X-Git-Url: http://xvm.mit.edu/gitweb/invirt/packages/invirt-console.git/blobdiff_plain/5a9b61b747ead3307eabd89e2c091fe8a31f4831..281bc8b42eeeb6b395c3430bd603b7dad59218ff:/files/usr/bin/sipb-xen-consolefs?ds=sidebyside
diff --git a/files/usr/bin/sipb-xen-consolefs b/files/usr/bin/sipb-xen-consolefs
index 380c94b..d5187c5 100755
--- a/files/usr/bin/sipb-xen-consolefs
+++ b/files/usr/bin/sipb-xen-consolefs
@@ -10,19 +10,14 @@ import os # for filesystem modes (O_RDONLY, etc)
import errno # for error number codes (ENOENT, etc)
# - note: these must be returned as negatives
+from syslog import *
+
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 ('/')
@@ -39,6 +34,8 @@ def getParts(path):
if path == '/':
return ['/']
else:
+ # [1:] because otherwise you get an empty list element from the
+ # initial '/'
return path[1:].split('/')
class MyStat:
@@ -59,39 +56,61 @@ class MyStat:
class ConsoleFS(Fuse):
"""
+ ConsoleFS creates a series of subdirectories each mirroring the same real
+ directory, except for a single file - the .k5login - which is dynamically
+ generated for each subdirectory
+
+ This filesystem only implements the getattr, getdir, read, and readlink
+ calls, beacuse this is a read-only filesystem
"""
def __init__(self, *args, **kw):
+ """Initialize the filesystem and set it to allow_other access besides
+ the user who mounts the filesystem (i.e. root)
+ """
Fuse.__init__(self, *args, **kw)
self.lasttime = time()
self.allow_other = 1
- print 'Init complete.'
+
+ openlog('sipb-xen-consolefs ', LOG_PID, LOG_DAEMON)
+
+ syslog(LOG_DEBUG, 'Init complete.')
def mirrorPath(self, path):
+ """Translate a virtual path to its real path counterpart"""
return realpath + "/".join(getParts(path)[1:])
def getMachines(self):
+ """Get the list of VMs in the database, clearing the cache if it's
+ older than 15 seconds"""
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):
+ """Calculate the UID of a machine-account, which is just machine_id+1000
+ """
return sipb_xen_database.Machine.get_by(name=machine_name).machine_id + 1000
def getK5login(self, machine_name):
+ """Build the ACL for a machine and turn it into a .k5login file
+ """
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):
+ """Convert Kerberos v4-style names to v5-style and append a default
+ realm if none is specified
+ """
if '@' in user:
(princ, realm) = user.split('@')
else:
princ = user
realm = "ATHENA.MIT.EDU"
- return princ.replace('.', '/') + realm
+ return princ.replace('.', '/') + '@' + realm
def getattr(self, path):
"""
@@ -108,60 +127,98 @@ class ConsoleFS(Fuse):
or the time of creation on Windows).
"""
- print "*** getattr: " + path
+ syslog(LOG_DEBUG, "*** getattr: " + path)
depth = getDepth(path)
parts = getParts(path)
st = MyStat()
+ # / is a directory
if path == '/':
st.st_mode = stat.S_IFDIR | 0755
st.st_nlink = 2
+ # /foo is a directory if foo is a machine - otherwise it doesn't exist
elif depth == 1:
if parts[-1] in self.getMachines():
st.st_mode = stat.S_IFDIR | 0755
st.st_nlink = 2
+ # Homedirs should be owned by the user whose homedir it is
st.st_uid = st.st_gid = self.getUid(parts[0])
else:
return -errno.ENOENT
+ # Catch the .k5login file, because it's a special case
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]))
+ # The .k5login file should be owned by the user whose homedir it is
st.st_uid = st.st_gid = self.getUid(parts[0])
+ # For anything else, we get the mirror path and call out to the OS
else:
stats = list(os.lstat(self.mirrorPath(path)))
+ # Shadow the UID and GID from the original homedir
stats[4:6] = [self.getUid(parts[0])] * 2
return tuple(stats)
return st.toTuple()
+ # This call isn't actually used in the version of Fuse on console, but we
+ # wanted to leave it implemented to ease the transition in the future
def readdir(self, path, offset):
- print '*** readdir', path, offset
+ """Return a generator with the listing for a directory
+ """
+ syslog(LOG_DEBUG, '*** readdir %s %s' % (path, offset))
for (value, zero) in self.getdir(path):
yield fuse.Direntry(value)
def getdir(self, path):
- print '*** getdir', path
+ """Return a list of tuples of the form (item, 0) with the contents of
+ the directory path
+
+ Fuse doesn't add '.' or '..' on its own, so we have to
+ """
+ syslog(LOG_DEBUG, '*** getdir %s' % path)
+
+ # '/' contains a directory for each machine
if path == '/':
- contents = ['.', '..']+self.getMachines()
+ contents = self.getMachines()
+ # The directory for each machine contains the same files as the realpath
+ # but also the .k5login
+ #
+ # The list is converted to a set so that we can handle the case where
+ # there is already a .k5login in the realpath gracefully
elif getDepth(path) == 1:
- contents = set(os.listdir(self.mirrorPath(path)) + ['.k5login', '.', '..'])
+ contents = set(os.listdir(self.mirrorPath(path)) + ['.k5login'])
+ # If it's not the root of the homedir, just pass the call onto the OS
+ # for realpath
else:
- contents = os.listdir(self.mirrorPath(path)) + ['.', '..']
- return [(i, 0) for i in contents]
+ contents = os.listdir(self.mirrorPath(path))
+ # Format the list the way that Fuse wants it - and don't forget to add
+ # '.' and '..'
+ return [(i, 0) for i in (list(contents) + ['.', '..'])]
- def read ( self, path, length, offset ):
- print '*** read', path, length, offset
+ def read(self, path, length, offset):
+ """Read length bytes starting at offset of path. In most cases, this
+ just gets passed on to the OS
+ """
+ syslog(LOG_DEBUG, '*** read %s %s %s' % (path, length, offset))
parts = getParts(path)
+ # If the depth is less than 2, then either it's a directory or the file
+ # doesn't exist
+ # (realistically this doesn't appear to ever happen)
if getDepth(path) < 2:
return -errno.ENOENT
+ # If we're asking for a real .k5login file, then create it and return
+ # the snippet requested
elif parts[1:] == ['.k5login']:
if parts[0] not in self.getMachines():
return -errno.ENOENT
else:
return self.getK5login(parts[0])[offset:length + offset]
+ # Otherwise, pass the call onto the OS
+ # (note that the file will get closed when this call returns and the
+ # file descriptor goes out of scope)
else:
fname = self.mirrorPath(path)
if not os.path.isfile(fname):
@@ -170,6 +227,16 @@ class ConsoleFS(Fuse):
f = open(fname)
f.seek(offset)
return f.read(length)
+
+ def readlink(self, path):
+ syslog(LOG_DEBUG, '*** readlink %s' % path)
+
+ # There aren't any symlinks here
+ if getDepth(path) < 2:
+ return -errno.ENOENT
+ # But there might be here
+ else:
+ return os.readlink(self.mirrorPath(path))
if __name__ == '__main__':
sipb_xen_database.connect('postgres://sipb-xen@sipb-xen-dev.mit.edu/sipb_xen')