportent *found = NULL;
533         struct addrinfo *ai = NULL;
534         char *found_path = NULL;
535         nfs_export *exp;
536         int i;
537         int dev_missing = 0;
538
539         if (readline(fileno(f), &lbuf, &lbuflen) != 1)
540                 return;
541
542         xlog(D_CALL, "nfsd_fh: inbuf '%s'", lbuf);
543
544         cp = lbuf;
545
546         dom = malloc(strlen(cp));
547         if (dom == NULL)
548                 return;
549         if (qword_get(&cp, dom, strlen(cp)) <= 0)
550                 goto out;
551         if (qword_get_int(&cp, &fsidtype) != 0)
552                 goto out;
553         if (fsidtype < 0 || fsidtype > 7)
554                 goto out; /* unknown type */
555         if ((fsidlen = qword_get(&cp, fsid, 32)) <= 0)
556                 goto out;
557         if (parse_fsid(fsidtype, fsidlen, fsid, &parsed))
558                 goto out;
559
560         auth_reload();
561
562         if (is_ipaddr_client(dom)) {
563                 ai = lookup_client_addr(dom);
564                 if (!ai)
565                         goto out;
566         }
567
568         /* Now determine export point for this fsid/domain */
569         for (i=0 ; i < MCL_MAXTYPES; i++) {
570                 nfs_export *next_exp;
571                 for (exp = exportlist[i].p_head; exp; exp = next_exp) {
572                         char *path;
573
574                         if (exp->m_export.e_flags & NFSEXP_CROSSMOUNT) {
575                                 static nfs_export *prev = NULL;
576                                 static void *mnt = NULL;
577                                 
578                                 if (prev == exp) {
579                                         /* try a submount */
580                                         path = next_mnt(&mnt, exp->m_export.e_path);
581                                         if (!path) {
582                                                 next_exp = exp->m_next;
583                                                 prev = NULL;
584                                                 continue;
585                                         }
586                                         next_exp = exp;
587                                 } else {
588                                         prev = exp;
589                                         mnt = NULL;
590                                         path = exp->m_export.e_path;
591                                         next_exp = exp;
592                                 }
593                         } else {
594                                 path = exp->m_export.e_path;
595                                 next_exp = exp->m_next;
596                         }
597
598                         if (!is_ipaddr_client(dom)
599                                         && !namelist_client_matches(exp, dom))
600                                 continue;
601                         if (exp->m_export.e_mountpoint &&
602                             !is_mountpoint(exp->m_export.e_mountpoint[0]?
603                                            exp->m_export.e_mountpoint:
604                                            exp->m_export.e_path))
605                                 dev_missing ++;
606
607                         if (!match_fsid(&parsed, exp, path))
608                                 continue;
609                         if (is_ipaddr_client(dom)
610                                         && !ipaddr_client_matches(exp, ai))
611                                 continue;
612                         if (!found || subexport(&exp->m_export, found)) {
613                                 found = &exp->m_export;
614                                 free(found_path);
615                                 found_path = strdup(path);
616                                 if (found_path == NULL)
617                                         goto out;
618                         } else if (strcmp(found->e_path, exp->m_export.e_path) != 0
619                                    && !subexport(found, &exp->m_export))
620                         {
621                                 xlog(L_WARNING, "%s and %s have same filehandle for %s, using first",
622                                      found_path, path, dom);
623                         } else {
624                                 /* same path, if one is V4ROOT, choose the other */
625                                 if (found->e_flags & NFSEXP_V4ROOT) {
626                                         found = &exp->m_export;
627                                         free(found_path);
628                                         found_path = strdup(path);
629                                         if (found_path == NULL)
630                                                 goto out;
631                                 }
632                         }
633                 }
634         }
635         if (found && 
636             found->e_mountpoint &&
637             !is_mountpoint(found->e_mountpoint[0]?
