[SoaS] [PATCH 1a] substitutes was: [PATCH 1/5] Support Live image mounting in fs.py

Frederick Grose fgrose at sugarlabs.org
Sat Sep 17 17:50:31 EDT 2011


Patch 1a of 2 substitute patches to replace an earlier patch with new
features:

commit 7389913c708d3f19ca029cf3f150bbfb08a768d3
Author: Frederick Grose <fgrose at sugarlabs.org>
Date:   Sat Sep 17 17:05:17 2011 -0400

    Enable mount options, particularly 'read-only', for greater safety.

    Provide parameters for mounting options, and code to recognize and
    implement various 'read-only' flag possibilities.

diff --git a/imgcreate/fs.py b/imgcreate/fs.py
index 69fb5f1..e71032e 100644
--- a/imgcreate/fs.py
+++ b/imgcreate/fs.py
@@ -122,9 +122,10 @@ def e2fsck(fs):

 class BindChrootMount:
     """Represents a bind mount of a directory into a chroot."""
-    def __init__(self, src, chroot, dest = None):
+    def __init__(self, src, chroot, dest=None, ops=None):
         self.src = src
         self.root = chroot
+        self.ops = ops

         if not dest:
             dest = src
@@ -132,17 +133,35 @@ class BindChrootMount:

         self.mounted = False

-    def mount(self):
+    def mount(self, ops=None):
         if self.mounted:
             return

         makedirs(self.dest)
-        rc = call(["/bin/mount", "--bind", self.src, self.dest])
+        args = ['/bin/mount', '--bind', self.src, self.dest]
+        rc = call(args)
         if rc != 0:
             raise MountError("Bind-mounting '%s' to '%s' failed" %
                              (self.src, self.dest))
+        if ops is None:
+            ops = self.ops
+        if ops in (['-o', 'remount,ro'], 'remount,ro,bind', 'remount,ro',
+                   ['-o', 'ro'], ['ro'], ['-r'], 'ro', '-r'):
+            self.remount('ro')
+
         self.mounted = True

+    def remount(self, ops):
+        if not self.mounted:
+            return
+
+        remount_ops = ''.join(('remount,', ops))
+        args = ['/bin/mount', '-o', remount_ops, self.dest]
+        rc = call(args)
+        if rc != 0:
+            raise MountError("%s of '%s' to '%s' failed." %
+                             (remount_ops, self.src, self.dest))
+
     def unmount(self):
         if not self.mounted:
             return
@@ -161,9 +180,11 @@ class BindChrootMount:

 class LoopbackMount:
     """LoopbackMount  compatibility layer for old API"""
-    def __init__(self, lofile, mountdir, fstype = None):
-        self.diskmount = DiskMount(LoopbackDisk(lofile,size =
0),mountdir,fstype,rmmountdir = True)
+    def __init__(self, lofile, mountdir, fstype=None, ops=None):
+        self.diskmount = DiskMount(LoopbackDisk(lofile, size=0), mountdir,
+                                   fstype, rmmountdir=True, ops=None)
         self.losetup = False
+        self.ops = ops

     def cleanup(self):
         self.diskmount.cleanup()
@@ -177,7 +198,7 @@ class LoopbackMount:
             self.losetup = False
             self.loopdev = None

-    def loopsetup(self):
+    def loopsetup(self, ops=None):
         if self.losetup:
             return

@@ -191,15 +212,22 @@ class LoopbackMount:

         self.loopdev = losetupOutput.split()[0]

-        rc = call(["/sbin/losetup", self.loopdev, self.lofile])
+        args = ['/sbin/losetup', self.loopdev, self.lofile]
+        if ops is None:
+            ops = self.ops
+        if ops in (['-o', 'ro'], ['ro'], ['-r'], 'ro', '-r'):
+            ops = ['-r']
+            # This is the only additional option supported, so far.
+            args += ops
+        rc = call(args)
         if rc != 0:
             raise MountError("Failed to allocate loop device for '%s'" %
                              self.lofile)

         self.losetup = True

-    def mount(self):
-        self.diskmount.mount()
+    def mount(self, ops=None):
+        self.diskmount.mount(ops)

 class SparseLoopbackMount(LoopbackMount):
     """SparseLoopbackMount  compatibility layer for old API"""
@@ -290,9 +318,10 @@ class RawDisk(Disk):

 class LoopbackDisk(Disk):
     """A Disk backed by a file via the loop module."""
-    def __init__(self, lofile, size):
+    def __init__(self, lofile, size, ops=None):
         Disk.__init__(self, size)
         self.lofile = lofile
+        self.ops = ops

     def fixed(self):
         return False
@@ -300,7 +329,7 @@ class LoopbackDisk(Disk):
     def exists(self):
         return os.path.exists(self.lofile)

