source: trunk/packages/sipb-xen-console/files/usr/bin/sipb-xen-consolefs @ 357

#!/usr/bin/python

import fuse
from fuse import Fuse

from time import time

import stat     # for file properties
import os         # for filesystem modes (O_RDONLY, etc)
import errno   # for error number codes (ENOENT, etc)
                           # - note: these must be returned as negatives

import sipb_xen_database

fuse.fuse_python_api = (0, 2)

realpath = "/home/machines/"

def dirFromList(list):
        """
        Return a properly formatted list of items suitable to a directory listing.
        ['a', 'b', 'c'] => [('a', 0), ('b', 0), ('c', 0)]
        """
        return [(x, 0) for x in list]

def getDepth(path):
        """
        Return the depth of a given path, zero-based from root ('/')
        """
        if path == '/':
                return 0
        else:
                return path.count('/')

def getParts(path):
        """
        Return the slash-separated parts of a given path as a list
        """
        if path == '/':
                return ['/']
        else:
                return path[1:].split('/')

class MyStat:
        def __init__(self):
                self.st_mode = 0
                self.st_ino = 0
                self.st_dev = 0
                self.st_nlink = 0
                self.st_uid = 0
                self.st_gid = 0
                self.st_size = 0
                self.st_atime = 0
                self.st_mtime = 0
                self.st_ctime = 0
        
        def toTuple(self):
                return (self.st_mode, self.st_ino, self.st_dev, self.st_nlink, self.st_uid, self.st_gid, self.st_size, self.st_atime, self.st_mtime, self.st_ctime)

class ConsoleFS(Fuse):
        """
        """
        
        def __init__(self, *args, **kw):
                Fuse.__init__(self, *args, **kw)
                self.lasttime = time()
                self.allow_other = 1
                print 'Init complete.'
        
        def mirrorPath(self, path):
                return realpath + "/".join(getParts(path)[1:])
        
        def getMachines(self):
                if time() - self.lasttime > 15:
                        self.lasttime = time()
                        sipb_xen_database.clear_cache()
                return [machine.name for machine in sipb_xen_database.Machine.select()]
        
        def getUid(self, machine_name):
                return sipb_xen_database.Machine.get_by(name=machine_name).machine_id + 1000
        
        def getK5login(self, machine_name):
                machine = sipb_xen_database.Machine.get_by(name=machine_name)
                users = [acl.user for acl in machine.acl]
                return "\n".join(map(self.userToPrinc, users) + [''])
        
        def userToPrinc(self, user):
                if '@' in user:
                        (princ, realm) = user.split('@')
                else:
                        princ = user
                        realm = "ATHENA.MIT.EDU"
                
                return princ.replace('.', '/') + '@' + realm
        
        def getattr(self, path):
                """
                - st_mode (protection bits)
                - st_ino (inode number)
                - st_dev (device)
                - st_nlink (number of hard links)
                - st_uid (user ID of owner)
                - st_gid (group ID of owner)
                - st_size (size of file, in bytes)
                - st_atime (time of most recent access)
                - st_mtime (time of most recent content modification)
                - st_ctime (platform dependent; time of most recent metadata change on Unix,
                                        or the time of creation on Windows).
                """
                
                print "*** getattr: " + path
                
                depth = getDepth(path)
                parts = getParts(path)
                
                st = MyStat()
                if path == '/':
                        st.st_mode = stat.S_IFDIR | 0755
                        st.st_nlink = 2
                elif depth == 1:
                        if parts[-1] in self.getMachines():
                                st.st_mode = stat.S_IFDIR | 0755
                                st.st_nlink = 2
                                st.st_uid = st.st_gid = self.getUid(parts[0])
                        else:
                                return -errno.ENOENT
                elif depth == 2 and parts[-1] == '.k5login':
                        st.st_mode = stat.S_IFREG | 0444
                        st.st_nlink = 1
                        st.st_size = len(self.getK5login(parts[0]))
                        st.st_uid = st.st_gid = self.getUid(parts[0])
                else:
                        stats = list(os.lstat(self.mirrorPath(path)))
                        stats[4:6] = [self.getUid(parts[0])] * 2
                        return tuple(stats)
                return st.toTuple()
        
        def readdir(self, path, offset):
                print '*** readdir', path, offset
                for (value, zero) in self.getdir(path):
                        yield fuse.Direntry(value)
        
        def getdir(self, path):
                print '*** getdir', path
                if path == '/':
                        contents = ['.', '..']+self.getMachines()
                elif getDepth(path) == 1:
                        contents = set(os.listdir(self.mirrorPath(path)) + ['.k5login', '.', '..'])
                else:
                        contents = os.listdir(self.mirrorPath(path)) + ['.', '..']
                return [(i, 0) for i in contents]
        
        def read ( self, path, length, offset ):
                print '*** read', path, length, offset
                
                parts = getParts(path)
                
                if getDepth(path) < 2:
                        return -errno.ENOENT
                elif parts[1:] == ['.k5login']:
                        if parts[0] not in self.getMachines():
                                return -errno.ENOENT
                        else:
                                return self.getK5login(parts[0])[offset:length + offset]
                else:
                        fname = self.mirrorPath(path)
                        if not os.path.isfile(fname):
                                return -errno.ENOENT
                        else:
                                f = open(fname)
                                f.seek(offset)
                                return f.read(length)

if __name__ == '__main__':
        sipb_xen_database.connect('postgres://sipb-xen@sipb-xen-dev.mit.edu/sipb_xen')
        usage="""
ConsoleFS [mount_path]
"""
        server = ConsoleFS()
        server.flags = 0
        server.main()