638                            found->e_mountpoint:
639                            found->e_path)) {
640                 /* Cannot export this yet 
641                  * should log a warning, but need to rate limit
642                    xlog(L_WARNING, "%s not exported as %d not a mountpoint",
643                    found->e_path, found->e_mountpoint);
644                  */
645                 /* FIXME we need to make sure we re-visit this later */
646                 goto out;
647         }
648         if (!found && dev_missing) {
649                 /* The missing dev could be what we want, so just be
650                  * quite rather than returning stale yet
651                  */
652                 goto out;
653         }
654
655         if (found)
656                 if (cache_export_ent(dom, found, found_path) < 0)
657                         found = 0;
658
659         qword_print(f, dom);
660         qword_printint(f, fsidtype);
661         qword_printhex(f, fsid, fsidlen);
662         /* The fsid -> path lookup can be quite expensive as it
663          * potentially stats and reads lots of devices, and some of those
664          * might have spun-down.  The Answer is not likely to
665          * change underneath us, and an 'exportfs -f' can always
666          * remove this from the kernel, so use a really log
667          * timeout.  Maybe this should be configurable on the command
668          * line.
669          */
670         qword_printint(f, 0x7fffffff);
671         if (found)
672                 qword_print(f, found_path);
673         qword_eol(f);
674  out:
675         if (found_path)
676                 free(found_path);
677         freeaddrinfo(ai);
678         free(dom);
679         xlog(D_CALL, "nfsd_fh: found %p path %s", found, found ? found->e_path : NULL);
680         return;         
681 }
682
683 static void write_fsloc(FILE *f, struct exportent *ep)
684 {
685         struct servers *servers;
686
687         if (ep->e_fslocmethod == FSLOC_NONE)
688                 return;
689
690         servers = replicas_lookup(ep->e_fslocmethod, ep->e_fslocdata);
691         if (!servers)
692                 return;
693         qword_print(f, "fsloc");
694         qword_printint(f, servers->h_num);
695         if (servers->h_num >= 0) {
696                 int i;
697                 for (i=0; i<servers->h_num; i++) {
698                         qword_print(f, servers->h_mp[i]->h_host);
699                         qword_print(f, servers->h_mp[i]->h_path);
700                 }
701         }
702         qword_printint(f, servers->h_referral);
703         release_replicas(servers);
704 }
705
706 static void write_secinfo(FILE *f, struct exportent *ep, int flag_mask)
707 {
708         struct sec_entry *p;
709
710         for (p = ep->e_secinfo; p->flav; p++)
711                 ; /* Do nothing */
712         if (p == ep->e_secinfo) {
713                 /* There was no sec= option */
714                 return;
715         }
716         qword_print(f, "secinfo");
717         qword_printint(f, p - ep->e_secinfo);
718         for (p = ep->e_secinfo; p->flav; p++) {
719                 qword_printint(f, p->flav->fnum);
720                 qword_printint(f, p->flags & flag_mask);
721         }
722
723 }
724
725 static int dump_to_cache(FILE *f, char *domain, char *path, struct exportent *exp)
726 {
727         qword_print(f, domain);
728         qword_print(f, path);
729         if (exp) {
730                 int different_fs = strcmp(path, exp->e_path) != 0;
731                 int flag_mask = different_fs ? ~NFSEXP_FSID : ~0;
732
733                 qword_printuint(f, time(0) + exp->e_ttl);
734                 qword_printint(f, exp->e_flags & flag_mask);
735                 qword_printint(f, exp->e_anonuid);
736                 qword_printint(f, exp->e_anongid);
737                 qword_printint(f, exp->e_fsid);
738                 write_fsloc(f, exp);
739                 write_secinfo(f, exp, flag_mask);
740                 if (exp->e_uuid == NULL || different_fs) {
741                         char u[16];
742                         if (uuid_by_path(path, 0, 16, u)) {
743                                 qword_print(f, "uuid");
744                                 qword_printhex(f, u, 16);
745                         }
746                 } else {
747                         char u[16];
748                         get_uuid(exp->e_uuid, 16, u);
749                         qword_print(f, "uuid");
750                         qword_printhex(f, u, 16);
751                 }
752         } else
753                 qword_printuint(f, time(0) + DEFAULT_TTL);
754         return qword_eol(f);
755 }
756
757 static int is_subdirectory(char *child, char *parent)
758 {
759         int l = strlen(parent);
760
761         return strcmp(child, parent) == 0
762                 || (strncmp(child, parent, l) == 0 && child[l] == '/');