-    def create(self):
+    def create(self, ops=None):
         if self.device is not None:
             return

@@ -313,9 +342,16 @@ class LoopbackDisk(Disk):
                              self.lofile)

         device = losetupOutput.split()[0]
+        args = ['/sbin/losetup', device, self.lofile]
+        if ops is None:
+            ops = self.ops
+        if ops in (['-o', 'ro'], ['ro'], ['-r'], 'ro', '-r'):
+            ops = ['-r']
+            # This is the only additional option supported, so far.
+            args += ops

         logging.info("Losetup add %s mapping to %s"  % (device,
self.lofile))
-        rc = call(["/sbin/losetup", device, self.lofile])
+        rc = call(args)
         if rc != 0:
             raise MountError("Failed to allocate loop device for '%s'" %
                              self.lofile)
@@ -329,11 +365,10 @@ class LoopbackDisk(Disk):
         self.device = None


-
 class SparseLoopbackDisk(LoopbackDisk):
     """A Disk backed by a sparse file via the loop module."""
-    def __init__(self, lofile, size):
-        LoopbackDisk.__init__(self, lofile, size)
+    def __init__(self, lofile, size, ops=None):
+        LoopbackDisk.__init__(self, lofile, size, ops=None)

     def expand(self, create = False, size = None):
         flags = os.O_WRONLY
@@ -362,9 +397,9 @@ class SparseLoopbackDisk(LoopbackDisk):
         os.ftruncate(fd, size)
         os.close(fd)

-    def create(self):
+    def create(self, ops=None):
         self.expand(create = True)
-        LoopbackDisk.create(self)
+        LoopbackDisk.create(self, ops=None)

 class Mount:
     """A generic base class to deal with mounting things."""
@@ -382,15 +417,17 @@ class Mount:

 class DiskMount(Mount):
     """A Mount object that handles mounting of a Disk."""
-    def __init__(self, disk, mountdir, fstype = None, rmmountdir = True):
+    def __init__(self, disk, mountdir, fstype=None, rmmountdir=True,
ops=None):
         Mount.__init__(self, mountdir)

         self.disk = disk
         self.fstype = fstype
+        self.ops = ops
         self.rmmountdir = rmmountdir

         self.mounted = False
         self.rmdir   = False
+        self.created = False

     def cleanup(self):
         Mount.cleanup(self)
@@ -420,12 +457,12 @@ class DiskMount(Mount):
                 pass
             self.rmdir = False

-
     def __create(self):
-        self.disk.create()
-
+        if not self.created:
+            self.disk.create()
+            self.created = True

-    def mount(self):
+    def mount(self, ops=None):
         if self.mounted:
             return

@@ -440,6 +477,10 @@ class DiskMount(Mount):
         args = [ "/bin/mount", self.disk.device, self.mountdir ]
         if self.fstype:
             args.extend(["-t", self.fstype])
+        if ops is None:
+            ops = self.ops
+        if ops is not None:
+            args.extend(['-o', ops])

         rc = call(args)
         if rc != 0:
@@ -448,6 +489,17 @@ class DiskMount(Mount):

         self.mounted = True

+    def remount(self, ops):
+        if not self.mounted:
+            return
+
+        remount_ops = ''.join(('remount,', ops))
+        args = ['/bin/mount', '-o', remount_ops, self.mountdir]
+        rc = call(args)
+        if rc != 0:
+            raise MountError("%s of '%s' to '%s' failed." %
+                             (remount_ops, self.disk.device,
self.mountdir))
+
 class ExtDiskMount(DiskMount):
     """A DiskMount object that is able to format/resize ext[23]
filesystems."""
     def __init__(self, disk, mountdir, fstype, blocksize, fslabel,
@@ -456,6 +508,7 @@ class ExtDiskMount(DiskMount):
         self.blocksize = blocksize
         self.fslabel = "_" + fslabel
         self.tmpdir = tmpdir
+        self.created = False

     def __format_filesystem(self):
         logging.info("Formating %s filesystem on %s" % (self.fstype,
self.disk.device))
@@ -487,6 +540,8 @@ class ExtDiskMount(DiskMount):
         return size

     def __create(self):
+        if self.created:
+            return
         resize = False
         if not self.disk.fixed() and self.disk.exists():
             resize = True
@@ -498,6 +553,8 @@ class ExtDiskMount(DiskMount):
         else:
             self.__format_filesystem()

