inotify: raise correct error if server is already started in a deep repository

When path is too long to be an Unix socket address, we create a socket in a
temporary directory and link from the long path to the shorter one.
But checks in server code at startup were insufficient in this case, and used
to raise an unclear "tried linking .hg/inotify.sock to a temporary socket but
.hg/inotify.sock already exists"

hgext/inotify/server.py

@@ -1,489 +1,492
 # server.py - common entry point for inotify status server
 #
 # Copyright 2009 Nicolas Dumazet <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 from mercurial.i18n import _
 from mercurial import cmdutil, osutil, util
 import common
 
 import errno
 import os
 import socket
 import stat
 import struct
 import sys
 import tempfile
 
 class AlreadyStartedException(Exception):
     pass
 class TimeoutException(Exception):
     pass
 
 def join(a, b):
     if a:
         if a[-1] == '/':
             return a + b
         return a + '/' + b
     return b
 
 def split(path):
     c = path.rfind('/')
     if c == -1:
         return '', path
     return path[:c], path[c + 1:]
 
 walk_ignored_errors = (errno.ENOENT, errno.ENAMETOOLONG)
 
 def walk(dirstate, absroot, root):
     '''Like os.walk, but only yields regular files.'''
 
     # This function is critical to performance during startup.
 
     def walkit(root, reporoot):
         files, dirs = [], []
 
         try:
             fullpath = join(absroot, root)
             for name, kind in osutil.listdir(fullpath):
                 if kind == stat.S_IFDIR:
                     if name == '.hg':
                         if not reporoot:
                             return
                     else:
                         dirs.append(name)
                         path = join(root, name)
                         if dirstate._ignore(path):
                             continue
                         for result in walkit(path, False):
                             yield result
                 elif kind in (stat.S_IFREG, stat.S_IFLNK):
                     files.append(name)
             yield fullpath, dirs, files
 
         except OSError, err:
             if err.errno == errno.ENOTDIR:
                 # fullpath was a directory, but has since been replaced
                 # by a file.
                 yield fullpath, dirs, files
             elif err.errno not in walk_ignored_errors:
                 raise
 
     return walkit(root, root == '')
 
 class directory(object):
     """
     Representing a directory
 
     * path is the relative path from repo root to this directory
     * files is a dict listing the files in this directory
         - keys are file names
         - values are file status
     * dirs is a dict listing the subdirectories
         - key are subdirectories names
         - values are directory objects
     """
     def __init__(self, relpath=''):
         self.path = relpath
         self.files = {}
         self.dirs = {}
 
     def dir(self, relpath):
         """
         Returns the directory contained at the relative path relpath.
         Creates the intermediate directories if necessary.
         """
         if not relpath:
             return self
         l = relpath.split('/')
         ret = self
         while l:
             next = l.pop(0)
             try:
                 ret = ret.dirs[next]
             except KeyError:
                 d = directory(join(ret.path, next))
                 ret.dirs[next] = d
                 ret = d
         return ret
 
     def walk(self, states, visited=None):
         """
         yield (filename, status) pairs for items in the trees
         that have status in states.
         filenames are relative to the repo root
         """
         for file, st in self.files.iteritems():
             if st in states:
                 yield join(self.path, file), st
         for dir in self.dirs.itervalues():
             if visited is not None:
                 visited.add(dir.path)
             for e in dir.walk(states):
                 yield e
 
     def lookup(self, states, path, visited):
         """
         yield root-relative filenames that match path, and whose
         status are in states:
         * if path is a file, yield path
         * if path is a directory, yield directory files
         * if path is not tracked, yield nothing
         """
         if path[-1] == '/':
             path = path[:-1]
 
         paths = path.split('/')
 
