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gpgfs
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Add rollback code when writing the index file fails

This commit is contained in:
Jarno Seppänen 2014-05-01 22:22:00 +03:00
parent 37c47591ba
commit 6a9ef541ab
1 changed files with 110 additions and 31 deletions
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141
gpgfs.py
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@ -18,12 +18,17 @@ magic = 'GPGFS1\n'
log = logging.getLogger(__name__) log = logging.getLogger(__name__)
def decrypt(gpg, path): def decrypt(gpg, path):
data = file(path).read() try:
data = file(path).read()
except IOError, err:
log.error("read failed: %s: %s", path, str(err))
raise FuseOSError(err.errno)
if not data: if not data:
return data return data
res = gpg.decrypt(data) res = gpg.decrypt(data)
if not res.ok: if not res.ok:
raise IOError, "decryption failed, %s" % path log.error("decryption failed, %s: %s", res.status, path)
raise FuseOSError(errno.EIO)
data = zlib.decompress(res.data) data = zlib.decompress(res.data)
log.debug('decrypted %s' % path) log.debug('decrypted %s' % path)
return data return data
@ -32,9 +37,19 @@ def encrypt(gpg, keyid, path, data):
data = zlib.compress(data, 1) data = zlib.compress(data, 1)
res = gpg.encrypt(data, keyid, armor=False) res = gpg.encrypt(data, keyid, armor=False)
if not res.ok: if not res.ok:
raise IOError, "encryption failed, keyid %s, path %s" % (keyid, path) log.error("encryption failed (keyid %s), %s: %s",
with file(path, 'w') as fd: keyid, res.status, path)
fd.write(res.data) raise FuseOSError(errno.EIO)
try:
with file(path+'.tmp', 'w') as fd:
fd.write(res.data)
os.rename(path+'.tmp', path)
except IOError, err:
log.error("write failed: %s: %s", path, str(err))
raise FuseOSError(err.errno)
finally:
try: os.remove(path+'.tmp')
except: pass
log.debug('encrypted %s' % path) log.debug('encrypted %s' % path)
class Entry: class Entry:
@ -168,8 +183,8 @@ class GpgFs(LoggingMixIn, Operations):
self.fd = 0 self.fd = 0
self._clear_write_cache() self._clear_write_cache()
def _write_index(self): def _write_index(self, suffix=''):
write_index(self.gpg, self.keyid, self.index_path, self.root) write_index(self.gpg, self.keyid, self.index_path + suffix, self.root)
def _find(self, path, parent=False): def _find(self, path, parent=False):
assert path.startswith('/') assert path.startswith('/')
@ -199,8 +214,13 @@ class GpgFs(LoggingMixIn, Operations):
mode &= 0777 mode &= 0777
ent = self._find(path) ent = self._find(path)
if ent.type == ENT_DIR: if ent.type == ENT_DIR:
prev_mode = ent.st_mode
ent.st_mode = mode ent.st_mode = mode
self._write_index() try:
self._write_index()
except:
ent.st_mode = prev_mode
raise
else: else:
encpath = self.encroot + '/' + ent.path encpath = self.encroot + '/' + ent.path
os.chmod(encpath, mode) os.chmod(encpath, mode)
@ -214,16 +234,24 @@ class GpgFs(LoggingMixIn, Operations):
dir, path = self._find(path, parent=True) dir, path = self._find(path, parent=True)
if path in dir.children: if path in dir.children:
raise FuseOSError(errno.EEXIST) raise FuseOSError(errno.EEXIST)
dir.children[path] = Entry(type=ENT_FILE, path=encpath, st_size=0)
log.debug('new path %s => %s', path, encpath)
encdir = self.encroot + '/' + encpath[:2] encdir = self.encroot + '/' + encpath[:2]
