| # portage: Lock management code |
| # Copyright 2004 Gentoo Foundation |
| # Distributed under the terms of the GNU General Public License v2 |
| # $Id$ |
| |
| |
| import errno, os, stat, time, types |
| from portage.exception import DirectoryNotFound, FileNotFound, \ |
| InvalidData, TryAgain |
| from portage.data import portage_gid |
| from portage.util import writemsg |
| from portage.localization import _ |
| |
| HARDLINK_FD = -2 |
| |
| # Used by emerge in order to disable the "waiting for lock" message |
| # so that it doesn't interfere with the status display. |
| _quiet = False |
| |
| def lockdir(mydir): |
| return lockfile(mydir,wantnewlockfile=1) |
| def unlockdir(mylock): |
| return unlockfile(mylock) |
| |
| def lockfile(mypath, wantnewlockfile=0, unlinkfile=0, |
| waiting_msg=None, flags=0): |
| """Creates all dirs upto, the given dir. Creates a lockfile |
| for the given directory as the file: directoryname+'.portage_lockfile'.""" |
| import fcntl |
| |
| if not mypath: |
| raise InvalidData("Empty path given") |
| |
| if type(mypath) == types.StringType and mypath[-1] == '/': |
| mypath = mypath[:-1] |
| |
| if type(mypath) == types.FileType: |
| mypath = mypath.fileno() |
| if type(mypath) == types.IntType: |
| lockfilename = mypath |
| wantnewlockfile = 0 |
| unlinkfile = 0 |
| elif wantnewlockfile: |
| base, tail = os.path.split(mypath) |
| lockfilename = os.path.join(base, "." + tail + ".portage_lockfile") |
| del base, tail |
| unlinkfile = 1 |
| else: |
| lockfilename = mypath |
| |
| if type(mypath) == types.StringType: |
| if not os.path.exists(os.path.dirname(mypath)): |
| raise DirectoryNotFound(os.path.dirname(mypath)) |
| if not os.path.exists(lockfilename): |
| old_mask=os.umask(000) |
| myfd = os.open(lockfilename, os.O_CREAT|os.O_RDWR,0660) |
| try: |
| if os.stat(lockfilename).st_gid != portage_gid: |
| os.chown(lockfilename,os.getuid(),portage_gid) |
| except OSError, e: |
| if e[0] == 2: # No such file or directory |
| return lockfile(mypath, wantnewlockfile=wantnewlockfile, |
| unlinkfile=unlinkfile, waiting_msg=waiting_msg, |
| flags=flags) |
| else: |
| writemsg("Cannot chown a lockfile. This could cause inconvenience later.\n"); |
| os.umask(old_mask) |
| else: |
| myfd = os.open(lockfilename, os.O_CREAT|os.O_RDWR,0660) |
| |
| elif type(mypath) == types.IntType: |
| myfd = mypath |
| |
| else: |
| raise ValueError("Unknown type passed in '%s': '%s'" % \ |
| (type(mypath), mypath)) |
| |
| # try for a non-blocking lock, if it's held, throw a message |
| # we're waiting on lockfile and use a blocking attempt. |
| locking_method = fcntl.lockf |
| try: |
| fcntl.lockf(myfd,fcntl.LOCK_EX|fcntl.LOCK_NB) |
| except IOError, e: |
| if "errno" not in dir(e): |
| raise |
| if e.errno in (errno.EACCES, errno.EAGAIN): |
| # resource temp unavailable; eg, someone beat us to the lock. |
| if flags & os.O_NONBLOCK: |
| raise TryAgain(mypath) |
| |
| global _quiet |
| if _quiet: |
| pass |
| elif waiting_msg is None: |
| if isinstance(mypath, int): |
| print "waiting for lock on fd %i" % myfd |
| else: |
| print "waiting for lock on %s" % lockfilename |
| elif waiting_msg: |
| print waiting_msg |
| # try for the exclusive lock now. |
| fcntl.lockf(myfd,fcntl.LOCK_EX) |
| elif e.errno == errno.ENOLCK: |
| # We're not allowed to lock on this FS. |
| os.close(myfd) |
| link_success = False |
| if lockfilename == str(lockfilename): |
| if wantnewlockfile: |
| try: |