         # we need to check separately for last node
         last = paths.pop()
 
         tree = self
         try:
             for dir in paths:
                 tree = tree.dirs[dir]
         except KeyError:
             # path is not tracked
             visited.add(tree.path)
             return
 
         try:
             # if path is a directory, walk it
             target = tree.dirs[last]
             visited.add(target.path)
             for file, st in target.walk(states, visited):
                 yield file
         except KeyError:
             try:
                 if tree.files[last] in states:
                     # path is a file
                     visited.add(tree.path)
                     yield path
             except KeyError:
                 # path is not tracked
                 pass
 
 class repowatcher(object):
     """
     Watches inotify events
     """
     statuskeys = 'almr!?'
 
     def __init__(self, ui, dirstate, root):
         self.ui = ui
         self.dirstate = dirstate
 
         self.wprefix = join(root, '')
         self.prefixlen = len(self.wprefix)
 
         self.tree = directory()
         self.statcache = {}
         self.statustrees = dict([(s, directory()) for s in self.statuskeys])
 
         self.ds_info = self.dirstate_info()
 
         self.last_event = None
 
 
     def handle_timeout(self):
         pass
 
     def dirstate_info(self):
         try:
             st = os.lstat(self.wprefix + '.hg/dirstate')
             return st.st_mtime, st.st_ino
         except OSError, err:
             if err.errno != errno.ENOENT:
                 raise
             return 0, 0
 
     def filestatus(self, fn, st):
         try:
             type_, mode, size, time = self.dirstate._map[fn][:4]
         except KeyError:
             type_ = '?'
         if type_ == 'n':
             st_mode, st_size, st_mtime = st
             if size == -1:
                 return 'l'
             if size and (size != st_size or (mode ^ st_mode) & 0100):
                 return 'm'
             if time != int(st_mtime):
                 return 'l'
             return 'n'
         if type_ == '?' and self.dirstate._dirignore(fn):
             # we must check not only if the file is ignored, but if any part
             # of its path match an ignore pattern
             return 'i'
         return type_
 
     def updatefile(self, wfn, osstat):
         '''
         update the file entry of an existing file.
 
         osstat: (mode, size, time) tuple, as returned by os.lstat(wfn)
         '''
 
         self._updatestatus(wfn, self.filestatus(wfn, osstat))
 
     def deletefile(self, wfn, oldstatus):
         '''
         update the entry of a file which has been deleted.
 
         oldstatus: char in statuskeys, status of the file before deletion
         '''
         if oldstatus == 'r':
             newstatus = 'r'
         elif oldstatus in 'almn':
             newstatus = '!'
         else:
             newstatus = None
 
         self.statcache.pop(wfn, None)
         self._updatestatus(wfn, newstatus)
 
     def _updatestatus(self, wfn, newstatus):
         '''
         Update the stored status of a file.
 
         newstatus: - char in (statuskeys + 'ni'), new status to apply.
                    - or None, to stop tracking wfn
         '''
         root, fn = split(wfn)
         d = self.tree.dir(root)
 
         oldstatus = d.files.get(fn)
         # oldstatus can be either:
         # - None : fn is new
         # - a char in statuskeys: fn is a (tracked) file
 
         if self.ui.debugflag and oldstatus != newstatus:
             self.ui.note(_('status: %r %s -> %s\n') %
                              (wfn, oldstatus, newstatus))
 
         if oldstatus and oldstatus in self.statuskeys \
             and oldstatus != newstatus:
             del self.statustrees[oldstatus].dir(root).files[fn]
 
         if newstatus in (None, 'i'):
             d.files.pop(fn, None)
         elif oldstatus != newstatus:
             d.files[fn] = newstatus
             if newstatus != 'n':
                 self.statustrees[newstatus].dir(root).files[fn] = newstatus
 
     def check_deleted(self, key):
         # Files that had been deleted but were present in the dirstate
         # may have vanished from the dirstate; we must clean them up.
         nuke = []
         for wfn, ignore in self.statustrees[key].walk(key):
             if wfn not in self.dirstate:
                 nuke.append(wfn)
         for wfn in nuke:
             root, fn = split(wfn)
             del self.statustrees[key].dir(root).files[fn]
             del self.tree.dir(root).files[fn]
 
     def update_hgignore(self):
         # An update of the ignore file can potentially change the
         # states of all unknown and ignored files.
 
