qx seems to loose the subpr. way for print /dev/tty #8374

p5pRT · 2006-03-17T08:40:21Z

Migrated from rt.perl.org#38748 (status was 'open')

Searchable as RT38748$

p5pRT · 2006-03-17T08:40:23Z

From ende@telefonica.net

Created by juanfc@lcc.uma.es

I send messages through /dev/tty with

exec echo >/dev/tty

in a tcl script that is called from a Perl script.

The Perl script is on forever with a loop, allowing me
a more easy control of both the Tcl script and the frequency
and actions I want the daemon do each 10 minutes.

In the "daemonized" perl script, that has the loop:

while (1) {
`/Users/home/bin/tclprocThatusesdevtty.tcl -a`;
# .....
sleep 600;
}

only the first time the Tcl program is runned, the messages sent
by the Tcl program are really sent to the /dev/tty. Then, no more
messages are seen in the Terminal. The perl script seems
running ok all the time and the Tcl program also seems been called...

If I do the same stuff with sh

while [ 1 -eq 1 ]; do
/Users/juanfc/bin/drg.tcl -a
# ....
sleep 600
done

there is no problem at all.

Perl Info


Flags:
     category=core
     severity=high

Site configuration information for perl v5.8.6:

Configured by root at Sun Mar 20 16:31:42 PST 2005.

Summary of my perl5 (revision 5 version 8 subversion 6) configuration:
   Platform:
     osname=darwin, osvers=8.0, archname=darwin-thread-multi-2level
     uname='darwin b28.apple.com 8.0 darwin kernel version 7.5.0: thu  
mar 3 18:48:46 pst 2005; root:xnuxnu-517.99.13.obj~1release_ppc power  
macintosh powerpc '
     config_args='-ds -e -Dprefix=/usr -Dccflags=-g  -pipe  - 
Dldflags=-Dman3ext=3pm -Duseithreads -Duseshrplib'
     hint=recommended, useposix=true, d_sigaction=define
     usethreads=define use5005threads=undef useithreads=define  
usemultiplicity=define
     useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
     use64bitint=undef use64bitall=undef uselongdouble=undef
     usemymalloc=n, bincompat5005=undef
   Compiler:
     cc='cc', ccflags ='-g -pipe -fno-common -DPERL_DARWIN -no-cpp- 
precomp -fno-strict-aliasing -I/usr/local/include',
     optimize='-Os',
     cppflags='-no-cpp-precomp -g -pipe -fno-common -DPERL_DARWIN -no- 
cpp-precomp -fno-strict-aliasing -I/usr/local/include'
     ccversion='', gccversion='3.3 20030304 (Apple Computer, Inc.  
build 1809)', gccosandvers=''
     intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=4321
     d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=8
     ivtype='long', ivsize=4, nvtype='double', nvsize=8,  
Off_t='off_t', lseeksize=8
     alignbytes=8, prototype=define
   Linker and Libraries:
     ld='env MACOSX_DEPLOYMENT_TARGET=10.3 cc', ldflags ='-L/usr/ 
local/lib'
     libpth=/usr/local/lib /usr/lib
     libs=-ldbm -ldl -lm -lc
     perllibs=-ldl -lm -lc
     libc=/usr/lib/libc.dylib, so=dylib, useshrplib=true,  
libperl=libperl.dylib
     gnulibc_version=''
   Dynamic Linking:
     dlsrc=dl_dlopen.xs, dlext=bundle, d_dlsymun=undef, ccdlflags=' '
     cccdlflags=' ', lddlflags='-bundle -undefined dynamic_lookup -L/ 
usr/local/lib'

Locally applied patches:
     23953 - fix for File::Path::rmtree CAN-2004-0452 security issue
     33990 - fix for setuid perl security issues


@INC for perl v5.8.6:
     /sw/lib/perl5
     /sw/lib/perl5/darwin
     /System/Library/Perl/5.8.6/darwin-thread-multi-2level
     /System/Library/Perl/5.8.6
     /Library/Perl/5.8.6/darwin-thread-multi-2level
     /Library/Perl/5.8.6
     /Library/Perl
     /Network/Library/Perl/5.8.6/darwin-thread-multi-2level
     /Network/Library/Perl/5.8.6
     /Network/Library/Perl
     /System/Library/Perl/Extras/5.8.6/darwin-thread-multi-2level
     /System/Library/Perl/Extras/5.8.6
     /Library/Perl/5.8.1/darwin-thread-multi-2level
     /Library/Perl/5.8.1
     .