763 }
764
765 static int path_matches(nfs_export *exp, char *path)
766 {
767         if (exp->m_export.e_flags & NFSEXP_CROSSMOUNT)
768                 return is_subdirectory(path, exp->m_export.e_path);
769         return strcmp(path, exp->m_export.e_path) == 0;
770 }
771
772 static int
773 export_matches(nfs_export *exp, char *dom, char *path, struct addrinfo *ai)
774 {
775         return path_matches(exp, path) && client_matches(exp, dom, ai);
776 }
777
778 static nfs_export *
779 lookup_export(char *dom, char *path, struct addrinfo *ai)
780 {
781         nfs_export *exp;
782         nfs_export *found = NULL;
783         int found_type = 0;
784         int i;
785
786         for (i=0 ; i < MCL_MAXTYPES; i++) {
787                 for (exp = exportlist[i].p_head; exp; exp = exp->m_next) {
788                         if (!export_matches(exp, dom, path, ai))
789                                 continue;
790                         if (!found) {
791                                 found = exp;
792                                 found_type = i;
793                                 continue;
794                         }
795                         /* Always prefer non-V4ROOT exports */
796                         if (exp->m_export.e_flags & NFSEXP_V4ROOT)
797                                 continue;
798                         if (found->m_export.e_flags & NFSEXP_V4ROOT) {
799                                 found = exp;
800                                 found_type = i;
801                                 continue;
802                         }
803
804                         /* If one is a CROSSMOUNT, then prefer the longest path */
805                         if (((found->m_export.e_flags & NFSEXP_CROSSMOUNT) ||
806                              (exp->m_export.e_flags & NFSEXP_CROSSMOUNT)) &&
807                             strlen(found->m_export.e_path) !=
808                             strlen(exp->m_export.e_path)) {
809
810                                 if (strlen(exp->m_export.e_path) >
811                                     strlen(found->m_export.e_path)) {
812                                         found = exp;
813                                         found_type = i;
814                                 }
815                                 continue;
816
817                         } else if (found_type == i && found->m_warned == 0) {
818                                 xlog(L_WARNING, "%s exported to both %s and %s, "
819                                      "arbitrarily choosing options from first",
820                                      path, found->m_client->m_hostname, exp->m_client->m_hostname,
821                                      dom);
822                                 found->m_warned = 1;
823                         }
824                 }
825         }
826         return found;
827 }
828
829 #ifdef HAVE_NFS_PLUGIN_H
830 #include <dlfcn.h>
831 #include <nfs-plugin.h>
832
833 /*
834  * Find the export entry for the parent of "pathname".
835  * Caller must not free returned exportent.
836  */
837 static struct exportent *lookup_parent_export(char *dom,
838                 const char *pathname, struct addrinfo *ai)
839 {
840         char *parent, *slash;
841         nfs_export *result;
842
843         parent = strdup(pathname);
844         if (parent == NULL) {
845                 xlog(D_GENERAL, "%s: failed to allocate parent path buffer",
846                         __func__);
847                 goto out_default;
848         }
849         xlog(D_CALL, "%s: pathname = '%s'", __func__, pathname);
850
851 again:
852         /* shorten pathname by one component */
853         slash = strrchr(parent, '/');
854         if (slash == NULL) {
855                 xlog(D_GENERAL, "%s: no slash found in pathname",
856                         __func__);
857                 goto out_default;
858         }
859         *slash = '\0';
860
861         if (strlen(parent) == 0) {
862                 result = lookup_export(dom, "/", ai);
863                 if (result == NULL) {
864                         xlog(L_ERROR, "%s: no root export found.", __func__);
865                         goto out_default;
866                 }
867                 goto out;
868         }
869
870         result = lookup_export(dom, parent, ai);
871         if (result == NULL) {
872                 xlog(D_GENERAL, "%s: lookup_export(%s) found nothing",
873                         __func__, parent);
874                 goto again;
875         }
876
877 out:
878         xlog(D_CALL, "%s: found export for %s", __func__, parent);
879         free(parent);
880         return &result->m_export;
881
882 out_default:
883         free(parent);
884         return mkexportent("*", "/", "insecure");
885 }
886
887 /*
888  * Walk through a set of FS locations and build an e_fslocdata string.
889  * Returns true if all went to plan; otherwise, false.
