Bug 436368

Summary: Double close in dd
Product: [Fedora] Fedora Reporter: Ulrich Drepper <drepper>
Component: coreutilsAssignee: Ondrej Vasik <ovasik>
Status: CLOSED RAWHIDE QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: low Docs Contact:
Priority: low    
Version: rawhideCC: meyering, twaugh
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OS: Linux   
Fixed In Version: Doc Type: Bug Fix
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Last Closed: 2008-03-11 08:55:49 EDT Type: ---
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Description Ulrich Drepper 2008-03-06 15:03:54 EST
Description of problem:

  strace -E LC_ALL=C dd if=/dev/zero of=/dev/null count=1 bs=1

shows that dd tries to close file descriptor 1 twice:

write(2, "1 byte (1 B) copied", 191 byte (1 B) copied)     = 19
write(2, ", 0.000151196 s, 6.6 kB/s\n", 26, 0.000151196 s, 6.6 kB/s
) = 26
close(1)                                = -1 EBADF (Bad file descriptor)
close(2)                                = 0

Version-Release number of selected component (if applicable):

How reproducible:

Steps to Reproduce:
1.run above command
Actual results:
double close

Expected results:
only one close

Additional info:
Comment 1 Ondrej Vasik 2008-03-07 03:13:22 EST
Thanks for report.
Caused by atexit(close_stdout).
This atexit close is (from comments) because of possible exit in external
function for parsing long options.
Second one is in cleanup function (from comments) necessary for call from signal
Maybe the easiest solution would be to differ between signal handling cleanup
and exit/quit cleanup (two functions or boolean for decision)...
Any other ideas?
Comment 2 Jim Meyering 2008-03-07 07:27:18 EST
Thanks for the report.  For the record, there was no harm in that double close,
other than the negligible overhead of the failing close syscall. In spite of
that, I've changed dd.c to avoid the unnecessary close_stdout call when possible:
Comment 3 Ondrej Vasik 2008-03-11 08:55:49 EDT
Built as coreutils-6.10-12.fc9 , closing RAWHIDE.