| if os.stat(lockfilename)[stat.ST_NLINK] == 1: |
| os.unlink(lockfilename) |
| except OSError: |
| pass |
| link_success = hardlink_lockfile(lockfilename) |
| if not link_success: |
| raise |
| locking_method = None |
| myfd = HARDLINK_FD |
| else: |
| raise |
| |
| |
| if type(lockfilename) == types.StringType and \ |
| myfd != HARDLINK_FD and _fstat_nlink(myfd) == 0: |
| # The file was deleted on us... Keep trying to make one... |
| os.close(myfd) |
| writemsg("lockfile recurse\n",1) |
| lockfilename, myfd, unlinkfile, locking_method = lockfile( |
| mypath, wantnewlockfile=wantnewlockfile, unlinkfile=unlinkfile, |
| waiting_msg=waiting_msg, flags=flags) |
| |
| writemsg(str((lockfilename,myfd,unlinkfile))+"\n",1) |
| return (lockfilename,myfd,unlinkfile,locking_method) |
| |
| def _fstat_nlink(fd): |
| """ |
| @param fd: an open file descriptor |
| @type fd: Integer |
| @rtype: Integer |
| @return: the current number of hardlinks to the file |
| """ |
| try: |
| return os.fstat(fd).st_nlink |
| except EnvironmentError, e: |
| if e.errno == errno.ENOENT: |
| # Some filesystems such as CIFS return |
| # ENOENT which means st_nlink == 0. |
| return 0 |
| raise |
| |
| def unlockfile(mytuple): |
| import fcntl |
| |
| #XXX: Compatability hack. |
| if len(mytuple) == 3: |
| lockfilename,myfd,unlinkfile = mytuple |
| locking_method = fcntl.flock |
| elif len(mytuple) == 4: |
| lockfilename,myfd,unlinkfile,locking_method = mytuple |
| else: |
| raise InvalidData |
| |
| if(myfd == HARDLINK_FD): |
| unhardlink_lockfile(lockfilename) |
| return True |
| |
| # myfd may be None here due to myfd = mypath in lockfile() |
| if type(lockfilename) == types.StringType and not os.path.exists(lockfilename): |
| writemsg("lockfile does not exist '%s'\n" % lockfilename,1) |
| if myfd is not None: |
| os.close(myfd) |
| return False |
| |
| try: |
| if myfd is None: |
| myfd = os.open(lockfilename, os.O_WRONLY,0660) |
| unlinkfile = 1 |
| locking_method(myfd,fcntl.LOCK_UN) |
| except OSError: |
| if type(lockfilename) == types.StringType: |
| os.close(myfd) |
| raise IOError("Failed to unlock file '%s'\n" % lockfilename) |
| |
| try: |
| # This sleep call was added to allow other processes that are |
| # waiting for a lock to be able to grab it before it is deleted. |
| # lockfile() already accounts for this situation, however, and |
| # the sleep here adds more time than is saved overall, so am |
| # commenting until it is proved necessary. |
| #time.sleep(0.0001) |
| if unlinkfile: |
| locking_method(myfd,fcntl.LOCK_EX|fcntl.LOCK_NB) |
| # We won the lock, so there isn't competition for it. |
| # We can safely delete the file. |
| writemsg("Got the lockfile...\n",1) |
| if _fstat_nlink(myfd) == 1: |
| os.unlink(lockfilename) |
| writemsg("Unlinked lockfile...\n",1) |
| locking_method(myfd,fcntl.LOCK_UN) |
| else: |
| writemsg("lockfile does not exist '%s'\n" % lockfilename,1) |
| os.close(myfd) |
| return False |
| except Exception, e: |
| writemsg("Failed to get lock... someone took it.\n",1) |
| writemsg(str(e)+"\n",1) |
| |
| # why test lockfilename? because we may have been handed an |
| # fd originally, and the caller might not like having their |
| # open fd closed automatically on them. |
| if type(lockfilename) == types.StringType: |
| os.close(myfd) |
| |
| return True |
| |
| |
| |
| |
| def hardlock_name(path): |
| return path+".hardlock-"+os.uname()[1]+"-"+str(os.getpid()) |
| |
| def hardlink_is_mine(link,lock): |
| try: |