890  */
891 static bool locations_to_fslocdata(struct jp_ops *ops,
892                 nfs_fsloc_set_t locations, char *fslocdata,
893                 size_t remaining, int *ttl)
894 {
895         char *server, *last_path, *rootpath, *ptr;
896         _Bool seen = false;
897
898         last_path = NULL;
899         rootpath = NULL;
900         server = NULL;
901         ptr = fslocdata;
902         *ttl = 0;
903
904         for (;;) {
905                 enum jp_status status;
906                 int len;
907
908                 status = ops->jp_get_next_location(locations, &server,
909                                                         &rootpath, ttl);
910                 if (status == JP_EMPTY)
911                         break;
912                 if (status != JP_OK) {
913                         xlog(D_GENERAL, "%s: failed to parse location: %s",
914                                 __func__, ops->jp_error(status));
915                         goto out_false;
916                 }
917                 xlog(D_GENERAL, "%s: Location: %s:%s",
918                         __func__, server, rootpath);
919
920                 if (last_path && strcmp(rootpath, last_path) == 0) {
921                         len = snprintf(ptr, remaining, "+%s", server);
922                         if (len < 0) {
923                                 xlog(D_GENERAL, "%s: snprintf: %m", __func__);
924                                 goto out_false;
925                         }
926                         if ((size_t)len >= remaining) {
927                                 xlog(D_GENERAL, "%s: fslocdata buffer overflow", __func__);
928                                 goto out_false;
929                         }
930                         remaining -= (size_t)len;
931                         ptr += len;
932                 } else {
933                         if (last_path == NULL)
934                                 len = snprintf(ptr, remaining, "%s@%s",
935                                                         rootpath, server);
936                         else
937                                 len = snprintf(ptr, remaining, ":%s@%s",
938                                                         rootpath, server);
939                         if (len < 0) {
940                                 xlog(D_GENERAL, "%s: snprintf: %m", __func__);
941                                 goto out_false;
942                         }
943                         if ((size_t)len >= remaining) {
944                                 xlog(D_GENERAL, "%s: fslocdata buffer overflow",
945                                         __func__);
946                                 goto out_false;
947                         }
948                         remaining -= (size_t)len;
949                         ptr += len;
950                         last_path = rootpath;
951                 }
952
953                 seen = true;
954                 free(rootpath);
955                 free(server);
956         }
957
958         xlog(D_CALL, "%s: fslocdata='%s', ttl=%d",
959                 __func__, fslocdata, *ttl);
960         return seen;
961
962 out_false:
963         free(rootpath);
964         free(server);
965         return false;
966 }
967
968 /*
969  * Walk through the set of FS locations and build an exportent.
970  * Returns pointer to an exportent if "junction" refers to a junction.
971  *
972  * Returned exportent points to static memory.
973  */
974 static struct exportent *locations_to_export(struct jp_ops *ops,
975                 nfs_fsloc_set_t locations, const char *junction,
976                 struct exportent *UNUSED(parent))
977 {
978         static char fslocdata[BUFSIZ];
979         struct exportent *exp;
980         int ttl;
981
982         fslocdata[0] = '\0';
983         if (!locations_to_fslocdata(ops, locations,
984                                         fslocdata, sizeof(fslocdata), &ttl))
985                 return NULL;
986
987         exp = mkexportent("*", (char *)junction, "");
988         if (exp == NULL) {
989                 xlog(L_ERROR, "%s: Failed to construct exportent", __func__);
990                 return NULL;
991         }
992
993         exp->e_uuid = NULL;
994         exp->e_ttl = ttl;
995
996         free(exp->e_fslocdata);
997         exp->e_fslocmethod = FSLOC_REFER;
998         exp->e_fslocdata = strdup(fslocdata);
999         if (exp->e_fslocdata == NULL) {
1000                 xlog(L_ERROR, "%s: No memory", __func__);
1001                 return NULL;
1002         }
1003         return exp;
1004 }
1005
1006 /*
1007  * Retrieve locations information in "junction" and dump it to the
1008  * kernel.  Returns pointer to an exportent if "junction" refers
1009  * to a junction.
1010  *
1011  * Returned exportent points to static memory.
