src/afs/VNOPS/afs_vnop_symlink.c

   1 /*
   2  * Copyright 2000, International Business Machines Corporation and others.
   3  * All Rights Reserved.
   4  *
   5  * This software has been released under the terms of the IBM Public
   6  * License.  For details, see the LICENSE file in the top-level source
   7  * directory or online at http://www.openafs.org/dl/license10.html
   8  */
   9
  10 /*
  11  * afs_vnop_symlink.c - symlink and readlink vnodeops.
  12  *
  13  * Implements:
  14  * afs_symlink
  15  * afs_MemHandleLink
  16  * afs_UFSHandleLink
  17  * afs_readlink
  18  *
  19  */
  20
  21 #include <afsconfig.h>
  22 #include "afs/param.h"
  23
  24
  25 #include "afs/sysincludes.h"    /* Standard vendor system headers */
  26 #include "afsincludes.h"        /* Afs-based standard headers */
  27 #include "afs/afs_stats.h"      /* statistics */
  28 #include "afs/afs_cbqueue.h"
  29 #include "afs/nfsclient.h"
  30 #include "afs/afs_osidnlc.h"
  31
  32 extern afs_rwlock_t afs_xvcache;
  33 extern afs_rwlock_t afs_xcbhash;
  34
  35 /* Note: There is the bare bones beginning of symlink hints in the now
  36  * defunct afs/afs_lookup.c file. Since they are not in use, making the call
  37  * is just a performance hit.
  38  */
  39
  40 static int
  41 afs_DisconCreateSymlink(struct vcache *avc, char *aname,
  42                         struct vrequest *areq) {
  43     struct dcache *tdc;
  44     struct osi_file *tfile;
  45     afs_size_t offset, len;
  46
  47     tdc = afs_GetDCache(avc, 0, areq, &offset, &len, 0);
  48     if (!tdc) {
  49         /* printf("afs_DisconCreateSymlink: can't get new dcache for symlink.\n"); */
  50         return ENETDOWN;
  51     }
  52
  53     len = strlen(aname);
  54     avc->f.m.Length = len;
  55
  56     ObtainWriteLock(&tdc->lock, 720);
  57     afs_AdjustSize(tdc, len);
  58     tdc->validPos = len;
  59     tfile = afs_CFileOpen(&tdc->f.inode);
  60     osi_Assert(tfile);
  61     afs_CFileWrite(tfile, 0, aname, len);
  62     afs_CFileClose(tfile);
  63     ReleaseWriteLock(&tdc->lock);
  64     return 0;
  65 }
  66
  67 /* don't set CDirty in here because RPC is called synchronously */
  68 int
  69 afs_symlink(OSI_VC_DECL(adp), char *aname, struct vattr *attrs,
  70             char *atargetName, struct vcache **tvcp, afs_ucred_t *acred)
  71 {
  72     afs_uint32 now = 0;
  73     struct vrequest *treq = NULL;
  74     afs_int32 code = 0;
  75     struct afs_conn *tc;
  76     struct VenusFid newFid;
  77     struct dcache *tdc;
  78     afs_size_t offset, len;
  79     afs_int32 alen;
  80     struct server *hostp = 0;
  81     struct vcache *tvc;
  82     struct AFSStoreStatus InStatus;
  83     struct AFSFetchStatus *OutFidStatus, *OutDirStatus;
  84     struct AFSCallBack CallBack;
  85     struct AFSVolSync tsync;
  86     struct volume *volp = 0;
  87     struct afs_fakestat_state fakestate;
  88     struct rx_connection *rxconn;
  89     XSTATS_DECLS;
  90     OSI_VC_CONVERT(adp);
  91
  92     AFS_STATCNT(afs_symlink);
  93     afs_Trace2(afs_iclSetp, CM_TRACE_SYMLINK, ICL_TYPE_POINTER, adp,
  94                ICL_TYPE_STRING, aname);
  95
  96     OutFidStatus = osi_AllocSmallSpace(sizeof(struct AFSFetchStatus));
  97     OutDirStatus = osi_AllocSmallSpace(sizeof(struct AFSFetchStatus));
  98     memset(&InStatus, 0, sizeof(InStatus));
  99
 100     if ((code = afs_CreateReq(&treq, acred)))
