I should have posted a follow-up to an earlier post of mine which is
similar it this if not the same. Chris Ritson brought to my attention
that this is most likely being caused by using UDP to communicate with
the amanda client. After switching amanda from UDP to TCP the dup2, and
any other AWK, NAWK, issues went away and everything is working as expected.

Gunnarsson, Gunnar wrote:
> Se below debug listing. Is this a know issue with dup2 ?
> 
> Thans Gunnar Gunnarsson
> 
> 1241554091.665921: sendbackup: pid 20149 ruid 91 euid 91 version
> 2.6.1: start at Tue May  5 22:08:11 2009 1241554091.666358:
> sendbackup: Version 2.6.1 1241554091.668434: sendbackup: pid 20149
> ruid 91 euid 91 version 2.6.1: rename at Tue May  5 22:08:11 2009 
> 1241554091.670599: sendbackup:   Parsed request as: program `amgtar' 
> 1241554091.670627: sendbackup:                      disk `/' 
> 1241554091.670648: sendbackup:                      device `/' 
> 1241554091.670669: sendbackup:                      level 2 
> 1241554091.670690: sendbackup:                      since NODATE 
> 1241554091.670710: sendbackup:                      options `' 
> 1241554091.671351: sendbackup: pipespawnv: stdoutfd is 0 
> 1241554091.672033: sendbackup: Spawning
> "/opt/sfw/libexec/amanda/application/amzfs-snapshot amzfs-snapshot
> PRE-DLE-BACKUP --execute-where client --config hansa --host hansabck
> --disk / --device / --level 2 --pfexec YES --pfexec-path
> /usr/bin/pfexec" in pipeline 1241554093.912552: sendbackup: script:
> PROPERTY directory //.zfs/snapshot/amanda-_-current 
> 1241554093.924144: sendbackup: pipespawnv: stdoutfd is 50 
> 1241554093.924271: sendbackup: Spawning "/usr/bin/gzip /usr/bin/gzip
> --fast" in pipeline 1241554093.925843: sendbackup: gnutar: pid 20165:
> /usr/bin/gzip1241554093.925981: sendbackup: pid 20165: /usr/bin/gzip
> --fast 1241554093.926548: sendbackup: pipespawnv: stdoutfd is 5120 
> 1241554093.926930: sendbackup: Spawning
> "/opt/sfw/libexec/amanda/application/amgtar amgtar support --config
> hansa --host hansabck --disk / --device /" in pipeline 
> 1241554093.996508: sendbackup: support line: CONFIG YES 
> 1241554093.996628: sendbackup: support line: HOST YES 
> 1241554093.996658: sendbackup: support line: DISK YES 
> 1241554093.996686: sendbackup: support line: MAX-LEVEL 9 
> 1241554093.996735: sendbackup: support line: INDEX-LINE YES 
> 1241554093.996765: sendbackup: support line: INDEX-XML NO 
> 1241554093.996793: sendbackup: support line: MESSAGE-LINE YES 
> 1241554093.996820: sendbackup: support line: MESSAGE-XML NO 
> 1241554093.996847: sendbackup: support line: RECORD YES 
> 1241554093.996875: sendbackup: support line: INCLUDE-FILE YES 
> 1241554093.996903: sendbackup: support line: INCLUDE-LIST YES 
> 1241554093.996932: sendbackup: support line: INCLUDE-OPTIONAL YES 
> 1241554093.996960: sendbackup: support line: EXCLUDE-FILE YES 
> 1241554093.996989: sendbackup: support line: EXCLUDE-LIST YES 
> 1241554093.997018: sendbackup: support line: EXCLUDE-OPTIONAL YES 
> 1241554093.997046: sendbackup: support line: COLLECTION NO 
> 1241554093.997075: sendbackup: support line: MULTI-ESTIMATE YES 
> 1241554093.997104: sendbackup: support line: CALCSIZE YES 
> 1241554094.002144: sendbackup: sendbackup: running
> "/opt/sfw/libexec/amanda/application/amgtar 1241554094.002274:
> sendbackup:  backup 1241554094.002297: sendbackup:  --message 
> 1241554094.002317: sendbackup:  line 1241554094.002337: sendbackup:
> --config 1241554094.002356: sendbackup:  hansa 1241554094.002376:
> sendbackup:  --host 1241554094.002396: sendbackup:  hansabck 
> 1241554094.002416: sendbackup:  --disk 1241554094.002435: sendbackup:
> / 1241554094.002454: sendbackup:  --device 1241554094.002473:
> sendbackup:  / 1241554094.002493: sendbackup:  --level 
> 1241554094.002512: sendbackup:  2 1241554094.002531: sendbackup:
> --index 1241554094.002550: sendbackup:  line 1241554094.002569:
> sendbackup:  --record 1241554094.002589: sendbackup:
> --atime-preserve 1241554094.002608: sendbackup:  NO 
> 1241554094.002627: sendbackup:  --check-device 1241554094.002647:
> sendbackup:  NO 1241554094.002666: sendbackup:  --directory 
> 1241554094.002686: sendbackup:  //.zfs/snapshot/amanda-_-current 
> 1241554094.002706: sendbackup: " 1241554094.003034: sendbackup:
> critical (fatal): Can't dup2: Bad file number 1241554094.003991:
> sendbackup: error: sendbackup: Can't dup2: Bad file number 
> 1241554094.043001: sendbackup: pipespawnv: stdoutfd is 171096 
> 1241554094.043703: sendbackup: Spawning
> "/opt/sfw/libexec/amanda/application/amzfs-snapshot amzfs-snapshot
> POST-DLE-BACKUP --execute-where client --config hansa --host hansabck
> --disk / --device / --level 2 --pfexec YES --pfexec-path
> /usr/bin/pfexec" in pipeline 1241554095.704958: sendbackup: pid 20149
> finish time Tue May  5 22:08:15 2009

-- 
Darin Perusich
Unix Systems Administrator
Cognigen Corporation
395 Youngs Rd.
Williamsville, NY 14221
Phone: 716-633-3463
Email: darinper AT cognigencorp DOT com