+        self.created = True
+
     def mount(self):
         self.__create()
         DiskMount.mount(self)
@@ -535,10 +592,12 @@ class ExtDiskMount(DiskMount):
         self.__resize_filesystem(size)
         return minsize

+
 class DeviceMapperSnapshot(object):
-    def __init__(self, imgloop, cowloop):
+    def __init__(self, imgloop, cowloop, ops=None):
         self.imgloop = imgloop
         self.cowloop = cowloop
+        self.ops = ops

         self.__created = False
         self.__name = None
@@ -546,15 +605,16 @@ class DeviceMapperSnapshot(object):
     def get_path(self):
         if self.__name is None:
             return None
+        return self.device
         return os.path.join("/dev/mapper", self.__name)
     path = property(get_path)

-    def create(self):
+    def create(self, ops=None):
         if self.__created:
             return

-        self.imgloop.create()
-        self.cowloop.create()
+        self.imgloop.create(self.ops)
+        self.cowloop.create(self.ops)

         self.__name = "imgcreate-%d-%d" % (os.getpid(),
                                            random.randint(0, 2**16))
@@ -567,13 +627,22 @@ class DeviceMapperSnapshot(object):

         args = ["/sbin/dmsetup", "create", self.__name,
                 "--uuid", "LIVECD-%s" % self.__name, "--table", table]
+        if ops is None:
+            ops = self.ops
+        if ops in (['-o', 'ro'], ['ro'], ['-r'], 'ro', '-r',
+                   ['--readonly'], '--readonly'):
+            ops = ['--readonly']
+            # This is the only additional option supported, so far.
+            args += ops
         if call(args) != 0:
+            time.sleep(1)
             self.cowloop.cleanup()
             self.imgloop.cleanup()
             raise SnapshotError("Could not create snapshot device using: "
+
                                 string.join(args, " "))

         self.__created = True
+        self.device = os.path.join('/dev/mapper', self.__name)

     def remove(self, ignore_errors = False):
         if not self.__created:




On Thu, Apr 14, 2011 at 12:02 PM, Frederick Grose <fgrose at gmail.com> wrote:

> [Patch 1/5]
> Author: Frederick Grose <fgrose at sugarlabs.org>
> Date:   Thu Apr 14 09:29:14 2011 -0400
>
>    Support Live image mounting.
>
>    Provide DiskMount with mount options, DeviceMapperSnapshot with a
>     device attribute, and a new LiveImageMount class.
>
> diff --git a/imgcreate/fs.py b/imgcreate/fs.py
> index d5307a2..0871182 100644
> --- a/imgcreate/fs.py
> +++ b/imgcreate/fs.py
> @@ -324,7 +324,6 @@ class LoopbackDisk(Disk):
>          self.device = None
>
>
> -
> class SparseLoopbackDisk(LoopbackDisk):
>      """A Disk backed by a sparse file via the loop module."""
>     def __init__(self, lofile, size):
> @@ -377,11 +376,12 @@ class Mount:
>
> class DiskMount(Mount):
>      """A Mount object that handles mounting of a Disk."""
> -    def __init__(self, disk, mountdir, fstype = None, rmmountdir = True):
> +    def __init__(self, disk, mountdir, fstype=None, rmmountdir=True,
> ops=None):
>         Mount.__init__(self, mountdir)
>
>         self.disk = disk
>         self.fstype = fstype
> +        self.ops = ops
>         self.rmmountdir = rmmountdir
>
>         self.mounted = False
> @@ -435,6 +435,8 @@ class DiskMount(Mount):
>          args = [ "/bin/mount", self.disk.device, self.mountdir ]
>         if self.fstype:
>              args.extend(["-t", self.fstype])
> +        if self.ops:
> +            args.extend(['-o', self.ops])
>
>         rc = call(args)
>          if rc != 0:
> @@ -530,6 +532,7 @@ class ExtDiskMount(DiskMount):
>          self.__resize_filesystem(size)
>         return minsize
>
> +
> class DeviceMapperSnapshot(object):
>      def __init__(self, imgloop, cowloop):
>         self.imgloop = imgloop
> @@ -541,6 +544,7 @@ class DeviceMapperSnapshot(object):
>     def get_path(self):
>          if self.__name is None:
>             return None
> +        return self.device
>         return os.path.join("/dev/mapper", self.__name)
>      path = property(get_path)
>
> @@ -569,6 +573,7 @@ class DeviceMapperSnapshot(object):
>                                  string.join(args, " "))
>
>         self.__created = True
> +        self.device = os.path.join('/dev/mapper', self.__name)
>
>      def remove(self, ignore_errors = False):
>         if not self.__created:
> @@ -610,6 +615,89 @@ class DeviceMapperSnapshot(object):
>         except ValueError:
>              raise SnapshotError("Failed to parse dmsetup status: " + out)
>
> +
> +class LiveImageMount(object):
> +    """A class for mounting a LiveOS image installed with an active
> overlay."""
> +
> +    def __init__(self, disk, mountdir, overlay, tmpdir='/tmp'):
> +        self.disk = disk
> +        self.mountdir = mountdir
> +        self.overlay = overlay
> +        self.tmpdir = tmpdir
> +        self.__created = False
> +        self.squashmnt = None
> +        self.homemnt = None
> +        self.mntlive = None
> +
> +    def __create(self):
> +        if self.__created:
> +            return
> +        self.liveosdevmnt = DiskMount(self.disk,
> +                                   os.path.join(self.tmpdir, 'device'))
> +        self.liveosdevmnt.mount()
> +        liveosdir = os.path.join(self.liveosdevmnt.mountdir, 'LiveOS')
> +        sqfs_img = os.path.join(liveosdir, 'squashfs.img')
> +        if os.path.exists(sqfs_img):
> +            self.squashloop = LoopbackDisk(sqfs_img, None)
> +            self.squashmnt = DiskMount(self.squashloop,
> +                                       os.path.join(self.tmpdir,
> 'squash'))
> +            self.squashmnt.mount()
> +            rootfs_img = os.path.join(self.squashmnt.mountdir,
> +                                      'LiveOS', 'ext3fs.img')
> +        else:
> +            rootfs_img = os.path.join(liveosdir, 'ext3fs.img')
> +            if not os.path.exists(rootfs_img):
> +                raise SnapshotError("Failed to find a LiveOS root image.")
> +        self.imgloop = LoopbackDisk(rootfs_img, None)
> +        self.overlay = os.path.join(liveosdir, self.overlay)
> +        self.cowloop = LoopbackDisk(self.overlay, None)
> +        home_img = os.path.join(liveosdir, 'home.img')
> +        self.dm_liveimage = DeviceMapperSnapshot(self.imgloop,
> self.cowloop)
> +        self.dm_livemount = DiskMount(self.dm_liveimage, self.mountdir)
> +        if os.path.exists(home_img):
> +            homedir = os.path.join(self.mountdir, 'home')
> +            self.homemnt = LoopbackMount(home_img, homedir)
> +        self.__created = True
> +
> +    def mount(self):
> +        try:
> +            self.__create()
> +            if not self.liveosdevmnt.mounted:
> +                self.liveosdevmnt.mount()
> +            if not self.squashmnt.mounted:
> +                self.squashmnt.mount()
> +            self.dm_livemount.mount()
> +            if self.homemnt:
> +                self.homemnt.mount()
> +            mntlivedir = os.path.join(self.mountdir, 'mnt', 'live')
> +            if not os.path.exists(mntlivedir):
> +                os.makedirs(mntlivedir)
> +            self.mntlive = BindChrootMount(self.liveosdevmnt.mountdir,
> +                                           '', mntlivedir)
> +            self.mntlive.mount()
> +        except MountError, e:
> +            raise SnapshotError("Failed to mount %s : %s" % (self.disk,
> e))
> +            self.cleanup()
> +
> +    def unmount(self):
> +        if self.mntlive:
> +            self.mntlive.unmount()
> +        if self.homemnt:
> +            self.homemnt.unmount()
> +        self.dm_livemount.unmount()
> +        self.liveosdevmnt.unmount()
> +
> +    def cleanup(self):
> +        self.unmount()
> +        if self.homemnt:
> +            self.homemnt.cleanup()
> +        self.dm_liveimage.remove()
> +        if self.squashmnt:
> +            self.squashmnt.cleanup()
> +        self.liveosdevmnt.cleanup()
> +        self.__created = False
> +
> +
> def create_image_minimizer(path, image, compress_type, target_size = None,
>                             tmpdir = "/tmp"):
>     """
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