 101         goto done2;
 102
 103     afs_InitFakeStat(&fakestate);
 104
 105     AFS_DISCON_LOCK();
 106
 107     code = afs_EvalFakeStat(&adp, &fakestate, treq);
 108     if (code)
 109         goto done;
 110
 111     if (strlen(aname) > AFSNAMEMAX || strlen(atargetName) > AFSPATHMAX) {
 112         code = ENAMETOOLONG;
 113         goto done;
 114     }
 115
 116     if (afs_IsDynroot(adp)) {
 117         code = afs_DynrootVOPSymlink(adp, acred, aname, atargetName);
 118         goto done;
 119     }
 120     if (afs_IsDynrootMount(adp)) {
 121         code = EROFS;
 122         goto done;
 123     }
 124
 125     code = afs_VerifyVCache(adp, treq);
 126     if (code) {
 127         code = afs_CheckCode(code, treq, 30);
 128         goto done;
 129     }
 130
 131     /** If the volume is read-only, return error without making an RPC to the
 132       * fileserver
 133       */
 134     if (adp->f.states & CRO) {
 135         code = EROFS;
 136         goto done;
 137     }
 138
 139     if (AFS_IS_DISCONNECTED && !AFS_IS_DISCON_RW) {
 140         code = ENETDOWN;
 141         goto done;
 142     }
 143
 144     InStatus.Mask = AFS_SETMODTIME | AFS_SETMODE;
 145     InStatus.ClientModTime = osi_Time();
 146     alen = strlen(atargetName); /* we want it to include the null */
 147     if ( (*atargetName == '#' || *atargetName == '%') && alen > 1 && atargetName[alen-1] == '.') {
 148         InStatus.UnixModeBits = 0644;   /* mt pt: null from "." at end */
 149         if (alen == 1)
 150             alen++;             /* Empty string */
 151     } else {
 152         InStatus.UnixModeBits = 0755;
 153         alen++;                 /* add in the null */
 154     }
 155     tdc = afs_GetDCache(adp, (afs_size_t) 0, treq, &offset, &len, 1);
 156     volp = afs_FindVolume(&adp->f.fid, READ_LOCK);      /*parent is also in same vol */
 157     ObtainWriteLock(&adp->lock, 156);
 158     if (tdc)
 159         ObtainWriteLock(&tdc->lock, 636);
 160     /* No further locks: if the SymLink succeeds, it does not matter what happens
 161      * to our local copy of the directory. If somebody tampers with it in the meantime,
 162      * the copy will be invalidated */
 163     if (!AFS_IS_DISCON_RW) {
 164         do {
 165             tc = afs_Conn(&adp->f.fid, treq, SHARED_LOCK, &rxconn);
 166             if (tc) {
 167                 hostp = tc->parent->srvr->server;
 168                 XSTATS_START_TIME(AFS_STATS_FS_RPCIDX_SYMLINK);
 169                 if (adp->f.states & CForeign) {
 170                     now = osi_Time();
 171                     RX_AFS_GUNLOCK();
 172                     code =
 173                         RXAFS_DFSSymlink(rxconn,
 174                                          (struct AFSFid *)&adp->f.fid.Fid,
 175                                          aname, atargetName, &InStatus,
 176                                          (struct AFSFid *)&newFid.Fid,
 177                                          OutFidStatus, OutDirStatus,
 178                                          &CallBack, &tsync);
 179                     RX_AFS_GLOCK();
 180                 } else {
 181                     RX_AFS_GUNLOCK();
 182                     code =
 183                         RXAFS_Symlink(rxconn, (struct AFSFid *)&adp->f.fid.Fid,
 184                                       aname, atargetName, &InStatus,
 185                                       (struct AFSFid *)&newFid.Fid,
