/*
 * Copyright 2000, International Business Machines Corporation and others.
 * All Rights Reserved.
 * 
 * This software has been released under the terms of the IBM Public
 * License.  For details, see the LICENSE file in the top-level source
 * directory or online at http://www.openafs.org/dl/license10.html
 */

/*
 * afs_vnop_symlink.c - symlink and readlink vnodeops.
 *
 * Implements:
 * afs_symlink
 * afs_MemHandleLink
 * afs_UFSHandleLink
 * afs_readlink
 *
 */

#include <afsconfig.h>
#include "afs/param.h"

RCSID("$Header$");

#include "afs/sysincludes.h"	/* Standard vendor system headers */
#include "afsincludes.h"	/* Afs-based standard headers */
#include "afs/afs_stats.h" /* statistics */
#include "afs/afs_cbqueue.h"
#include "afs/nfsclient.h"
#include "afs/afs_osidnlc.h"

extern afs_rwlock_t afs_xvcache;
extern afs_rwlock_t afs_xcbhash;

/* Note: There is the bare bones beginning of symlink hints in the now
 * defunct afs/afs_lookup.c file. Since they are not in use, making the call
 * is just a performance hit.
 */


/* don't set CDirty in here because RPC is called synchronously */
int
afs_symlink
#ifdef	AFS_OSF_ENV
  (ndp, attrs, atargetName)
    struct nameidata *ndp;
    struct vattr *attrs;
    register char *atargetName; {
    register struct vcache *adp = VTOAFS(ndp->ni_dvp);
    char *aname = ndp->ni_dent.d_name;
    struct ucred *acred = ndp->ni_cred;
#else	/* AFS_OSF_ENV */
  (OSI_VC_ARG(adp), aname, attrs, atargetName, acred)
    OSI_VC_DECL(adp);
    char *atargetName;
    char *aname;
    struct vattr *attrs;
    struct AFS_UCRED *acred; {
#endif
    afs_uint32 now = 0;
    struct vrequest treq;
    afs_int32 code;
    struct conn *tc;
    struct VenusFid newFid;
    struct dcache *tdc;
    afs_size_t offset, len;
    afs_int32 alen;
    struct server *hostp=0;
    struct vcache *tvc;
    struct AFSStoreStatus InStatus;
    struct AFSFetchStatus OutFidStatus, OutDirStatus;
    struct AFSCallBack CallBack;
    struct AFSVolSync tsync;
    struct volume*    volp=0;
    struct afs_fakestat_state fakestate;
    XSTATS_DECLS
    OSI_VC_CONVERT(adp)
    
    AFS_STATCNT(afs_symlink);
    afs_Trace2(afs_iclSetp, CM_TRACE_SYMLINK, ICL_TYPE_POINTER, adp,
                ICL_TYPE_STRING, aname);

    if ((code = afs_InitReq(&treq, acred)))
	goto done2;

    afs_InitFakeStat(&fakestate);
    code = afs_EvalFakeStat(&adp, &fakestate, &treq);
    if (code)
	goto done;

    if (strlen(aname) > AFSNAMEMAX || strlen(atargetName) > AFSPATHMAX) {
	code = ENAMETOOLONG;
	goto done;
    }

    if (afs_IsDynroot(adp)) {
	code = afs_DynrootVOPSymlink(adp, acred, aname, atargetName);
	goto done;
    }

    code = afs_VerifyVCache(adp, &treq);
    if (code) { 
	code = afs_CheckCode(code, &treq, 30);
	goto done;
    }

    /** If the volume is read-only, return error without making an RPC to the
      * fileserver
      */
    if ( adp->states & CRO ) {
        code = EROFS;
	goto done;
    }

    InStatus.Mask = AFS_SETMODTIME | AFS_SETMODE;
    InStatus.ClientModTime = osi_Time();
    alen = strlen(atargetName);	    /* we want it to include the null */
    if (*atargetName == '#' || *atargetName == '%') {
	InStatus.UnixModeBits = 0644;	/* mt pt: null from "." at end */
        if (alen == 1) alen++;	/* Empty string */
    } else {
	InStatus.UnixModeBits = 0755;
	alen++;	    /* add in the null */
    }
    tdc = afs_GetDCache(adp, (afs_size_t) 0, &treq, &offset, &len, 1);
    volp = afs_FindVolume(&adp->fid, READ_LOCK); /*parent is also in same vol*/
    ObtainWriteLock(&adp->lock,156);
    if (tdc) ObtainWriteLock(&tdc->lock, 636);
    ObtainSharedLock(&afs_xvcache,17);  /* prevent others from creating this entry */
    /* XXX Pay attention to afs_xvcache around the whole thing!! XXX */
    do {
	tc = afs_Conn(&adp->fid, &treq, SHARED_LOCK);
	if (tc) {
	    hostp = tc->srvr->server;
	    XSTATS_START_TIME(AFS_STATS_FS_RPCIDX_SYMLINK);
	    if (adp->states & CForeign) {
		now = osi_Time();
		RX_AFS_GUNLOCK();
		code = RXAFS_DFSSymlink(tc->id, (struct AFSFid *) &adp->fid.Fid, aname,
				     atargetName, &InStatus, (struct AFSFid *) &newFid.Fid,
				     &OutFidStatus, &OutDirStatus, &CallBack, &tsync);
		RX_AFS_GLOCK();
	    } else {
		RX_AFS_GUNLOCK();
		code = RXAFS_Symlink(tc->id, (struct AFSFid *) &adp->fid.Fid, aname,
				     atargetName, &InStatus, (struct AFSFid *) &newFid.Fid,
				     &OutFidStatus, &OutDirStatus, &tsync);
		RX_AFS_GLOCK();
	    }
          XSTATS_END_TIME;
	}
	else code = -1;
    } while 
       (afs_Analyze(tc, code, &adp->fid, &treq,
                   AFS_STATS_FS_RPCIDX_SYMLINK, SHARED_LOCK, NULL));