| return os.stat(link).st_nlink == 2 |
| except OSError: |
| return False |
| |
| def hardlink_lockfile(lockfilename, max_wait=14400): |
| """Does the NFS, hardlink shuffle to ensure locking on the disk. |
| We create a PRIVATE lockfile, that is just a placeholder on the disk. |
| Then we HARDLINK the real lockfile to that private file. |
| If our file can 2 references, then we have the lock. :) |
| Otherwise we lather, rise, and repeat. |
| We default to a 4 hour timeout. |
| """ |
| |
| start_time = time.time() |
| myhardlock = hardlock_name(lockfilename) |
| reported_waiting = False |
| |
| while(time.time() < (start_time + max_wait)): |
| # We only need it to exist. |
| myfd = os.open(myhardlock, os.O_CREAT|os.O_RDWR,0660) |
| os.close(myfd) |
| |
| if not os.path.exists(myhardlock): |
| raise FileNotFound( |
| _("Created lockfile is missing: %(filename)s") % \ |
| {"filename" : myhardlock}) |
| |
| try: |
| res = os.link(myhardlock, lockfilename) |
| except OSError: |
| pass |
| |
| if hardlink_is_mine(myhardlock, lockfilename): |
| # We have the lock. |
| if reported_waiting: |
| print |
| return True |
| |
| if reported_waiting: |
| writemsg(".") |
| else: |
| reported_waiting = True |
| from portage.const import PORTAGE_BIN_PATH |
| print |
| print "Waiting on (hardlink) lockfile: (one '.' per 3 seconds)" |
| print "This is a feature to prevent distfiles corruption." |
| print "%s/clean_locks can fix stuck locks." % PORTAGE_BIN_PATH |
| print "Lockfile: " + lockfilename |
| time.sleep(3) |
| |
| os.unlink(myhardlock) |
| return False |
| |
| def unhardlink_lockfile(lockfilename): |
| myhardlock = hardlock_name(lockfilename) |
| if hardlink_is_mine(myhardlock, lockfilename): |
| # Make sure not to touch lockfilename unless we really have a lock. |
| try: |
| os.unlink(lockfilename) |
| except OSError: |
| pass |
| try: |
| os.unlink(myhardlock) |
| except OSError: |
| pass |
| |
| def hardlock_cleanup(path, remove_all_locks=False): |
| mypid = str(os.getpid()) |
| myhost = os.uname()[1] |
| mydl = os.listdir(path) |
| |
| results = [] |
| mycount = 0 |
| |
| mylist = {} |
| for x in mydl: |
| if os.path.isfile(path+"/"+x): |
| parts = x.split(".hardlock-") |
| if len(parts) == 2: |
| filename = parts[0] |
| hostpid = parts[1].split("-") |
| host = "-".join(hostpid[:-1]) |
| pid = hostpid[-1] |
| |
| if filename not in mylist: |
| mylist[filename] = {} |
| if host not in mylist[filename]: |
| mylist[filename][host] = [] |
| mylist[filename][host].append(pid) |
| |
| mycount += 1 |
| |
| |
| results.append("Found %(count)s locks" % {"count":mycount}) |
| |
| for x in mylist: |
| if myhost in mylist[x] or remove_all_locks: |
| mylockname = hardlock_name(path+"/"+x) |
| if hardlink_is_mine(mylockname, path+"/"+x) or \ |
| not os.path.exists(path+"/"+x) or \ |
| remove_all_locks: |
| for y in mylist[x]: |
| for z in mylist[x][y]: |
| filename = path+"/"+x+".hardlock-"+y+"-"+z |
| if filename == mylockname: |
| continue |
| try: |
| # We're sweeping through, unlinking everyone's locks. |
| os.unlink(filename) |
| results.append(_("Unlinked: ") + filename) |
| except OSError: |
| pass |
| try: |
| os.unlink(path+"/"+x) |
| results.append(_("Unlinked: ") + path+"/"+x) |
| os.unlink(mylockname) |
| results.append(_("Unlinked: ") + mylockname) |
| except OSError: |
| pass |
| else: |
| try: |
| os.unlink(mylockname) |
| results.append(_("Unlinked: ") + mylockname) |
| except OSError: |
| pass |
| |
| return results |
| |