[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] [Xend] Fix appending policy module to end of grub's config file
xen-devel-bounces@xxxxxxxxxxxxxxxxxxx wrote on 11/12/2007 06:41:38 AM: > Stefan Berger writes ("[Xen-devel] [PATCH] [Xend] Fix appending > policy module to end of grub's config file"): > > Index: root/xen-unstable.hg/tools/python/xen/util/bootloader.py > > =================================================================== > > --- root.orig/xen-unstable.hg/tools/python/xen/util/bootloader.py > > +++ root/xen-unstable.hg/tools/python/xen/util/bootloader.py > > @@ -64,6 +64,8 @@ def get_kernel_val(index, att): > > > > def set_boot_policy(title_idx, filename): > > boottitles = get_boot_policies() > > + for key in boottitles.iterkeys(): > > + boottitles[key] += ".bin" > > if boottitles.has_key(title_idx): > > rm_policy_from_boottitle(title_idx, [ boottitles[title_idx] ]) > > rc = add_boot_policy(title_idx, filename) > > Having investigated this situation I'm not really convinced that this > patch is correct. One problem that the various Bootloader classes in > bootloader.py seem to disagree about what `title_idx' is in this > context ? The Grub class uses line numbers but LatePolicyLoader seems > always to use DEFAULT_TITLE (ie, `any') which seems odd. Perhaps I > have misread the code. The Grub class uses the title_idx as the index of the title entry, not the line number. You may have 3 'title' entries in your grub config file, then you have possible indices 0,1,2. The LatePolicyLoader class does not work on grub's configuration file, but a simple text file that contains only one entry indicating which policy to load once xend has started. > > What your change seems to be addressing is a confusion about whether > it's a filename (with `.bin') or a stripped version. The relevant That's correct. The '.bin' appended to a policy's name results in the filename. > stripped version seems to be the one generated in > LatePolicyLoader.add_boot_policy, which just strips `.bin', but > compare this with Grub.get_boot_policies which strips `.bin' but also > various stuff from the front of what I think is the same kind of path. > > I'm afraid I wasn't able to conclude which of the disagreeing parts > the code were right or wrong, or I would have suggested an alternative > way to fix the problem. > > Even if the right answer is just to deal with the discrepancy over > `.bin' in this way in set_boot_policy, editing the whole array seems a > strange way to go about it. Why not just amend the result of the > actual lookup ? eg > rm_policy_from_boottitle(title_idx, [ boottitles[title_idx] + '.bin' ]) Yes, you are correct, this would have probably been easier. > > > @@ -335,6 +337,8 @@ class Grub(Bootloader): > > os.write(tmp_fd, line) > > > > if module_line != "" and not found: > > + if ord(line[-1]) not in [ 10 ]: > > + os.write(tmp_fd, '\n') > > os.write(tmp_fd, module_line) > > found = True > > Why the circumlocutions with `ord' and `in [ ... ]' ? line[-1] = '\n' would have done the same. > > As an aside, bootloader.py currently contains multiple bootfile > parsers and editors, containing a lot of very similar code. I make it > 4 parsers and 3 parser-mutators. Surely these should be combined as > far as possible ? The problem with the parsers is that they all work slightly different and have different code branches inside of them. I would not want to add additional parameters to a unified parser function that requires construction of if - then - else clauses so that it behaves differently depending on its intended purpose. Thanks. Stefan > > Ian. > > _______________________________________________ > Xen-devel mailing list > Xen-devel@xxxxxxxxxxxxxxxxxxx > http://lists.xensource.com/xen-devel _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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