    UpgradeSToWLock(&afs_xvcache,40);
    if (code) {
	if (code < 0) {
	  ObtainWriteLock(&afs_xcbhash, 499);
	  afs_DequeueCallback(adp);
	  adp->states &= ~CStatd;
	  ReleaseWriteLock(&afs_xcbhash);
	  osi_dnlc_purgedp(adp);
	}
	ReleaseWriteLock(&adp->lock);
	ReleaseWriteLock(&afs_xvcache);
	if (tdc) {
	    ReleaseWriteLock(&tdc->lock);
	    afs_PutDCache(tdc);
	}
	goto done;
    }
    /* otherwise, we should see if we can make the change to the dir locally */
    if (afs_LocalHero(adp, tdc, &OutDirStatus, 1)) {
	/* we can do it locally */
	code = afs_dir_Create(&tdc->f.inode, aname, &newFid.Fid);
	if (code) { 
	    ZapDCE(tdc);	/* surprise error -- use invalid value */
	    DZap(&tdc->f.inode);
	}
    }
    if (tdc) {
	ReleaseWriteLock(&tdc->lock);
	afs_PutDCache(tdc);
    }
    newFid.Cell = adp->fid.Cell;
    newFid.Fid.Volume = adp->fid.Fid.Volume;
    ReleaseWriteLock(&adp->lock);

    /* now we're done with parent dir, create the link's entry.  Note that
     * no one can get a pointer to the new cache entry until we release 
     * the xvcache lock. */
    tvc = afs_NewVCache(&newFid, hostp);
    ObtainWriteLock(&tvc->lock,157);
    ObtainWriteLock(&afs_xcbhash, 500);
    tvc->states |= CStatd;		/* have valid info */
    tvc->states &= ~CBulkFetching;

    if (adp->states & CForeign) {
	tvc->states |= CForeign;
	/* We don't have to worry about losing the callback since we're doing it 
	 * under the afs_xvcache lock actually, afs_NewVCache may drop the 
	 * afs_xvcache lock, if it calls afs_FlushVCache */
        tvc->cbExpires = CallBack.ExpirationTime + now;
        afs_QueueCallback(tvc, CBHash(CallBack.ExpirationTime), volp);
    } else {
	tvc->cbExpires = 0x7fffffff;	/* never expires, they can't change */
     /* since it never expires, we don't have to queue the callback */
    }
    ReleaseWriteLock(&afs_xcbhash);
    afs_ProcessFS(tvc, &OutFidStatus, &treq);

    if (!tvc->linkData) {
	tvc->linkData = (char *) afs_osi_Alloc(alen);
	strncpy(tvc->linkData, atargetName, alen-1);
	tvc->linkData[alen-1] = 0;
    }
    ReleaseWriteLock(&tvc->lock);
    ReleaseWriteLock(&afs_xvcache);
    afs_PutVCache(tvc);
    code = 0;
done:
    afs_PutFakeStat(&fakestate);
    if ( volp ) 
	afs_PutVolume(volp, READ_LOCK);
    code = afs_CheckCode(code, &treq, 31);
done2:
#ifdef  AFS_OSF_ENV
    AFS_RELE(ndp->ni_dvp);
#endif  /* AFS_OSF_ENV */
    return code;
}

int afs_MemHandleLink(register struct vcache *avc, struct vrequest *areq)
{
      register struct dcache *tdc;
      register char *tp, *rbuf;
      afs_size_t offset, len;
      afs_int32 tlen, alen;
      register afs_int32 code;

