move and update repofs

1 files changed, 43 insertions, 7 deletions

diff --git a/proof-of-concept/repofs.py b/repofs.py
index d3ad279..1656ab2 100755
--- a/proof-of-concept/repofs.py
+++ b/repofs.py
@@ -1,4 +1,9 @@
 #!/usr/bin/python
+# repofs.py - Export the contents of a package repo as a readonly filesystem.
+# 
+# Copyright 2009 Red Hat, Inc. GPLv2+ BOILERPLATE GOES HERE.
+#
+# Author: Will Woods <wwoods@redhat.com>
 
 import os
 import glob
@@ -103,7 +108,7 @@ class SimpleYumRepo(object):
         inf = open(rpm)
         # Find RPM header and read compression algorithm
         # Skip forward to gzipped CPIO archive
-        # FIXME: Awful. Just awful.
+        # FIXME: Awful. Just awful. At least use rpm2cpio.
         header = inf.read(409600)
         offset = header.index("\x1f\x8b")
         del header
@@ -121,25 +126,55 @@ class SimpleYumRepo(object):
         cpio.stdin.close()
         cpio.wait()
 
-class Repofs(Fuse):
+class FuseRO(Fuse):
+    '''A Fuse subclass for implementing readonly filesystems.'''
+    # chmod chown create link mkdir mknod rename rmdir setxattr(?) symlink
+    # truncate unlink write
+    def __rofs(self, *args):
+        '''Raises OSError(EROFS,"Read-only filesystem")'''
+        raise OSError(errno.EROFS, "Read-only filesystem")
+    chmod = __rofs
+    chown = __rofs
+    link = __rofs
+    mkdir = __rofs
+    rename = __rofs
+    rmdir = __rofs
+    setxattr = __rofs # You might override this so you can store xattrs
+    symlink = __rofs
+    truncate = __rofs
+    unlink = __rofs
+    def write(self, *args):
+        '''write() function that raises IOError(EBADF)
+        You can't open files for writing; this is a readonly filesystem!'''
+        raise IOError(errno.EBADF, "write() on readonly filesystem")
+    def _check_open(self, flags):
+        '''checks the open() flags, and returns False if write access
+        was requested. Returns True otherwise.'''
+        accmode = os.O_RDONLY | os.O_WRONLY | os.O_RDWR
+        return (flags & accmode) == os.O_RDONLY
+
+class Repofs(FuseRO):
     def __init__(self, *args, **kw):
         Fuse.__init__(self, *args, **kw)
 
+    # FIXME: this logging is terrible
+    def log(self,message):
+        self.logfile.write("%s %s\n" % (time.asctime(), message))
+        
     def fsinit(self):
         if not os.path.isdir(self.cachedir):
             os.makedirs(self.cachedir)
+        # FIXME this logging is awful
         self.logfile = open(os.path.join(self.cachedir,".log"),"a",0)
         self.log("fsinit(path=%s). Hang on.." % self.repopath)
-        # TODO: figure out the repo type (Yum, etc) and use the right class
+        # TODO: figure out the repo type (Yum, etc) and use the right class.
+        # That way we can support other distros. Yay!
         self.repos = []
         for rp in self.repopath.split(":"):
             r = SimpleYumRepo(path=rp, cachedir=self.cachedir)
             self.repos.append(r)
             self.log(" cachedir=%s, repopath=%s" % (r.cachedir, r.path))
 
-    def log(self,message):
-        self.logfile.write("%s %s\n" % (time.asctime(), message))
-        
     def _package_for_file(self, path):
         for repo in self.repos:
             packages = repo.packages_for_file(path)
@@ -198,6 +233,8 @@ class Repofs(Fuse):
         return local_s
 
     # XXX explicitly declare other functions that return proper error codes?
+    
+    # FIXME: use file objects instead?
 
     def open(self, path, flags):
         self.log("open(%s,%s)" % (path,flags))
@@ -219,7 +256,6 @@ class Repofs(Fuse):
     def main(self, *a, **kw):
         return Fuse.main(self, *a, **kw)
 
-    # FIXME need some kind of destroy() that removes the per-instance cache
 
 def main():
     usage = 'Repofs: mount a package repo and export all the files in the packages.\n\n' + Fuse.fusage