 186                                       OutFidStatus, OutDirStatus, &tsync);
 187                     RX_AFS_GLOCK();
 188                 }
 189                 XSTATS_END_TIME;
 190             } else
 191                 code = -1;
 192         } while (afs_Analyze
 193                     (tc, rxconn, code, &adp->f.fid, treq, AFS_STATS_FS_RPCIDX_SYMLINK,
 194                      SHARED_LOCK, NULL));
 195     } else {
 196         newFid.Cell = adp->f.fid.Cell;
 197         newFid.Fid.Volume = adp->f.fid.Fid.Volume;
 198         afs_GenFakeFid(&newFid, VREG, 0);
 199     }
 200
 201     ObtainWriteLock(&afs_xvcache, 40);
 202     if (code) {
 203         if (code < 0) {
 204             afs_StaleVCache(adp);
 205         }
 206         ReleaseWriteLock(&adp->lock);
 207         ReleaseWriteLock(&afs_xvcache);
 208         if (tdc) {
 209             ReleaseWriteLock(&tdc->lock);
 210             afs_PutDCache(tdc);
 211         }
 212         goto done;
 213     }
 214     /* otherwise, we should see if we can make the change to the dir locally */
 215     if (AFS_IS_DISCON_RW || afs_LocalHero(adp, tdc, OutDirStatus, 1)) {
 216         /* we can do it locally */
 217         ObtainWriteLock(&afs_xdcache, 293);
 218         /* If the following fails because the name has been created in the meantime, the
 219          * directory is out-of-date - the file server knows best! */
 220         code = afs_dir_Create(tdc, aname, &newFid.Fid);
 221         ReleaseWriteLock(&afs_xdcache);
 222         if (code && !AFS_IS_DISCON_RW) {
 223             ZapDCE(tdc);        /* surprise error -- use invalid value */
 224             DZap(tdc);
 225         }
 226     }
 227     if (tdc) {
 228         ReleaseWriteLock(&tdc->lock);
 229         afs_PutDCache(tdc);
 230     }
 231     newFid.Cell = adp->f.fid.Cell;
 232     newFid.Fid.Volume = adp->f.fid.Fid.Volume;
 233     ReleaseWriteLock(&adp->lock);
 234
 235     /* now we're done with parent dir, create the link's entry.  Note that
 236      * no one can get a pointer to the new cache entry until we release
 237      * the xvcache lock. */
 238     tvc = afs_NewVCache(&newFid, hostp);
 239     if (!tvc)
 240     {
 241         code = -2;
 242         ReleaseWriteLock(&afs_xvcache);
 243         goto done;
 244     }
 245     ObtainWriteLock(&tvc->lock, 157);
 246     ObtainWriteLock(&afs_xcbhash, 500);
 247     tvc->f.states |= CStatd;    /* have valid info */
 248     tvc->f.states &= ~CBulkFetching;
 249
 250     if (adp->f.states & CForeign) {
 251         tvc->f.states |= CForeign;
 252         /* We don't have to worry about losing the callback since we're doing it
 253          * under the afs_xvcache lock actually, afs_NewVCache may drop the
 254          * afs_xvcache lock, if it calls afs_FlushVCache */
 255         tvc->cbExpires = CallBack.ExpirationTime + now;
 256         afs_QueueCallback(tvc, CBHash(CallBack.ExpirationTime), volp);
 257     } else {
 258         tvc->cbExpires = 0x7fffffff;    /* never expires, they can't change */
 259         /* since it never expires, we don't have to queue the callback */
 260     }
 261     ReleaseWriteLock(&afs_xcbhash);
 262
 263     if (AFS_IS_DISCON_RW) {
 264         attrs->va_mode = InStatus.UnixModeBits;
 265         afs_GenDisconStatus(adp, tvc, &newFid, attrs, treq, VLNK);
 266         code = afs_DisconCreateSymlink(tvc, atargetName, treq);