Environment for perl v5.8.6:
     DYLD_LIBRARY_PATH (unset)
     HOME=/Users/juanfc
     LANG (unset)
     LANGUAGE (unset)
     LD_LIBRARY_PATH (unset)
     LOGDIR (unset)
     PATH=/sw/bin:/sw/sbin:/Library/Tcl/bin:/bin:/sbin:/usr/bin:/usr/ 
sbin:/Developer/Tools:/usr/X11R6/bin:/usr/local/teTeX/bin/powerpc- 
apple-darwin-current:/Users/juanfc/bin:/Users/juanfc/ubin:/Users/ 
juanfc/perls:/opt/local/bin:.:/usr/local/bin
     PERL5LIB=/sw/lib/perl5:/sw/lib/perl5/darwin
     PERL_BADLANG (unset)
     SHELL=/bin/tcsh

p5pRT · 2006-03-17T14:25:41Z

From @rgarcia

On 3/17/06, via RT ende <perlbug-followup@perl.org> wrote:

while (1) {
`/Users/home/bin/tclprocThatusesdevtty.tcl -a`;

What happens if you use system() instead of `` ? system doesn't
intercept the output of the command like `` does -- `` being intended
to capture output, not to simply run an external program.

 \# \.\.\.\.\.
 sleep 600;
}

only the first time the Tcl program is runned, the messages sent
by the Tcl program are really sent to the /dev/tty. Then, no more
messages are seen in the Terminal. The perl script seems
running ok all the time and the Tcl program also seems been called...

p5pRT · 2006-03-17T14:25:42Z

The RT System itself - Status changed from 'new' to 'open'

p5pRT · 2006-03-17T15:05:00Z

From shouldbedomo@mac.com

On 2006â??03â??17, at 09:40, ende (via RT) wrote:

I send messages through /dev/tty with
exec echo >/dev/tty
in a tcl script that is called from a Perl script.

The Perl script is on forever with a loop, allowing me
a more easy control of both the Tcl script and the frequency
and actions I want the daemon do each 10 minutes.

Can you make a short script (or pair of scripts) in pure Perl that
show the problem? I ask because, if the process really is a daemon,
it should not have a controlling terminal, and so /dev/tty should not
be openable at all (not even once). Here's an example on Mac OS X
(your platform -- basically BSD-ish):

$ perl -MPOSIX=setsid -lwe 'unless (fork) {setsid; qx(tty > /dev/
tty); sleep 300}'
sh: line 1: /dev/tty: Device not configured

and the same on PPC Linux:

$ perl -MPOSIX=setsid -lwe 'unless (fork) {setsid; qx(tty > /dev/
tty); sleep 300}'
sh: /dev/tty: No such device or address

(In both cases, we are seeing a complaint sent by the shell to
standard error, which is still open, and which is not captured by qx().)
--
Dominic Dunlop

p5pRT · 2006-03-18T01:22:58Z

From ende@telefonica.net

#!/usr/local/bin/perl
#
# it is the 5.8.8
#
# drgrun.pl
#
# this is script that never ends (is _like_ a daemon)
#
#

while (1) {
`/Users/me/bin/script.tcl -a`;

sleep 600;
}

# END

# ####################
# Tcl script script.tcl

eval [list exec echo >/dev/tty " -->> \[$cola\] [string range
[urldecod [file tail $que]] 0 $cosaEnActualL]" ]

# ####################

# this script calls programs that could use stdout

# The first time the script is called the echo > /dev/tty works but,
then
# it gets dummy. If you run it in sh

#!/bin/bash

while [ 1 -eq 1 ]; do
/Users/me/bin/script.tcl -a

sleep 600
done

# all goes well, no problem. bash does not interfere with the output of
# the Tcl script. I don't like to use sh because it uses an external
# program, sleep...

El 17/03/2006, a las 16:05, Dominic Dunlop via RT escribió:

On 2006â€“03â€“17, at 09:40, ende (via RT) wrote:
I send messages through /dev/tty with
exec echo >/dev/tty
in a tcl script that is called from a Perl script.

The Perl script is on forever with a loop, allowing me
a more easy control of both the Tcl script and the frequency
and actions I want the daemon do each 10 minutes.
Can you make a short script (or pair of scripts) in pure Perl that
show the problem? I ask because, if the process really is a daemon,
it should not have a controlling terminal, and so /dev/tty should not
be openable at all (not even once). Here's an example on Mac OS X
(your platform -- basically BSD-ish):

$ perl -MPOSIX=setsid -lwe 'unless (fork) {setsid; qx(tty > /dev/
tty); sleep 300}'
sh: line 1: /dev/tty: Device not configured

and the same on PPC Linux:

$ perl -MPOSIX=setsid -lwe 'unless (fork) {setsid; qx(tty > /dev/
tty); sleep 300}'
sh: /dev/tty: No such device or address

(In both cases, we are seeing a complaint sent by the shell to
standard error, which is still open, and which is not captured by qx
().)
--
Dominic Dunlop

p5pRT · 2016-07-12T14:17:38Z

From @dcollinsn

This ticket badly needs to be reviewed by a Darwin expert. Is there something that we need to work around on this OS? (Can you summarize it and update the ticket name?)

