nfs: support ability to set file checksum(s) via dot command

Motivation:

Some admin scripts (such as client to enstore) will need this
ability in the near future.

Modification:

Add the operation type to PSET.  Support overwrite and multiple
sets only if user is ROOT.

Result:

Requirement satisfied.

Target: master
Requires-book: yes
Requires-notes: yes
Patch: https://rb.dcache.org/r/11923
Acked-by: Tigran

docs/TheBook/src/main/markdown/rf-dot-commands.md

@@ -68,6 +68,47 @@ A comma-delimited list of `type:value` pairs for all checksums stored in the dat
     $ cat ".(get)(test_file-Thu_Oct_23_10:39:37_CDT_2014-109)(checksums)"
     $ ADLER32:66300001
 
+## SET CHECKSUM
+
+Set a checksum value for a file.   An ordinary user can only set one
+checksum (type, value) pair, and cannot overwrite existing values.  A ROOT
+user is allowed to set multiple types (successively) and also to overwrite
+values for any type.
+
+### USAGE:
+
+    touch ".(fset)(<filename>)(checksum)(<type>)(<value>)"
+
+##### EXAMPLES:
+
+    [arossi@otfrid volatile]$ touch testfile
+
+    [arossi@otfrid volatile]$ cat ".(get)(testfile)(checksum)"
+
+    [arossi@otfrid volatile]$ touch ".(fset)(testfile)(checksum)(ADLER32)(ffffffff)"
+
+    [arossi@otfrid volatile]$ cat ".(get)(testfile)(checksum)"
+    ADLER32:ffffffff
+
+    [arossi@otfrid volatile]$ touch ".(fset)(testfile)(checksum)(ADLER32)(fffffff0)"
+    touch: setting times of ‘.(fset)(testfile)(checksum)(ADLER32)(fffffff0)’: Operation not permitted
+
+    [arossi@otfrid volatile]$ ksu
+    Authenticated arossi@FNAL.GOV
+    Account root: authorization for arossi@FNAL.GOV successful
+    Changing uid to root (0)
+
+    [root@otfrid volatile]# touch ".(fset)(testfile)(checksum)(ADLER32)(fffffff0)"
+
+    [root@otfrid volatile]# cat ".(get)(testfile)(checksum)"
+    ADLER32:fffffff0
+
+    [root@otfrid volatile]# touch ".(fset)(testfile)(checksum)(MD5)(12341234123412345678567856785678)"
+
+    [root@otfrid volatile]# cat ".(get)(testfile)(checksum)"
+    ADLER32:fffffff0, MD5:12341234123412345678567856785678
+
+
 ## GET PIN(S)
 
 Get pins on a given file.

modules/chimera/src/main/java/org/dcache/chimera/FsInode_PCRC.java

@@ -28,33 +28,29 @@
  * @author arossi
  */
 public class FsInode_PCRC extends FsInode_PGET {
-    private String _checksum;
 
     public FsInode_PCRC(FileSystemProvider fs, long ino) {
         super(fs, ino, FsInodeType.PCRC);
     }
 
     protected String value() throws ChimeraFsException {
-        if (_checksum == null) {
-            Set<Checksum> results = _fs.getInodeChecksums(this);
-            StringBuilder sb = new StringBuilder();
-
-            Iterator<Checksum> it = results.iterator();
-            if (it.hasNext()) {
-                Checksum result = it.next();
-                sb.append(result.getType()).append(':').append(
-                                result.getValue());
-            }
-
-            while (it.hasNext()) {
-                Checksum result = it.next();
-                sb.append(", ").append(result.getType()).append(':').append(
-                                result.getValue());
-            }
-
-            sb.append(NEWLINE);
-            _checksum = sb.toString();
+        Set<Checksum> results = _fs.getInodeChecksums(this);
+        StringBuilder sb = new StringBuilder();
+
+        Iterator<Checksum> it = results.iterator();
+        if (it.hasNext()) {
+            Checksum result = it.next();
+            sb.append(result.getType()).append(':').append(
+                            result.getValue());
         }
-        return _checksum;
+
+        while (it.hasNext()) {
+            Checksum result = it.next();
+            sb.append(", ").append(result.getType()).append(':').append(
+                            result.getValue());
+        }
+
+        sb.append(NEWLINE);
+        return sb.toString();
     }
 }

modules/chimera/src/main/java/org/dcache/chimera/FsInode_PSET.java

@@ -19,16 +19,20 @@
 import com.google.common.base.Charsets;
 
 import java.util.Arrays;
+import java.util.Set;
 import java.util.concurrent.TimeUnit;
 
 import org.dcache.chimera.posix.Stat;
+import org.dcache.util.Checksum;
+import org.dcache.util.ChecksumType;
 
 public class FsInode_PSET extends FsInode {
-    private static final String SIZE = "size";
-    private static final String IO = "io";
-    private static final String ONLN = "bringonline";
-    private static final String STG = "stage";
-    private static final String PIN = "pin";
+    private static final String SIZE   = "size";
+    private static final String IO     = "io";
+    private static final String ONLN   = "bringonline";
+    private static final String STG    = "stage";
+    private static final String PIN    = "pin";
+    private static final String CKS    = "checksum";
 
     private final String[] _args;
 
