*Synopsis*: ksh93's built-in "tail -f" cannot be interrupted if "suspended"
CR 6919591 changed on Mar 29 2010 by <User 1-5Q-9201>
=== Field ============ === New Value ============= === Old Value =============
Root Cause Another Bug Fix
====================== =========================== ===========================
*Change Request ID*: 6919591
*Synopsis*: ksh93's built-in "tail -f" cannot be interrupted if "suspended"
Product: solaris
Category: shell
Subcategory: korn93
Type: Defect
Subtype: Functionality
Status: 7-Fix in Progress
Substatus:
Priority: 2-High
Introduced In Release: solaris_nevada
Introduced In Build: snv_128
Responsible Engineer: <User 1-5Q-9201>
Keywords: 2010.02-reviewed, oss-request, oss-sponsor
=== *Description* ============================================================
On a system running snv_131 and the following version of ksh93
devildoll $ ksh93 -c 'print "${.sh.version}"'
Version JMP 93t+ 2009-10-12
tail appears to be a ksh93 built-in. If I monitor a log file using "tail -f"
and then suspend (using ^S) and resume the tail, it appears that I can no
longer interrupt the process.
devildoll $ tail -f /etc/motd
Sun Microsystems Inc. SunOS 5.11 snv_131 January 2010
^Z[1] + Stopped tail -f /dev/null
devildoll $ fg
tail -f /dev/null
^C
Here's a pstack(1) of the process
6720: -ksh
fffffd7fff2ecf7a nanosleep (fffffd7fffdfbe10, 0)
fffffd7fff095382 b_tail () + b8a
fffffd7fff172607 sh_exec () + 308f
fffffd7fff16f0ef sh_eval () + 287
fffffd7fff102151 b_hist () + a49
fffffd7fff172607 sh_exec () + 308f
fffffd7fff1494c6 exfile () + 786
fffffd7fff148caa sh_main () + 822
0000000000400e72 main () + 52
0000000000400ccc ???????? ()
And a truss(1) including sending the signal
6720: nanosleep(0xFFFFFD7FFFDFBE10, 0x00000000) = 0
6720: fstat(5, 0xFFFFFD7FFFDFBD90) = 0
6720: nanosleep(0xFFFFFD7FFFDFBE10, 0x00000000) = 0
6720: fstat(5, 0xFFFFFD7FFFDFBD90) = 0
6720: nanosleep(0xFFFFFD7FFFDFBE10, 0x00000000) = 0
6720: fstat(5, 0xFFFFFD7FFFDFBD90) = 0
6720: nanosleep(0xFFFFFD7FFFDFBE10, 0x00000000) = 0
6720: fstat(5, 0xFFFFFD7FFFDFBD90) = 0
6720: nanosleep(0xFFFFFD7FFFDFBE10, 0x00000000) = 0
6720: fstat(5, 0xFFFFFD7FFFDFBD90) = 0
6720: nanosleep(0xFFFFFD7FFFDFBE10, 0x00000000) = 0
6720: fstat(5, 0xFFFFFD7FFFDFBD90) = 0
6720: Received signal #2, SIGINT, in nanosleep() [caught]
6720: nanosleep(0xFFFFFD7FFFDFBE10, 0x00000000) Err#4 EINTR
6720: lwp_sigmask(SIG_SETMASK, 0x00000002, 0x00000000) = 0xFFBFFEFF
[0x0000FFFF]
6720: sigaction(SIGINT, 0xFFFFFD7FFFDFB6D0, 0xFFFFFD7FFFDFB750) = 0
6720: setcontext(0xFFFFFD7FFFDFB4A0)
6720: fstat(5, 0xFFFFFD7FFFDFBD90) = 0
6720: nanosleep(0xFFFFFD7FFFDFBE10, 0x00000000) = 0
6720: fstat(5, 0xFFFFFD7FFFDFBD90) = 0
6720: nanosleep(0xFFFFFD7FFFDFBE10, 0x00000000) = 0
6720: fstat(5, 0xFFFFFD7FFFDFBD90) = 0
6720: nanosleep(0xFFFFFD7FFFDFBE10, 0x00000000) = 0
*** (#1 of 2): 2010-01-24 23:45:26 GMT+00:00 <User 1-5Q-13979>
Sorry, the ^S above should have been ^Z - namely it really is the job control
suspend character.
*** (#2 of 2): 2010-02-07 04:01:31 GMT+00:00 <User 1-5Q-13979>
=== *Public Comments* ========================================================
Glenn Fowler (AT&T Research AST developer) said this about this bug:
> the report confuses ^S and ^Z
> the intention is probably ^Z
> I don't see the problem on sol11.i386 Version JMP 93t+ 2010-01-20
Roland Mainz (OpenSolaris ksh93-integration project lead) says:
> I can"t reproduce the bug either. Is it possible that the reporter
> mixed ^S/^Q (terminal output stop/resume functionality) with
> ^Z (shell command to put the current job into the background)
> ?
*** (#1 of 2): 2010-02-04 23:30:49 GMT+00:00 <User 1-5Q-1267>
Not sure if the question is being posed to me but the issue is definitely with
^Z using the ksh93 in snv_132.
*** (#2 of 2): 2010-02-07 04:01:31 GMT+00:00 <User 1-5Q-13979>
=== *Workaround* =============================================================
Use /usr/bin/tail instead.
*** (#1 of 1): 2010-01-25 07:57:28 GMT+00:00 <User 1-5Q-13979>
=== *Additional Details* =====================================================
Targeted Release: solaris_nevada
Commit To Fix In Build: snv_137
Fixed In Build:
Integrated In Build:
Verified In Build:
See Also:
Duplicate of:
Hooks:
Hook1:
Hook2:
Hook3:
Hook4:
Hook5: <email address omitted>
Hook6: <email address omitted>
Program Management:
Root Cause: Another Bug Fix
Fix Affects Documentation: No
Fix Affects Localization: No
=== *History* ================================================================
Date Submitted: 2010-01-24 23:45:26 GMT+00:00
Submitted By: <User 1-5Q-13979>
Status Changed Date Updated Updated By
3-Accepted 2010-03-29 02:44:29 GMT+00:00 <User 1-5Q-9201>
7-Fix in Progress 2010-03-29 03:17:46 GMT+00:00 <User 1-5Q-9201>
=== *Service Request* ========================================================
Impact: Significant
Functionality: Primary
Severity: 2
Product Name: solaris
Product Release: solaris_nevada
Product Build: snv_131
Operating System: 5.11
Hardware: generic
Submitted Date: 2010-01-24 23:45:26 GMT+00:00
=== *Multiple Release (MR) Cluster* - 0 ======================================
