Bug 56540 - batch scanning (microtek2 drivers) kills everything in sight
batch scanning (microtek2 drivers) kills everything in sight
Product: Red Hat Linux
Classification: Retired
Component: sane-backends (Show other bugs)
i386 Linux
medium Severity medium
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Assigned To: Tim Waugh
Depends On:
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Reported: 2001-11-20 13:52 EST by Michal Jaegermann
Modified: 2008-05-01 11:38 EDT (History)
0 users

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Doc Type: Bug Fix
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Last Closed: 2002-03-04 18:50:32 EST
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Attachments (Terms of Use)
a patch to make possible batch scanning with microtek2 driver (666 bytes, patch)
2001-11-20 13:53 EST, Michal Jaegermann
no flags Details | Diff

  None (edit)
Description Michal Jaegermann 2001-11-20 13:52:14 EST
Description of Problem:

At least with microtek2 driver 'scanimage' in a batch mode and using
a document feeder has a nasty habit of killing all processes it can
reach.  Effects are much more spectacular when doing a test from
a root account. :-)

The problem is that 'cancel_scan()' is using a read with transfer
length of 0 after it detected "out of pages to scan" condition
(a generic I/O error is used for that - sigh!).  Subsequently
it is doing a cleanup job with 'close(ms->fd[1]);' followed by
'kill(ms->pid, SIGTERM);'.  The problem is that in such case both
ms->fd[1] and ms->pid were already set earlier to (-1).  While this
is not that bad with 'close' (still likely an undefined behaviour)
this is an "ouch time" with 'kill'; things work like they are written
but hard to believe that in an intended way.

I could test that only for microtek2 driver but 'kill' is used quite
widely in other backends as well.

An attached minimal patch fixes the problem at least for microtek2.


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Comment 1 Michal Jaegermann 2001-11-20 13:53:41 EST
Created attachment 38066 [details]
a patch to make possible batch scanning with microtek2 driver
Comment 2 Tim Waugh 2001-11-20 17:38:52 EST
Already applied in sane-backends-1.0.6-2, currently in rawhide.
Comment 3 Michal Jaegermann 2002-03-04 18:50:27 EST
> Already applied in sane-backends-1.0.6-2, currently in rawhide.
That is nice but sane-backends-1.0.5-4.1, build Thu Dec 20 06:24:10 2001
and released at the beginning of January as an update for 7.2 distro,
have the same problem as I just found when scanner I got now for testing
kicked me out from an X windows session.
Comment 4 Tim Waugh 2002-03-05 04:15:44 EST
The update contains just security fixes and not extra bug fixes.  This bug is
fixed in rawhide, and will appear in the next release.

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