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Commit 6e2383e5 authored by Jeremy Hylton's avatar Jeremy Hylton
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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.
parent 2267079d
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Showing with 113 additions and 82 deletions
src/ZODB/fsrecover.py
View file @ 6e2383e5
......@@ -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 scan(file, pos):
"""Return a potential transaction location following pos in file.
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(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()
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