if not os.path.exists(encdir): if not os.path.exists(encdir):
os.mkdir(encdir, 0755) os.mkdir(encdir, 0755)
fd = os.open(self.encroot + '/' + encpath, fd = os.open(self.encroot + '/' + encpath,
os.O_WRONLY | os.O_CREAT, mode & 0777) os.O_WRONLY | os.O_CREAT, mode & 0777)
os.close(fd) os.close(fd)
prev_mtime = dir.st_mtime
dir.children[path] = Entry(type=ENT_FILE, path=encpath, st_size=0)
log.debug('new path %s => %s', path, encpath)
dir.st_mtime = int(time.time()) dir.st_mtime = int(time.time())
self._write_index() try:
self._write_index()
except:
try: os.remove(self.encroot + '/' + encpath)
except: pass
del dir.children[path]
dir.st_mtime = prev_mtime
raise
self.fd += 1 self.fd += 1
return self.fd return self.fd
@ -234,10 +262,19 @@ class GpgFs(LoggingMixIn, Operations):
ent = self._find(self.write_path) ent = self._find(self.write_path)
encpath = self.encroot + '/' + ent.path encpath = self.encroot + '/' + ent.path
buf = ''.join(self.write_buf) buf = ''.join(self.write_buf)
encrypt(self.gpg, self.keyid, encpath, buf)
ent.st_size = len(buf)
self._write_index()
self.write_buf = [buf] self.write_buf = [buf]
encrypt(self.gpg, self.keyid, encpath+'.new', buf)
prev_size = ent.st_size
ent.st_size = len(buf)
try:
self._write_index(suffix='.new')
except:
os.remove(encpath+'.new')
ent.st_size = prev_size
raise
# FIXME renames cannot fail, right?
os.rename(encpath+'.new', encpath)
os.rename(self.index_path+'.new', self.index_path)
self.write_dirty = False self.write_dirty = False
log.debug('flushed %d bytes to %s', len(buf), self.write_path) log.debug('flushed %d bytes to %s', len(buf), self.write_path)
return 0 return 0
@ -266,12 +303,18 @@ class GpgFs(LoggingMixIn, Operations):
dir, path = self._find(path, parent=True) dir, path = self._find(path, parent=True)
if path in dir.children: if path in dir.children:
raise FuseOSError(errno.EEXIST) raise FuseOSError(errno.EEXIST)
prev_mtime = dir.st_mtime
dir.children[path] = Entry(type=ENT_DIR, children={}, dir.children[path] = Entry(type=ENT_DIR, children={},
st_mode=(mode & 0777), st_mode=(mode & 0777),
st_mtime=int(time.time()), st_mtime=int(time.time()),
st_ctime=int(time.time())) st_ctime=int(time.time()))
dir.st_mtime = int(time.time()) dir.st_mtime = int(time.time())
self._write_index() try:
self._write_index()
except:
del dir.children[path]
dir.st_mtime = prev_mtime
raise
def open(self, path, flags): def open(self, path, flags):
return 0 return 0
@ -301,15 +344,24 @@ class GpgFs(LoggingMixIn, Operations):
if old_name not in old_dir.children: if old_name not in old_dir.children:
raise FuseOSError(errno.ENOENT) raise FuseOSError(errno.ENOENT)
new_dir, new_name = self._find(new, parent=True) new_dir, new_name = self._find(new, parent=True)
if new_name in new_dir.children: prev_ent = new_dir.children.get(new_name)
ent = new_dir.children[new_name] if prev_ent and prev_ent.type == ENT_DIR and prev_ent.children:
if ent.type == ENT_FILE: raise FuseOSError(errno.ENOTEMPTY)
os.remove(self.encroot + '/' + ent.path) prev_old_mtime = old_dir.st_mtime
elif ent.children: prev_new_mtime = new_dir.st_mtime
raise FuseOSError(errno.ENOTEMPTY)
new_dir.children[new_name] = old_dir.children.pop(old_name) new_dir.children[new_name] = old_dir.children.pop(old_name)
old_dir.st_mtime = new_dir.st_mtime = int(time.time()) old_dir.st_mtime = new_dir.st_mtime = int(time.time())