1012  */
1013 static struct exportent *invoke_junction_ops(void *handle, char *dom,
1014                 const char *junction, struct addrinfo *ai)
1015 {
1016         struct exportent *parent, *exp = NULL;
1017         nfs_fsloc_set_t locations;
1018         enum jp_status status;
1019         struct jp_ops *ops;
1020         char *error;
1021
1022         ops = (struct jp_ops *)dlsym(handle, "nfs_junction_ops");
1023         error = dlerror();
1024         if (error != NULL) {
1025                 xlog(D_GENERAL, "%s: dlsym(jp_junction_ops): %s",
1026                         __func__, error);
1027                 return NULL;
1028         }
1029         if (ops->jp_api_version != JP_API_VERSION) {
1030                 xlog(D_GENERAL, "%s: unrecognized junction API version: %u",
1031                         __func__, ops->jp_api_version);
1032                 return NULL;
1033         }
1034
1035         status = ops->jp_init(false);
1036         if (status != JP_OK) {
1037                 xlog(D_GENERAL, "%s: failed to resolve %s: %s",
1038                         __func__, junction, ops->jp_error(status));
1039                 return NULL;
1040         }
1041
1042         status = ops->jp_get_locations(junction, &locations);
1043         switch (status) {
1044         case JP_OK:
1045                 break;
1046         case JP_NOTJUNCTION:
1047                 xlog(D_GENERAL, "%s: %s is not a junction",
1048                         __func__, junction);
1049                 goto out;
1050         default:
1051                 xlog(L_WARNING, "Dangling junction %s: %s",
1052                         junction, ops->jp_error(status));
1053                 goto out;
1054         }
1055
1056         parent = lookup_parent_export(dom, junction, ai);
1057         if (parent == NULL)
1058                 goto out;
1059
1060         exp = locations_to_export(ops, locations, junction, parent);
1061
1062         ops->jp_put_locations(locations);
1063
1064 out:
1065         ops->jp_done();
1066         return exp;
1067 }
1068
1069 /*
1070  * Load the junction plug-in, then try to resolve "pathname".
1071  * Returns pointer to an initialized exportent if "junction"
1072  * refers to a junction, or NULL if not.
1073  *
1074  * Returned exportent points to static memory.
1075  */
1076 static struct exportent *lookup_junction(char *dom, const char *pathname,
1077                 struct addrinfo *ai)
1078 {
1079         struct exportent *exp;
1080         void *handle;
1081
1082         handle = dlopen("libnfsjunct.so", RTLD_NOW);
1083         if (handle == NULL) {
1084                 xlog(D_GENERAL, "%s: dlopen: %s", __func__, dlerror());
1085                 return NULL;
1086         }
1087         (void)dlerror();        /* Clear any error */
1088
1089         exp = invoke_junction_ops(handle, dom, pathname, ai);
1090
1091         /* We could leave it loaded to make junction resolution
1092          * faster next time.  However, if we want to replace the
1093          * library, that would require restarting mountd. */
1094         (void)dlclose(handle);
1095         return exp;
1096 }
1097 #else   /* !HAVE_NFS_PLUGIN_H */
1098 static inline struct exportent *lookup_junction(char *UNUSED(dom),
1099                 const char *UNUSED(pathname), struct addrinfo *UNUSED(ai))
1100 {
1101         return NULL;
1102 }
1103 #endif  /* !HAVE_NFS_PLUGIN_H */
1104
1105 static void nfsd_export(FILE *f)
1106 {
1107         /* requests are:
1108          *  domain path
1109          * determine export options and return:
1110          *  domain path expiry flags anonuid anongid fsid
1111          */
1112
1113         char *cp;
1114         char *dom, *path;
1115         nfs_export *found = NULL;
1116         struct addrinfo *ai = NULL;
1117
1118         if (readline(fileno(f), &lbuf, &lbuflen) != 1)
1119                 return;
1120
1121         xlog(D_CALL, "nfsd_export: inbuf '%s'", lbuf);
1122
1123         cp = lbuf;
1124         dom = malloc(strlen(cp));
1125         path = malloc(strlen(cp));
1126
1127         if (!dom || !path)
1128                 goto out;
1129
1130         if (qword_get(&cp, dom, strlen(lbuf)) <= 0)
1131                 goto out;
