[elbe-devel] [PATCH v3 5/5] hdimg: Use losetup wrapper for grubinstaller97

[Olivier Dion]

Instead of using fixed loop device /dev/loop0 and /dev/poop0,
grubinstaller uses its losetup wrapper to dynamicaly get a device.
This is because the fixed device could be busy, even though it has
been detached.

Also add an exception catching and log it.  This is because the
finally block can shadow an exception throwed in the try block.

Signed-off-by: Olivier Dion <dion at linutronix.de>
---
 elbepack/hdimg.py | 27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/elbepack/hdimg.py b/elbepack/hdimg.py
index c33efa08..5478cbda 100644
--- a/elbepack/hdimg.py
+++ b/elbepack/hdimg.py
@@ -238,14 +238,16 @@ class grubinstaller97(grubinstaller_base):
         imagemnt = os.path.join(target, "imagemnt")
         imagemntfs = Filesystem(imagemnt)
         try:
-            do('cp -a /dev/loop0 /dev/poop0')
+            loopdev = self.losetup(self.fs['/'].filename)
+            loopnum = loopdev.replace("/dev/loop", "")
+            poopdev = "/dev/poop" + loopnum
 
-            do('losetup /dev/poop0 "%s"' % self.fs['/'].filename)
-            do('kpartx -as /dev/poop0')
+            do('cp -a %s %s' % (loopdev, poopdev))
+            do('kpartx -as %s' % poopdev)
 
             for entry in self.fs.depthlist():
-                do('mount /dev/mapper/poop0p%d %s' %
-                   (entry.partnum, imagemntfs.fname(entry.mountpoint)))
+                do('mount /dev/mapper/poop%sp%d %s' %
+                   (loopnum, entry.partnum, imagemntfs.fname(entry.mountpoint)))
 
             do("mount --bind /dev %s" % imagemntfs.fname("dev"))
             do("mount --bind /proc %s" % imagemntfs.fname("proc"))
@@ -254,7 +256,7 @@ class grubinstaller97(grubinstaller_base):
             do('mkdir -p "%s"' % imagemntfs.fname("boot/grub"))
 
             devmap = open(imagemntfs.fname("boot/grub/device.map"), "w")
-            devmap.write("(hd0) /dev/poop0\n")
+            devmap.write("(hd0) %s\n" % poopdev)
             devmap.close()
 
             chroot(imagemnt, "update-initramfs -u -k all")
@@ -268,8 +270,11 @@ class grubinstaller97(grubinstaller_base):
 
             chroot(imagemnt, "update-grub")
 
-            do("chroot %s grub-install --no-floppy /dev/poop0" %
-               (imagemnt))
+            do("chroot %s grub-install --no-floppy %s" %
+               (imagemnt, poopdev))
+
+        except Exception as E:
+            logging.exception(E)
 
         finally:
             os.unlink(imagemntfs.fname("boot/grub/device.map"))
@@ -278,11 +283,11 @@ class grubinstaller97(grubinstaller_base):
             do("umount %s" % imagemntfs.fname("sys"), allow_fail=True)
 
             for entry in reversed(self.fs.depthlist()):
-                do('umount /dev/mapper/poop0p%d' % entry.partnum,
+                do('umount /dev/mapper/poop%sp%d' % (loopnum, entry.partnum),
                    allow_fail=True)
 
-            do('kpartx -d /dev/poop0', allow_fail=True)
-            do("losetup -d /dev/poop0", allow_fail=True)
+            do("kpartx -d %s" % poopdev, allow_fail=True)
+            do("losetup -d %s" % poopdev, allow_fail=True)
 
 
 class simple_fstype(object):
-- 
2.26.0