         # XXX If the user has other ignore files outside the repo, or
         # changes their list of ignore files at run time, we'll
         # potentially never see changes to them.  We could get the
         # client to report to us what ignore data they're using.
         # But it's easier to do nothing than to open that can of
         # worms.
 
         if '_ignore' in self.dirstate.__dict__:
             delattr(self.dirstate, '_ignore')
             self.ui.note(_('rescanning due to .hgignore change\n'))
             self.handle_timeout()
             self.scan()
 
     def getstat(self, wpath):
         try:
             return self.statcache[wpath]
         except KeyError:
             try:
                 return self.stat(wpath)
             except OSError, err:
                 if err.errno != errno.ENOENT:
                     raise
 
     def stat(self, wpath):
         try:
             st = os.lstat(join(self.wprefix, wpath))
             ret = st.st_mode, st.st_size, st.st_mtime
             self.statcache[wpath] = ret
             return ret
         except OSError:
             self.statcache.pop(wpath, None)
             raise
 
 class socketlistener(object):
     """
     Listens for client queries on unix socket inotify.sock
     """
     def __init__(self, ui, root, repowatcher, timeout):
         self.ui = ui
         self.repowatcher = repowatcher
         self.sock = socket.socket(socket.AF_UNIX)
         self.sockpath = join(root, '.hg/inotify.sock')
-        self.realsockpath = None
+
+        self.realsockpath = self.sockpath
+        if os.path.islink(self.sockpath):
+            if os.path.exists(self.sockpath):
+                self.realsockpath = os.readlink(self.sockpath)
+            else:
+                raise util.Abort('inotify-server: cannot start: '
+                                '.hg/inotify.sock is a broken symlink')
         try:
-            self.sock.bind(self.sockpath)
+            self.sock.bind(self.realsockpath)
         except socket.error, err:
             if err.args[0] == errno.EADDRINUSE:
                 raise AlreadyStartedException(_('cannot start: socket is '
                                                 'already bound'))
             if err.args[0] == "AF_UNIX path too long":
-                if os.path.islink(self.sockpath) and \
-                        not os.path.exists(self.sockpath):
-                    raise util.Abort('inotify-server: cannot start: '
-                                    '.hg/inotify.sock is a broken symlink')
                 tempdir = tempfile.mkdtemp(prefix="hg-inotify-")
                 self.realsockpath = os.path.join(tempdir, "inotify.sock")
                 try:
                     self.sock.bind(self.realsockpath)
                     os.symlink(self.realsockpath, self.sockpath)
                 except (OSError, socket.error), inst:
                     try:
                         os.unlink(self.realsockpath)
                     except:
                         pass
                     os.rmdir(tempdir)
                     if inst.errno == errno.EEXIST:
                         raise AlreadyStartedException(_('cannot start: tried '
                             'linking .hg/inotify.sock to a temporary socket but'
                             ' .hg/inotify.sock already exists'))
                     raise
             else:
                 raise
         self.sock.listen(5)
         self.fileno = self.sock.fileno
 
     def answer_stat_query(self, cs):
         names = cs.read().split('\0')
 
         states = names.pop()
 
         self.ui.note(_('answering query for %r\n') % states)
 
         visited = set()
         if not names:
             def genresult(states, tree):
                 for fn, state in tree.walk(states):
                     yield fn
         else:
             def genresult(states, tree):
                 for fn in names:
                     for f in tree.lookup(states, fn, visited):
                         yield f
 
         return ['\0'.join(r) for r in [
             genresult('l', self.repowatcher.statustrees['l']),
             genresult('m', self.repowatcher.statustrees['m']),
             genresult('a', self.repowatcher.statustrees['a']),
             genresult('r', self.repowatcher.statustrees['r']),
             genresult('!', self.repowatcher.statustrees['!']),
             '?' in states
                 and genresult('?', self.repowatcher.statustrees['?'])
                 or [],
             [],
             'c' in states and genresult('n', self.repowatcher.tree) or [],
             visited
             ]]
 