1132         if (qword_get(&cp, path, strlen(lbuf)) <= 0)
1133                 goto out;
1134
1135         auth_reload();
1136
1137         if (is_ipaddr_client(dom)) {
1138                 ai = lookup_client_addr(dom);
1139                 if (!ai)
1140                         goto out;
1141         }
1142
1143         found = lookup_export(dom, path, ai);
1144
1145         if (found) {
1146                 if (dump_to_cache(f, dom, path, &found->m_export) < 0) {
1147                         xlog(L_WARNING,
1148                              "Cannot export %s, possibly unsupported filesystem"
1149                              " or fsid= required", path);
1150                         dump_to_cache(f, dom, path, NULL);
1151                 }
1152         } else {
1153                 dump_to_cache(f, dom, path, lookup_junction(dom, path, ai));
1154         }
1155  out:
1156         xlog(D_CALL, "nfsd_export: found %p path %s", found, path ? path : NULL);
1157         if (dom) free(dom);
1158         if (path) free(path);
1159         freeaddrinfo(ai);
1160 }
1161
1162
1163 struct {
1164         char *cache_name;
1165         void (*cache_handle)(FILE *f);
1166         FILE *f;
1167         char vbuf[RPC_CHAN_BUF_SIZE];
1168 } cachelist[] = {
1169         { "auth.unix.ip", auth_unix_ip, NULL, ""},
1170         { "auth.unix.gid", auth_unix_gid, NULL, ""},
1171         { "nfsd.export", nfsd_export, NULL, ""},
1172         { "nfsd.fh", nfsd_fh, NULL, ""},
1173         { NULL, NULL, NULL, ""}
1174 };
1175
1176 extern int manage_gids;
1177
1178 /**
1179  * cache_open - prepare communications channels with kernel RPC caches
1180  *
1181  */
1182 void cache_open(void) 
1183 {
1184         int i;
1185         for (i=0; cachelist[i].cache_name; i++ ) {
1186                 char path[100];
1187                 if (!manage_gids && cachelist[i].cache_handle == auth_unix_gid)
1188                         continue;
1189                 sprintf(path, "/proc/net/rpc/%s/channel", cachelist[i].cache_name);
1190                 cachelist[i].f = fopen(path, "r+");
1191                 if (cachelist[i].f != NULL) {
1192                         setvbuf(cachelist[i].f, cachelist[i].vbuf, _IOLBF, 
1193                                 RPC_CHAN_BUF_SIZE);
1194                 }
1195         }
1196 }
1197
1198 /**
1199  * cache_set_fds - prepare cache file descriptors for one iteration of the service loop
1200  * @fdset: pointer to fd_set to prepare
1201  */
1202 void cache_set_fds(fd_set *fdset)
1203 {
1204         int i;
1205         for (i=0; cachelist[i].cache_name; i++) {
1206                 if (cachelist[i].f)
1207                         FD_SET(fileno(cachelist[i].f), fdset);
1208         }
1209 }
1210
1211 /**
1212  * cache_process_req - process any active cache file descriptors during service loop iteration
1213  * @fdset: pointer to fd_set to examine for activity
1214  */
1215 int cache_process_req(fd_set *readfds) 
1216 {
1217         int i;
1218         int cnt = 0;
1219         for (i=0; cachelist[i].cache_name; i++) {
1220                 if (cachelist[i].f != NULL &&
1221                     FD_ISSET(fileno(cachelist[i].f), readfds)) {
1222                         cnt++;
1223                         cachelist[i].cache_handle(cachelist[i].f);
1224                         FD_CLR(fileno(cachelist[i].f), readfds);
1225                 }
1226         }
1227         return cnt;
1228 }
1229
1230
1231 /*
1232  * Give IP->domain and domain+path->options to kernel
1233  * % echo nfsd $IP  $[now+DEFAULT_TTL] $domain > /proc/net/rpc/auth.unix.ip/channel
1234  * % echo $domain $path $[now+DEFAULT_TTL] $options $anonuid $anongid $fsid > /proc/net/rpc/nfsd.export/channel
1235  */
1236
1237 static int cache_export_ent(char *domain, struct exportent *exp, char *path)
1238 {
1239         int err;
1240         FILE *f = fopen("/proc/net/rpc/nfsd.export/channel", "w");
1241         if (!f)
1242                 return -1;
1243
1244         err = dump_to_cache(f, domain, exp->e_path, exp);
1245         if (err) {
1246                 xlog(L_WARNING,
1247                      "Cannot export %s, possibly unsupported filesystem or"