 267         if (code) {
 268             /* XXX - When this goes wrong, we need to tidy up the changes we made to
 269              * the parent, and get rid of the vcache we just created */
 270             ReleaseWriteLock(&tvc->lock);
 271             ReleaseWriteLock(&afs_xvcache);
 272             afs_PutVCache(tvc);
 273             goto done;
 274         }
 275         afs_DisconAddDirty(tvc, VDisconCreate, 0);
 276     } else {
 277         afs_ProcessFS(tvc, OutFidStatus, treq);
 278     }
 279
 280     if (!tvc->linkData) {
 281         tvc->linkData = afs_osi_Alloc(alen);
 282         osi_Assert(tvc->linkData != NULL);
 283         strncpy(tvc->linkData, atargetName, alen - 1);
 284         tvc->linkData[alen - 1] = 0;
 285     }
 286     ReleaseWriteLock(&tvc->lock);
 287     ReleaseWriteLock(&afs_xvcache);
 288     if (tvcp)
 289         *tvcp = tvc;
 290     else
 291         afs_PutVCache(tvc);
 292     code = 0;
 293   done:
 294     afs_PutFakeStat(&fakestate);
 295     if (volp)
 296         afs_PutVolume(volp, READ_LOCK);
 297     AFS_DISCON_UNLOCK();
 298     code = afs_CheckCode(code, treq, 31);
 299     afs_DestroyReq(treq);
 300   done2:
 301     osi_FreeSmallSpace(OutFidStatus);
 302     osi_FreeSmallSpace(OutDirStatus);
 303     return code;
 304 }
 305
 306 int
 307 afs_MemHandleLink(struct vcache *avc, struct vrequest *areq)
 308 {
 309     struct dcache *tdc;
 310     char *tp, *rbuf;
 311     afs_size_t offset, len;
 312     afs_int32 tlen, alen;
 313     afs_int32 code;
 314
 315     AFS_STATCNT(afs_MemHandleLink);
 316     /* two different formats, one for links protected 644, have a "." at
 317      * the end of the file name, which we turn into a null.  Others,
 318      * protected 755, we add a null to the end of */
 319     if (!avc->linkData) {
 320         void *addr;
 321         tdc = afs_GetDCache(avc, (afs_size_t) 0, areq, &offset, &len, 0);
 322         if (!tdc) {
 323             return EIO;
 324         }
 325         /* otherwise we have the data loaded, go for it */
 326         if (len > 1024) {
 327             afs_PutDCache(tdc);
 328             return EFAULT;
 329         }
 330         if (avc->f.m.Mode & 0111)
 331             alen = len + 1;     /* regular link */
 332         else
 333             alen = len;         /* mt point */
 334         rbuf = osi_AllocLargeSpace(AFS_LRALLOCSIZ);
 335         ObtainReadLock(&tdc->lock);
 336         addr = afs_MemCacheOpen(&tdc->f.inode);
 337         tlen = len;
 338         code = afs_MemReadBlk(addr, 0, rbuf, tlen);
 339         afs_MemCacheClose(addr);
 340         ReleaseReadLock(&tdc->lock);
 341         afs_PutDCache(tdc);
 342         rbuf[alen - 1] = 0;
 343         alen = strlen(rbuf) + 1;
 344         tp = afs_osi_Alloc(alen);       /* make room for terminating null */
 345         osi_Assert(tp != NULL);
 346         memcpy(tp, rbuf, alen);
 347         osi_FreeLargeSpace(rbuf);
 348         if (code != len) {
 349             afs_osi_Free(tp, alen);
 350             return EIO;
 351         }
 352         avc->linkData = tp;
 353     }
 354     return 0;
 355 }
 356
 357 int
 358 afs_UFSHandleLink(struct vcache *avc, struct vrequest *areq)
 359 {
 360     struct dcache *tdc;
 361     char *tp, *rbuf;
 362     void *tfile;
 363     afs_size_t offset, len;
 364     afs_int32 tlen, alen;
 365     afs_int32 code;
 366
