Fix some serious bugs in fsrecover.

When a corrupted record is found, it guesses a location for the next
good transaction header.  If the guessed location happened to have a
'c' character at just the right spot, it would think it was at the end
of the file.

Fix in off-by-one bug in scan() that lead to failure.

Do more sanity checks for invalid transaction headers following a
scan.

Use restore() instead of store() to copy data.  This change should
maximize the chance that the recovered storage is identical except for
the damaged records.

Add tests from the trunk and remove test in testFileStorage.

src/ZODB/fsrecover.py

@@ -11,8 +11,6 @@
 # FOR A PARTICULAR PURPOSE
 #
 ##############################################################################
-
-
 """Simple script for repairing damaged FileStorage files.
 
 Usage: %s [-f] input output
@@ -94,64 +92,92 @@ class ErrorFound(Exception): pass
 def error(mess, *args):
     raise ErrorFound(mess % args)
 
-def read_transaction_header(file, pos, file_size):
+def read_txn_header(f, pos, file_size, outp, ltid):
     # Read the transaction record
-    file.seek(pos)
-    h = file.read(23)
+    f.seek(pos)
+    h = f.read(23)
     if len(h) < 23:
         raise EOFError
 
     tid, stl, status, ul, dl, el = unpack(">8s8scHHH",h)
     if el < 0: el=t32-el
 
-    tl=u64(stl)
-
-    if status=='c': raise EOFError
+    tl = u64(stl)
 
-    if pos+(tl+8) > file_size:
+    if pos + (tl + 8) > file_size:
         error("bad transaction length at %s", pos)
 
-    if status not in ' up':
-        error('invalid status, %s, at %s', status, pos)
+    if tl < (23 + ul + dl + el):
+        error("invalid transaction length, %s, at %s", tl, pos)
+
+    if ltid and tid < ltid:
+        error("time-stamp reducation %s < %s, at %s", u64(tid), u64(ltid), pos)
+
+    if status == "c":
+        truncate(f, pos, file_size, output)
+        raise EOFError
 
-    if tl < (23+ul+dl+el):
-        error('invalid transaction length, %s, at %s', tl, pos)
+    if status not in " up":
+        error("invalid status, %r, at %s", status, pos)
 
-    tpos=pos
-    tend=tpos+tl
+    tpos = pos
+    tend = tpos + tl
 
-    if status=='u':
+    if status == "u":
         # Undone transaction, skip it
-        file.seek(tend)
-        h = file.read(8)
+        f.seek(tend)
+        h = f.read(8)
         if h != stl:
-            error('inconsistent transaction length at %s', pos)
+            error("inconsistent transaction length at %s", pos)
         pos = tend + 8
-        return pos, None
+        return pos, None, tid
 
     pos = tpos+(23+ul+dl+el)
-    user = file.read(ul)
-    description = file.read(dl)
+    user = f.read(ul)
+    description = f.read(dl)
     if el:
-        try: e=loads(file.read(el))
+        try: e=loads(f.read(el))
         except: e={}
     else: e={}
 
     result = RecordIterator(tid, status, user, description, e, pos, tend,
-                            file, tpos)
-    pos=tend
+                            f, tpos)
+    pos = tend
 
     # Read the (intentionally redundant) transaction length
-    file.seek(pos)
-    h = file.read(8)
+    f.seek(pos)
+    h = f.read(8)
     if h != stl:
         error("redundant transaction length check failed at %s", pos)
     pos += 8
 
-    return pos, result
+    return pos, result, tid
+
+def truncate(f, pos, file_size, outp):
+    """Copy data from pos to end of f to a .trNNN file."""
+
+    i = 0
+    while 1:
+        trname = outp + ".tr%d" % i
+        if os.path.exists(trname):
+            i += 1
+    tr = open(trname, "wb")
+    copy(f, tr, file_size - pos)
+    f.seek(pos)
+    tr.close()
+
+def copy(src, dst, n):
+    while n:
+        buf = src.read(8096)
+        if not buf:
+            break
+        if len(buf) > n:
+            buf = buf[:n]
+        dst.write(buf)
+        n -= len(buf)
 
-def scan(file, pos):
-    """Return a potential transaction location following pos in file.
+def scan(f, pos):
+    """Return a potential transaction location following pos in f.
 
     This routine scans forward from pos looking for the last data
     record in a transaction.  A period '.' always occurs at the end of
@@ -163,30 +189,30 @@ def scan(file, pos):
     actually a transaction header.
     """
     while 1:
-        file.seek(pos)
-        data = file.read(8096)
+        f.seek(pos)
+        data = f.read(8096)
         if not data:
             return 0
 
         s = 0
         while 1:
-            l = data.find('.', s)
+            l = data.find(".", s)
             if l < 0:
                 pos += len(data)
                 break
             # If we are less than 8 bytes from the end of the
             # string, we need to read more data.
-            if l > len(data) - 8:
+            s = l + 1
+            if s > len(data) - 8:
                 pos += l
                 break
-            s = l + 1
             tl = u64(data[s:s+8])
             if tl < pos:
                 return pos + s + 8
 
 def iprogress(i):
     if i % 2:
-        print '.',
+        print ".",
     else:
         print (i/2) % 10,
     sys.stdout.flush()
@@ -197,7 +223,7 @@ def progress(p):
 
