bash closes fd twice.

[Yoriyuki Yamagata]

Dear list, 

I found that bash tries to close the same fd twice, consecutively.  I’m using 
Mac OS X Yosemite, and bash is the newest available (bash-master from 
http://tiswww.case.edu/php/chet/bash/bashtop.html yesterday).

To reproduce the phenomenon, just run this shell script.

— begin ---
#!/Users/XXXX/bin/bash

set -- `cat "testfile" | sed '/^\#/d’`
— end ---
Name it testscript

testfile is the empty file.

Then, run druss

$ sudo dtruss -fa sudo -u XXXX ./testscript

The part of output:

96765/0x20858e:    173615  173171 173168 fork()          = 96766 0
96766/0x208590:        74:        0:       0 fork()              = 0 0
96766/0x208590:        75       5      0 thread_selfid(0x0, 0x0, 0x0)           
 = 2131344 0
96766/0x208590:        77       3      0 bsdthread_register(0x7FFF95D0E3E0, 
0x7FFF95D0E3D0, 0x2000)              = -1 Err#22
96765/0x20858e:    173714       4      0 sigprocmask(0x3, 0x7FFF59BFD7A0, 0x0)  
         = 0x0 0
96765/0x20858e:    173717       3      1 close(0x4)              = 0 0
96765/0x20858e:    173739       1      0 close(0x4)              = -1 Err#9

I do not know it is an important problem, but closing the same file descriptor 
twice could be fishy.

Or maybe I missed something?

Best,
 — 
Yoriyuki Yamagata
National Institute of Advanced Science and Technology (AIST), Senior Researcher
http://staff.aist.go.jp/yoriyuki.yamagata/en/