--
Respectfully,
Dan Collins

p5pRT · 2016-07-12T14:17:39Z

From [Unknown Contact. See original ticket]

This ticket badly needs to be reviewed by a Darwin expert. Is there something that we need to work around on this OS? (Can you summarize it and update the ticket name?)

--
Respectfully,
Dan Collins

p5pRT · 2016-07-12T14:17:39Z

@dcollinsn - Status changed from 'open' to 'stalled'

p5pRT · 2016-07-12T17:18:05Z

From @arc

Dan Collins via RT <perlbug-comment@perl.org> wrote:

This ticket badly needs to be reviewed by a Darwin expert. Is there something that we need to work around on this OS? (Can you summarize it and update the ticket name?)

I've tried and failed to reproduce this:

$ uname -sr
Darwin 13.4.0
$ perl -wE 'say $^V'
v5.24.0
$ echo 'puts $tcl_version' | tclsh
8.6
$ cat outer.pl
#! /usr/bin/env perl
while (1) {
`./inner.tcl -a`;
sleep 2;
}
$ cat inner.tcl
#! /usr/bin/env tclsh
exec echo foo >/dev/tty
$ chmod +x outer.pl inner.tcl
$ ./outer.pl
foo
foo
foo
^C

It seems to me that whatever bug existed when this ticket was filed a
decade ago has subsequently been fixed, and I suggest this ticket can
therefore be closed now. Alternatively, if the original requestor can
submit complete, self-contained scripts that still reproduce the
problem (the incomplete Tcl program in transaction 131257 merely fails
with a "no such variable" error before it runs anything at all), we
can surely investigate further.

--
Aaron Crane ** http://aaroncrane.co.uk/

p5pRT · 2016-07-12T17:33:21Z

From @dcollinsn

On Tue Jul 12 10:18:05 2016, arc wrote:

Dan Collins via RT <perlbug-comment@perl.org> wrote:

This ticket badly needs to be reviewed by a Darwin expert. Is there
something that we need to work around on this OS? (Can you summarize
it and update the ticket name?)

I've tried and failed to reproduce this:

$ uname -sr
Darwin 13.4.0
$ perl -wE 'say $^V'
v5.24.0
$ echo 'puts $tcl_version' | tclsh
8.6
$ cat outer.pl
#! /usr/bin/env perl
while (1) {
`./inner.tcl -a`;
sleep 2;
}
$ cat inner.tcl
#! /usr/bin/env tclsh
exec echo foo >/dev/tty
$ chmod +x outer.pl inner.tcl
$ ./outer.pl
foo
foo
foo
^C

It seems to me that whatever bug existed when this ticket was filed a
decade ago has subsequently been fixed, and I suggest this ticket can
therefore be closed now. Alternatively, if the original requestor can
submit complete, self-contained scripts that still reproduce the
problem (the incomplete Tcl program in transaction 131257 merely fails
with a "no such variable" error before it runs anything at all), we
can surely investigate further.

Thank you, Aaron.

Taking with the intent to close in 7 days unless there is anyone who can provide a test case that we can reproduce.

--
Respectfully,
Dan Collins

p5pRT · 2016-07-12T17:33:21Z

The RT System itself - Status changed from 'stalled' to 'open'

toddr · 2020-01-31T07:59:34Z

I think this case was not closed by mistake. Closing it now.

p5pRT added Severity High distro-darwin needsTest type-OS-interaction type-core labels Oct 18, 2019

toddr closed this as completed Jan 31, 2020

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qx seems to loose the subpr. way for print /dev/tty #8374

qx seems to loose the subpr. way for print /dev/tty #8374

p5pRT commented Mar 17, 2006

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toddr commented Jan 31, 2020

qx seems to loose the subpr. way for print /dev/tty #8374

qx seems to loose the subpr. way for print /dev/tty #8374

Comments

p5pRT commented Mar 17, 2006

p5pRT commented Mar 17, 2006

From ende@telefonica.net

Created by juanfc@lcc.uma.es

p5pRT commented Mar 17, 2006

From @rgarcia

p5pRT commented Mar 17, 2006

p5pRT commented Mar 17, 2006

From shouldbedomo@mac.com

p5pRT commented Mar 18, 2006

From ende@telefonica.net

p5pRT commented Jul 12, 2016

From @dcollinsn

p5pRT commented Jul 12, 2016

From [Unknown Contact. See original ticket]

p5pRT commented Jul 12, 2016

p5pRT commented Jul 12, 2016

From @arc

p5pRT commented Jul 12, 2016

From @dcollinsn

p5pRT commented Jul 12, 2016

toddr commented Jan 31, 2020