      AFS_STATCNT(afs_MemHandleLink);
      /* two different formats, one for links protected 644, have a "." at
	 the end of the file name, which we turn into a null.  Others, 
	 protected 755,	we add a null to the end of */
      if (!avc->linkData) {
	  void *addr;
	  tdc = afs_GetDCache(avc, (afs_size_t) 0, areq, &offset, &len, 0);
	  if (!tdc) {
	      return EIO;
	  }
	  /* otherwise we have the data loaded, go for it */
	  if (len > 1024) {
	      afs_PutDCache(tdc);
	      return EFAULT;
	  }
	  if (avc->m.Mode	& 0111)	alen = len+1;	/* regular link */
	  else alen = len;			/* mt point */
	  rbuf = (char *) osi_AllocLargeSpace(AFS_LRALLOCSIZ);
	  ObtainReadLock(&tdc->lock);
          addr = afs_MemCacheOpen(tdc->f.inode);
	  tlen = len;
          code = afs_MemReadBlk(addr, 0, rbuf, tlen);
	  afs_MemCacheClose(addr);
	  ReleaseReadLock(&tdc->lock);
	  afs_PutDCache(tdc);
	  rbuf[alen-1] = 0;
	  alen = strlen(rbuf) + 1;
	  tp = afs_osi_Alloc(alen); /* make room for terminating null */
	  memcpy(tp, rbuf, alen);
	  osi_FreeLargeSpace(rbuf);
	  if (code != len) {
	      afs_osi_Free(tp, alen);
	      return EIO;
	  }
	  avc->linkData = tp;
      }
      return 0;
  }

int afs_UFSHandleLink(register struct vcache *avc, struct vrequest *areq)
{
    register struct dcache *tdc;
    register char *tp, *rbuf;
    void *tfile;
    afs_size_t offset, len;
    afs_int32 tlen, alen;
    register afs_int32 code;

    /* two different formats, one for links protected 644, have a "." at the
       end of the file name, which we turn into a null.  Others, protected
       755, we add a null to the end of */
    AFS_STATCNT(afs_UFSHandleLink);
    if (!avc->linkData) {
	tdc = afs_GetDCache(avc, (afs_size_t) 0, areq, &offset, &len, 0);
	afs_Trace3(afs_iclSetp, CM_TRACE_UFSLINK, ICL_TYPE_POINTER, avc,
			ICL_TYPE_POINTER, tdc,
			ICL_TYPE_OFFSET, ICL_HANDLE_OFFSET(avc->m.Length));
	if (!tdc) {
	    return EIO;
	}
	/* otherwise we have the data loaded, go for it */
	if (len > 1024) {
	    afs_PutDCache(tdc);
	    return EFAULT;
	}
	if (avc->m.Mode	& 0111)	alen = len+1;	/* regular link */
	else alen = len;			/* mt point */
	rbuf = (char *) osi_AllocLargeSpace(AFS_LRALLOCSIZ);
	tlen = len;
	ObtainReadLock(&tdc->lock);
	tfile = osi_UFSOpen (tdc->f.inode);
	code = afs_osi_Read(tfile, -1, rbuf, tlen);
	osi_UFSClose(tfile);
	ReleaseReadLock(&tdc->lock);
	afs_PutDCache(tdc);
	rbuf[alen-1] = '\0';
	alen = strlen(rbuf) + 1;
	tp = afs_osi_Alloc(alen);	/* make room for terminating null */
	memcpy(tp, rbuf, alen);
	osi_FreeLargeSpace(rbuf);
	if (code != tlen) {
	    afs_osi_Free(tp, alen);
	    return EIO;
	}
	avc->linkData = tp;
    }
    return 0;
}

int
afs_readlink(OSI_VC_ARG(avc), auio, acred)
    OSI_VC_DECL(avc);
    struct uio *auio;
    struct AFS_UCRED *acred; 
{
    register afs_int32 code;
    struct vrequest treq;
    register char *tp;
    struct afs_fakestat_state fakestat;
    OSI_VC_CONVERT(avc)

    AFS_STATCNT(afs_readlink);
    afs_Trace1(afs_iclSetp, CM_TRACE_READLINK, ICL_TYPE_POINTER, avc);
    if ((code = afs_InitReq(&treq, acred))) return code;
    afs_InitFakeStat(&fakestat);
    code = afs_EvalFakeStat(&avc, &fakestat, &treq);
    if (code) goto done;
    code = afs_VerifyVCache(avc, &treq);
    if (code) goto done;
    if (vType(avc) != VLNK) {
	code = EINVAL;
	goto done;
    }
    ObtainWriteLock(&avc->lock,158);
    code = afs_HandleLink(avc, &treq);
    /* finally uiomove it to user-land */
    if (code == 0) {
	tp = avc->linkData;
	if (tp) AFS_UIOMOVE(tp, strlen(tp), UIO_READ, auio, code);
	else {
	    code = EIO;
	}
    }
    ReleaseWriteLock(&avc->lock);
done:
    afs_PutFakeStat(&fakestat);
    code = afs_CheckCode(code, &treq, 32);
    return code;
}