 def main():
     try:
-        opts, (inp, outp) = getopt.getopt(sys.argv[1:], 'fv:pP:')
+        opts, (inp, outp) = getopt.getopt(sys.argv[1:], "fv:pP:")
     except getopt.error:
         die()
         print __doc__ % argv[0]
@@ -205,58 +231,63 @@ def main():
     force = partial = verbose = 0
     pack = None
     for opt, v in opts:
-        if opt == '-v':
+        if opt == "-v":
             verbose = int(v)
-        elif opt == '-p':
+        elif opt == "-p":
             partial = 1
-        elif opt == '-f':
+        elif opt == "-f":
             force = 1
-        elif opt == '-P':
+        elif opt == "-P":
             pack = time.time() - float(v)
 
     recover(inp, outp, verbose, partial, force, pack)
 
 def recover(inp, outp, verbose=0, partial=0, force=0, pack=0):
-    print 'Recovering', inp, 'into', outp
+    print "Recovering", inp, "into", outp
 
     if os.path.exists(outp) and not force:
         die("%s exists" % outp)
 
-    file = open(inp, "rb")
-    if file.read(4) != ZODB.FileStorage.packed_version:
+    f = open(inp, "rb")
+    if f.read(4) != ZODB.FileStorage.packed_version:
         die("input is not a file storage")
 
-    file.seek(0,2)
-    file_size = file.tell()
+    f.seek(0,2)
+    file_size = f.tell()
 
     ofs = ZODB.FileStorage.FileStorage(outp, create=1)
     _ts = None
     ok = 1
     prog1 = 0
-    preindex = {}
     undone = 0
 
     pos = 4
+    ltid = None
     while pos:
         try:
-            npos, transaction = read_transaction_header(file, pos, file_size)
+            npos, txn, tid = read_txn_header(f, pos, file_size, outp, ltid)
         except EOFError:
             break
-        except:
-            print "\n%s: %s\n" % sys.exc_info()[:2]
+        except (KeyboardInterrupt, SystemExit):
+            raise
+        except Exception, err:
+            print "error reading txn header:", err
             if not verbose:
                 progress(prog1)
-            pos = scan(file, pos)
+            pos = scan(f, pos)
+            if verbose > 1:
+                print "looking for valid txn header at", pos
             continue
+        ltid = tid
 
-        if transaction is None:
+        if txn is None:
             undone = undone + npos - pos
             pos = npos
             continue
         else:
             pos = npos
 
-        tid = transaction.tid
+        tid = txn.tid
 
         if _ts is None:
             _ts = TimeStamp(tid)
@@ -264,58 +295,59 @@ def recover(inp, outp, verbose=0, partial=0, force=0, pack=0):
             t = TimeStamp(tid)
             if t <= _ts:
                 if ok:
-                    print ('Time stamps out of order %s, %s' % (_ts, t))
+                    print ("Time stamps out of order %s, %s" % (_ts, t))
                 ok = 0
                 _ts = t.laterThan(_ts)
                 tid = `_ts`
             else:
                 _ts = t
                 if not ok:
-                    print ('Time stamps back in order %s' % (t))
+                    print ("Time stamps back in order %s" % (t))
                     ok = 1
 
-        if verbose:
-            print 'begin',
-            if verbose > 1:
-                print
-            sys.stdout.flush()
-
-        ofs.tpc_begin(transaction, tid, transaction.status)
+        ofs.tpc_begin(txn, tid, txn.status)
 
         if verbose:
-            print 'begin', pos, _ts,
+            print "begin", pos, _ts,
             if verbose > 1:
                 print
             sys.stdout.flush()
 
         nrec = 0
         try:
-            for r in transaction:
-                oid = r.oid
+            for r in txn:
                 if verbose > 1:
-                    print u64(oid), r.version, len(r.data)
-                pre = preindex.get(oid)
-                s = ofs.store(oid, pre, r.data, r.version, transaction)
-                preindex[oid] = s
+                    if r.data is None:
+                        l = "bp"
+                    else:
+                        l = len(r.data)
+                        
+                    print "%7d %s %s" % (u64(r.oid), l, r.version)
+                s = ofs.restore(r.oid, r.serial, r.data, r.version,
+                                r.data_txn, txn)
                 nrec += 1
-        except:
+        except (KeyboardInterrupt, SystemExit):
+            raise
+        except Exception, err:
             if partial and nrec:
-                ofs._status = 'p'
-                ofs.tpc_vote(transaction)
-                ofs.tpc_finish(transaction)
+                ofs._status = "p"
+                ofs.tpc_vote(txn)
+                ofs.tpc_finish(txn)
                 if verbose:
-                    print 'partial'
+                    print "partial"
             else:
-                ofs.tpc_abort(transaction)
-            print "\n%s: %s\n" % sys.exc_info()[:2]
+                ofs.tpc_abort(txn)
+            print "error copying transaction:", err
             if not verbose:
                 progress(prog1)
-            pos = scan(file, pos)
+            pos = scan(f, pos)
+            if verbose > 1:
+                print "looking for valid txn header at", pos
         else:
-            ofs.tpc_vote(transaction)
-            ofs.tpc_finish(transaction)
+            ofs.tpc_vote(txn)
+            ofs.tpc_finish(txn)
             if verbose:
-                print 'finish'
+                print "finish"
                 sys.stdout.flush()
 
         if not verbose:
@@ -338,7 +370,6 @@ def recover(inp, outp, verbose=0, partial=0, force=0, pack=0):
 
     ofs.close()
 
-
-if __name__ == '__main__':
+if __name__ == "__main__":
     main()