1248                      " fsid= required", exp->e_path);
1249         }
1250
1251         while (err == 0 && (exp->e_flags & NFSEXP_CROSSMOUNT) && path) {
1252                 /* really an 'if', but we can break out of
1253                  * a 'while' more easily */
1254                 /* Look along 'path' for other filesystems
1255                  * and export them with the same options
1256                  */
1257                 struct stat stb;
1258                 size_t l = strlen(exp->e_path);
1259                 __dev_t dev;
1260
1261                 if (strlen(path) <= l || path[l] != '/' ||
1262                     strncmp(exp->e_path, path, l) != 0)
1263                         break;
1264                 if (stat(exp->e_path, &stb) != 0)
1265                         break;
1266                 dev = stb.st_dev;
1267                 while(path[l] == '/') {
1268                         char c;
1269                         /* errors for submount should fail whole filesystem */
1270                         int err2;
1271
1272                         l++;
1273                         while (path[l] != '/' && path[l])
1274                                 l++;
1275                         c = path[l];
1276                         path[l] = 0;
1277                         err2 = lstat(path, &stb);
1278                         path[l] = c;
1279                         if (err2 < 0)
1280                                 break;
1281                         if (stb.st_dev == dev)
1282                                 continue;
1283                         dev = stb.st_dev;
1284                         path[l] = 0;
1285                         dump_to_cache(f, domain, path, exp);
1286                         path[l] = c;
1287                 }
1288                 break;
1289         }
1290
1291         fclose(f);
1292         return err;
1293 }
1294
1295 /**
1296  * cache_export - Inform kernel of a new nfs_export
1297  * @exp: target nfs_export
1298  * @path: NUL-terminated C string containing export path
1299  */
1300 int cache_export(nfs_export *exp, char *path)
1301 {
1302         char buf[INET6_ADDRSTRLEN];
1303         int err;
1304         FILE *f;
1305
1306         f = fopen("/proc/net/rpc/auth.unix.ip/channel", "w");
1307         if (!f)
1308                 return -1;
1309
1310
1311         qword_print(f, "nfsd");
1312         qword_print(f,
1313                 host_ntop(get_addrlist(exp->m_client, 0), buf, sizeof(buf)));
1314         qword_printuint(f, time(0) + exp->m_export.e_ttl);
1315         qword_print(f, exp->m_client->m_hostname);
1316         err = qword_eol(f);
1317         
1318         fclose(f);
1319
1320         err = cache_export_ent(exp->m_client->m_hostname, &exp->m_export, path)
1321                 || err;
1322         return err;
1323 }
1324
1325 /**
1326  * cache_get_filehandle - given an nfs_export, get its root filehandle
1327  * @exp: target nfs_export
1328  * @len: length of requested file handle
1329  * @p: NUL-terminated C string containing export path
1330  *
1331  * Returns pointer to NFS file handle of root directory of export
1332  *
1333  * { 
1334  *   echo $domain $path $length 
1335  *   read filehandle <&0
1336  * } <> /proc/fs/nfsd/filehandle
1337  */
1338 struct nfs_fh_len *
1339 cache_get_filehandle(nfs_export *exp, int len, char *p)
1340 {
1341         FILE *f = fopen("/proc/fs/nfsd/filehandle", "r+");
1342         char buf[200];
1343         char *bp = buf;
1344         int failed;
1345         static struct nfs_fh_len fh;
1346
1347         if (!f)
1348                 f = fopen("/proc/fs/nfs/filehandle", "r+");
1349         if (!f)
1350                 return NULL;
1351
1352         qword_print(f, exp->m_client->m_hostname);
1353         qword_print(f, p);
1354         qword_printint(f, len); 
1355         failed = qword_eol(f);
1356         
1357         if (!failed)
1358                 failed = (fgets(buf, sizeof(buf), f) == NULL);
1359         fclose(f);
1360         if (failed)
1361                 return NULL;
1362         memset(fh.fh_handle, 0, sizeof(fh.fh_handle));
1363         fh.fh_size = qword_get(&bp, (char *)fh.fh_handle, NFS3_FHSIZE);
1364         return &fh;
1365 }