     def answer_dbug_query(self):
         return ['\0'.join(self.repowatcher.debug())]
 
     def accept_connection(self):
         sock, addr = self.sock.accept()
 
         cs = common.recvcs(sock)
         version = ord(cs.read(1))
 
         if version != common.version:
             self.ui.warn(_('received query from incompatible client '
                            'version %d\n') % version)
             try:
                 # try to send back our version to the client
                 # this way, the client too is informed of the mismatch
                 sock.sendall(chr(common.version))
             except:
                 pass
             return
 
         type = cs.read(4)
 
         if type == 'STAT':
             results = self.answer_stat_query(cs)
         elif type == 'DBUG':
             results = self.answer_dbug_query()
         else:
             self.ui.warn(_('unrecognized query type: %s\n') % type)
             return
 
         try:
             try:
                 v = chr(common.version)
 
                 sock.sendall(v + type + struct.pack(common.resphdrfmts[type],
                                             *map(len, results)))
                 sock.sendall(''.join(results))
             finally:
                 sock.shutdown(socket.SHUT_WR)
         except socket.error, err:
             if err.args[0] != errno.EPIPE:
                 raise
 
 if sys.platform == 'linux2':
     import linuxserver as _server
 else:
     raise ImportError
 
 master = _server.master
 
 def start(ui, dirstate, root, opts):
     timeout = opts.get('idle_timeout')
     if timeout:
         timeout = float(timeout) * 60000
     else:
         timeout = None
 
     class service(object):
         def init(self):
             try:
                 self.master = master(ui, dirstate, root, timeout)
             except AlreadyStartedException, inst:
                 raise util.Abort("inotify-server: %s" % inst)
 
         def run(self):
             try:
                 try:
                     self.master.run()
                 except TimeoutException:
                     pass
             finally:
                 self.master.shutdown()
 
     if 'inserve' not in sys.argv:
         runargs = util.hgcmd() + ['inserve', '-R', root]
     else:
         runargs = util.hgcmd() + sys.argv[1:]
 
     pidfile = ui.config('inotify', 'pidfile')
     if opts['daemon'] and pidfile is not None and 'pid-file' not in runargs:
         runargs.append("--pid-file=%s" % pidfile)
 
     service = service()
     logfile = ui.config('inotify', 'log')
 
     appendpid = ui.configbool('inotify', 'appendpid', False)
 
     ui.debug('starting inotify server: %s\n' % ' '.join(runargs))
     cmdutil.service(opts, initfn=service.init, runfn=service.run,
                     logfile=logfile, runargs=runargs, appendpid=appendpid)

tests/test-inotify-issue1208.t

@@ -1,29 +1,36
 
   $ "$TESTDIR/hghave" inotify || exit 80
   $ echo "[extensions]" >> $HGRCPATH
   $ echo "inotify=" >> $HGRCPATH
   $ p="xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
   $ hg init $p
   $ cd $p
 
 fail
 
   $ ln -sf doesnotexist .hg/inotify.sock
   $ hg st
   abort: inotify-server: cannot start: .hg/inotify.sock is a broken symlink
   inotify-client: could not start inotify server: child process failed to start
   $ hg inserve
   abort: inotify-server: cannot start: .hg/inotify.sock is a broken symlink
   [255]
   $ rm .hg/inotify.sock
 
 inserve
 
   $ hg inserve -d --pid-file=hg.pid
   $ cat hg.pid >> "$DAEMON_PIDS"
 
 status
 
   $ hg status
   ? hg.pid
+
+if we try to start twice the server, make sure we get a correct error
+
+  $ hg inserve -d --pid-file=hg2.pid
+  abort: inotify-server: cannot start: socket is already bound
+  abort: child process failed to start
+  [255]
   $ kill `cat hg.pid`