 367     /* two different formats, one for links protected 644, have a "." at the
 368      * end of the file name, which we turn into a null.  Others, protected
 369      * 755, we add a null to the end of */
 370     AFS_STATCNT(afs_UFSHandleLink);
 371     if (!avc->linkData) {
 372         tdc = afs_GetDCache(avc, (afs_size_t) 0, areq, &offset, &len, 0);
 373         afs_Trace3(afs_iclSetp, CM_TRACE_UFSLINK, ICL_TYPE_POINTER, avc,
 374                    ICL_TYPE_POINTER, tdc, ICL_TYPE_OFFSET,
 375                    ICL_HANDLE_OFFSET(avc->f.m.Length));
 376         if (!tdc) {
 377             if (AFS_IS_DISCONNECTED)
 378                 return ENETDOWN;
 379             else
 380                 return EIO;
 381         }
 382         /* otherwise we have the data loaded, go for it */
 383         if (len > 1024) {
 384             afs_PutDCache(tdc);
 385             return EFAULT;
 386         }
 387         if (avc->f.m.Mode & 0111)
 388             alen = len + 1;     /* regular link */
 389         else
 390             alen = len;         /* mt point */
 391         rbuf = osi_AllocLargeSpace(AFS_LRALLOCSIZ);
 392         tlen = len;
 393         ObtainReadLock(&tdc->lock);
 394         tfile = osi_UFSOpen(&tdc->f.inode);
 395         if (!tfile) {
 396             ReleaseReadLock(&tdc->lock);
 397             afs_PutDCache(tdc);
 398             osi_FreeLargeSpace(rbuf);
 399             return EIO;
 400         }
 401         code = afs_osi_Read(tfile, -1, rbuf, tlen);
 402         osi_UFSClose(tfile);
 403         ReleaseReadLock(&tdc->lock);
 404         afs_PutDCache(tdc);
 405         rbuf[alen - 1] = '\0';
 406         alen = strlen(rbuf) + 1;
 407         tp = afs_osi_Alloc(alen);       /* make room for terminating null */
 408         osi_Assert(tp != NULL);
 409         memcpy(tp, rbuf, alen);
 410         osi_FreeLargeSpace(rbuf);
 411         if (code != tlen) {
 412             afs_osi_Free(tp, alen);
 413             return EIO;
 414         }
 415         avc->linkData = tp;
 416     }
 417     return 0;
 418 }
 419
 420 int
 421 afs_readlink(OSI_VC_DECL(avc), struct uio *auio, afs_ucred_t *acred)
 422 {
 423     afs_int32 code;
 424     struct vrequest *treq = NULL;
 425     char *tp;
 426     struct afs_fakestat_state fakestat;
 427     OSI_VC_CONVERT(avc);
 428
 429     AFS_STATCNT(afs_readlink);
 430     afs_Trace1(afs_iclSetp, CM_TRACE_READLINK, ICL_TYPE_POINTER, avc);
 431     if ((code = afs_CreateReq(&treq, acred)))
 432         return code;
 433     afs_InitFakeStat(&fakestat);
 434
 435     AFS_DISCON_LOCK();
 436
 437     code = afs_EvalFakeStat(&avc, &fakestat, treq);
 438     if (code)
 439         goto done;
 440     code = afs_VerifyVCache(avc, treq);
 441     if (code)
 442         goto done;
 443     if (vType(avc) != VLNK) {
 444         code = EINVAL;
 445         goto done;
 446     }
 447     ObtainWriteLock(&avc->lock, 158);
 448     code = afs_HandleLink(avc, treq);
 449     /* finally uiomove it to user-land */
 450     if (code == 0) {
 451         tp = avc->linkData;
 452         if (tp)
 453             AFS_UIOMOVE(tp, strlen(tp), UIO_READ, auio, code);
 454         else {
 455             code = EIO;
 456         }
 457     }
 458     ReleaseWriteLock(&avc->lock);
 459   done:
 460     afs_PutFakeStat(&fakestat);
 461     AFS_DISCON_UNLOCK();
 462     code = afs_CheckCode(code, treq, 32);
 463     afs_DestroyReq(treq);
 464     return code;
 465 }