Public bug reported:
A persistent bug exists in the update notifier that affects the
ttf-mscorefonts-installer and may also affect other packages. On boot, a user
is presented with an update notification indicating that the
ttf-mscorefonts-installer failed to install and needs installation:
---snip---
The following packages requested additional data downloads after package
installation, but the data could not be downloaded or could not be
processed.
ttf-mscorefonts-installer
The download will be attempted again later, or you can try the download
again now. Running this command requires an active Internet connection.
---snip---
Running the command fails. Manual installation of the
ttf-mscorefonts-installer does not correct the notification. The issue was
traced to the /usr/lib/update-notifier/package-data-downloader script.
There are several issues in the package-data-downloader script:
1. The function process_download_requests() checks the hook date against the
stamp date for a installation package, such as
Hook File: /usr/share/package-data-downloads/ttf-mscorefonts-installer
Stamp File:
/var/lib/update-notifier/package-data-downloads/ttf-mscorefonts-installer
with the code:
---snip---
try:
hook_date = os.stat(file).st_mtime
stamp_date = os.stat(stampfile).st_mtime
if hook_date < stamp_date:
continue
---snip---
The stamp file exist if there was a previous installation that did not produce
a permanent failure. However, a normal failure sets up the condition to run
this script. The failure condition is not cleared on success. The code
related to determining success and failure is:
---snip---
result = subprocess.call(command)
if result:
# There's no sense redownloading if the script fails
permanent_failures.append(relfile)
else:
create_or_update_stampfile(stampfile)
---snip---
Therefore, in the event of a non-permanent failure, the stamp file is created
or updated which prevents an followup download to correct the non-permanent
failure.
2. The function process_download_requests() also tests for keywords 'script',
'should-download', 'url', and 'sha256' in the para list from the Hook file to
determine action:
---snip---
for para in hook.iter_paragraphs(open(file)):
* if 'script' in para:
if not files:
record_failure(relfile)
break
* command = [para['script']]
* if 'should-download' in para:
db = debconf.DebconfCommunicator('update-notifier')
try:
* should = db.get(para['should-download'])
if should == "false":
# Do nothing with this file.
break
except:
pass
finally:
db.shutdown()
# Download each file and verify the sum
try:
downloaded = set()
for i in range(len(files)):
print("%s: downloading %s" % (relfile, files[i]))
dest_file = download_file(files[i], sums[i])
if dest_file:
command.append(dest_file)
downloaded.add(dest_file)
else:
record_failure(relfile)
break
if relfile in failures + permanent_failures:
break
sys.stdout.flush()
result = subprocess.call(command)
if result:
# There's no sense redownloading if the script fails
permanent_failures.append(relfile)
else:
create_or_update_stampfile(stampfile)
# cleanup
for f in downloaded:
os.remove(f)
break
except Exception:
traceback.print_exc(file=sys.stderr)
record_failure(relfile)
# The 'script' is always the last stanza
break
# Not in a 'script' stanza, so we should have some urls
try:
* files.append(para['url'])
* sums.append(para['sha256'])
except Exception as e:
if not isinstance(e, KeyError):
traceback.print_exc(file=sys.stderr)
record_failure(relfile)
break
---snip---
where * note the lines affected. These keywords begin with an uppercase in the
related files:
---snip---
Url: http://downloads.sourceforge.net/corefonts/webdin32.exe
Sha256: 64595b5abc1080fba8610c5c34fab5863408e806aafe84653ca8575bed17d75a
Script: /usr/lib/msttcorefonts/update-ms-fonts
Should-Download: msttcorefonts/accepted-mscorefonts-eula
---snip---
3. The function process_download_requests() tracks so called "failures" and
"permanent_failures". When a failure occurs, the following code sets up the
condition for reprocessing later using the function trigger_update_notifier():
---snip---
previous_failures = existing_permanent_failures()
# We only report about "permanent" failures when there are new ones,
# but we want the whole list of permanently-failing hooks so when
# we clobber the update-notifier file we don't lose information the
# user may not have seen yet
if permanent_failures:
new_failures = False
for failure in permanent_failures:
if failure not in previous_failures:
mark_hook_failed(failure, permanent=True)
previous_failures.append(failure)
new_failures = True
if new_failures:
trigger_update_notifier(previous_failures, permanent=True)
# Filter out new failure reports for permanently-failed packages
our_failures = [x for x in failures if x not in previous_failures]
if our_failures:
for failure in our_failures:
mark_hook_failed(failure)
trigger_update_notifier(our_failures)
---snip---
SOLUTION:
====================
The existing code set up several conditions based on the existence of the
following files:
stamp file
notifier file
notifier permanent file
The conditions are:
EXISTS ( stamp file )
EXISTS ( stamp file AND notifier file )
EXISTS ( notifier file AND notifier permanent file )
EXISTS ( notifier permanent file )
When no permanent failures are found (no notifier permanent file), the
stamp file is set even when normal failures exist (notifier file). This
causes the next script execution to skip to the next install item. In
the event of success, failure conditions are cleared, but the notifier
files are never cleared causing persistent requests to update that never
get fulfilled.