@@ -42,6 +46,8 @@ public boolean isDirectory() {
         return false;
     }
 
+    public boolean isChecksum() { return CKS.equals(_args[0]); }
+
     @Override
     public int read(long pos, byte[] data, int offset, int len) {
         return -1;
@@ -70,10 +76,12 @@ public void setStat(Stat newStat) throws ChimeraFsException
                 case PIN:
                     handlePinRequest();
                     break;
+                case CKS:
+                    handleSetChecksum();
+                    break;
                 default:
                     break;
             }
-
         }
     }
 
@@ -152,4 +160,37 @@ private void handlePinRequest() throws ChimeraFsException {
             _fs.pin(new FsInode(_fs, ino()), lifetime);
         }
     }
+
+    /*
+     *  This method allows overwrite only with ROOT access.
+     *  It also allows a non-ROOT user to set only one checksum
+     *  (type, value) pair.
+     */
+    private void handleSetChecksum() throws ChimeraFsException {
+        if (_args.length != 3) {
+            throw new InvalidArgumentChimeraException("incorrect number of arguments.");
+        }
+
+        Set<Checksum> checksums = _fs.getInodeChecksums(this);
+        ChecksumType type = ChecksumType.getChecksumType(_args[1]);
+
+        try {
+            /*
+             * The filesystem implementation does not allow
+             * overwrite using the 'setInodeChecksum' method, so
+             * an explicit deletion is required.
+             */
+            if (checksums.stream().anyMatch(c -> type.equals(c.getType()))) {
+                _fs.removeInodeChecksum(this, type.getType());
+            }
+
+            Checksum cks = new Checksum(type, _args[2]);
+            _fs.setInodeChecksum(this, type.getType(), cks.getValue());
+        } catch (IllegalArgumentException e) {
+            throw new InvalidArgumentChimeraException("Invalid checksum: "
+                                                                      + _args[2]
+                                                                      + "; "
+                                                                      + e.getMessage());
+        }
+    }
 }

modules/dcache-nfs/src/main/java/org/dcache/chimera/nfsv41/door/ChimeraVfs.java

@@ -28,6 +28,7 @@
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.nio.charset.StandardCharsets;
+import java.security.AccessController;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.StringTokenizer;
@@ -96,6 +97,7 @@
 import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.dcache.chimera.FileSystemProvider.StatCacheOption.NO_STAT;
 import static org.dcache.chimera.FileSystemProvider.StatCacheOption.STAT;
+import static org.dcache.chimera.FsInodeType.PSET;
 import static org.dcache.nfs.v4.xdr.nfs4_prot.ACCESS4_EXTEND;
 import static org.dcache.nfs.v4.xdr.nfs4_prot.ACCESS4_MODIFY;
 import static org.dcache.nfs.v4.xdr.nfs4_prot.ACE4_INHERIT_ONLY_ACE;
@@ -318,6 +320,9 @@ public Stat getattr(Inode inode) throws IOException {
     public void setattr(Inode inode, Stat stat) throws IOException {
 	FsInode fsInode = toFsInode(inode);
         try {
+            if (shouldRejectAttributeUpdates(fsInode)) {
+                throw new PermException("setStat not allowed.");
+            }
             fsInode.setStat(toChimeraStat(stat));
         } catch (InvalidArgumentChimeraException e) {
             throw new InvalException(e.getMessage());
@@ -455,6 +460,18 @@ private boolean shouldRejectUpdates(FsInode fsInode) throws ChimeraFsException {
                     || !_fs.getInodeLocations(fsInode, StorageGenericLocation.DISK).isEmpty());
     }
 
+    private boolean shouldRejectAttributeUpdates(FsInode fsInode)
+                    throws ChimeraFsException {
+        return fsInode.type() == PSET
+                        && ((FsInode_PSET)fsInode).isChecksum()
+                        && !isRoot()
+                        && !_fs.getInodeChecksums(fsInode).isEmpty();
+    }
+
+    private boolean isRoot() {
+        return Subjects.isRoot(Subject.getSubject(AccessController.getContext()));
+    }
+
     @Override
     public boolean hasIOLayout(Inode inode) throws IOException {
         FsInode fsInode = toFsInode(inode);