self._write_index() try:
self._write_index()
except:
old_dir.children[old_name] = new_dir.children.pop(new_name)
if prev_ent:
new_dir.children[new_name] = prev_ent
old_dir.st_mtime = prev_old_mtime
new_dir.st_mtime = prev_new_mtime
raise
if prev_ent and prev_ent.type == ENT_FILE:
os.remove(self.encroot + '/' + prev_ent.path)
def rmdir(self, path): def rmdir(self, path):
parent, path = self._find(path, parent=True) parent, path = self._find(path, parent=True)
@ -320,9 +372,15 @@ class GpgFs(LoggingMixIn, Operations):
raise FuseOSError(errno.ENOTDIR) raise FuseOSError(errno.ENOTDIR)
if ent.children: if ent.children:
raise FuseOSError(errno.ENOTEMPTY) raise FuseOSError(errno.ENOTEMPTY)
prev_mtime = parent.st_mtime
del parent.children[path] del parent.children[path]
parent.st_mtime = int(time.time()) parent.st_mtime = int(time.time())
self._write_index() try:
self._write_index()
except:
parent.children[path] = ent
parent.st_mtime = prev_mtime
raise
def setxattr(self, path, name, value, options, position = 0): def setxattr(self, path, name, value, options, position = 0):
raise FuseOSError(errno.ENOSYS) raise FuseOSError(errno.ENOSYS)
@ -339,14 +397,23 @@ class GpgFs(LoggingMixIn, Operations):
ent = self._find(path) ent = self._find(path)
encpath = self.encroot + '/' + ent.path encpath = self.encroot + '/' + ent.path
if length == 0: if length == 0:
with open(encpath, 'r+') as f: with open(encpath+'.new', 'w') as f:
f.truncate(0) pass
else: else:
buf = decrypt(self.gpg, encpath) buf = decrypt(self.gpg, encpath)
buf = buf[:length] buf = buf[:length]
encrypt(self.gpg, self.keyid, encpath, buf) encrypt(self.gpg, self.keyid, encpath+'.new', buf)
prev_size = ent.st_size
ent.st_size = length ent.st_size = length
self._write_index() try:
self._write_index(suffix='.new')
except:
ent.st_size = prev_size
os.remove(encpath+'.new')
raise
# FIXME renames cannot fail, right?
os.rename(encpath+'.new', encpath)
os.rename(self.index_path+'.new', self.index_path)
def unlink(self, path): def unlink(self, path):
if self.write_path == path: if self.write_path == path:
@ -355,20 +422,32 @@ class GpgFs(LoggingMixIn, Operations):
dir, name = self._find(path, parent=True) dir, name = self._find(path, parent=True)
if name not in dir.children: if name not in dir.children:
raise FuseOSError(errno.ENOENT) raise FuseOSError(errno.ENOENT)
encpath = self.encroot + '/' + dir.children[name].path ent = dir.children[name]
os.remove(encpath) encpath = self.encroot + '/' + ent.path
del dir.children[name] del dir.children[name]
prev_mtime = dir.st_mtime
dir.st_mtime = int(time.time()) dir.st_mtime = int(time.time())
self._write_index() try:
self._write_index()
except:
dir.children[name] = ent
dir.st_mtime = prev_mtime
raise
os.remove(encpath)
def utimens(self, path, times = None): def utimens(self, path, times = None):
ent = self._find(path) ent = self._find(path)
if ent.type == ENT_DIR: if ent.type == ENT_DIR:
prev_mtime = ent.st_mtime
if times is None: if times is None:
ent.st_mtime = int(time.time()) ent.st_mtime = int(time.time())
else: else:
ent.st_mtime = times[1] ent.st_mtime = times[1]
self._write_index() try:
self._write_index()
except:
ent.st_mtime = prev_mtime
raise
else: else:
# flush may mess with mtime # flush may mess with mtime
self.flush(path, 0) self.flush(path, 0)