For part 1, adding code handle the failure condition when a stamp file exists
would be prudent:
---snip---
try:
> if not os.path.exists(NOTIFIER_FILE) and not
> os.path.exists(NOTIFIER_PERMANENT_FILE):
>>>> hook_date = os.stat(file).st_mtime
>>>> stamp_date = os.stat(stampfile).st_mtime
>>>> if hook_date < stamp_date:
>>>> continue
> elif os.path.exists(stampfile):
> os.unlink(stampfile)
---snip---
where > indicated the added/modded code. This corrects the problem by allowing
any perceived failures, permanent or not, to reinstall the downloads. It
always removes the stampfile so that if a permanent failure develops, it is
handled correctly later.
For part 2, the paragraph keyword lookups may or may not care about case, but
update the keywords:
'script', 'should-download', 'url', 'sha256'
to:
'Script', 'Should-Download', 'Url', 'Sha256'
so that they match the file.
For part 3, the comment suggests that the so called "update-notifier file" will
be clobbered, but it never is. On a non-permament failure, the failed and
permanent-failure marker files are removed when function
create_or_update_stampfile() is called. The code should be changed to handle
cleared failure conditions (i.e., empty failure lists) as follows:
---snip---
previous_failures = existing_permanent_failures()
# We only report about "permanent" failures when there are new ones,
# but we want the whole list of permanently-failing hooks so when
# we clobber the update-notifier file we don't lose information the
# user may not have seen yet
if permanent_failures:
new_failures = False
for failure in permanent_failures:
if failure not in previous_failures:
mark_hook_failed(failure, permanent=True)
previous_failures.append(failure)
new_failures = True
if new_failures:
trigger_update_notifier(previous_failures, permanent=True)
> if not previous_failures and os.path.exists(NOTIFIER_PERMANENT_FILE):
> os.unlink(NOTIFIER_PERMANENT_FILE)
# Filter out new failure reports for permanently-failed packages
our_failures = [x for x in failures if x not in previous_failures]
if our_failures:
for failure in our_failures:
mark_hook_failed(failure)
trigger_update_notifier(our_failures)
> elif os.path.exists(NOTIFIER_FILE):
> os.unlink(NOTIFIER_FILE)
---snip---
where > indicated the added code.
In total, when no failure is found, the script will create the stamp
file and clear the notifier files. For permanent failures, the stamp
file is not created and any notifier files will persist until the next
attempted update. For normal failures, the stamp and non-permanent
notifier file persists until the next attempted update. On any update,
if notifier files exist, the script will attempt to correct the install.
If just the stamp file exists, then that install is skipped.
** Affects: update-notifier (Ubuntu)
Importance: Undecided
Status: New
** Tags: package-data-downloader ttf-mscorefonts-installer update-notifier
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https://bugs.launchpad.net/bugs/1621629
Title:
package-data-downloader fails to process download requests
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