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