/* called with locked scp; ensures that we have an ACL cache entry for the
* user specified by the parameter "userp."
* In pathological race conditions, this function may return success without
* having loaded the entry properly (due to a racing callback revoke), so this
* function must also be called in a while loop to make sure that we eventually
* succeed.
*/
long cm_GetAccessRights(struct cm_scache *scp, struct cm_user *userp,
struct cm_req *reqp)
{
long code;
cm_fid_t tfid;
cm_scache_t *aclScp = NULL;
int got_cb = 0;
cm_volume_t * volp = cm_FindVolumeByFID(&scp->fid, userp, reqp);
/* pretty easy: just force a pass through the fetch status code */
osi_Log2(afsd_logp, "GetAccessRights scp 0x%p user 0x%p", scp, userp);
/* first, start by finding out whether we have a directory or something
* else, so we can find what object's ACL we need.
*/
if (scp->fileType == CM_SCACHETYPE_DIRECTORY ||
cm_accessPerFileCheck ||
!volp || (volp->flags & CM_VOLUMEFLAG_DFS_VOLUME))
{
code = cm_SyncOp(scp, NULL, userp, reqp, 0,
CM_SCACHESYNC_NEEDCALLBACK | CM_SCACHESYNC_GETSTATUS | CM_SCACHESYNC_FORCECB);
if (!code)
cm_SyncOpDone(scp, NULL, CM_SCACHESYNC_NEEDCALLBACK | CM_SCACHESYNC_GETSTATUS);
else
osi_Log3(afsd_logp, "GetAccessRights syncop failure scp %x user %x code %x", scp, userp, code);
} else {
/* not a dir, use parent dir's acl */
cm_SetFid(&tfid, scp->fid.cell, scp->fid.volume, scp->parentVnode, scp->parentUnique);
lock_ReleaseWrite(&scp->rw);
code = cm_GetSCache(&tfid, NULL, &aclScp, userp, reqp);
if (code) {
lock_ObtainWrite(&scp->rw);
goto _done;
}
osi_Log2(afsd_logp, "GetAccessRights parent scp %x user %x", aclScp, userp);
lock_ObtainWrite(&aclScp->rw);
code = cm_SyncOp(aclScp, NULL, userp, reqp, 0,
CM_SCACHESYNC_NEEDCALLBACK | CM_SCACHESYNC_GETSTATUS | CM_SCACHESYNC_FORCECB);
if (!code)
cm_SyncOpDone(aclScp, NULL,
CM_SCACHESYNC_NEEDCALLBACK | CM_SCACHESYNC_GETSTATUS);
else
osi_Log3(afsd_logp, "GetAccessRights parent syncop failure scp %x user %x code %x", aclScp, userp, code);
lock_ReleaseWrite(&aclScp->rw);
cm_ReleaseSCache(aclScp);
lock_ObtainWrite(&scp->rw);
}
_done:
if (volp)
cm_PutVolume(volp);
return code;
}
/* called with scp write-locked, check to see if we have the ACL info we need
* and can get it w/o blocking for any locks.
*
* Never drops the scp lock, but may fail if the access control info comes from
* the parent directory, and the parent's scache entry can't be found, or it
* can't be locked. Thus, this must always be called in a while loop to stabilize
* things, since we can always lose the race condition getting to the parent vnode.
*/
int cm_HaveAccessRights(struct cm_scache *scp, struct cm_user *userp, afs_uint32 rights,
afs_uint32 *outRightsp)
{
cm_scache_t *aclScp;
long code;
cm_fid_t tfid;
int didLock;
long trights;
int release = 0; /* Used to avoid a call to cm_HoldSCache in the directory case */
didLock = 0;
if (scp->fileType == CM_SCACHETYPE_DIRECTORY || cm_accessPerFileCheck) {
aclScp = scp; /* not held, not released */
} else {
cm_SetFid(&tfid, scp->fid.cell, scp->fid.volume, scp->parentVnode, scp->parentUnique);
aclScp = cm_FindSCache(&tfid);
if (!aclScp)
return 0;
if (aclScp != scp) {
if (aclScp->fid.vnode < scp->fid.vnode)
lock_ReleaseWrite(&scp->rw);
lock_ObtainRead(&aclScp->rw);
if (aclScp->fid.vnode < scp->fid.vnode)
lock_ObtainWrite(&scp->rw);
/* check that we have a callback, too */
if (!cm_HaveCallback(aclScp)) {
/* can't use it */
lock_ReleaseRead(&aclScp->rw);
cm_ReleaseSCache(aclScp);
return 0;
}
didLock = 1;
}
release = 1;
}
lock_AssertAny(&aclScp->rw);
/* now if rights is a subset of the public rights, we're done.
* Otherwise, if we an explicit acl entry, we're also in good shape,
* and can definitively answer.
*/
#ifdef AFS_FREELANCE_CLIENT
if (cm_freelanceEnabled &&
aclScp->fid.cell==AFS_FAKE_ROOT_CELL_ID &&
aclScp->fid.volume==AFS_FAKE_ROOT_VOL_ID)
{
*outRightsp = aclScp->anyAccess;
} else
#endif
if ((~aclScp->anyAccess & rights) == 0) {
*outRightsp = rights;
} else {
/* we have to check the specific rights info */
code = cm_FindACLCache(aclScp, userp, &trights);
if (code) {
code = 0;
goto done;
}
*outRightsp = trights;
}
if (scp->fileType > 0 && scp->fileType != CM_SCACHETYPE_DIRECTORY) {
/* check mode bits */
if ((scp->unixModeBits & 0400) == 0) {
osi_Log2(afsd_logp,"cm_HaveAccessRights UnixMode removing READ scp 0x%p unix 0%o",
scp, scp->unixModeBits);
*outRightsp &= ~PRSFS_READ;
}
if ((scp->unixModeBits & 0200) == 0 && (rights != (PRSFS_WRITE | PRSFS_LOCK))) {
osi_Log2(afsd_logp,"cm_HaveAccessRights UnixMode removing WRITE scp 0x%p unix 0%o",
scp, scp->unixModeBits);
*outRightsp &= ~PRSFS_WRITE;
}
if ((scp->unixModeBits & 0200) == 0 && !cm_deleteReadOnly) {
osi_Log2(afsd_logp,"cm_HaveAccessRights UnixMode removing DELETE scp 0x%p unix 0%o",
scp, scp->unixModeBits);
*outRightsp &= ~PRSFS_DELETE;
}
}
/* if the user can insert, we must assume they can read/write as well
* because we do not have the ability to determine if the current user
* is the owner of the file. We will have to make the call to the
* file server and let the file server tell us if the request should
* be denied.
*/
if ((*outRightsp & PRSFS_INSERT) && (scp->creator == userp))
*outRightsp |= PRSFS_READ | PRSFS_WRITE;
/* if the user can obtain a write-lock, read-locks are implied */
if (*outRightsp & PRSFS_WRITE)
*outRightsp |= PRSFS_LOCK;
code = 1;
/* fall through */
done:
if (didLock)
lock_ReleaseRead(&aclScp->rw);
if (release)
cm_ReleaseSCache(aclScp);
return code;
}
